* potential race in FUSE's readdir() + releasedir()?
@ 2022-07-03 14:36 Nikolaus Rath
2022-07-06 8:35 ` Miklos Szeredi
0 siblings, 1 reply; 3+ messages in thread
From: Nikolaus Rath @ 2022-07-03 14:36 UTC (permalink / raw)
To: Linux FS Devel, fuse-devel, miklos
Hello,
I am seeing something that to me looks like a race between FUSE's
readdir() and releasedir() handlers. On kernel 5.18, the FUSE daemon
seems to (ocasionally) receive a releasedir() request while a readdir()
request with the same `struct fuse_file_info *fi->fh` is still active
(i.e., the FUSE daemon hasn't sent a reply to the kernel for this yet).
Could this be a bug in the kernel? Or is there something else that could
explain this?
Best,
-Nikolaus
--
GPG Fingerprint: ED31 791B 2C5C 1613 AF38 8B8A D113 FCAC 3C4E 599F
»Time flies like an arrow, fruit flies like a Banana.«
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: potential race in FUSE's readdir() + releasedir()?
2022-07-03 14:36 potential race in FUSE's readdir() + releasedir()? Nikolaus Rath
@ 2022-07-06 8:35 ` Miklos Szeredi
2022-07-11 8:33 ` [fuse-devel] " Nikolaus Rath
0 siblings, 1 reply; 3+ messages in thread
From: Miklos Szeredi @ 2022-07-06 8:35 UTC (permalink / raw)
To: Linux FS Devel, fuse-devel, miklos
On Sun, 3 Jul 2022 at 16:37, Nikolaus Rath <Nikolaus@rath.org> wrote:
>
> Hello,
>
> I am seeing something that to me looks like a race between FUSE's
> readdir() and releasedir() handlers. On kernel 5.18, the FUSE daemon
> seems to (ocasionally) receive a releasedir() request while a readdir()
> request with the same `struct fuse_file_info *fi->fh` is still active
> (i.e., the FUSE daemon hasn't sent a reply to the kernel for this yet).
>
> Could this be a bug in the kernel? Or is there something else that could
> explain this?
Is there a log where this can be observed?
Thanks,
Miklos
\
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [fuse-devel] potential race in FUSE's readdir() + releasedir()?
2022-07-06 8:35 ` Miklos Szeredi
@ 2022-07-11 8:33 ` Nikolaus Rath
0 siblings, 0 replies; 3+ messages in thread
From: Nikolaus Rath @ 2022-07-11 8:33 UTC (permalink / raw)
To: Miklos Szeredi; +Cc: Linux FS Devel, fuse-devel, miklos
On Jul 06 2022, Miklos Szeredi <miklos@szeredi.hu> wrote:
> On Sun, 3 Jul 2022 at 16:37, Nikolaus Rath <Nikolaus@rath.org> wrote:
>>
>> Hello,
>>
>> I am seeing something that to me looks like a race between FUSE's
>> readdir() and releasedir() handlers. On kernel 5.18, the FUSE daemon
>> seems to (ocasionally) receive a releasedir() request while a readdir()
>> request with the same `struct fuse_file_info *fi->fh` is still active
>> (i.e., the FUSE daemon hasn't sent a reply to the kernel for this yet).
>>
>> Could this be a bug in the kernel? Or is there something else that could
>> explain this?
>
> Is there a log where this can be observed?
Not so far, I haven't been able to reproduce it with debug logging
enabled.
The way that I'm inferring what's happening is from a crash due to
writing to freed memory. My fi->fh points to a malloc'ed area that is
free'd in releasedir(), and written to in readdir().
Best,
-Nikolaus
--
GPG Fingerprint: ED31 791B 2C5C 1613 AF38 8B8A D113 FCAC 3C4E 599F
»Time flies like an arrow, fruit flies like a Banana.«
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-07-11 8:35 UTC | newest]
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2022-07-03 14:36 potential race in FUSE's readdir() + releasedir()? Nikolaus Rath
2022-07-06 8:35 ` Miklos Szeredi
2022-07-11 8:33 ` [fuse-devel] " Nikolaus Rath
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