From 99219a3fbc2dcf2eaa954f7b2ac27299fd7894cd Mon Sep 17 00:00:00 2001 From: "bibo,mao" Date: Mon, 2 Oct 2006 02:17:35 -0700 Subject: [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 --- kernel/kprobes.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 41dfda50e22a..610c837ad9e0 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) -- cgit v1.2.2