From: Bart Van Assche bvanassche@acm.org
[ Upstream commit 9b03b713082a31a5b90e0a893c72aa620e255c26 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/block/null_blk.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c index e9776ca0996b0..b4078901dbcb9 100644 --- a/drivers/block/null_blk.c +++ b/drivers/block/null_blk.c @@ -1593,7 +1593,12 @@ static void null_nvm_unregister(struct nullb *nullb) {}
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);