From 06cc978d3ff226072780f74897800b33e78abb57 Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Sat, 2 Oct 2021 18:23:02 +0900 Subject: block: genhd: fix double kfree() in __alloc_disk_node() syzbot is reporting use-after-free read at bdev_free_inode() [1], for kfree() from __alloc_disk_node() is called before bdev_free_inode() (which is called after RCU grace period) reads bdev->bd_disk and calls kfree(bdev->bd_disk). Fix use-after-free read followed by double kfree() problem by making sure that bdev->bd_disk is NULL when calling iput(). Link: https://syzkaller.appspot.com/bug?extid=8281086e8a6fbfbd952a [1] Reported-by: syzbot Signed-off-by: Tetsuo Handa Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/e6dd13c5-8db0-4392-6e78-a42ee5d2a1c4@i-love.sakura.ne.jp Signed-off-by: Jens Axboe --- block/bdev.c | 2 +- block/genhd.c | 1 + 2 files changed, 2 insertions(+), 1 deletion(-) (limited to 'block') diff --git a/block/bdev.c b/block/bdev.c index cf2780cb44a7..485a258b0ab3 100644 --- a/block/bdev.c +++ b/block/bdev.c @@ -490,7 +490,6 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno) bdev = I_BDEV(inode); mutex_init(&bdev->bd_fsfreeze_mutex); spin_lock_init(&bdev->bd_size_lock); - bdev->bd_disk = disk; bdev->bd_partno = partno; bdev->bd_inode = inode; bdev->bd_stats = alloc_percpu(struct disk_stats); @@ -498,6 +497,7 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno) iput(inode); return NULL; } + bdev->bd_disk = disk; return bdev; } diff --git a/block/genhd.c b/block/genhd.c index 7b6e5e1cf956..496e8458c357 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -1268,6 +1268,7 @@ struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id, out_destroy_part_tbl: xa_destroy(&disk->part_tbl); + disk->part0->bd_disk = NULL; iput(disk->part0->bd_inode); out_free_bdi: bdi_put(disk->bdi); -- cgit From 1dbdd99b511c966be9147ad72991a2856ac76f22 Mon Sep 17 00:00:00 2001 From: Johannes Thumshirn Date: Mon, 4 Oct 2021 16:22:07 +0900 Subject: block: decode QUEUE_FLAG_HCTX_ACTIVE in debugfs output While debugging an issue we've found that $DEBUGFS/block/$disk/state doesn't decode QUEUE_FLAG_HCTX_ACTIVE but only displays its numerical value. Add QUEUE_FLAG(HCTX_ACTIVE) to the blk_queue_flag_name array so it'll get decoded properly. Signed-off-by: Johannes Thumshirn Link: https://lore.kernel.org/r/4351076388918075bd80ef07756f9d2ce63be12c.1633332053.git.johannes.thumshirn@wdc.com Signed-off-by: Jens Axboe --- block/blk-mq-debugfs.c | 1 + 1 file changed, 1 insertion(+) (limited to 'block') diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c index 4b66d2776eda..3b38d15723de 100644 --- a/block/blk-mq-debugfs.c +++ b/block/blk-mq-debugfs.c @@ -129,6 +129,7 @@ static const char *const blk_queue_flag_name[] = { QUEUE_FLAG_NAME(PCI_P2PDMA), QUEUE_FLAG_NAME(ZONE_RESETALL), QUEUE_FLAG_NAME(RQ_ALLOC_TIME), + QUEUE_FLAG_NAME(HCTX_ACTIVE), QUEUE_FLAG_NAME(NOWAIT), }; #undef QUEUE_FLAG_NAME -- cgit