From: bibo,mao Date: Mon, 2 Oct 2006 09:17:35 +0000 (-0700) Subject: [PATCH] kretprobe spinlock deadlock patch X-Git-Tag: v2.6.19-rc1~454 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=99219a3fbc2dcf2eaa954f7b2ac27299fd7894cd;p=linux-2.6 [PATCH] kretprobe spinlock deadlock patch kprobe_flush_task() possibly calls kfree function during holding kretprobe_lock spinlock, if kfree function is probed by kretprobe that will incur spinlock deadlock. This patch moves kfree function out scope of kretprobe_lock. Signed-off-by: bibo, mao Signed-off-by: Ananth N Mavinakayanahalli Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c index 7a97544f15..d98e44b16f 100644 --- a/arch/i386/kernel/kprobes.c +++ b/arch/i386/kernel/kprobes.c @@ -396,11 +396,12 @@ no_kprobe: fastcall void *__kprobes trampoline_handler(struct pt_regs *regs) { struct kretprobe_instance *ri = NULL; - struct hlist_head *head; + struct hlist_head *head, empty_rp; struct hlist_node *node, *tmp; unsigned long flags, orig_ret_address = 0; unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline; + INIT_HLIST_HEAD(&empty_rp); spin_lock_irqsave(&kretprobe_lock, flags); head = kretprobe_inst_table_head(current); @@ -429,7 +430,7 @@ fastcall void *__kprobes trampoline_handler(struct pt_regs *regs) } orig_ret_address = (unsigned long)ri->ret_addr; - recycle_rp_inst(ri); + recycle_rp_inst(ri, &empty_rp); if (orig_ret_address != trampoline_address) /* @@ -444,6 +445,10 @@ fastcall void *__kprobes trampoline_handler(struct pt_regs *regs) spin_unlock_irqrestore(&kretprobe_lock, flags); + hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { + hlist_del(&ri->hlist); + kfree(ri); + } return (void*)orig_ret_address; } diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c index 9c9c8fcdfb..51217d6328 100644 --- a/arch/ia64/kernel/kprobes.c +++ b/arch/ia64/kernel/kprobes.c @@ -338,12 +338,13 @@ static void kretprobe_trampoline(void) int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) { struct kretprobe_instance *ri = NULL; - struct hlist_head *head; + struct hlist_head *head, empty_rp; struct hlist_node *node, *tmp; unsigned long flags, orig_ret_address = 0; unsigned long trampoline_address = ((struct fnptr *)kretprobe_trampoline)->ip; + INIT_HLIST_HEAD(&empty_rp); spin_lock_irqsave(&kretprobe_lock, flags); head = kretprobe_inst_table_head(current); @@ -369,7 +370,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) ri->rp->handler(ri, regs); orig_ret_address = (unsigned long)ri->ret_addr; - recycle_rp_inst(ri); + recycle_rp_inst(ri, &empty_rp); if (orig_ret_address != trampoline_address) /* @@ -387,6 +388,10 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) spin_unlock_irqrestore(&kretprobe_lock, flags); preempt_enable_no_resched(); + hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { + hlist_del(&ri->hlist); + kfree(ri); + } /* * By returning a non-zero value, we are telling * kprobe_handler() that we don't want the post_handler diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index 46d2fd0e57..7b8d12b902 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -260,11 +260,12 @@ void kretprobe_trampoline_holder(void) int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) { struct kretprobe_instance *ri = NULL; - struct hlist_head *head; + struct hlist_head *head, empty_rp; struct hlist_node *node, *tmp; unsigned long flags, orig_ret_address = 0; unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline; + INIT_HLIST_HEAD(&empty_rp); spin_lock_irqsave(&kretprobe_lock, flags); head = kretprobe_inst_table_head(current); @@ -290,7 +291,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) ri->rp->handler(ri, regs); orig_ret_address = (unsigned long)ri->ret_addr; - recycle_rp_inst(ri); + recycle_rp_inst(ri, &empty_rp); if (orig_ret_address != trampoline_address) /* @@ -308,6 +309,10 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) spin_unlock_irqrestore(&kretprobe_lock, flags); preempt_enable_no_resched(); + hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { + hlist_del(&ri->hlist); + kfree(ri); + } /* * By returning a non-zero value, we are telling * kprobe_handler() that we don't want the post_handler diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c index ca28fb0b37..4d9ff5ce4c 100644 --- a/arch/s390/kernel/kprobes.c +++ b/arch/s390/kernel/kprobes.c @@ -369,11 +369,12 @@ void __kprobes kretprobe_trampoline_holder(void) int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) { struct kretprobe_instance *ri = NULL; - struct hlist_head *head; + struct hlist_head *head, empty_rp; struct hlist_node *node, *tmp; unsigned long flags, orig_ret_address = 0; unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline; + INIT_HLIST_HEAD(&empty_rp); spin_lock_irqsave(&kretprobe_lock, flags); head = kretprobe_inst_table_head(current); @@ -399,7 +400,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) ri->rp->handler(ri, regs); orig_ret_address = (unsigned long)ri->ret_addr; - recycle_rp_inst(ri); + recycle_rp_inst(ri, &empty_rp); if (orig_ret_address != trampoline_address) { /* @@ -417,6 +418,10 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) spin_unlock_irqrestore(&kretprobe_lock, flags); preempt_enable_no_resched(); + hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { + hlist_del(&ri->hlist); + kfree(ri); + } /* * By returning a non-zero value, we are telling * kprobe_handler() that we don't want the post_handler diff --git a/arch/x86_64/kernel/kprobes.c b/arch/x86_64/kernel/kprobes.c index d04f0ab2ff..ac241567e6 100644 --- a/arch/x86_64/kernel/kprobes.c +++ b/arch/x86_64/kernel/kprobes.c @@ -405,11 +405,12 @@ no_kprobe: int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) { struct kretprobe_instance *ri = NULL; - struct hlist_head *head; + struct hlist_head *head, empty_rp; struct hlist_node *node, *tmp; unsigned long flags, orig_ret_address = 0; unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline; + INIT_HLIST_HEAD(&empty_rp); spin_lock_irqsave(&kretprobe_lock, flags); head = kretprobe_inst_table_head(current); @@ -435,7 +436,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) ri->rp->handler(ri, regs); orig_ret_address = (unsigned long)ri->ret_addr; - recycle_rp_inst(ri); + recycle_rp_inst(ri, &empty_rp); if (orig_ret_address != trampoline_address) /* @@ -453,6 +454,10 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) spin_unlock_irqrestore(&kretprobe_lock, flags); preempt_enable_no_resched(); + hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { + hlist_del(&ri->hlist); + kfree(ri); + } /* * By returning a non-zero value, we are telling * kprobe_handler() that we don't want the post_handler diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index a5c5a0cb0d..ac4c0559f7 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -202,7 +202,7 @@ void unregister_kretprobe(struct kretprobe *rp); struct kretprobe_instance *get_free_rp_inst(struct kretprobe *rp); void add_rp_inst(struct kretprobe_instance *ri); void kprobe_flush_task(struct task_struct *tk); -void recycle_rp_inst(struct kretprobe_instance *ri); +void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head); #else /* CONFIG_KPROBES */ #define __kprobes /**/ diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 41dfda50e2..610c837ad9 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -319,7 +319,8 @@ void __kprobes add_rp_inst(struct kretprobe_instance *ri) } /* Called with kretprobe_lock held */ -void __kprobes recycle_rp_inst(struct kretprobe_instance *ri) +void __kprobes recycle_rp_inst(struct kretprobe_instance *ri, + struct hlist_head *head) { /* remove rp inst off the rprobe_inst_table */ hlist_del(&ri->hlist); @@ -331,7 +332,7 @@ void __kprobes recycle_rp_inst(struct kretprobe_instance *ri) hlist_add_head(&ri->uflist, &ri->rp->free_instances); } else /* Unregistering */ - kfree(ri); + hlist_add_head(&ri->hlist, head); } struct hlist_head __kprobes *kretprobe_inst_table_head(struct task_struct *tsk) @@ -348,17 +349,23 @@ struct hlist_head __kprobes *kretprobe_inst_table_head(struct task_struct *tsk) void __kprobes kprobe_flush_task(struct task_struct *tk) { struct kretprobe_instance *ri; - struct hlist_head *head; + struct hlist_head *head, empty_rp; struct hlist_node *node, *tmp; unsigned long flags = 0; + INIT_HLIST_HEAD(&empty_rp); spin_lock_irqsave(&kretprobe_lock, flags); head = kretprobe_inst_table_head(tk); hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { if (ri->task == tk) - recycle_rp_inst(ri); + recycle_rp_inst(ri, &empty_rp); } spin_unlock_irqrestore(&kretprobe_lock, flags); + + hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { + hlist_del(&ri->hlist); + kfree(ri); + } } static inline void free_rp_inst(struct kretprobe *rp)