Messages in this thread Patch in this message | | | Date | Sat, 24 May 2008 23:45:02 +0530 | From | Abhishek Sagar <> | Subject | [PATCH] ftrace: safe traversal of ftrace_hash hlist |
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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 <sagar.abhishek@gmail.com> --- Accommodate traversal of ftrace_hash hlist with concurrent insertions.
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 89bd9a6..bfba25c 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)
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