From c2d3f25dda016d9697c5416810d4528770f0a281 Mon Sep 17 00:00:00 2001 From: Ralf Baechle Date: Wed, 9 Oct 2013 14:08:09 +0200 Subject: uprobes: Remove the wrong __weak attribute linux/uprobes.h declares arch_uprobe_skip_sstep() as a weak function. But as there is no definition of generic version so when trying to build uprobes for an architecture that doesn't yet have a arch_uprobe_skip_sstep() implementation, the vmlinux will try to call arch_uprobe_skip_sstep() somehwere in Stupidhistan leading to a system crash. We rather want a proper link error so remove arch_uprobe_skip_sstep(). Signed-off-by: Ralf Baechle Signed-off-by: Oleg Nesterov --- include/linux/uprobes.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/uprobes.h') diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index 06f28beed7c2..e6fba627ea45 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -123,7 +123,7 @@ extern int uprobe_post_sstep_notifier(struct pt_regs *regs); extern int uprobe_pre_sstep_notifier(struct pt_regs *regs); extern void uprobe_notify_resume(struct pt_regs *regs); extern bool uprobe_deny_signal(void); -extern bool __weak arch_uprobe_skip_sstep(struct arch_uprobe *aup, struct pt_regs *regs); +extern bool arch_uprobe_skip_sstep(struct arch_uprobe *aup, struct pt_regs *regs); extern void uprobe_clear_state(struct mm_struct *mm); #else /* !CONFIG_UPROBES */ struct uprobes_state { -- cgit v1.2.3 From 3ab679661721b1ec2aaad99a801870ed59ab1110 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Wed, 16 Oct 2013 19:39:37 +0200 Subject: uprobes: Teach uprobe_copy_process() to handle CLONE_VFORK uprobe_copy_process() does nothing if the child shares ->mm with the forking process, but there is a special case: CLONE_VFORK. In this case it would be more correct to do dup_utask() but avoid dup_xol(). This is not that important, the child should not unwind its stack too much, this can corrupt the parent's stack, but at least we need this to allow to ret-probe __vfork() itself. Note: in theory, it would be better to check task_pt_regs(p)->sp instead of CLONE_VFORK, we need to dup_utask() if and only if the child can return from the function called by the parent. But this needs the arch-dependant helper, and I think that nobody actually does clone(same_stack, CLONE_VM). Reported-by: Martin Cermak Reported-by: David Smith Signed-off-by: Oleg Nesterov --- include/linux/uprobes.h | 4 ++-- kernel/events/uprobes.c | 10 ++++++++-- kernel/fork.c | 2 +- 3 files changed, 11 insertions(+), 5 deletions(-) (limited to 'include/linux/uprobes.h') diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index e6fba627ea45..9e0d5a6fe7a8 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -117,7 +117,7 @@ extern void uprobe_start_dup_mmap(void); extern void uprobe_end_dup_mmap(void); extern void uprobe_dup_mmap(struct mm_struct *oldmm, struct mm_struct *newmm); extern void uprobe_free_utask(struct task_struct *t); -extern void uprobe_copy_process(struct task_struct *t); +extern void uprobe_copy_process(struct task_struct *t, unsigned long flags); extern unsigned long __weak uprobe_get_swbp_addr(struct pt_regs *regs); extern int uprobe_post_sstep_notifier(struct pt_regs *regs); extern int uprobe_pre_sstep_notifier(struct pt_regs *regs); @@ -174,7 +174,7 @@ static inline unsigned long uprobe_get_swbp_addr(struct pt_regs *regs) static inline void uprobe_free_utask(struct task_struct *t) { } -static inline void uprobe_copy_process(struct task_struct *t) +static inline void uprobe_copy_process(struct task_struct *t, unsigned long flags) { } static inline void uprobe_clear_state(struct mm_struct *mm) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 9f282e14925d..ae9e1d2ef256 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1415,7 +1415,7 @@ static void dup_xol_work(struct callback_head *work) /* * Called in context of a new clone/fork from copy_process. */ -void uprobe_copy_process(struct task_struct *t) +void uprobe_copy_process(struct task_struct *t, unsigned long flags) { struct uprobe_task *utask = current->utask; struct mm_struct *mm = current->mm; @@ -1424,7 +1424,10 @@ void uprobe_copy_process(struct task_struct *t) t->utask = NULL; - if (mm == t->mm || !utask || !utask->return_instances) + if (!utask || !utask->return_instances) + return; + + if (mm == t->mm && !(flags & CLONE_VFORK)) return; if (dup_utask(t, utask)) @@ -1435,6 +1438,9 @@ void uprobe_copy_process(struct task_struct *t) if (!area) return uprobe_warn(t, "dup xol area"); + if (mm == t->mm) + return; + /* TODO: move it into the union in uprobe_task */ work = kmalloc(sizeof(*work), GFP_KERNEL); if (!work) diff --git a/kernel/fork.c b/kernel/fork.c index d3603b81246b..8531609b6a82 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1489,7 +1489,7 @@ static struct task_struct *copy_process(unsigned long clone_flags, perf_event_fork(p); trace_task_newtask(p, clone_flags); - uprobe_copy_process(p); + uprobe_copy_process(p, clone_flags); return p; -- cgit v1.2.3 From 3820b4d2789f5166afdb136bb14f93166e6cfbc2 Mon Sep 17 00:00:00 2001 From: "David A. Long" Date: Tue, 15 Oct 2013 17:04:16 -0400 Subject: uprobes: Move function declarations out of arch Move the function declarations from the arch headers to the common header, since only the function bodies are architecture-specific. These changes are from Vincent Rabin's uprobes patch. [ oleg: update arch/powerpc/include/asm/uprobes.h ] Signed-off-by: Rabin Vincent Signed-off-by: David A. Long Signed-off-by: Oleg Nesterov --- arch/powerpc/include/asm/uprobes.h | 7 ------- arch/x86/include/asm/uprobes.h | 7 ------- include/linux/uprobes.h | 8 ++++++++ 3 files changed, 8 insertions(+), 14 deletions(-) (limited to 'include/linux/uprobes.h') diff --git a/arch/powerpc/include/asm/uprobes.h b/arch/powerpc/include/asm/uprobes.h index 23016020915e..b6fc3178372a 100644 --- a/arch/powerpc/include/asm/uprobes.h +++ b/arch/powerpc/include/asm/uprobes.h @@ -45,11 +45,4 @@ struct arch_uprobe_task { unsigned long saved_trap_nr; }; -extern int arch_uprobe_analyze_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long addr); -extern int arch_uprobe_pre_xol(struct arch_uprobe *aup, struct pt_regs *regs); -extern int arch_uprobe_post_xol(struct arch_uprobe *aup, struct pt_regs *regs); -extern bool arch_uprobe_xol_was_trapped(struct task_struct *tsk); -extern int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, void *data); -extern void arch_uprobe_abort_xol(struct arch_uprobe *aup, struct pt_regs *regs); -extern unsigned long arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs *regs); #endif /* _ASM_UPROBES_H */ diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h index 6e5197910fd8..b20b4d68b934 100644 --- a/arch/x86/include/asm/uprobes.h +++ b/arch/x86/include/asm/uprobes.h @@ -49,11 +49,4 @@ struct arch_uprobe_task { unsigned int saved_tf; }; -extern int arch_uprobe_analyze_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long addr); -extern int arch_uprobe_pre_xol(struct arch_uprobe *aup, struct pt_regs *regs); -extern int arch_uprobe_post_xol(struct arch_uprobe *aup, struct pt_regs *regs); -extern bool arch_uprobe_xol_was_trapped(struct task_struct *tsk); -extern int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, void *data); -extern void arch_uprobe_abort_xol(struct arch_uprobe *aup, struct pt_regs *regs); -extern unsigned long arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs *regs); #endif /* _ASM_UPROBES_H */ diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index 9e0d5a6fe7a8..28473e3f6068 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -30,6 +30,7 @@ struct vm_area_struct; struct mm_struct; struct inode; +struct notifier_block; #ifdef CONFIG_ARCH_SUPPORTS_UPROBES # include @@ -125,6 +126,13 @@ extern void uprobe_notify_resume(struct pt_regs *regs); extern bool uprobe_deny_signal(void); extern bool arch_uprobe_skip_sstep(struct arch_uprobe *aup, struct pt_regs *regs); extern void uprobe_clear_state(struct mm_struct *mm); +extern int arch_uprobe_analyze_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long addr); +extern int arch_uprobe_pre_xol(struct arch_uprobe *aup, struct pt_regs *regs); +extern int arch_uprobe_post_xol(struct arch_uprobe *aup, struct pt_regs *regs); +extern bool arch_uprobe_xol_was_trapped(struct task_struct *tsk); +extern int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, void *data); +extern void arch_uprobe_abort_xol(struct arch_uprobe *aup, struct pt_regs *regs); +extern unsigned long arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs *regs); #else /* !CONFIG_UPROBES */ struct uprobes_state { }; -- cgit v1.2.3 From f72d41fa902fb19a9b63028202a400b0ce497491 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 5 Nov 2013 19:50:39 +0100 Subject: uprobes: Export write_opcode() as uprobe_write_opcode() set_swbp() and set_orig_insn() are __weak, but this is pointless because write_opcode() is static. Export write_opcode() as uprobe_write_opcode() for the upcoming arm port, this way it can actually override set_swbp() and use __opcode_to_mem_arm(bpinsn) instead if UPROBE_SWBP_INSN. Signed-off-by: Oleg Nesterov --- include/linux/uprobes.h | 1 + kernel/events/uprobes.c | 14 +++++++------- 2 files changed, 8 insertions(+), 7 deletions(-) (limited to 'include/linux/uprobes.h') diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index 28473e3f6068..319eae70fe84 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -109,6 +109,7 @@ extern int __weak set_swbp(struct arch_uprobe *aup, struct mm_struct *mm, unsign extern int __weak set_orig_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr); extern bool __weak is_swbp_insn(uprobe_opcode_t *insn); extern bool __weak is_trap_insn(uprobe_opcode_t *insn); +extern int uprobe_write_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t); extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc); extern int uprobe_apply(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, bool); extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc); diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index fbcff61b5099..0ac346ae5edb 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -245,12 +245,12 @@ static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t * the architecture. If an arch has variable length instruction and the * breakpoint instruction is not of the smallest length instruction * supported by that architecture then we need to modify is_trap_at_addr and - * write_opcode accordingly. This would never be a problem for archs that - * have fixed length instructions. + * uprobe_write_opcode accordingly. This would never be a problem for archs + * that have fixed length instructions. */ /* - * write_opcode - write the opcode at a given virtual address. + * uprobe_write_opcode - write the opcode at a given virtual address. * @mm: the probed process address space. * @vaddr: the virtual address to store the opcode. * @opcode: opcode to be written at @vaddr. @@ -261,7 +261,7 @@ static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t * For mm @mm, write the opcode at @vaddr. * Return 0 (success) or a negative errno. */ -static int write_opcode(struct mm_struct *mm, unsigned long vaddr, +int uprobe_write_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t opcode) { struct page *old_page, *new_page; @@ -315,7 +315,7 @@ put_old: */ int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr) { - return write_opcode(mm, vaddr, UPROBE_SWBP_INSN); + return uprobe_write_opcode(mm, vaddr, UPROBE_SWBP_INSN); } /** @@ -330,7 +330,7 @@ int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned int __weak set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr) { - return write_opcode(mm, vaddr, *(uprobe_opcode_t *)auprobe->insn); + return uprobe_write_opcode(mm, vaddr, *(uprobe_opcode_t *)auprobe->insn); } static int match_uprobe(struct uprobe *l, struct uprobe *r) @@ -577,7 +577,7 @@ static int prepare_uprobe(struct uprobe *uprobe, struct file *file, if (ret) goto out; - /* write_opcode() assumes we don't cross page boundary */ + /* uprobe_write_opcode() assumes we don't cross page boundary */ BUG_ON((uprobe->offset & ~PAGE_MASK) + UPROBE_SWBP_INSN_SIZE > PAGE_SIZE); -- cgit v1.2.3