2d623c94fb
[ Upstream commit e169bd4fb2b36c4b2bee63c35c740c85daeb2e86 ]
Move set_capacity() outside of the section procected by (&d->lock).
To avoid possible interrupt unsafe locking scenario:
CPU0 CPU1
---- ----
[1] lock(&bdev->bd_size_lock);
local_irq_disable();
[2] lock(&d->lock);
[3] lock(&bdev->bd_size_lock);
<Interrupt>
[4] lock(&d->lock);
*** DEADLOCK ***
Where [1](&bdev->bd_size_lock) hold by zram_add()->set_capacity().
[2]lock(&d->lock) hold by aoeblk_gdalloc(). And aoeblk_gdalloc()
is trying to acquire [3](&bdev->bd_size_lock) at set_capacity() call.
In this situation an attempt to acquire [4]lock(&d->lock) from
aoecmd_cfg_rsp() will lead to deadlock.
So the simplest solution is breaking lock dependency
[2](&d->lock) -> [3](&bdev->bd_size_lock) by moving set_capacity()
outside.
Signed-off-by: Maksim Kiselev <bigunclemax@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240124072436.3745720-2-bigunclemax@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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|---|---|---|
| .. | ||
| Makefile | ||
| aoe.h | ||
| aoeblk.c | ||
| aoechr.c | ||
| aoecmd.c | ||
| aoedev.c | ||
| aoemain.c | ||
| aoenet.c | ||