[PATCH] blktrace: Fix output non-blktrace event when blk_classic option enabled

[PATCH] blktrace: Fix output non-blktrace event when blk_classic option enabled

[Yang Jihong]

When the blk_classic option is enabled, non-blktrace events must be
filtered out. Otherwise, events of other types are output in the blktrace
classic format, which is unexpected.

The problem can be triggered in the following ways:

  # echo 1 > /sys/kernel/debug/tracing/options/blk_classic
  # echo 1 > /sys/kernel/debug/tracing/events/enable
  # echo blk > /sys/kernel/debug/tracing/current_tracer
  # cat /sys/kernel/debug/tracing/trace_pipe

Fixes: c71a89615411 ("blktrace: add ftrace plugin")
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
---
 kernel/trace/blktrace.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index a995ea1ef849..a66cff5a1857 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -1548,7 +1548,8 @@ blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
 
 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
 {
-	if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
+	if ((iter->ent->type != TRACE_BLK) ||
+	    !(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
 		return TRACE_TYPE_UNHANDLED;
 
 	return print_one_line(iter, true);
-- 
2.30.GIT

Re: [PATCH] blktrace: Fix output non-blktrace event when blk_classic option enabled

[Yang Jihong]

Hello,

PING.

Thanks,
Yang.

On 2022/11/22 12:04, Yang Jihong wrote:
> When the blk_classic option is enabled, non-blktrace events must be
> filtered out. Otherwise, events of other types are output in the blktrace
> classic format, which is unexpected.
> 
> The problem can be triggered in the following ways:
> 
>    # echo 1 > /sys/kernel/debug/tracing/options/blk_classic
>    # echo 1 > /sys/kernel/debug/tracing/events/enable
>    # echo blk > /sys/kernel/debug/tracing/current_tracer
>    # cat /sys/kernel/debug/tracing/trace_pipe
> 
> Fixes: c71a89615411 ("blktrace: add ftrace plugin")
> Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
> ---
>   kernel/trace/blktrace.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
> index a995ea1ef849..a66cff5a1857 100644
> --- a/kernel/trace/blktrace.c
> +++ b/kernel/trace/blktrace.c
> @@ -1548,7 +1548,8 @@ blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
>   
>   static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
>   {
> -	if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
> +	if ((iter->ent->type != TRACE_BLK) ||
> +	    !(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
>   		return TRACE_TYPE_UNHANDLED;
>   
>   	return print_one_line(iter, true);
> 

Re: [PATCH] blktrace: Fix output non-blktrace event when blk_classic option enabled

[Jens Axboe]

On 12/6/22 6:34 PM, Yang Jihong wrote:
> Hello,
> 
> PING.

Get your company email fixed so that messages don't get marked as spam,
that would help ensure your patches are more visible.

-- 
Jens Axboe

Re: [PATCH] blktrace: Fix output non-blktrace event when blk_classic option enabled

[Jens Axboe]

On Tue, 22 Nov 2022 12:04:10 +0800, Yang Jihong wrote:
> When the blk_classic option is enabled, non-blktrace events must be
> filtered out. Otherwise, events of other types are output in the blktrace
> classic format, which is unexpected.
> 
> The problem can be triggered in the following ways:
> 
>   # echo 1 > /sys/kernel/debug/tracing/options/blk_classic
>   # echo 1 > /sys/kernel/debug/tracing/events/enable
>   # echo blk > /sys/kernel/debug/tracing/current_tracer
>   # cat /sys/kernel/debug/tracing/trace_pipe
> 
> [...]

Applied, thanks!

[1/1] blktrace: Fix output non-blktrace event when blk_classic option enabled
      commit: f596da3efaf4130ff61cd029558845808df9bf99

Best regards,
-- 
Jens Axboe

Re: [PATCH] blktrace: Fix output non-blktrace event when blk_classic option enabled

[Yang Jihong]

Hello,

On 2022/12/9 0:26, Jens Axboe wrote:
> Get your company email fixed so that messages don't get marked as spam,
> that would help ensure your patches are more visible.

OK, I'll consult with the relevant department of our company about this 
issue.

Thanks,
Yang