* [Patch] Remove debugfs entries on bad path
@ 2009-05-18 12:59 Stefan Raspl
2009-05-19 1:14 ` Li Zefan
0 siblings, 1 reply; 4+ messages in thread
From: Stefan Raspl @ 2009-05-18 12:59 UTC (permalink / raw
To: linux-btrace, Jens Axboe, linux-kernel, schwidefsky,
heiko.carstens
debugfs directory entries for devices are not removed on bad path.
If so, subsequent attempts to start blktrace on the respective
devices will not succeed due to existing directories.
Signed-off-by: Stefan Raspl <stefan.raspl@linux.vnet.ibm.com>
---
kernel/trace/blktrace.c | 1 +
1 file changed, 1 insertion(+)
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -262,6 +262,7 @@ static void blk_trace_free(struct blk_tr
{
debugfs_remove(bt->msg_file);
debugfs_remove(bt->dropped_file);
+ debugfs_remove(bt->dir);
relay_close(bt->rchan);
free_percpu(bt->sequence);
free_percpu(bt->msg_data);
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Patch] Remove debugfs entries on bad path
2009-05-18 12:59 [Patch] Remove debugfs entries on bad path Stefan Raspl
@ 2009-05-19 1:14 ` Li Zefan
2009-05-19 6:46 ` [Patch] blktrace: remove " Stefan Raspl
0 siblings, 1 reply; 4+ messages in thread
From: Li Zefan @ 2009-05-19 1:14 UTC (permalink / raw
To: raspl; +Cc: linux-btrace, Jens Axboe, linux-kernel, schwidefsky,
heiko.carstens
A better title:
[Patch] blktrace: remove debugfs entries on bad path
Stefan Raspl wrote:
> debugfs directory entries for devices are not removed on bad path.
Can you be more elaborate on how to reproduce this issue?
> If so, subsequent attempts to start blktrace on the respective
> devices will not succeed due to existing directories.
>
> Signed-off-by: Stefan Raspl <stefan.raspl@linux.vnet.ibm.com>
>
> ---
> kernel/trace/blktrace.c | 1 +
> 1 file changed, 1 insertion(+)
>
> --- a/kernel/trace/blktrace.c
> +++ b/kernel/trace/blktrace.c
> @@ -262,6 +262,7 @@ static void blk_trace_free(struct blk_tr
> {
> debugfs_remove(bt->msg_file);
> debugfs_remove(bt->dropped_file);
> + debugfs_remove(bt->dir);
> relay_close(bt->rchan);
> free_percpu(bt->sequence);
> free_percpu(bt->msg_data);
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Patch] blktrace: remove debugfs entries on bad path
2009-05-19 1:14 ` Li Zefan
@ 2009-05-19 6:46 ` Stefan Raspl
2009-05-19 7:07 ` Li Zefan
0 siblings, 1 reply; 4+ messages in thread
From: Stefan Raspl @ 2009-05-19 6:46 UTC (permalink / raw
To: Li Zefan
Cc: linux-btrace, Jens Axboe, linux-kernel, schwidefsky,
heiko.carstens
Li Zefan wrote:
> A better title:
> [Patch] blktrace: remove debugfs entries on bad path
>
> Stefan Raspl wrote:
>> debugfs directory entries for devices are not removed on bad path.
>
> Can you be more elaborate on how to reproduce this issue?
It can happen for most bad pathes within do_blk_trace_setup(). One
way to trigger is to set the Vmalloc space via the respective kernel
parameter to a value that is so small that it will not suffice for
the 2MB per device and cpu that is required. For instance, set
vmalloc=10M and start blktrace on a system with 2 cpus on 7 devices.
Depending on how much Vmalloc space is still free, the final 2 or 3
devices will fail with a message like this:
BLKTRACESETUP(2) /dev/sdu failed: 5/Input/output error
Best regards,
Stefan Raspl
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Patch] blktrace: remove debugfs entries on bad path
2009-05-19 6:46 ` [Patch] blktrace: remove " Stefan Raspl
@ 2009-05-19 7:07 ` Li Zefan
0 siblings, 0 replies; 4+ messages in thread
From: Li Zefan @ 2009-05-19 7:07 UTC (permalink / raw
To: raspl; +Cc: linux-btrace, Jens Axboe, linux-kernel, schwidefsky,
heiko.carstens
Stefan Raspl wrote:
> Li Zefan wrote:
>> A better title:
>> [Patch] blktrace: remove debugfs entries on bad path
>>
>> Stefan Raspl wrote:
>>> debugfs directory entries for devices are not removed on bad path.
>> Can you be more elaborate on how to reproduce this issue?
>
> It can happen for most bad pathes within do_blk_trace_setup(). One
Now I see what you meant by "bad path". :)
I'd say "some failure pathes", but not "most".
> way to trigger is to set the Vmalloc space via the respective kernel
> parameter to a value that is so small that it will not suffice for
> the 2MB per device and cpu that is required. For instance, set
> vmalloc=10M and start blktrace on a system with 2 cpus on 7 devices.
> Depending on how much Vmalloc space is still free, the final 2 or 3
> devices will fail with a message like this:
>
> BLKTRACESETUP(2) /dev/sdu failed: 5/Input/output error
>
Yes, this can happen under extreme memory stress.
Thanks for the fix:
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Could you resend the patch to Ingo, with a better title and a better
changelog (but IMHO we don't need to explain how to set up a memory
stress to trigger this issue) and my ack tag? Now blktrace patches
go to Ingo.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2009-05-19 7:06 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2009-05-18 12:59 [Patch] Remove debugfs entries on bad path Stefan Raspl
2009-05-19 1:14 ` Li Zefan
2009-05-19 6:46 ` [Patch] blktrace: remove " Stefan Raspl
2009-05-19 7:07 ` Li Zefan
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).