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authorBart Van Assche <bvanassche@acm.org>2020-03-09 21:26:22 -0700
committerJens Axboe <axboe@kernel.dk>2020-03-10 07:09:59 -0600
commit9b03b713082a31a5b90e0a893c72aa620e255c26 (patch)
tree3b2ea73c40c95c8f36a33a96ffb9a881c5a7a129
parent2004bfdef945fe55196db6b9cdf321fbc75bb0de (diff)
null_blk: Handle null_add_dev() failures properly
If null_add_dev() fails then null_del_dev() is called with a NULL argument. Make null_del_dev() handle this scenario correctly. This patch fixes the following KASAN complaint: null-ptr-deref in null_del_dev+0x28/0x280 [null_blk] Read of size 8 at addr 0000000000000000 by task find/1062 Call Trace: dump_stack+0xa5/0xe6 __kasan_report.cold+0x65/0x99 kasan_report+0x16/0x20 __asan_load8+0x58/0x90 null_del_dev+0x28/0x280 [null_blk] nullb_group_drop_item+0x7e/0xa0 [null_blk] client_drop_item+0x53/0x80 [configfs] configfs_rmdir+0x395/0x4e0 [configfs] vfs_rmdir+0xb6/0x220 do_rmdir+0x238/0x2c0 __x64_sys_unlinkat+0x75/0x90 do_syscall_64+0x6f/0x2f0 entry_SYSCALL_64_after_hwframe+0x49/0xbe Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Cc: Johannes Thumshirn <jth@kernel.org> Cc: Hannes Reinecke <hare@suse.com> Cc: Ming Lei <ming.lei@redhat.com> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--drivers/block/null_blk_main.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
index 80d3dcb8722c..d21c82c8863f 100644
--- a/drivers/block/null_blk_main.c
+++ b/drivers/block/null_blk_main.c
@@ -1469,7 +1469,12 @@ static const struct blk_mq_ops null_mq_ops = {
static void null_del_dev(struct nullb *nullb)
{
- struct nullb_device *dev = nullb->dev;
+ struct nullb_device *dev;
+
+ if (!nullb)
+ return;
+
+ dev = nullb->dev;
ida_simple_remove(&nullb_indexes, nullb->index);