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| author | Christoph Hellwig <hch@lst.de> | 2021-08-16 15:46:24 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-08-23 12:54:31 -0600 |
| commit | d152c682f03ceb65c0d9663d4ba6ee2d46aa784d (patch) | |
| tree | 31cc1a85256072b4d65d881472c2f6ace7c10178 /block/blk-sysfs.c | |
| parent | 61a35cfc26334fe1c8e970ca8fafeae2daae257d (diff) | |
| download | lwn-d152c682f03ceb65c0d9663d4ba6ee2d46aa784d.tar.gz lwn-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-sysfs.c')
| -rw-r--r-- | block/blk-sysfs.c | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 586507a5b8c2..7fd99487300c 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -90,9 +90,9 @@ static ssize_t queue_ra_show(struct request_queue *q, char *page) { unsigned long ra_kb; - if (!queue_has_disk(q)) + if (!q->disk) return -EINVAL; - ra_kb = queue_to_disk(q)->bdi->ra_pages << (PAGE_SHIFT - 10); + ra_kb = q->disk->bdi->ra_pages << (PAGE_SHIFT - 10); return queue_var_show(ra_kb, page); } @@ -102,12 +102,12 @@ queue_ra_store(struct request_queue *q, const char *page, size_t count) unsigned long ra_kb; ssize_t ret; - if (!queue_has_disk(q)) + if (!q->disk) return -EINVAL; ret = queue_var_store(&ra_kb, page, count); if (ret < 0) return ret; - queue_to_disk(q)->bdi->ra_pages = ra_kb >> (PAGE_SHIFT - 10); + q->disk->bdi->ra_pages = ra_kb >> (PAGE_SHIFT - 10); return ret; } @@ -254,9 +254,8 @@ queue_max_sectors_store(struct request_queue *q, const char *page, size_t count) spin_lock_irq(&q->queue_lock); q->limits.max_sectors = max_sectors_kb << 1; - if (queue_has_disk(q)) - queue_to_disk(q)->bdi->io_pages = - max_sectors_kb >> (PAGE_SHIFT - 10); + if (q->disk) + q->disk->bdi->io_pages = max_sectors_kb >> (PAGE_SHIFT - 10); spin_unlock_irq(&q->queue_lock); return ret; |