From 5f81018753dfd4989e33ece1f0cb6b8aae498b82 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Thu, 15 Jun 2023 13:52:36 +0200 Subject: fprobe: Release rethook after the ftrace_ops is unregistered While running bpf selftests it's possible to get following fault: general protection fault, probably for non-canonical address \ 0x6b6b6b6b6b6b6b6b: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC NOPTI ... Call Trace: fprobe_handler+0xc1/0x270 ? __pfx_bpf_testmod_init+0x10/0x10 ? __pfx_bpf_testmod_init+0x10/0x10 ? bpf_fentry_test1+0x5/0x10 ? bpf_fentry_test1+0x5/0x10 ? bpf_testmod_init+0x22/0x80 ? do_one_initcall+0x63/0x2e0 ? rcu_is_watching+0xd/0x40 ? kmalloc_trace+0xaf/0xc0 ? do_init_module+0x60/0x250 ? __do_sys_finit_module+0xac/0x120 ? do_syscall_64+0x37/0x90 ? entry_SYSCALL_64_after_hwframe+0x72/0xdc In unregister_fprobe function we can't release fp->rethook while it's possible there are some of its users still running on another cpu. Moving rethook_free call after fp->ops is unregistered with unregister_ftrace_function call. Link: https://lore.kernel.org/all/20230615115236.3476617-1-jolsa@kernel.org/ Fixes: 5b0ab78998e3 ("fprobe: Add exit_handler support") Cc: stable@vger.kernel.org Reviewed-by: Steven Rostedt (Google) Signed-off-by: Jiri Olsa Acked-by: Masami Hiramatsu (Google) Signed-off-by: Masami Hiramatsu (Google) --- kernel/trace/fprobe.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c index 18d36842faf5..0121e8c0d54e 100644 --- a/kernel/trace/fprobe.c +++ b/kernel/trace/fprobe.c @@ -364,19 +364,13 @@ int unregister_fprobe(struct fprobe *fp) fp->ops.saved_func != fprobe_kprobe_handler)) return -EINVAL; - /* - * rethook_free() starts disabling the rethook, but the rethook handlers - * may be running on other processors at this point. To make sure that all - * current running handlers are finished, call unregister_ftrace_function() - * after this. - */ - if (fp->rethook) - rethook_free(fp->rethook); - ret = unregister_ftrace_function(&fp->ops); if (ret < 0) return ret; + if (fp->rethook) + rethook_free(fp->rethook); + ftrace_free_filter(&fp->ops); return ret; -- cgit v1.2.3 From 5415ccd50a8620c8cbaa32d6f18c946c453566f5 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Wed, 5 Jul 2023 20:17:29 +0530 Subject: bpf: Fix max stack depth check for async callbacks The check_max_stack_depth pass happens after the verifier's symbolic execution, and attempts to walk the call graph of the BPF program, ensuring that the stack usage stays within bounds for all possible call chains. There are two cases to consider: bpf_pseudo_func and bpf_pseudo_call. In the former case, the callback pointer is loaded into a register, and is assumed that it is passed to some helper later which calls it (however there is no way to be sure), but the check remains conservative and accounts the stack usage anyway. For this particular case, asynchronous callbacks are skipped as they execute asynchronously when their corresponding event fires. The case of bpf_pseudo_call is simpler and we know that the call is definitely made, hence the stack depth of the subprog is accounted for. However, the current check still skips an asynchronous callback even if a bpf_pseudo_call was made for it. This is erroneous, as it will miss accounting for the stack usage of the asynchronous callback, which can be used to breach the maximum stack depth limit. Fix this by only skipping asynchronous callbacks when the instruction is not a pseudo call to the subprog. Fixes: 7ddc80a476c2 ("bpf: Teach stack depth check about async callbacks.") Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20230705144730.235802-2-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 11e54dd8b6dd..930b5555cfd3 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5642,8 +5642,9 @@ continue_func: verbose(env, "verifier bug. subprog has tail_call and async cb\n"); return -EFAULT; } - /* async callbacks don't increase bpf prog stack size */ - continue; + /* async callbacks don't increase bpf prog stack size unless called directly */ + if (!bpf_pseudo_call(insn + i)) + continue; } i = next_insn; -- cgit v1.2.3 From ae2ad293d6be143ad223f5f947cca07bcbe42595 Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Tue, 20 Jun 2023 16:07:47 +0800 Subject: sched/fair: Use recent_used_cpu to test p->cpus_ptr When checking whether a recently used CPU can be a potential idle candidate, recent_used_cpu should be used to test p->cpus_ptr as p->recent_used_cpu is not equal to recent_used_cpu and candidate decision is made based on recent_used_cpu here. Fixes: 89aafd67f28c ("sched/fair: Use prev instead of new target as recent_used_cpu") Signed-off-by: Miaohe Lin Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Phil Auld Acked-by: Mel Gorman Link: https://lore.kernel.org/r/20230620080747.359122-1-linmiaohe@huawei.com --- kernel/sched/fair.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index a80a73909dc2..b3e25be58e2b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7174,7 +7174,7 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target) recent_used_cpu != target && cpus_share_cache(recent_used_cpu, target) && (available_idle_cpu(recent_used_cpu) || sched_idle_cpu(recent_used_cpu)) && - cpumask_test_cpu(p->recent_used_cpu, p->cpus_ptr) && + cpumask_test_cpu(recent_used_cpu, p->cpus_ptr) && asym_fits_cpu(task_util, util_min, util_max, recent_used_cpu)) { return recent_used_cpu; } -- cgit v1.2.3 From aff037078ecaecf34a7c2afab1341815f90fba5e Mon Sep 17 00:00:00 2001 From: Suren Baghdasaryan Date: Thu, 29 Jun 2023 17:56:12 -0700 Subject: sched/psi: use kernfs polling functions for PSI trigger polling Destroying psi trigger in cgroup_file_release causes UAF issues when a cgroup is removed from under a polling process. This is happening because cgroup removal causes a call to cgroup_file_release while the actual file is still alive. Destroying the trigger at this point would also destroy its waitqueue head and if there is still a polling process on that file accessing the waitqueue, it will step on the freed pointer: do_select vfs_poll do_rmdir cgroup_rmdir kernfs_drain_open_files cgroup_file_release cgroup_pressure_release psi_trigger_destroy wake_up_pollfree(&t->event_wait) // vfs_poll is unblocked synchronize_rcu kfree(t) poll_freewait -> UAF access to the trigger's waitqueue head Patch [1] fixed this issue for epoll() case using wake_up_pollfree(), however the same issue exists for synchronous poll() case. The root cause of this issue is that the lifecycles of the psi trigger's waitqueue and of the file associated with the trigger are different. Fix this by using kernfs_generic_poll function when polling on cgroup-specific psi triggers. It internally uses kernfs_open_node->poll waitqueue head with its lifecycle tied to the file's lifecycle. This also renders the fix in [1] obsolete, so revert it. [1] commit c2dbe32d5db5 ("sched/psi: Fix use-after-free in ep_remove_wait_queue()") Fixes: 0e94682b73bf ("psi: introduce psi monitor") Closes: https://lore.kernel.org/all/20230613062306.101831-1-lujialin4@huawei.com/ Reported-by: Lu Jialin Signed-off-by: Suren Baghdasaryan Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20230630005612.1014540-1-surenb@google.com --- include/linux/psi.h | 5 +++-- include/linux/psi_types.h | 3 +++ kernel/cgroup/cgroup.c | 2 +- kernel/sched/psi.c | 29 +++++++++++++++++++++-------- 4 files changed, 28 insertions(+), 11 deletions(-) (limited to 'kernel') diff --git a/include/linux/psi.h b/include/linux/psi.h index ab26200c2803..e0745873e3f2 100644 --- a/include/linux/psi.h +++ b/include/linux/psi.h @@ -23,8 +23,9 @@ void psi_memstall_enter(unsigned long *flags); void psi_memstall_leave(unsigned long *flags); int psi_show(struct seq_file *s, struct psi_group *group, enum psi_res res); -struct psi_trigger *psi_trigger_create(struct psi_group *group, - char *buf, enum psi_res res, struct file *file); +struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf, + enum psi_res res, struct file *file, + struct kernfs_open_file *of); void psi_trigger_destroy(struct psi_trigger *t); __poll_t psi_trigger_poll(void **trigger_ptr, struct file *file, diff --git a/include/linux/psi_types.h b/include/linux/psi_types.h index 040c089581c6..f1fd3a8044e0 100644 --- a/include/linux/psi_types.h +++ b/include/linux/psi_types.h @@ -137,6 +137,9 @@ struct psi_trigger { /* Wait queue for polling */ wait_queue_head_t event_wait; + /* Kernfs file for cgroup triggers */ + struct kernfs_open_file *of; + /* Pending event flag */ int event; diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index bfe3cd8ccf36..f55a40db065f 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -3730,7 +3730,7 @@ static ssize_t pressure_write(struct kernfs_open_file *of, char *buf, } psi = cgroup_psi(cgrp); - new = psi_trigger_create(psi, buf, res, of->file); + new = psi_trigger_create(psi, buf, res, of->file, of); if (IS_ERR(new)) { cgroup_put(cgrp); return PTR_ERR(new); diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index 81fca77397f6..9bb3f2b3ccfc 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -493,8 +493,12 @@ static u64 update_triggers(struct psi_group *group, u64 now, bool *update_total, continue; /* Generate an event */ - if (cmpxchg(&t->event, 0, 1) == 0) - wake_up_interruptible(&t->event_wait); + if (cmpxchg(&t->event, 0, 1) == 0) { + if (t->of) + kernfs_notify(t->of->kn); + else + wake_up_interruptible(&t->event_wait); + } t->last_event_time = now; /* Reset threshold breach flag once event got generated */ t->pending_event = false; @@ -1271,8 +1275,9 @@ int psi_show(struct seq_file *m, struct psi_group *group, enum psi_res res) return 0; } -struct psi_trigger *psi_trigger_create(struct psi_group *group, - char *buf, enum psi_res res, struct file *file) +struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf, + enum psi_res res, struct file *file, + struct kernfs_open_file *of) { struct psi_trigger *t; enum psi_states state; @@ -1331,7 +1336,9 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, t->event = 0; t->last_event_time = 0; - init_waitqueue_head(&t->event_wait); + t->of = of; + if (!of) + init_waitqueue_head(&t->event_wait); t->pending_event = false; t->aggregator = privileged ? PSI_POLL : PSI_AVGS; @@ -1388,7 +1395,10 @@ void psi_trigger_destroy(struct psi_trigger *t) * being accessed later. Can happen if cgroup is deleted from under a * polling process. */ - wake_up_pollfree(&t->event_wait); + if (t->of) + kernfs_notify(t->of->kn); + else + wake_up_interruptible(&t->event_wait); if (t->aggregator == PSI_AVGS) { mutex_lock(&group->avgs_lock); @@ -1465,7 +1475,10 @@ __poll_t psi_trigger_poll(void **trigger_ptr, if (!t) return DEFAULT_POLLMASK | EPOLLERR | EPOLLPRI; - poll_wait(file, &t->event_wait, wait); + if (t->of) + kernfs_generic_poll(t->of, wait); + else + poll_wait(file, &t->event_wait, wait); if (cmpxchg(&t->event, 1, 0) == 1) ret |= EPOLLPRI; @@ -1535,7 +1548,7 @@ static ssize_t psi_write(struct file *file, const char __user *user_buf, return -EBUSY; } - new = psi_trigger_create(&psi_system, buf, res, file); + new = psi_trigger_create(&psi_system, buf, res, file, NULL); if (IS_ERR(new)) { mutex_unlock(&seq->lock); return PTR_ERR(new); -- cgit v1.2.3 From cf0a624dc706c306294c14e6b3e7694702f25191 Mon Sep 17 00:00:00 2001 From: "Tzvetomir Stoyanov (VMware)" Date: Mon, 3 Jul 2023 07:28:53 +0300 Subject: kernel/trace: Fix cleanup logic of enable_trace_eprobe The enable_trace_eprobe() function enables all event probes, attached to given trace probe. If an error occurs in enabling one of the event probes, all others should be roll backed. There is a bug in that roll back logic - instead of all event probes, only the failed one is disabled. Link: https://lore.kernel.org/all/20230703042853.1427493-1-tz.stoyanov@gmail.com/ Reported-by: Dan Carpenter Fixes: 7491e2c44278 ("tracing: Add a probe that attaches to trace events") Signed-off-by: Tzvetomir Stoyanov (VMware) Acked-by: Masami Hiramatsu (Google) Reviewed-by: Steven Rostedt (Google) Signed-off-by: Masami Hiramatsu (Google) --- kernel/trace/trace_eprobe.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c index 67e854979d53..3f04f0ffe0d7 100644 --- a/kernel/trace/trace_eprobe.c +++ b/kernel/trace/trace_eprobe.c @@ -675,6 +675,7 @@ static int enable_trace_eprobe(struct trace_event_call *call, struct trace_eprobe *ep; bool enabled; int ret = 0; + int cnt = 0; tp = trace_probe_primary_from_call(call); if (WARN_ON_ONCE(!tp)) @@ -698,12 +699,25 @@ static int enable_trace_eprobe(struct trace_event_call *call, if (ret) break; enabled = true; + cnt++; } if (ret) { /* Failed to enable one of them. Roll back all */ - if (enabled) - disable_eprobe(ep, file->tr); + if (enabled) { + /* + * It's a bug if one failed for something other than memory + * not being available but another eprobe succeeded. + */ + WARN_ON_ONCE(ret != -ENOMEM); + + list_for_each_entry(pos, trace_probe_probe_list(tp), list) { + ep = container_of(pos, struct trace_eprobe, tp); + disable_eprobe(ep, file->tr); + if (!--cnt) + break; + } + } if (file) trace_probe_remove_file(tp, file); else -- cgit v1.2.3 From 5f0c584daf7464f04114c65dd07269ee2bfedc13 Mon Sep 17 00:00:00 2001 From: Ze Gao Date: Mon, 3 Jul 2023 17:23:36 +0800 Subject: fprobe: add unlock to match a succeeded ftrace_test_recursion_trylock Unlock ftrace recursion lock when fprobe_kprobe_handler() is failed because of some running kprobe. Link: https://lore.kernel.org/all/20230703092336.268371-1-zegao@tencent.com/ Fixes: 3cc4e2c5fbae ("fprobe: make fprobe_kprobe_handler recursion free") Reported-by: Yafang Closes: https://lore.kernel.org/linux-trace-kernel/CALOAHbC6UpfFOOibdDiC7xFc5YFUgZnk3MZ=3Ny6we=AcrNbew@mail.gmail.com/ Signed-off-by: Ze Gao Acked-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Reviewed-by: Steven Rostedt (Google) Signed-off-by: Masami Hiramatsu (Google) --- kernel/trace/fprobe.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c index 0121e8c0d54e..58e4b3607aef 100644 --- a/kernel/trace/fprobe.c +++ b/kernel/trace/fprobe.c @@ -102,12 +102,14 @@ static void fprobe_kprobe_handler(unsigned long ip, unsigned long parent_ip, if (unlikely(kprobe_running())) { fp->nmissed++; - return; + goto recursion_unlock; } kprobe_busy_begin(); __fprobe_handler(ip, parent_ip, ops, fregs); kprobe_busy_end(); + +recursion_unlock: ftrace_test_recursion_unlock(bit); } -- cgit v1.2.3 From e1164787f22b51010cfdc6a5e41b744435836b79 Mon Sep 17 00:00:00 2001 From: Li zeming Date: Wed, 5 Jul 2023 03:43:59 +0800 Subject: kprobes: Remove unnecessary ‘NULL’ values from correct_ret_addr MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The 'correct_ret_addr' pointer is always set in the later code, no need to initialize it at definition time. Link: https://lore.kernel.org/all/20230704194359.3124-1-zeming@nfschina.com/ Signed-off-by: Li zeming Acked-by: Masami Hiramatsu (Google) Signed-off-by: Masami Hiramatsu (Google) --- kernel/kprobes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 00e177de91cc..fd713ab439c2 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2007,9 +2007,9 @@ void __weak arch_kretprobe_fixup_return(struct pt_regs *regs, unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs, void *frame_pointer) { - kprobe_opcode_t *correct_ret_addr = NULL; struct kretprobe_instance *ri = NULL; struct llist_node *first, *node = NULL; + kprobe_opcode_t *correct_ret_addr; struct kretprobe *rp; /* Find correct address and all nodes for this frame. */ -- cgit v1.2.3 From ed9492dfef8738ca68879f5690dda5a04f1897dc Mon Sep 17 00:00:00 2001 From: Li zeming Date: Wed, 12 Jul 2023 02:53:53 +0800 Subject: kernel: kprobes: Remove unnecessary ‘0’ values MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit it is assigned first, so it does not need to initialize the assignment. Link: https://lore.kernel.org/all/20230711185353.3218-1-zeming@nfschina.com/ Signed-off-by: Li zeming Acked-by: Masami Hiramatsu (Google) Signed-off-by: Masami Hiramatsu (Google) --- kernel/kprobes.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index fd713ab439c2..a009c8ccd8ea 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1072,7 +1072,7 @@ static int kprobe_ftrace_enabled; static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops, int *cnt) { - int ret = 0; + int ret; lockdep_assert_held(&kprobe_mutex); @@ -1110,7 +1110,7 @@ static int arm_kprobe_ftrace(struct kprobe *p) static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops, int *cnt) { - int ret = 0; + int ret; lockdep_assert_held(&kprobe_mutex); @@ -2692,7 +2692,7 @@ void kprobe_free_init_mem(void) static int __init init_kprobes(void) { - int i, err = 0; + int i, err; /* FIXME allocate the probe table, currently defined statically */ /* initialize all list heads */ -- cgit v1.2.3 From 195b9cb5b288fec1c871ef89f78cc9a7461aad3a Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Fri, 7 Jul 2023 23:03:19 +0900 Subject: fprobe: Ensure running fprobe_exit_handler() finished before calling rethook_free() Ensure running fprobe_exit_handler() has finished before calling rethook_free() in the unregister_fprobe() so that caller can free the fprobe right after unregister_fprobe(). unregister_fprobe() ensured that all running fprobe_entry/exit_handler() have finished by calling unregister_ftrace_function() which synchronizes RCU. But commit 5f81018753df ("fprobe: Release rethook after the ftrace_ops is unregistered") changed to call rethook_free() after unregister_ftrace_function(). So call rethook_stop() to make rethook disabled before unregister_ftrace_function() and ensure it again. Here is the possible code flow that can call the exit handler after unregister_fprobe(). ------ CPU1 CPU2 call unregister_fprobe(fp) ... __fprobe_handler() rethook_hook() on probed function unregister_ftrace_function() return from probed function rethook hooks find rh->handler == fprobe_exit_handler call fprobe_exit_handler() rethook_free(): set rh->handler = NULL; return from unreigster_fprobe; call fp->exit_handler() <- (*) ------ (*) At this point, the exit handler is called after returning from unregister_fprobe(). This fixes it as following; ------ CPU1 CPU2 call unregister_fprobe() ... rethook_stop(): set rh->handler = NULL; __fprobe_handler() rethook_hook() on probed function unregister_ftrace_function() return from probed function rethook hooks find rh->handler == NULL return from rethook rethook_free() return from unreigster_fprobe; ------ Link: https://lore.kernel.org/all/168873859949.156157.13039240432299335849.stgit@devnote2/ Fixes: 5f81018753df ("fprobe: Release rethook after the ftrace_ops is unregistered") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) Reviewed-by: Steven Rostedt (Google) --- include/linux/rethook.h | 1 + kernel/trace/fprobe.c | 3 +++ kernel/trace/rethook.c | 13 +++++++++++++ 3 files changed, 17 insertions(+) (limited to 'kernel') diff --git a/include/linux/rethook.h b/include/linux/rethook.h index c8ac1e5afcd1..bdbe6717f45a 100644 --- a/include/linux/rethook.h +++ b/include/linux/rethook.h @@ -59,6 +59,7 @@ struct rethook_node { }; struct rethook *rethook_alloc(void *data, rethook_handler_t handler); +void rethook_stop(struct rethook *rh); void rethook_free(struct rethook *rh); void rethook_add_node(struct rethook *rh, struct rethook_node *node); struct rethook_node *rethook_try_get(struct rethook *rh); diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c index 58e4b3607aef..2571f7f3d5f2 100644 --- a/kernel/trace/fprobe.c +++ b/kernel/trace/fprobe.c @@ -366,6 +366,9 @@ int unregister_fprobe(struct fprobe *fp) fp->ops.saved_func != fprobe_kprobe_handler)) return -EINVAL; + if (fp->rethook) + rethook_stop(fp->rethook); + ret = unregister_ftrace_function(&fp->ops); if (ret < 0) return ret; diff --git a/kernel/trace/rethook.c b/kernel/trace/rethook.c index 60f6cb2b486b..468006cce7ca 100644 --- a/kernel/trace/rethook.c +++ b/kernel/trace/rethook.c @@ -53,6 +53,19 @@ static void rethook_free_rcu(struct rcu_head *head) kfree(rh); } +/** + * rethook_stop() - Stop using a rethook. + * @rh: the struct rethook to stop. + * + * Stop using a rethook to prepare for freeing it. If you want to wait for + * all running rethook handler before calling rethook_free(), you need to + * call this first and wait RCU, and call rethook_free(). + */ +void rethook_stop(struct rethook *rh) +{ + WRITE_ONCE(rh->handler, NULL); +} + /** * rethook_free() - Free struct rethook. * @rh: the struct rethook to be freed. -- cgit v1.2.3 From d0a3022f30629a208e5944022caeca3568add9e7 Mon Sep 17 00:00:00 2001 From: Beau Belgrave Date: Thu, 29 Jun 2023 23:50:48 +0000 Subject: tracing/user_events: Fix struct arg size match check When users register an event the name of the event and it's argument are checked to ensure they match if the event already exists. Normally all arguments are in the form of "type name", except for when the type starts with "struct ". In those cases, the size of the struct is passed in addition to the name, IE: "struct my_struct a 20" for an argument that is of type "struct my_struct" with a field name of "a" and has the size of 20 bytes. The current code does not honor the above case properly when comparing a match. This causes the event register to fail even when the same string was used for events that contain a struct argument within them. The example above "struct my_struct a 20" generates a match string of "struct my_struct a" omitting the size field. Add the struct size of the existing field when generating a comparison string for a struct field to ensure proper match checking. Link: https://lkml.kernel.org/r/20230629235049.581-2-beaub@linux.microsoft.com Cc: stable@vger.kernel.org Fixes: e6f89a149872 ("tracing/user_events: Ensure user provided strings are safely formatted") Signed-off-by: Beau Belgrave Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace_events_user.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c index 4f5e74bbdab2..33cb6af31f39 100644 --- a/kernel/trace/trace_events_user.c +++ b/kernel/trace/trace_events_user.c @@ -1317,6 +1317,9 @@ static int user_field_set_string(struct ftrace_event_field *field, pos += snprintf(buf + pos, LEN_OR_ZERO, " "); pos += snprintf(buf + pos, LEN_OR_ZERO, "%s", field->name); + if (str_has_prefix(field->type, "struct ")) + pos += snprintf(buf + pos, LEN_OR_ZERO, " %d", field->size); + if (colon) pos += snprintf(buf + pos, LEN_OR_ZERO, ";"); -- cgit v1.2.3 From c9e4bf607d8c431452ef362c00e62ce999bbae93 Mon Sep 17 00:00:00 2001 From: Azat Khuzhin Date: Tue, 11 Jul 2023 13:48:12 +0200 Subject: PM: hibernate: Fix writing maj:min to /sys/power/resume resume_store() first calls lookup_bdev() and after tries to handle maj:min, but it does not reset the error before, hence if you will write maj:min you will get ENOENT: # echo 259:2 >| /sys/power/resume bash: echo: write error: No such file or directory This also should fix hiberation via systemd, since it uses this way. Fixes: 1e8c813b083c4 ("PM: hibernate: don't use early_lookup_bdev in resume_store") Signed-off-by: Azat Khuzhin Reviewed-by: Christoph Hellwig [ rjw: Subject edits ] Signed-off-by: Rafael J. Wysocki --- kernel/power/hibernate.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index f62e89d0d906..e1b4bfa938dd 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -1179,6 +1179,7 @@ static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr, unsigned maj, min, offset; char *p, dummy; + error = 0; if (sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2 || sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3) { -- cgit v1.2.3 From 3a8395b565b5b4f019b3dc182be4c4541eb35ac8 Mon Sep 17 00:00:00 2001 From: Chungkai Yang Date: Wed, 5 Jul 2023 16:59:07 +0800 Subject: PM: QoS: Restore support for default value on frequency QoS Commit 8d36694245f2 ("PM: QoS: Add check to make sure CPU freq is non-negative") makes sure CPU freq is non-negative to avoid negative value converting to unsigned data type. However, when the value is PM_QOS_DEFAULT_VALUE, pm_qos_update_target specifically uses c->default_value which is set to FREQ_QOS_MIN/MAX_DEFAULT_VALUE when cpufreq_policy_alloc is executed, for this case handling. Adding check for PM_QOS_DEFAULT_VALUE to let default setting work will fix this problem. Fixes: 8d36694245f2 ("PM: QoS: Add check to make sure CPU freq is non-negative") Link: https://lore.kernel.org/lkml/20230626035144.19717-1-Chung-kai.Yang@mediatek.com/ Link: https://lore.kernel.org/lkml/20230627071727.16646-1-Chung-kai.Yang@mediatek.com/ Link: https://lore.kernel.org/lkml/CAJZ5v0gxNOWhC58PHeUhW_tgf6d1fGJVZ1x91zkDdht11yUv-A@mail.gmail.com/ Signed-off-by: Chungkai Yang Cc: 6.0+ # 6.0+ Signed-off-by: Rafael J. Wysocki --- kernel/power/qos.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/power/qos.c b/kernel/power/qos.c index af51ed6d45ef..782d3b41c1f3 100644 --- a/kernel/power/qos.c +++ b/kernel/power/qos.c @@ -426,6 +426,11 @@ late_initcall(cpu_latency_qos_init); /* Definitions related to the frequency QoS below. */ +static inline bool freq_qos_value_invalid(s32 value) +{ + return value < 0 && value != PM_QOS_DEFAULT_VALUE; +} + /** * freq_constraints_init - Initialize frequency QoS constraints. * @qos: Frequency QoS constraints to initialize. @@ -531,7 +536,7 @@ int freq_qos_add_request(struct freq_constraints *qos, { int ret; - if (IS_ERR_OR_NULL(qos) || !req || value < 0) + if (IS_ERR_OR_NULL(qos) || !req || freq_qos_value_invalid(value)) return -EINVAL; if (WARN(freq_qos_request_active(req), @@ -563,7 +568,7 @@ EXPORT_SYMBOL_GPL(freq_qos_add_request); */ int freq_qos_update_request(struct freq_qos_request *req, s32 new_value) { - if (!req || new_value < 0) + if (!req || freq_qos_value_invalid(new_value)) return -EINVAL; if (WARN(!freq_qos_request_active(req), -- cgit v1.2.3 From 4369016497319a9635702da010d02af1ebb1849d Mon Sep 17 00:00:00 2001 From: Pu Lehui Date: Tue, 11 Jul 2023 19:58:48 +0800 Subject: bpf: cpumap: Fix memory leak in cpu_map_update_elem Syzkaller reported a memory leak as follows: BUG: memory leak unreferenced object 0xff110001198ef748 (size 192): comm "syz-executor.3", pid 17672, jiffies 4298118891 (age 9.906s) hex dump (first 32 bytes): 00 00 00 00 4a 19 00 00 80 ad e3 e4 fe ff c0 00 ....J........... 00 b2 d3 0c 01 00 11 ff 28 f5 8e 19 01 00 11 ff ........(....... backtrace: [] __cpu_map_entry_alloc+0xf7/0xb00 [] cpu_map_update_elem+0x2fe/0x3d0 [] bpf_map_update_value.isra.0+0x2bd/0x520 [] map_update_elem+0x4cb/0x720 [] __se_sys_bpf+0x8c3/0xb90 [] do_syscall_64+0x30/0x40 [] entry_SYSCALL_64_after_hwframe+0x61/0xc6 BUG: memory leak unreferenced object 0xff110001198ef528 (size 192): comm "syz-executor.3", pid 17672, jiffies 4298118891 (age 9.906s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [] __cpu_map_entry_alloc+0x260/0xb00 [] cpu_map_update_elem+0x2fe/0x3d0 [] bpf_map_update_value.isra.0+0x2bd/0x520 [] map_update_elem+0x4cb/0x720 [] __se_sys_bpf+0x8c3/0xb90 [] do_syscall_64+0x30/0x40 [] entry_SYSCALL_64_after_hwframe+0x61/0xc6 BUG: memory leak unreferenced object 0xff1100010fd93d68 (size 8): comm "syz-executor.3", pid 17672, jiffies 4298118891 (age 9.906s) hex dump (first 8 bytes): 00 00 00 00 00 00 00 00 ........ backtrace: [] kvmalloc_node+0x11e/0x170 [] __cpu_map_entry_alloc+0x2f0/0xb00 [] cpu_map_update_elem+0x2fe/0x3d0 [] bpf_map_update_value.isra.0+0x2bd/0x520 [] map_update_elem+0x4cb/0x720 [] __se_sys_bpf+0x8c3/0xb90 [] do_syscall_64+0x30/0x40 [] entry_SYSCALL_64_after_hwframe+0x61/0xc6 In the cpu_map_update_elem flow, when kthread_stop is called before calling the threadfn of rcpu->kthread, since the KTHREAD_SHOULD_STOP bit of kthread has been set by kthread_stop, the threadfn of rcpu->kthread will never be executed, and rcpu->refcnt will never be 0, which will lead to the allocated rcpu, rcpu->queue and rcpu->queue->queue cannot be released. Calling kthread_stop before executing kthread's threadfn will return -EINTR. We can complete the release of memory resources in this state. Fixes: 6710e1126934 ("bpf: introduce new bpf cpu map type BPF_MAP_TYPE_CPUMAP") Signed-off-by: Pu Lehui Acked-by: Jesper Dangaard Brouer Acked-by: Hou Tao Link: https://lore.kernel.org/r/20230711115848.2701559-1-pulehui@huaweicloud.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/cpumap.c | 40 ++++++++++++++++++++++++---------------- 1 file changed, 24 insertions(+), 16 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c index 8a33e8747a0e..6ae02be7a48e 100644 --- a/kernel/bpf/cpumap.c +++ b/kernel/bpf/cpumap.c @@ -122,22 +122,6 @@ static void get_cpu_map_entry(struct bpf_cpu_map_entry *rcpu) atomic_inc(&rcpu->refcnt); } -/* called from workqueue, to workaround syscall using preempt_disable */ -static void cpu_map_kthread_stop(struct work_struct *work) -{ - struct bpf_cpu_map_entry *rcpu; - - rcpu = container_of(work, struct bpf_cpu_map_entry, kthread_stop_wq); - - /* Wait for flush in __cpu_map_entry_free(), via full RCU barrier, - * as it waits until all in-flight call_rcu() callbacks complete. - */ - rcu_barrier(); - - /* kthread_stop will wake_up_process and wait for it to complete */ - kthread_stop(rcpu->kthread); -} - static void __cpu_map_ring_cleanup(struct ptr_ring *ring) { /* The tear-down procedure should have made sure that queue is @@ -165,6 +149,30 @@ static void put_cpu_map_entry(struct bpf_cpu_map_entry *rcpu) } } +/* called from workqueue, to workaround syscall using preempt_disable */ +static void cpu_map_kthread_stop(struct work_struct *work) +{ + struct bpf_cpu_map_entry *rcpu; + int err; + + rcpu = container_of(work, struct bpf_cpu_map_entry, kthread_stop_wq); + + /* Wait for flush in __cpu_map_entry_free(), via full RCU barrier, + * as it waits until all in-flight call_rcu() callbacks complete. + */ + rcu_barrier(); + + /* kthread_stop will wake_up_process and wait for it to complete */ + err = kthread_stop(rcpu->kthread); + if (err) { + /* kthread_stop may be called before cpu_map_kthread_run + * is executed, so we need to release the memory related + * to rcpu. + */ + put_cpu_map_entry(rcpu); + } +} + static void cpu_map_bpf_prog_run_skb(struct bpf_cpu_map_entry *rcpu, struct list_head *listp, struct xdp_cpumap_stats *stats) -- cgit v1.2.3 From 7d8b31b73c79835572611ed1eed649e4d2e14245 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 17 May 2023 14:51:48 +0200 Subject: tracing: arm64: Avoid missing-prototype warnings These are all tracing W=1 warnings in arm64 allmodconfig about missing prototypes: kernel/trace/trace_kprobe_selftest.c:7:5: error: no previous prototype for 'kprobe_trace_selftest_target' [-Werror=missing-pro totypes] kernel/trace/ftrace.c:329:5: error: no previous prototype for '__register_ftrace_function' [-Werror=missing-prototypes] kernel/trace/ftrace.c:372:5: error: no previous prototype for '__unregister_ftrace_function' [-Werror=missing-prototypes] kernel/trace/ftrace.c:4130:15: error: no previous prototype for 'arch_ftrace_match_adjust' [-Werror=missing-prototypes] kernel/trace/fgraph.c:243:15: error: no previous prototype for 'ftrace_return_to_handler' [-Werror=missing-prototypes] kernel/trace/fgraph.c:358:6: error: no previous prototype for 'ftrace_graph_sleep_time_control' [-Werror=missing-prototypes] arch/arm64/kernel/ftrace.c:460:6: error: no previous prototype for 'prepare_ftrace_return' [-Werror=missing-prototypes] arch/arm64/kernel/ptrace.c:2172:5: error: no previous prototype for 'syscall_trace_enter' [-Werror=missing-prototypes] arch/arm64/kernel/ptrace.c:2195:6: error: no previous prototype for 'syscall_trace_exit' [-Werror=missing-prototypes] Move the declarations to an appropriate header where they can be seen by the caller and callee, and make sure the headers are included where needed. Link: https://lore.kernel.org/linux-trace-kernel/20230517125215.930689-1-arnd@kernel.org Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Will Deacon Cc: Kees Cook Cc: Florent Revest Signed-off-by: Arnd Bergmann Acked-by: Catalin Marinas [ Fixed ftrace_return_to_handler() to handle CONFIG_HAVE_FUNCTION_GRAPH_RETVAL case ] Signed-off-by: Steven Rostedt (Google) --- arch/arm64/include/asm/ftrace.h | 4 ++++ arch/arm64/include/asm/syscall.h | 3 +++ arch/arm64/kernel/syscall.c | 3 --- include/linux/ftrace.h | 9 +++++++++ kernel/trace/fgraph.c | 1 + kernel/trace/ftrace_internal.h | 5 +++-- kernel/trace/trace_kprobe_selftest.c | 3 +++ 7 files changed, 23 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h index 21ac1c5c71d3..ab158196480c 100644 --- a/arch/arm64/include/asm/ftrace.h +++ b/arch/arm64/include/asm/ftrace.h @@ -211,6 +211,10 @@ static inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_ret_regs { return ret_regs->fp; } + +void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent, + unsigned long frame_pointer); + #endif /* ifdef CONFIG_FUNCTION_GRAPH_TRACER */ #endif diff --git a/arch/arm64/include/asm/syscall.h b/arch/arm64/include/asm/syscall.h index 4cfe9b49709b..ab8e14b96f68 100644 --- a/arch/arm64/include/asm/syscall.h +++ b/arch/arm64/include/asm/syscall.h @@ -85,4 +85,7 @@ static inline int syscall_get_arch(struct task_struct *task) return AUDIT_ARCH_AARCH64; } +int syscall_trace_enter(struct pt_regs *regs); +void syscall_trace_exit(struct pt_regs *regs); + #endif /* __ASM_SYSCALL_H */ diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c index 5a668d7f3c1f..b1ae2f2eaf77 100644 --- a/arch/arm64/kernel/syscall.c +++ b/arch/arm64/kernel/syscall.c @@ -75,9 +75,6 @@ static inline bool has_syscall_work(unsigned long flags) return unlikely(flags & _TIF_SYSCALL_WORK); } -int syscall_trace_enter(struct pt_regs *regs); -void syscall_trace_exit(struct pt_regs *regs); - static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, const syscall_fn_t syscall_table[]) { diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 8e59bd954153..ce156c7704ee 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -41,6 +41,15 @@ struct ftrace_ops; struct ftrace_regs; struct dyn_ftrace; +char *arch_ftrace_match_adjust(char *str, const char *search); + +#ifdef CONFIG_HAVE_FUNCTION_GRAPH_RETVAL +struct fgraph_ret_regs; +unsigned long ftrace_return_to_handler(struct fgraph_ret_regs *ret_regs); +#else +unsigned long ftrace_return_to_handler(unsigned long frame_pointer); +#endif + #ifdef CONFIG_FUNCTION_TRACER /* * If the arch's mcount caller does not support all of ftrace's diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c index cd2c35b1dd8f..c83c005e654e 100644 --- a/kernel/trace/fgraph.c +++ b/kernel/trace/fgraph.c @@ -15,6 +15,7 @@ #include #include "ftrace_internal.h" +#include "trace.h" #ifdef CONFIG_DYNAMIC_FTRACE #define ASSIGN_OPS_HASH(opsname, val) \ diff --git a/kernel/trace/ftrace_internal.h b/kernel/trace/ftrace_internal.h index 382775edf690..5012c04f92c0 100644 --- a/kernel/trace/ftrace_internal.h +++ b/kernel/trace/ftrace_internal.h @@ -2,6 +2,9 @@ #ifndef _LINUX_KERNEL_FTRACE_INTERNAL_H #define _LINUX_KERNEL_FTRACE_INTERNAL_H +int __register_ftrace_function(struct ftrace_ops *ops); +int __unregister_ftrace_function(struct ftrace_ops *ops); + #ifdef CONFIG_FUNCTION_TRACER extern struct mutex ftrace_lock; @@ -15,8 +18,6 @@ int ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs); #else /* !CONFIG_DYNAMIC_FTRACE */ -int __register_ftrace_function(struct ftrace_ops *ops); -int __unregister_ftrace_function(struct ftrace_ops *ops); /* Keep as macros so we do not need to define the commands */ # define ftrace_startup(ops, command) \ ({ \ diff --git a/kernel/trace/trace_kprobe_selftest.c b/kernel/trace/trace_kprobe_selftest.c index 16548ee4c8c6..3851cd1e6a62 100644 --- a/kernel/trace/trace_kprobe_selftest.c +++ b/kernel/trace/trace_kprobe_selftest.c @@ -1,4 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 + +#include "trace_kprobe_selftest.h" + /* * Function used during the kprobe self test. This function is in a separate * compile unit so it can be compile with CC_FLAGS_FTRACE to ensure that it -- cgit v1.2.3 From 7e42907f3a7b4ce3a2d1757f6d78336984daf8f5 Mon Sep 17 00:00:00 2001 From: Zheng Yejian Date: Sun, 9 Jul 2023 06:51:44 +0800 Subject: ring-buffer: Fix deadloop issue on reading trace_pipe Soft lockup occurs when reading file 'trace_pipe': watchdog: BUG: soft lockup - CPU#6 stuck for 22s! [cat:4488] [...] RIP: 0010:ring_buffer_empty_cpu+0xed/0x170 RSP: 0018:ffff88810dd6fc48 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000246 RCX: ffffffff93d1aaeb RDX: ffff88810a280040 RSI: 0000000000000008 RDI: ffff88811164b218 RBP: ffff88811164b218 R08: 0000000000000000 R09: ffff88815156600f R10: ffffed102a2acc01 R11: 0000000000000001 R12: 0000000051651901 R13: 0000000000000000 R14: ffff888115e49500 R15: 0000000000000000 [...] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8d853c2000 CR3: 000000010dcd8000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __find_next_entry+0x1a8/0x4b0 ? peek_next_entry+0x250/0x250 ? down_write+0xa5/0x120 ? down_write_killable+0x130/0x130 trace_find_next_entry_inc+0x3b/0x1d0 tracing_read_pipe+0x423/0xae0 ? tracing_splice_read_pipe+0xcb0/0xcb0 vfs_read+0x16b/0x490 ksys_read+0x105/0x210 ? __ia32_sys_pwrite64+0x200/0x200 ? switch_fpu_return+0x108/0x220 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x61/0xc6 Through the vmcore, I found it's because in tracing_read_pipe(), ring_buffer_empty_cpu() found some buffer is not empty but then it cannot read anything due to "rb_num_of_entries() == 0" always true, Then it infinitely loop the procedure due to user buffer not been filled, see following code path: tracing_read_pipe() { ... ... waitagain: tracing_wait_pipe() // 1. find non-empty buffer here trace_find_next_entry_inc() // 2. loop here try to find an entry __find_next_entry() ring_buffer_empty_cpu(); // 3. find non-empty buffer peek_next_entry() // 4. but peek always return NULL ring_buffer_peek() rb_buffer_peek() rb_get_reader_page() // 5. because rb_num_of_entries() == 0 always true here // then return NULL // 6. user buffer not been filled so goto 'waitgain' // and eventually leads to an deadloop in kernel!!! } By some analyzing, I found that when resetting ringbuffer, the 'entries' of its pages are not all cleared (see rb_reset_cpu()). Then when reducing the ringbuffer, and if some reduced pages exist dirty 'entries' data, they will be added into 'cpu_buffer->overrun' (see rb_remove_pages()), which cause wrong 'overrun' count and eventually cause the deadloop issue. To fix it, we need to clear every pages in rb_reset_cpu(). Link: https://lore.kernel.org/linux-trace-kernel/20230708225144.3785600-1-zhengyejian1@huawei.com Cc: stable@vger.kernel.org Fixes: a5fb833172eca ("ring-buffer: Fix uninitialized read_stamp") Signed-off-by: Zheng Yejian Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ring_buffer.c | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 834b361a4a66..14d8001140c8 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -5242,28 +5242,34 @@ unsigned long ring_buffer_size(struct trace_buffer *buffer, int cpu) } EXPORT_SYMBOL_GPL(ring_buffer_size); +static void rb_clear_buffer_page(struct buffer_page *page) +{ + local_set(&page->write, 0); + local_set(&page->entries, 0); + rb_init_page(page->page); + page->read = 0; +} + static void rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer) { + struct buffer_page *page; + rb_head_page_deactivate(cpu_buffer); cpu_buffer->head_page = list_entry(cpu_buffer->pages, struct buffer_page, list); - local_set(&cpu_buffer->head_page->write, 0); - local_set(&cpu_buffer->head_page->entries, 0); - local_set(&cpu_buffer->head_page->page->commit, 0); - - cpu_buffer->head_page->read = 0; + rb_clear_buffer_page(cpu_buffer->head_page); + list_for_each_entry(page, cpu_buffer->pages, list) { + rb_clear_buffer_page(page); + } cpu_buffer->tail_page = cpu_buffer->head_page; cpu_buffer->commit_page = cpu_buffer->head_page; INIT_LIST_HEAD(&cpu_buffer->reader_page->list); INIT_LIST_HEAD(&cpu_buffer->new_pages); - local_set(&cpu_buffer->reader_page->write, 0); - local_set(&cpu_buffer->reader_page->entries, 0); - local_set(&cpu_buffer->reader_page->page->commit, 0); - cpu_buffer->reader_page->read = 0; + rb_clear_buffer_page(cpu_buffer->reader_page); local_set(&cpu_buffer->entries_bytes, 0); local_set(&cpu_buffer->overrun, 0); -- cgit v1.2.3 From 26efd79c4624294e553aeaa3439c646729bad084 Mon Sep 17 00:00:00 2001 From: Zheng Yejian Date: Wed, 12 Jul 2023 14:04:52 +0800 Subject: ftrace: Fix possible warning on checking all pages used in ftrace_process_locs() As comments in ftrace_process_locs(), there may be NULL pointers in mcount_loc section: > Some architecture linkers will pad between > the different mcount_loc sections of different > object files to satisfy alignments. > Skip any NULL pointers. After commit 20e5227e9f55 ("ftrace: allow NULL pointers in mcount_loc"), NULL pointers will be accounted when allocating ftrace pages but skipped before adding into ftrace pages, this may result in some pages not being used. Then after commit 706c81f87f84 ("ftrace: Remove extra helper functions"), warning may occur at: WARN_ON(pg->next); To fix it, only warn for case that no pointers skipped but pages not used up, then free those unused pages after releasing ftrace_lock. Link: https://lore.kernel.org/linux-trace-kernel/20230712060452.3175675-1-zhengyejian1@huawei.com Cc: stable@vger.kernel.org Fixes: 706c81f87f84 ("ftrace: Remove extra helper functions") Suggested-by: Steven Rostedt Signed-off-by: Zheng Yejian Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ftrace.c | 45 +++++++++++++++++++++++++++++++-------------- 1 file changed, 31 insertions(+), 14 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 3740aca79fe7..05c0024815bf 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3305,6 +3305,22 @@ static int ftrace_allocate_records(struct ftrace_page *pg, int count) return cnt; } +static void ftrace_free_pages(struct ftrace_page *pages) +{ + struct ftrace_page *pg = pages; + + while (pg) { + if (pg->records) { + free_pages((unsigned long)pg->records, pg->order); + ftrace_number_of_pages -= 1 << pg->order; + } + pages = pg->next; + kfree(pg); + pg = pages; + ftrace_number_of_groups--; + } +} + static struct ftrace_page * ftrace_allocate_pages(unsigned long num_to_init) { @@ -3343,17 +3359,7 @@ ftrace_allocate_pages(unsigned long num_to_init) return start_pg; free_pages: - pg = start_pg; - while (pg) { - if (pg->records) { - free_pages((unsigned long)pg->records, pg->order); - ftrace_number_of_pages -= 1 << pg->order; - } - start_pg = pg->next; - kfree(pg); - pg = start_pg; - ftrace_number_of_groups--; - } + ftrace_free_pages(start_pg); pr_info("ftrace: FAILED to allocate memory for functions\n"); return NULL; } @@ -6471,9 +6477,11 @@ static int ftrace_process_locs(struct module *mod, unsigned long *start, unsigned long *end) { + struct ftrace_page *pg_unuse = NULL; struct ftrace_page *start_pg; struct ftrace_page *pg; struct dyn_ftrace *rec; + unsigned long skipped = 0; unsigned long count; unsigned long *p; unsigned long addr; @@ -6536,8 +6544,10 @@ static int ftrace_process_locs(struct module *mod, * object files to satisfy alignments. * Skip any NULL pointers. */ - if (!addr) + if (!addr) { + skipped++; continue; + } end_offset = (pg->index+1) * sizeof(pg->records[0]); if (end_offset > PAGE_SIZE << pg->order) { @@ -6551,8 +6561,10 @@ static int ftrace_process_locs(struct module *mod, rec->ip = addr; } - /* We should have used all pages */ - WARN_ON(pg->next); + if (pg->next) { + pg_unuse = pg->next; + pg->next = NULL; + } /* Assign the last page to ftrace_pages */ ftrace_pages = pg; @@ -6574,6 +6586,11 @@ static int ftrace_process_locs(struct module *mod, out: mutex_unlock(&ftrace_lock); + /* We should have used all pages unless we skipped some */ + if (pg_unuse) { + WARN_ON(!skipped); + ftrace_free_pages(pg_unuse); + } return ret; } -- cgit v1.2.3 From bec3c25c247c4f88a33d79675a09e1644c9a3114 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" Date: Wed, 12 Jul 2023 10:52:35 -0400 Subject: tracing: Stop FORTIFY_SOURCE complaining about stack trace caller The stack_trace event is an event created by the tracing subsystem to store stack traces. It originally just contained a hard coded array of 8 words to hold the stack, and a "size" to know how many entries are there. This is exported to user space as: name: kernel_stack ID: 4 format: field:unsigned short common_type; offset:0; size:2; signed:0; field:unsigned char common_flags; offset:2; size:1; signed:0; field:unsigned char common_preempt_count; offset:3; size:1; signed:0; field:int common_pid; offset:4; size:4; signed:1; field:int size; offset:8; size:4; signed:1; field:unsigned long caller[8]; offset:16; size:64; signed:0; print fmt: "\t=> %ps\n\t=> %ps\n\t=> %ps\n" "\t=> %ps\n\t=> %ps\n\t=> %ps\n" "\t=> %ps\n\t=> %ps\n",i (void *)REC->caller[0], (void *)REC->caller[1], (void *)REC->caller[2], (void *)REC->caller[3], (void *)REC->caller[4], (void *)REC->caller[5], (void *)REC->caller[6], (void *)REC->caller[7] Where the user space tracers could parse the stack. The library was updated for this specific event to only look at the size, and not the array. But some older users still look at the array (note, the older code still checks to make sure the array fits inside the event that it read. That is, if only 4 words were saved, the parser would not read the fifth word because it will see that it was outside of the event size). This event was changed a while ago to be more dynamic, and would save a full stack even if it was greater than 8 words. It does this by simply allocating more ring buffer to hold the extra words. Then it copies in the stack via: memcpy(&entry->caller, fstack->calls, size); As the entry is struct stack_entry, that is created by a macro to both create the structure and export this to user space, it still had the caller field of entry defined as: unsigned long caller[8]. When the stack is greater than 8, the FORTIFY_SOURCE code notices that the amount being copied is greater than the source array and complains about it. It has no idea that the source is pointing to the ring buffer with the required allocation. To hide this from the FORTIFY_SOURCE logic, pointer arithmetic is used: ptr = ring_buffer_event_data(event); entry = ptr; ptr += offsetof(typeof(*entry), caller); memcpy(ptr, fstack->calls, size); Link: https://lore.kernel.org/all/20230612160748.4082850-1-svens@linux.ibm.com/ Link: https://lore.kernel.org/linux-trace-kernel/20230712105235.5fc441aa@gandalf.local.home Cc: Masami Hiramatsu Cc: Mark Rutland Reported-by: Sven Schnelle Tested-by: Sven Schnelle Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 4529e264cb86..20122eeccf97 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3118,6 +3118,7 @@ static void __ftrace_trace_stack(struct trace_buffer *buffer, struct ftrace_stack *fstack; struct stack_entry *entry; int stackidx; + void *ptr; /* * Add one, for this function and the call to save_stack_trace() @@ -3161,9 +3162,25 @@ static void __ftrace_trace_stack(struct trace_buffer *buffer, trace_ctx); if (!event) goto out; - entry = ring_buffer_event_data(event); + ptr = ring_buffer_event_data(event); + entry = ptr; + + /* + * For backward compatibility reasons, the entry->caller is an + * array of 8 slots to store the stack. This is also exported + * to user space. The amount allocated on the ring buffer actually + * holds enough for the stack specified by nr_entries. This will + * go into the location of entry->caller. Due to string fortifiers + * checking the size of the destination of memcpy() it triggers + * when it detects that size is greater than 8. To hide this from + * the fortifiers, we use "ptr" and pointer arithmetic to assign caller. + * + * The below is really just: + * memcpy(&entry->caller, fstack->calls, size); + */ + ptr += offsetof(typeof(*entry), caller); + memcpy(ptr, fstack->calls, size); - memcpy(&entry->caller, fstack->calls, size); entry->size = nr_entries; if (!call_filter_check_discard(call, entry, buffer, event)) -- cgit v1.2.3 From 8cc32a9bbf2934d90762d9de0187adcb5ad46a11 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Wed, 28 Jun 2023 11:19:26 -0700 Subject: kallsyms: strip LTO-only suffixes from promoted global functions Commit 6eb4bd92c1ce ("kallsyms: strip LTO suffixes from static functions") stripped all function/variable suffixes started with '.' regardless of whether those suffixes are generated at LTO mode or not. In fact, as far as I know, in LTO mode, when a static function/variable is promoted to the global scope, '.llvm.<...>' suffix is added. The existing mechanism breaks live patch for a LTO kernel even if no .llvm.<...> symbols are involved. For example, for the following kernel symbols: $ grep bpf_verifier_vlog /proc/kallsyms ffffffff81549f60 t bpf_verifier_vlog ffffffff8268b430 d bpf_verifier_vlog._entry ffffffff8282a958 d bpf_verifier_vlog._entry_ptr ffffffff82e12a1f d bpf_verifier_vlog.__already_done 'bpf_verifier_vlog' is a static function. '_entry', '_entry_ptr' and '__already_done' are static variables used inside 'bpf_verifier_vlog', so llvm promotes them to file-level static with prefix 'bpf_verifier_vlog.'. Note that the func-level to file-level static function promotion also happens without LTO. Given a symbol name 'bpf_verifier_vlog', with LTO kernel, current mechanism will return 4 symbols to live patch subsystem which current live patching subsystem cannot handle it. With non-LTO kernel, only one symbol is returned. In [1], we have a lengthy discussion, the suggestion is to separate two cases: (1). new symbols with suffix which are generated regardless of whether LTO is enabled or not, and (2). new symbols with suffix generated only when LTO is enabled. The cleanup_symbol_name() should only remove suffixes for case (2). Case (1) should not be changed so it can work uniformly with or without LTO. This patch removed LTO-only suffix '.llvm.<...>' so live patching and tracing should work the same way for non-LTO kernel. The cleanup_symbol_name() in scripts/kallsyms.c is also changed to have the same filtering pattern so both kernel and kallsyms tool have the same expectation on the order of symbols. [1] https://lore.kernel.org/live-patching/20230615170048.2382735-1-song@kernel.org/T/#u Fixes: 6eb4bd92c1ce ("kallsyms: strip LTO suffixes from static functions") Reported-by: Song Liu Signed-off-by: Yonghong Song Reviewed-by: Zhen Lei Reviewed-by: Nick Desaulniers Acked-by: Song Liu Link: https://lore.kernel.org/r/20230628181926.4102448-1-yhs@fb.com Signed-off-by: Kees Cook --- kernel/kallsyms.c | 5 ++--- scripts/kallsyms.c | 6 +++--- 2 files changed, 5 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index 7982cc9d497c..016d997131d4 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -174,11 +174,10 @@ static bool cleanup_symbol_name(char *s) * LLVM appends various suffixes for local functions and variables that * must be promoted to global scope as part of LTO. This can break * hooking of static functions with kprobes. '.' is not a valid - * character in an identifier in C. Suffixes observed: + * character in an identifier in C. Suffixes only in LLVM LTO observed: * - foo.llvm.[0-9a-f]+ - * - foo.[0-9a-f]+ */ - res = strchr(s, '.'); + res = strstr(s, ".llvm."); if (res) { *res = '\0'; return true; diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index d387c9381650..16c87938b316 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -349,10 +349,10 @@ static void cleanup_symbol_name(char *s) * ASCII[_] = 5f * ASCII[a-z] = 61,7a * - * As above, replacing '.' with '\0' does not affect the main sorting, - * but it helps us with subsorting. + * As above, replacing the first '.' in ".llvm." with '\0' does not + * affect the main sorting, but it helps us with subsorting. */ - p = strchr(s, '.'); + p = strstr(s, ".llvm."); if (p) *p = '\0'; } -- cgit v1.2.3 From 6018b585e8c6fa7d85d4b38d9ce49a5b67be7078 Mon Sep 17 00:00:00 2001 From: Mohamed Khalfella Date: Wed, 12 Jul 2023 22:30:21 +0000 Subject: tracing/histograms: Add histograms to hist_vars if they have referenced variables Hist triggers can have referenced variables without having direct variables fields. This can be the case if referenced variables are added for trigger actions. In this case the newly added references will not have field variables. Not taking such referenced variables into consideration can result in a bug where it would be possible to remove hist trigger with variables being refenced. This will result in a bug that is easily reproducable like so $ cd /sys/kernel/tracing $ echo 'synthetic_sys_enter char[] comm; long id' >> synthetic_events $ echo 'hist:keys=common_pid.execname,id.syscall:vals=hitcount:comm=common_pid.execname' >> events/raw_syscalls/sys_enter/trigger $ echo 'hist:keys=common_pid.execname,id.syscall:onmatch(raw_syscalls.sys_enter).synthetic_sys_enter($comm, id)' >> events/raw_syscalls/sys_enter/trigger $ echo '!hist:keys=common_pid.execname,id.syscall:vals=hitcount:comm=common_pid.execname' >> events/raw_syscalls/sys_enter/trigger [ 100.263533] ================================================================== [ 100.264634] BUG: KASAN: slab-use-after-free in resolve_var_refs+0xc7/0x180 [ 100.265520] Read of size 8 at addr ffff88810375d0f0 by task bash/439 [ 100.266320] [ 100.266533] CPU: 2 PID: 439 Comm: bash Not tainted 6.5.0-rc1 #4 [ 100.267277] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-20220807_005459-localhost 04/01/2014 [ 100.268561] Call Trace: [ 100.268902] [ 100.269189] dump_stack_lvl+0x4c/0x70 [ 100.269680] print_report+0xc5/0x600 [ 100.270165] ? resolve_var_refs+0xc7/0x180 [ 100.270697] ? kasan_complete_mode_report_info+0x80/0x1f0 [ 100.271389] ? resolve_var_refs+0xc7/0x180 [ 100.271913] kasan_report+0xbd/0x100 [ 100.272380] ? resolve_var_refs+0xc7/0x180 [ 100.272920] __asan_load8+0x71/0xa0 [ 100.273377] resolve_var_refs+0xc7/0x180 [ 100.273888] event_hist_trigger+0x749/0x860 [ 100.274505] ? kasan_save_stack+0x2a/0x50 [ 100.275024] ? kasan_set_track+0x29/0x40 [ 100.275536] ? __pfx_event_hist_trigger+0x10/0x10 [ 100.276138] ? ksys_write+0xd1/0x170 [ 100.276607] ? do_syscall_64+0x3c/0x90 [ 100.277099] ? entry_SYSCALL_64_after_hwframe+0x6e/0xd8 [ 100.277771] ? destroy_hist_data+0x446/0x470 [ 100.278324] ? event_hist_trigger_parse+0xa6c/0x3860 [ 100.278962] ? __pfx_event_hist_trigger_parse+0x10/0x10 [ 100.279627] ? __kasan_check_write+0x18/0x20 [ 100.280177] ? mutex_unlock+0x85/0xd0 [ 100.280660] ? __pfx_mutex_unlock+0x10/0x10 [ 100.281200] ? kfree+0x7b/0x120 [ 100.281619] ? ____kasan_slab_free+0x15d/0x1d0 [ 100.282197] ? event_trigger_write+0xac/0x100 [ 100.282764] ? __kasan_slab_free+0x16/0x20 [ 100.283293] ? __kmem_cache_free+0x153/0x2f0 [ 100.283844] ? sched_mm_cid_remote_clear+0xb1/0x250 [ 100.284550] ? __pfx_sched_mm_cid_remote_clear+0x10/0x10 [ 100.285221] ? event_trigger_write+0xbc/0x100 [ 100.285781] ? __kasan_check_read+0x15/0x20 [ 100.286321] ? __bitmap_weight+0x66/0xa0 [ 100.286833] ? _find_next_bit+0x46/0xe0 [ 100.287334] ? task_mm_cid_work+0x37f/0x450 [ 100.287872] event_triggers_call+0x84/0x150 [ 100.288408] trace_event_buffer_commit+0x339/0x430 [ 100.289073] ? ring_buffer_event_data+0x3f/0x60 [ 100.292189] trace_event_raw_event_sys_enter+0x8b/0xe0 [ 100.295434] syscall_trace_enter.constprop.0+0x18f/0x1b0 [ 100.298653] syscall_enter_from_user_mode+0x32/0x40 [ 100.301808] do_syscall_64+0x1a/0x90 [ 100.304748] entry_SYSCALL_64_after_hwframe+0x6e/0xd8 [ 100.307775] RIP: 0033:0x7f686c75c1cb [ 100.310617] Code: 73 01 c3 48 8b 0d 65 3c 10 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 21 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 35 3c 10 00 f7 d8 64 89 01 48 [ 100.317847] RSP: 002b:00007ffc60137a38 EFLAGS: 00000246 ORIG_RAX: 0000000000000021 [ 100.321200] RAX: ffffffffffffffda RBX: 000055f566469ea0 RCX: 00007f686c75c1cb [ 100.324631] RDX: 0000000000000001 RSI: 0000000000000001 RDI: 000000000000000a [ 100.328104] RBP: 00007ffc60137ac0 R08: 00007f686c818460 R09: 000000000000000a [ 100.331509] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000009 [ 100.334992] R13: 0000000000000007 R14: 000000000000000a R15: 0000000000000007 [ 100.338381] We hit the bug because when second hist trigger has was created has_hist_vars() returned false because hist trigger did not have variables. As a result of that save_hist_vars() was not called to add the trigger to trace_array->hist_vars. Later on when we attempted to remove the first histogram find_any_var_ref() failed to detect it is being used because it did not find the second trigger in hist_vars list. With this change we wait until trigger actions are created so we can take into consideration if hist trigger has variable references. Also, now we check the return value of save_hist_vars() and fail trigger creation if save_hist_vars() fails. Link: https://lore.kernel.org/linux-trace-kernel/20230712223021.636335-1-mkhalfella@purestorage.com Cc: stable@vger.kernel.org Fixes: 067fe038e70f6 ("tracing: Add variable reference handling to hist triggers") Signed-off-by: Mohamed Khalfella Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace_events_hist.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index b97d3ad832f1..c8c61381eba4 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -6663,13 +6663,15 @@ static int event_hist_trigger_parse(struct event_command *cmd_ops, if (get_named_trigger_data(trigger_data)) goto enable; - if (has_hist_vars(hist_data)) - save_hist_vars(hist_data); - ret = create_actions(hist_data); if (ret) goto out_unreg; + if (has_hist_vars(hist_data) || hist_data->n_var_refs) { + if (save_hist_vars(hist_data)) + goto out_unreg; + } + ret = tracing_map_init(hist_data->map); if (ret) goto out_unreg; -- cgit v1.2.3 From d5a821896360cc8b93a15bd888fabc858c038dc0 Mon Sep 17 00:00:00 2001 From: Zheng Yejian Date: Thu, 13 Jul 2023 22:14:35 +0800 Subject: tracing: Fix memory leak of iter->temp when reading trace_pipe kmemleak reports: unreferenced object 0xffff88814d14e200 (size 256): comm "cat", pid 336, jiffies 4294871818 (age 779.490s) hex dump (first 32 bytes): 04 00 01 03 00 00 00 00 08 00 00 00 00 00 00 00 ................ 0c d8 c8 9b ff ff ff ff 04 5a ca 9b ff ff ff ff .........Z...... backtrace: [] __kmalloc+0x4f/0x140 [] trace_find_next_entry+0xbb/0x1d0 [] trace_print_lat_context+0xaf/0x4e0 [] print_trace_line+0x3e0/0x950 [] tracing_read_pipe+0x2d9/0x5a0 [] vfs_read+0x143/0x520 [] ksys_read+0xbd/0x160 [] do_syscall_64+0x3f/0x90 [] entry_SYSCALL_64_after_hwframe+0x6e/0xd8 when reading file 'trace_pipe', 'iter->temp' is allocated or relocated in trace_find_next_entry() but not freed before 'trace_pipe' is closed. To fix it, free 'iter->temp' in tracing_release_pipe(). Link: https://lore.kernel.org/linux-trace-kernel/20230713141435.1133021-1-zhengyejian1@huawei.com Cc: stable@vger.kernel.org Fixes: ff895103a84ab ("tracing: Save off entry when peeking at next entry") Signed-off-by: Zheng Yejian Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 20122eeccf97..be847d45d81c 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6781,6 +6781,7 @@ static int tracing_release_pipe(struct inode *inode, struct file *file) free_cpumask_var(iter->started); kfree(iter->fmt); + kfree(iter->temp); mutex_destroy(&iter->mutex); kfree(iter); -- cgit v1.2.3 From d5f28bb1ce04636b285726ee2a5afa3a514025f4 Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Sat, 8 Jul 2023 01:38:03 +0900 Subject: fprobes: Add a comment why fprobe_kprobe_handler exits if kprobe is running Add a comment the reason why fprobe_kprobe_handler() exits if any other kprobe is running. Link: https://lore.kernel.org/all/168874788299.159442.2485957441413653858.stgit@devnote2/ Suggested-by: Steven Rostedt Link: https://lore.kernel.org/all/20230706120916.3c6abf15@gandalf.local.home/ Signed-off-by: Masami Hiramatsu (Google) Reviewed-by: Steven Rostedt (Google) --- kernel/trace/fprobe.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c index 2571f7f3d5f2..59321d22f43e 100644 --- a/kernel/trace/fprobe.c +++ b/kernel/trace/fprobe.c @@ -100,6 +100,12 @@ static void fprobe_kprobe_handler(unsigned long ip, unsigned long parent_ip, return; } + /* + * This user handler is shared with other kprobes and is not expected to be + * called recursively. So if any other kprobe handler is running, this will + * exit as kprobe does. See the section 'Share the callbacks with kprobes' + * in Documentation/trace/fprobe.rst for more information. + */ if (unlikely(kprobe_running())) { fp->nmissed++; goto recursion_unlock; -- cgit v1.2.3 From 66bcf65d6cf0ca6540e2341e88ee7ef02dbdda08 Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Tue, 11 Jul 2023 23:15:29 +0900 Subject: tracing/probes: Fix to avoid double count of the string length on the array If an array is specified with the ustring or symstr, the length of the strings are accumlated on both of 'ret' and 'total', which means the length is double counted. Just set the length to the 'ret' value for avoiding double counting. Link: https://lore.kernel.org/all/168908492917.123124.15076463491122036025.stgit@devnote2/ Reported-by: Dan Carpenter Closes: https://lore.kernel.org/all/8819b154-2ba1-43c3-98a2-cbde20892023@moroto.mountain/ Fixes: 88903c464321 ("tracing/probe: Add ustring type for user-space string") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) Reviewed-by: Steven Rostedt (Google) --- kernel/trace/trace_probe_tmpl.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h index 00707630788d..4735c5cb76fa 100644 --- a/kernel/trace/trace_probe_tmpl.h +++ b/kernel/trace/trace_probe_tmpl.h @@ -156,11 +156,11 @@ stage3: code++; goto array; case FETCH_OP_ST_USTRING: - ret += fetch_store_strlen_user(val + code->offset); + ret = fetch_store_strlen_user(val + code->offset); code++; goto array; case FETCH_OP_ST_SYMSTR: - ret += fetch_store_symstrlen(val + code->offset); + ret = fetch_store_symstrlen(val + code->offset); code++; goto array; default: -- cgit v1.2.3 From b41326b5e0f82e93592c4366359917b5d67b529f Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Tue, 11 Jul 2023 23:15:38 +0900 Subject: tracing/probes: Fix not to count error code to total length Fix not to count the error code (which is minus value) to the total used length of array, because it can mess up the return code of process_fetch_insn_bottom(). Also clear the 'ret' value because it will be used for calculating next data_loc entry. Link: https://lore.kernel.org/all/168908493827.123124.2175257289106364229.stgit@devnote2/ Reported-by: Dan Carpenter Closes: https://lore.kernel.org/all/8819b154-2ba1-43c3-98a2-cbde20892023@moroto.mountain/ Fixes: 9b960a38835f ("tracing: probeevent: Unify fetch_insn processing common part") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) Reviewed-by: Steven Rostedt (Google) --- kernel/trace/trace_probe_tmpl.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h index 4735c5cb76fa..ed9d57c6b041 100644 --- a/kernel/trace/trace_probe_tmpl.h +++ b/kernel/trace/trace_probe_tmpl.h @@ -204,6 +204,8 @@ stage3: array: /* the last stage: Loop on array */ if (code->op == FETCH_OP_LP_ARRAY) { + if (ret < 0) + ret = 0; total += ret; if (++i < code->param) { code = s3; -- cgit v1.2.3 From e38e2c6a9efc435f9de344b7c91f7697e01b47d5 Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Tue, 11 Jul 2023 23:15:48 +0900 Subject: tracing/probes: Fix to update dynamic data counter if fetcharg uses it Fix to update dynamic data counter ('dyndata') and max length ('maxlen') only if the fetcharg uses the dynamic data. Also get out arg->dynamic from unlikely(). This makes dynamic data address wrong if process_fetch_insn() returns error on !arg->dynamic case. Link: https://lore.kernel.org/all/168908494781.123124.8160245359962103684.stgit@devnote2/ Suggested-by: Steven Rostedt Link: https://lore.kernel.org/all/20230710233400.5aaf024e@gandalf.local.home/ Fixes: 9178412ddf5a ("tracing: probeevent: Return consumed bytes of dynamic area") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) Reviewed-by: Steven Rostedt (Google) --- kernel/trace/trace_probe_tmpl.h | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h index ed9d57c6b041..185da001f4c3 100644 --- a/kernel/trace/trace_probe_tmpl.h +++ b/kernel/trace/trace_probe_tmpl.h @@ -267,11 +267,13 @@ store_trace_args(void *data, struct trace_probe *tp, void *rec, if (unlikely(arg->dynamic)) *dl = make_data_loc(maxlen, dyndata - base); ret = process_fetch_insn(arg->code, rec, dl, base); - if (unlikely(ret < 0 && arg->dynamic)) { - *dl = make_data_loc(0, dyndata - base); - } else { - dyndata += ret; - maxlen -= ret; + if (arg->dynamic) { + if (unlikely(ret < 0)) { + *dl = make_data_loc(0, dyndata - base); + } else { + dyndata += ret; + maxlen -= ret; + } } } } -- cgit v1.2.3 From 4ed8f337dee32df71435689c19d22e4ee846e15a Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Tue, 11 Jul 2023 23:15:57 +0900 Subject: Revert "tracing: Add "(fault)" name injection to kernel probes" This reverts commit 2e9906f84fc7c99388bb7123ade167250d50f1c0. It was turned out that commit 2e9906f84fc7 ("tracing: Add "(fault)" name injection to kernel probes") did not work correctly and probe events still show just '(fault)' (instead of '"(fault)"'). Also, current '(fault)' is more explicit that it faulted. This also moves FAULT_STRING macro to trace.h so that synthetic event can keep using it, and uses it in trace_probe.c too. Link: https://lore.kernel.org/all/168908495772.123124.1250788051922100079.stgit@devnote2/ Link: https://lore.kernel.org/all/20230706230642.3793a593@rorschach.local.home/ Cc: stable@vger.kernel.org Cc: Andrew Morton Cc: Tom Zanussi Signed-off-by: Masami Hiramatsu (Google) Reviewed-by: Steven Rostedt (Google) --- kernel/trace/trace.h | 2 ++ kernel/trace/trace_probe.c | 2 +- kernel/trace/trace_probe_kernel.h | 31 ++++++------------------------- 3 files changed, 9 insertions(+), 26 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 79bdefe9261b..eee1f3ca4749 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -113,6 +113,8 @@ enum trace_type { #define MEM_FAIL(condition, fmt, ...) \ DO_ONCE_LITE_IF(condition, pr_err, "ERROR: " fmt, ##__VA_ARGS__) +#define FAULT_STRING "(fault)" + #define HIST_STACKTRACE_DEPTH 16 #define HIST_STACKTRACE_SIZE (HIST_STACKTRACE_DEPTH * sizeof(unsigned long)) #define HIST_STACKTRACE_SKIP 5 diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 2d2616678295..591399ddcee5 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -65,7 +65,7 @@ int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent) int len = *(u32 *)data >> 16; if (!len) - trace_seq_puts(s, "(fault)"); + trace_seq_puts(s, FAULT_STRING); else trace_seq_printf(s, "\"%s\"", (const char *)get_loc_data(data, ent)); diff --git a/kernel/trace/trace_probe_kernel.h b/kernel/trace/trace_probe_kernel.h index c4e1d4c03a85..6deae2ce34f8 100644 --- a/kernel/trace/trace_probe_kernel.h +++ b/kernel/trace/trace_probe_kernel.h @@ -2,8 +2,6 @@ #ifndef __TRACE_PROBE_KERNEL_H_ #define __TRACE_PROBE_KERNEL_H_ -#define FAULT_STRING "(fault)" - /* * This depends on trace_probe.h, but can not include it due to * the way trace_probe_tmpl.h is used by trace_kprobe.c and trace_eprobe.c. @@ -15,16 +13,8 @@ static nokprobe_inline int fetch_store_strlen_user(unsigned long addr) { const void __user *uaddr = (__force const void __user *)addr; - int ret; - ret = strnlen_user_nofault(uaddr, MAX_STRING_SIZE); - /* - * strnlen_user_nofault returns zero on fault, insert the - * FAULT_STRING when that occurs. - */ - if (ret <= 0) - return strlen(FAULT_STRING) + 1; - return ret; + return strnlen_user_nofault(uaddr, MAX_STRING_SIZE); } /* Return the length of string -- including null terminal byte */ @@ -44,18 +34,7 @@ fetch_store_strlen(unsigned long addr) len++; } while (c && ret == 0 && len < MAX_STRING_SIZE); - /* For faults, return enough to hold the FAULT_STRING */ - return (ret < 0) ? strlen(FAULT_STRING) + 1 : len; -} - -static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void *base, int len) -{ - if (ret >= 0) { - *(u32 *)dest = make_data_loc(ret, __dest - base); - } else { - strscpy(__dest, FAULT_STRING, len); - ret = strlen(__dest) + 1; - } + return (ret < 0) ? ret : len; } /* @@ -76,7 +55,8 @@ fetch_store_string_user(unsigned long addr, void *dest, void *base) __dest = get_loc_data(dest, base); ret = strncpy_from_user_nofault(__dest, uaddr, maxlen); - set_data_loc(ret, dest, __dest, base, maxlen); + if (ret >= 0) + *(u32 *)dest = make_data_loc(ret, __dest - base); return ret; } @@ -107,7 +87,8 @@ fetch_store_string(unsigned long addr, void *dest, void *base) * probing. */ ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen); - set_data_loc(ret, dest, __dest, base, maxlen); + if (ret >= 0) + *(u32 *)dest = make_data_loc(ret, __dest - base); return ret; } -- cgit v1.2.3 From 797311bce5c2ac90b8d65e357603cfd410d36ebb Mon Sep 17 00:00:00 2001 From: "Masami Hiramatsu (Google)" Date: Tue, 11 Jul 2023 23:16:07 +0900 Subject: tracing/probes: Fix to record 0-length data_loc in fetch_store_string*() if fails Fix to record 0-length data to data_loc in fetch_store_string*() if it fails to get the string data. Currently those expect that the data_loc is updated by store_trace_args() if it returns the error code. However, that does not work correctly if the argument is an array of strings. In that case, store_trace_args() only clears the first entry of the array (which may have no error) and leaves other entries. So it should be cleared by fetch_store_string*() itself. Also, 'dyndata' and 'maxlen' in store_trace_args() should be updated only if it is used (ret > 0 and argument is a dynamic data.) Link: https://lore.kernel.org/all/168908496683.123124.4761206188794205601.stgit@devnote2/ Fixes: 40b53b771806 ("tracing: probeevent: Add array type support") Cc: stable@vger.kernel.org Reviewed-by: Steven Rostedt (Google) Signed-off-by: Masami Hiramatsu (Google) --- kernel/trace/trace_probe_kernel.h | 13 +++++++++---- kernel/trace/trace_probe_tmpl.h | 10 +++------- kernel/trace/trace_uprobe.c | 3 ++- 3 files changed, 14 insertions(+), 12 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_probe_kernel.h b/kernel/trace/trace_probe_kernel.h index 6deae2ce34f8..bb723eefd7b7 100644 --- a/kernel/trace/trace_probe_kernel.h +++ b/kernel/trace/trace_probe_kernel.h @@ -37,6 +37,13 @@ fetch_store_strlen(unsigned long addr) return (ret < 0) ? ret : len; } +static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void *base) +{ + if (ret < 0) + ret = 0; + *(u32 *)dest = make_data_loc(ret, __dest - base); +} + /* * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf * with max length and relative data location. @@ -55,8 +62,7 @@ fetch_store_string_user(unsigned long addr, void *dest, void *base) __dest = get_loc_data(dest, base); ret = strncpy_from_user_nofault(__dest, uaddr, maxlen); - if (ret >= 0) - *(u32 *)dest = make_data_loc(ret, __dest - base); + set_data_loc(ret, dest, __dest, base); return ret; } @@ -87,8 +93,7 @@ fetch_store_string(unsigned long addr, void *dest, void *base) * probing. */ ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen); - if (ret >= 0) - *(u32 *)dest = make_data_loc(ret, __dest - base); + set_data_loc(ret, dest, __dest, base); return ret; } diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h index 185da001f4c3..3935b347f874 100644 --- a/kernel/trace/trace_probe_tmpl.h +++ b/kernel/trace/trace_probe_tmpl.h @@ -267,13 +267,9 @@ store_trace_args(void *data, struct trace_probe *tp, void *rec, if (unlikely(arg->dynamic)) *dl = make_data_loc(maxlen, dyndata - base); ret = process_fetch_insn(arg->code, rec, dl, base); - if (arg->dynamic) { - if (unlikely(ret < 0)) { - *dl = make_data_loc(0, dyndata - base); - } else { - dyndata += ret; - maxlen -= ret; - } + if (arg->dynamic && likely(ret > 0)) { + dyndata += ret; + maxlen -= ret; } } } diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index 8b92e34ff0c8..7b47e9a2c010 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -170,7 +170,8 @@ fetch_store_string(unsigned long addr, void *dest, void *base) */ ret++; *(u32 *)dest = make_data_loc(ret, (void *)dst - base); - } + } else + *(u32 *)dest = make_data_loc(0, (void *)dst - base); return ret; } -- cgit v1.2.3