diff options
| author | Maksim Kiselev <bigunclemax@gmail.com> | 2024-01-24 10:24:36 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-03-01 13:34:49 +0100 |
| commit | 673629018ba04906899dcb631beec34d871f709c (patch) | |
| tree | 8c352344cc0f016a733897e335655da19d703ace | |
| parent | 89f67051613c90be32ef01aefe96fe0adb8da9b1 (diff) | |
| download | linux-rpi-673629018ba04906899dcb631beec34d871f709c.tar.gz linux-rpi-673629018ba04906899dcb631beec34d871f709c.tar.bz2 linux-rpi-673629018ba04906899dcb631beec34d871f709c.zip | |
aoe: avoid potential deadlock at set_capacity
[ 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>
| -rw-r--r-- | drivers/block/aoe/aoeblk.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/block/aoe/aoeblk.c b/drivers/block/aoe/aoeblk.c index cf6883756155..37eff1c97451 100644 --- a/drivers/block/aoe/aoeblk.c +++ b/drivers/block/aoe/aoeblk.c @@ -333,6 +333,7 @@ aoeblk_gdalloc(void *vp) struct gendisk *gd; mempool_t *mp; struct blk_mq_tag_set *set; + sector_t ssize; ulong flags; int late = 0; int err; @@ -395,7 +396,7 @@ aoeblk_gdalloc(void *vp) gd->minors = AOE_PARTITIONS; gd->fops = &aoe_bdops; gd->private_data = d; - set_capacity(gd, d->ssize); + ssize = d->ssize; snprintf(gd->disk_name, sizeof gd->disk_name, "etherd/e%ld.%d", d->aoemajor, d->aoeminor); @@ -404,6 +405,8 @@ aoeblk_gdalloc(void *vp) spin_unlock_irqrestore(&d->lock, flags); + set_capacity(gd, ssize); + err = device_add_disk(NULL, gd, aoe_attr_groups); if (err) goto out_disk_cleanup; |