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From: Tetsuo Handa <>
To: Christoph Hellwig <>
Cc: Alexander Viro <>,
	Jens Axboe <>,,
	linux-fsdevel <>
Subject: Re: [PATCH] block: add filemap_invalidate_lock_killable()
Date: Sat, 12 Feb 2022 17:28:09 +0900	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On 2022/01/04 22:26, Tetsuo Handa wrote:
> On 2022/01/04 16:14, Christoph Hellwig wrote:
>> On Mon, Jan 03, 2022 at 07:49:11PM +0900, Tetsuo Handa wrote:
>>> syzbot is reporting hung task at blkdev_fallocate() [1], for it can take
>>> minutes with mapping->invalidate_lock held. Since fallocate() has to accept
>>> size > MAX_RW_COUNT bytes, we can't predict how long it will take. Thus,
>>> mitigate this problem by using killable wait where possible.
>> Well, but that also means we want all other users of the invalidate_lock
>> to be killable, as fallocate vs fallocate synchronization is probably
>> not the interesting case.
> Right. But being responsive to SIGKILL is generally preferable.
> syzbot (and other syzkaller based fuzzing) is reporting many hung task reports,
> but many of such reports are simply overstressing.
> We can't use killable lock wait for release operation because it is a "void"
> function. But we can use killable lock wait for majority of operations which
> are not "void" functions. Use of killable lock wait where possible can improve
> situation.

If there is no alternative, can we apply this patch?

  reply	other threads:[~2022-02-12  8:28 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-03  9:11 [syzbot] INFO: task hung in blkdev_fallocate syzbot
2022-01-03 10:49 ` [PATCH] block: add filemap_invalidate_lock_killable() Tetsuo Handa
2022-01-04  7:14   ` Christoph Hellwig
2022-01-04 13:26     ` Tetsuo Handa
2022-02-12  8:28       ` Tetsuo Handa [this message]
2022-02-14  8:17         ` Christoph Hellwig

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