From e65cefe87beda627c0bfba39b387ee4bffedc93c Mon Sep 17 00:00:00 2001 From: Adrian Bunk Date: Fri, 3 Feb 2006 03:03:42 -0800 Subject: [PATCH] kernel/kprobes.c: fix a warning #ifndef ARCH_SUPPORTS_KRETPROBES kernel/kprobes.c:353: warning: 'pre_handler_kretprobe' defined but not used Signed-off-by: Adrian Bunk Acked-by: Ananth N Mavinakayanahalli Acked-by: "Keshavamurthy, Anil S" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kprobes.c | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-) (limited to 'kernel/kprobes.c') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 3ea6325228da..95ad7f8db3d6 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -344,23 +344,6 @@ void __kprobes kprobe_flush_task(struct task_struct *tk) spin_unlock_irqrestore(&kretprobe_lock, flags); } -/* - * This kprobe pre_handler is registered with every kretprobe. When probe - * hits it will set up the return probe. - */ -static int __kprobes pre_handler_kretprobe(struct kprobe *p, - struct pt_regs *regs) -{ - struct kretprobe *rp = container_of(p, struct kretprobe, kp); - unsigned long flags = 0; - - /*TODO: consider to only swap the RA after the last pre_handler fired */ - spin_lock_irqsave(&kretprobe_lock, flags); - arch_prepare_kretprobe(rp, regs); - spin_unlock_irqrestore(&kretprobe_lock, flags); - return 0; -} - static inline void free_rp_inst(struct kretprobe *rp) { struct kretprobe_instance *ri; @@ -578,6 +561,23 @@ void __kprobes unregister_jprobe(struct jprobe *jp) #ifdef ARCH_SUPPORTS_KRETPROBES +/* + * This kprobe pre_handler is registered with every kretprobe. When probe + * hits it will set up the return probe. + */ +static int __kprobes pre_handler_kretprobe(struct kprobe *p, + struct pt_regs *regs) +{ + struct kretprobe *rp = container_of(p, struct kretprobe, kp); + unsigned long flags = 0; + + /*TODO: consider to only swap the RA after the last pre_handler fired */ + spin_lock_irqsave(&kretprobe_lock, flags); + arch_prepare_kretprobe(rp, regs); + spin_unlock_irqrestore(&kretprobe_lock, flags); + return 0; +} + int __kprobes register_kretprobe(struct kretprobe *rp) { int ret = 0; -- cgit v1.2.2 From 278ff9537030bbb292b33504f5e1f6e0126793eb Mon Sep 17 00:00:00 2001 From: Ananth N Mavinakayanahalli Date: Fri, 3 Feb 2006 03:03:43 -0800 Subject: [PATCH] Kprobes: Fix deadlock in function-return probes When two function-return probes are inserted on kfree()[1] and the second on say, sys_link()[2], and later [2] is unregistered, we have a deadlock as kfree is called with the kretprobe_lock held and the function-return probe on kfree will also try to grab the same lock. However, we can move the kfree() during unregistration to outside the spinlock as we are sure that no instances from the free list will be used after synchronized_sched() returns during the unregistration process. Thanks to Masami Hiramatsu for spotting this. Signed-off-by: Ananth N Mavinakayanahalli Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kprobes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/kprobes.c') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 95ad7f8db3d6..fef1af8a73ce 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -631,12 +631,12 @@ void __kprobes unregister_kretprobe(struct kretprobe *rp) unregister_kprobe(&rp->kp); /* No race here */ spin_lock_irqsave(&kretprobe_lock, flags); - free_rp_inst(rp); while ((ri = get_used_rp_inst(rp)) != NULL) { ri->rp = NULL; hlist_del(&ri->uflist); } spin_unlock_irqrestore(&kretprobe_lock, flags); + free_rp_inst(rp); } static int __init init_kprobes(void) -- cgit v1.2.2