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| author | Lai Jiangshan <laijs@cn.fujitsu.com> | 2010-03-02 17:54:50 +0800 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2010-03-02 21:11:47 -0500 |
| commit | ac91d85456372a90af5b85eb6620fd2efb1e431b (patch) | |
| tree | df15f1b8c3c6b8b5a6367f70a527b2da7e240361 /kernel/trace | |
| parent | 3a5b27bf6f29574d667230c7e76e4b83fe3014e0 (diff) | |
| download | blackbird-op-linux-ac91d85456372a90af5b85eb6620fd2efb1e431b.tar.gz blackbird-op-linux-ac91d85456372a90af5b85eb6620fd2efb1e431b.zip | |
tracing: Fix warning in s_next of trace file ops
This warning in s_next() can be triggered by lseek():
[<c018b3f7>] ? s_next+0x77/0x80
[<c013e3c1>] warn_slowpath_common+0x81/0xa0
[<c018b3f7>] ? s_next+0x77/0x80
[<c013e3fa>] warn_slowpath_null+0x1a/0x20
[<c018b3f7>] s_next+0x77/0x80
[<c01efa77>] traverse+0x117/0x200
[<c01eff13>] seq_lseek+0xa3/0x120
[<c01efe70>] ? seq_lseek+0x0/0x120
[<c01d7081>] vfs_llseek+0x41/0x50
[<c01d8116>] sys_llseek+0x66/0xa0
[<c0102bd0>] sysenter_do_call+0x12/0x26
The iterator "leftover" variable is zeroed in the opening of the trace
file. But lseek can call s_start() which will call s_next() without
reseting the "leftover" variable back to zero, which might trigger
the WARN_ON_ONCE(iter->leftover) that is in s_next().
Cc: stable@kernel.org
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4B8CE06A.9090207@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/trace.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 032c57ca6502..5edf410bc540 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1703,6 +1703,7 @@ static void *s_start(struct seq_file *m, loff_t *pos) ftrace_enable_cpu(); + iter->leftover = 0; for (p = iter; p && l < *pos; p = s_next(m, p, &l)) ; |
