From: YueHaibing <yuehaibing@huawei.com>
Date: Mon, 27 May 2019 22:22:09 +0800
Subject: scsi: scsi_dh_alua: Fix possible null-ptr-deref
Git-commit: 12e750bc62044de096ab9a95201213fd912b9994
Patch-mainline: v5.2-rc3
References: git-fixes
If alloc_workqueue fails in alua_init, it should return -ENOMEM, otherwise
it will trigger null-ptr-deref while unloading module which calls
destroy_workqueue dereference
wq->lock like this:
BUG: KASAN: null-ptr-deref in __lock_acquire+0x6b4/0x1ee0
Read of size 8 at addr 0000000000000080 by task syz-executor.0/7045
CPU: 0 PID: 7045 Comm: syz-executor.0 Tainted: G C 5.1.0+ #28
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1
Call Trace:
dump_stack+0xa9/0x10e
__kasan_report+0x171/0x18d
? __lock_acquire+0x6b4/0x1ee0
kasan_report+0xe/0x20
__lock_acquire+0x6b4/0x1ee0
lock_acquire+0xb4/0x1b0
__mutex_lock+0xd8/0xb90
drain_workqueue+0x25/0x290
destroy_workqueue+0x1f/0x3f0
__x64_sys_delete_module+0x244/0x330
do_syscall_64+0x72/0x2a0
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Reported-by: Hulk Robot <hulkci@huawei.com>
Fixes: 03197b61c5ec ("scsi_dh_alua: Use workqueue for RTPG")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Lee Duncan <lduncan@suse.com>
---
drivers/scsi/device_handler/scsi_dh_alua.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index d7ac498ba35a..2a9dcb8973b7 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -1174,10 +1174,8 @@ static int __init alua_init(void)
int r;
kaluad_wq = alloc_workqueue("kaluad", WQ_MEM_RECLAIM, 0);
- if (!kaluad_wq) {
- /* Temporary failure, bypass */
- return SCSI_DH_DEV_TEMP_BUSY;
- }
+ if (!kaluad_wq)
+ return -ENOMEM;
r = scsi_register_device_handler(&alua_dh);
if (r != 0) {