[PATCH][GIT PULL] tracing: Fix warning in s_next of trace file ops
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From: Steven Rostedt on 3 Mar 2010 11:20 Ingo, Please pull the latest tip/tracing/urgent tree, which can be found at: git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git tip/tracing/urgent Lai Jiangshan (1): tracing: Fix warning in s_next of trace file ops ---- kernel/trace/trace.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) --------------------------- commit ac91d85456372a90af5b85eb6620fd2efb1e431b Author: Lai Jiangshan <laijs(a)cn.fujitsu.com> Date: Tue Mar 2 17:54:50 2010 +0800 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(a)kernel.org Signed-off-by: Lai Jiangshan <laijs(a)cn.fujitsu.com> LKML-Reference: <4B8CE06A.9090207(a)cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt(a)goodmis.org> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 032c57c..5edf410 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)) ; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |