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authorChristoph Hellwig <hch@lst.de>2021-08-16 15:46:24 +0200
committerJens Axboe <axboe@kernel.dk>2021-08-23 20:54:31 +0200
commitd152c682f03ceb65c0d9663d4ba6ee2d46aa784d (patch)
tree31cc1a85256072b4d65d881472c2f6ace7c10178 /block/blk-cgroup.c
parentblock: hold a request_queue reference for the lifetime of struct gendisk (diff)
downloadlinux-d152c682f03ceb65c0d9663d4ba6ee2d46aa784d.tar.xz
linux-d152c682f03ceb65c0d9663d4ba6ee2d46aa784d.zip
block: add an explicit ->disk backpointer to the request_queue
Replace the magic lookup through the kobject tree with an explicit backpointer, given that the device model links are set up and torn down at times when I/O is still possible, leading to potential NULL or invalid pointer dereferences. Fixes: edb0872f44ec ("block: move the bdi from the request_queue to the gendisk") Reported-by: syzbot <syzbot+aa0801b6b32dca9dda82@syzkaller.appspotmail.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Tested-by: Sven Schnelle <svens@linux.ibm.com> Link: https://lore.kernel.org/r/20210816134624.GA24234@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-cgroup.c')
-rw-r--r--block/blk-cgroup.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index b8ec47dcce42..f575aa42922b 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -489,9 +489,9 @@ static int blkcg_reset_stats(struct cgroup_subsys_state *css,
const char *blkg_dev_name(struct blkcg_gq *blkg)
{
- if (!queue_has_disk(blkg->q) || !queue_to_disk(blkg->q)->bdi->dev)
+ if (!blkg->q->disk || !blkg->q->disk->bdi->dev)
return NULL;
- return bdi_dev_name(queue_to_disk(blkg->q)->bdi);
+ return bdi_dev_name(blkg->q->disk->bdi);
}
/**