From: Abhishek Sagar Date: Sat, 24 May 2008 18:15:02 +0000 (+0530) Subject: ftrace: safe traversal of ftrace_hash hlist X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=ffdaa3582b6b39d625d585d07e329ffdc925e971;p=linux-beck.git ftrace: safe traversal of ftrace_hash hlist Hi Steven, I noticed that concurrent instances of ftrace_record_ip() have a race between ftrace_hash list traversal during ftrace_ip_in_hash() (before acquiring ftrace_shutdown_lock) and ftrace_add_hash(). If it's so then this should fix it. Signed-off-by: Abhishek Sagar Cc: rostedt@goodmis.org Signed-off-by: Thomas Gleixner --- diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 2552454609cf..9b7c54f8a62f 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -201,7 +201,7 @@ ftrace_ip_in_hash(unsigned long ip, unsigned long key) struct hlist_node *t; int found = 0; - hlist_for_each_entry(p, t, &ftrace_hash[key], node) { + hlist_for_each_entry_rcu(p, t, &ftrace_hash[key], node) { if (p->ip == ip) { found = 1; break; @@ -214,7 +214,7 @@ ftrace_ip_in_hash(unsigned long ip, unsigned long key) static inline void ftrace_add_hash(struct dyn_ftrace *node, unsigned long key) { - hlist_add_head(&node->node, &ftrace_hash[key]); + hlist_add_head_rcu(&node->node, &ftrace_hash[key]); } static void ftrace_free_rec(struct dyn_ftrace *rec)