Messages in this thread Patch in this message | | | Date | Thu, 2 Jul 2009 06:54:58 GMT | From | tip-bot for Xiao Guangrong <> | Subject | [tip:tracing/urgent] tracing: Fix trace_print_seq() |
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Commit-ID: e1af3aec3e2e7d21d4b3054323779d478c19d907 Gitweb: http://git.kernel.org/tip/e1af3aec3e2e7d21d4b3054323779d478c19d907 Author: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> AuthorDate: Wed, 1 Jul 2009 16:50:25 +0800 Committer: Ingo Molnar <mingo@elte.hu> CommitDate: Thu, 2 Jul 2009 08:51:13 +0200
tracing: Fix trace_print_seq()
We will lose something if trace_seq->buffer[0] is 0, because the copy length is calculated by strlen() in seq_puts(), so using seq_write() instead of seq_puts().
There have a example: after reboot:
# echo kmemtrace > current_tracer # echo 0 > options/kmem_minimalistic # cat trace # tracer: kmemtrace # #
Nothing is exported, because the first byte of trace_seq->buffer[ ] is KMEMTRACE_USER_ALLOC.
( the value of KMEMTRACE_USER_ALLOC is zero, seeing kmemtrace_print_alloc_user() in kernel/trace/kmemtrace.c)
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Acked-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <4A4B2351.5010300@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
--- kernel/trace/trace_output.c | 3 +-- 1 files changed, 1 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index 7938f3a..e0c2545 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -27,8 +27,7 @@ void trace_print_seq(struct seq_file *m, struct trace_seq *s) { int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len; - s->buffer[len] = 0; - seq_puts(m, s->buffer); + seq_write(m, s->buffer, len); trace_seq_init(s); }
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