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From: Ming Lei <ming.lei@redhat.com>
To: "Thomas Hellström" <thomas.hellstrom@linux.intel.com>
Cc: Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
	John Garry <john.g.garry@oracle.com>,
	stable@vger.kernel.org
Subject: Re: [PATCH V2] block: mark GFP_NOIO around sysfs ->store()
Date: Mon, 13 Jan 2025 17:01:04 +0800	[thread overview]
Message-ID: <Z4TWUCoZV_NVzHMa@fedora> (raw)
In-Reply-To: <076ee902633a7293393748cb972cc4a7743ec5c1.camel@linux.intel.com>

On Mon, Jan 13, 2025 at 09:50:37AM +0100, Thomas Hellström wrote:
> Hi!
> 
> On Mon, 2025-01-13 at 16:41 +0800, Ming Lei wrote:
> > sysfs ->store is called with queue freezed, meantime we have several
> > ->store() callbacks(update_nr_requests, wbt, scheduler) to allocate
> > memory with GFP_KERNEL which may run into direct reclaim code path,
> > then potential deadlock can be caused.
> > 
> > Fix the issue by marking NOIO around sysfs ->store()
> > 
> > Reviewed-by: Christoph Hellwig <hch@lst.de>
> > Reviewed-by: John Garry <john.g.garry@oracle.com>
> > Reported-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> > Closes:
> > https://lore.kernel.org/linux-block/ead7c5ce5138912c1f3179d62370b84a64014a38.camel@linux.intel.com/
> > Fixes: bd166ef183c2 ("blk-mq-sched: add framework for MQ capable IO
> > schedulers")
> 
> Does this fix also the #2 lockdep splat in that email?

No.

The #2 splat fix has been merged to for-6.14/block, and this patch only
covers the one reported in the Closes link.

https://lore.kernel.org/linux-block/20250110054726.1499538-1-hch@lst.de/


Thanks, 
Ming


  reply	other threads:[~2025-01-13  9:01 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-13  8:41 [PATCH V2] block: mark GFP_NOIO around sysfs ->store() Ming Lei
2025-01-13  8:50 ` Thomas Hellström
2025-01-13  9:01   ` Ming Lei [this message]
2025-01-13  9:05     ` Thomas Hellström

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