Commit-ID: d4d34b981a5327eec956c6cb4cce397ce6f57279
Gitweb: http://git.kernel.org/tip/d4d34b981a5327eec956c6cb4cce397ce6f57279
Author: Steven Rostedt <srostedt@xxxxxxxxxx>
AuthorDate: Fri, 4 Nov 2011 20:32:39 -0400
Committer: Steven Rostedt <rostedt@xxxxxxxxxxx>
CommitDate: Mon, 7 Nov 2011 13:48:05 -0500
ftrace: Fix hash record accounting bug
If the set_ftrace_filter is cleared by writing just whitespace to
it, then the filter hash refcounts will be decremented but not
updated. This causes two bugs:
1) No functions will be enabled for tracing when they all should be
2) If the users clears the set_ftrace_filter twice, it will crash ftrace:
------------[ cut here ]------------
WARNING: at /home/rostedt/work/git/linux-trace.git/kernel/trace/ftrace.c:1384 __ftrace_hash_rec_update.part.27+0x157/0x1a7()
Modules linked in:
Pid: 2330, comm: bash Not tainted 3.1.0-test+ #32
Call Trace:
[<ffffffff81051828>] warn_slowpath_common+0x83/0x9b
[<ffffffff8105185a>] warn_slowpath_null+0x1a/0x1c
[<ffffffff810ba362>] __ftrace_hash_rec_update.part.27+0x157/0x1a7
[<ffffffff810ba6e8>] ? ftrace_regex_release+0xa7/0x10f
[<ffffffff8111bdfe>] ? kfree+0xe5/0x115
[<ffffffff810ba51e>] ftrace_hash_move+0x2e/0x151
[<ffffffff810ba6fb>] ftrace_regex_release+0xba/0x10f
[<ffffffff8112e49a>] fput+0xfd/0x1c2
[<ffffffff8112b54c>] filp_close+0x6d/0x78
[<ffffffff8113a92d>] sys_dup3+0x197/0x1c1
[<ffffffff8113a9a6>] sys_dup2+0x4f/0x54
[<ffffffff8150cac2>] system_call_fastpath+0x16/0x1b
---[ end trace 77a3a7ee73794a02 ]---
Link: http://lkml.kernel.org/r/20111101141420.GA4918@debian
Reported-by: Rabin Vincent <rabin@xxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
kernel/trace/ftrace.c | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 0fcc6ca..7caa450 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1210,7 +1210,9 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable,
if (!src->count) {
free_ftrace_hash_rcu(*dst);
rcu_assign_pointer(*dst, EMPTY_HASH);
- return 0;
+ /* still need to update the function records */
+ ret = 0;
+ goto out;
}
/*
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|