From c3a6cf19e695c8b0a9bf8b5933f863e12d878b7c Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Fri, 18 Oct 2019 10:31:43 +0100 Subject: export: avoid code duplication in include/linux/export.h include/linux/export.h has lots of code duplication between EXPORT_SYMBOL and EXPORT_SYMBOL_NS. To improve the maintainability and readability, unify the implementation. When the symbol has no namespace, pass the empty string "" to the 'ns' parameter. The drawback of this change is, it grows the code size. When the symbol has no namespace, sym->namespace was previously NULL, but it is now an empty string "". So, it increases 1 byte for every no namespace EXPORT_SYMBOL. A typical kernel configuration has 10K exported symbols, so it increases 10KB in rough estimation. I did not come up with a good idea to refactor it without increasing the code size. I am not sure how big a deal it is, but at least include/linux/export.h looks nicer. Reviewed-by: Greg Kroah-Hartman Signed-off-by: Masahiro Yamada [maennich: rebase on top of 3 fixes for the namespace feature] Signed-off-by: Matthias Maennich Signed-off-by: Jessica Yu --- kernel/module.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index ff2d7359a418..26c13173da3d 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1400,7 +1400,7 @@ static int verify_namespace_is_imported(const struct load_info *info, char *imported_namespace; namespace = kernel_symbol_namespace(sym); - if (namespace) { + if (namespace && namespace[0]) { imported_namespace = get_modinfo(info, "import_ns"); while (imported_namespace) { if (strcmp(namespace, imported_namespace) == 0) -- cgit v1.2.3 From e585e6469d6f476b82aa148dc44aaf7ae269a4e2 Mon Sep 17 00:00:00 2001 From: Divya Indi Date: Wed, 14 Aug 2019 10:55:24 -0700 Subject: tracing: Verify if trace array exists before destroying it. A trace array can be destroyed from userspace or kernel. Verify if the trace array exists before proceeding to destroy/remove it. Link: http://lkml.kernel.org/r/1565805327-579-3-git-send-email-divya.indi@oracle.com Reviewed-by: Aruna Ramakrishna Signed-off-by: Divya Indi [ Removed unneeded braces ] Signed-off-by: Steven Rostedt (VMware) --- kernel/module.c | 6 +++++- kernel/trace/trace.c | 15 ++++++++++++--- 2 files changed, 17 insertions(+), 4 deletions(-) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index ff2d7359a418..6e2fd40a6ed9 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -3728,7 +3728,6 @@ static int complete_formation(struct module *mod, struct load_info *info) module_enable_ro(mod, false); module_enable_nx(mod); - module_enable_x(mod); /* Mark state as coming so strong_try_module_get() ignores us, * but kallsyms etc. can see us. */ @@ -3751,6 +3750,11 @@ static int prepare_coming_module(struct module *mod) if (err) return err; + /* Make module executable after ftrace is enabled */ + mutex_lock(&module_mutex); + module_enable_x(mod); + mutex_unlock(&module_mutex); + blocking_notifier_call_chain(&module_notify_list, MODULE_STATE_COMING, mod); return 0; diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index db7d06a26861..fa4f742fc449 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -8556,17 +8556,26 @@ static int __remove_instance(struct trace_array *tr) return 0; } -int trace_array_destroy(struct trace_array *tr) +int trace_array_destroy(struct trace_array *this_tr) { + struct trace_array *tr; int ret; - if (!tr) + if (!this_tr) return -EINVAL; mutex_lock(&event_mutex); mutex_lock(&trace_types_lock); - ret = __remove_instance(tr); + ret = -ENODEV; + + /* Making sure trace array exists before destroying it. */ + list_for_each_entry(tr, &ftrace_trace_arrays, list) { + if (tr == this_tr) { + ret = __remove_instance(tr); + break; + } + } mutex_unlock(&trace_types_lock); mutex_unlock(&event_mutex); -- cgit v1.2.3 From 5d603311615f612320bb77bd2a82553ef1ced5b7 Mon Sep 17 00:00:00 2001 From: Konstantin Khorenko Date: Wed, 13 Nov 2019 12:29:50 +0300 Subject: kernel/module.c: wakeup processes in module_wq on module unload Fix the race between load and unload a kernel module. sys_delete_module() try_stop_module() mod->state = _GOING add_unformed_module() old = find_module_all() (old->state == _GOING => wait_event_interruptible()) During pre-condition finished_loading() rets 0 schedule() (never gets waken up later) free_module() mod->state = _UNFORMED list_del_rcu(&mod->list) (dels mod from "modules" list) return The race above leads to modprobe hanging forever on loading a module. Error paths on loading module call wake_up_all(&module_wq) after freeing module, so let's do the same on straight module unload. Fixes: 6e6de3dee51a ("kernel/module.c: Only return -EEXIST for modules that have finished loading") Reviewed-by: Prarit Bhargava Signed-off-by: Konstantin Khorenko Signed-off-by: Jessica Yu --- kernel/module.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index 26c13173da3d..bdbf95726cb7 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1033,6 +1033,8 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user, strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module)); free_module(mod); + /* someone could wait for the module in add_unformed_module() */ + wake_up_all(&module_wq); return 0; out: mutex_unlock(&module_mutex); -- cgit v1.2.3