============================================ WARNING: possible recursive locking detected 4.15.0-rc8+ #269 Not tainted -------------------------------------------- syz-executor3/16345 is trying to acquire lock: (&vq->mutex){+.+.}, at: [<00000000f20f6281>] vhost_dev_lock_vqs drivers/vhost/vhost.c:907 [inline] (&vq->mutex){+.+.}, at: [<00000000f20f6281>] vhost_process_iotlb_msg drivers/vhost/vhost.c:997 [inline] (&vq->mutex){+.+.}, at: [<00000000f20f6281>] vhost_chr_write_iter+0x278/0x1580 drivers/vhost/vhost.c:1046 but task is already holding lock: (&vq->mutex){+.+.}, at: [<00000000f20f6281>] vhost_dev_lock_vqs drivers/vhost/vhost.c:907 [inline] (&vq->mutex){+.+.}, at: [<00000000f20f6281>] vhost_process_iotlb_msg drivers/vhost/vhost.c:997 [inline] (&vq->mutex){+.+.}, at: [<00000000f20f6281>] vhost_chr_write_iter+0x278/0x1580 drivers/vhost/vhost.c:1046 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&vq->mutex); lock(&vq->mutex); *** DEADLOCK *** May be due to missing lock nesting notation 1 lock held by syz-executor3/16345: #0: (&vq->mutex){+.+.}, at: [<00000000f20f6281>] vhost_dev_lock_vqs drivers/vhost/vhost.c:907 [inline] #0: (&vq->mutex){+.+.}, at: [<00000000f20f6281>] vhost_process_iotlb_msg drivers/vhost/vhost.c:997 [inline] #0: (&vq->mutex){+.+.}, at: [<00000000f20f6281>] vhost_chr_write_iter+0x278/0x1580 drivers/vhost/vhost.c:1046 stack backtrace: CPU: 1 PID: 16345 Comm: syz-executor3 Not tainted 4.15.0-rc8+ #269 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 print_deadlock_bug kernel/locking/lockdep.c:1756 [inline] check_deadlock kernel/locking/lockdep.c:1800 [inline] validate_chain kernel/locking/lockdep.c:2396 [inline] __lock_acquire+0xe8f/0x3e00 kernel/locking/lockdep.c:3426 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3914 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 vhost_dev_lock_vqs drivers/vhost/vhost.c:907 [inline] vhost_process_iotlb_msg drivers/vhost/vhost.c:997 [inline] vhost_chr_write_iter+0x278/0x1580 drivers/vhost/vhost.c:1046 vhost_net_chr_write_iter+0x59/0x70 drivers/vhost/net.c:1353 call_write_iter include/linux/fs.h:1772 [inline] new_sync_write fs/read_write.c:469 [inline] __vfs_write+0x684/0x970 fs/read_write.c:482 vfs_write+0x189/0x510 fs/read_write.c:544 SYSC_write fs/read_write.c:589 [inline] SyS_write+0xef/0x220 fs/read_write.c:581 entry_SYSCALL_64_fastpath+0x29/0xa0 RIP: 0033:0x452ee9 RSP: 002b:00007f6d5889dc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452ee9 RDX: 000000000000042d RSI: 0000000020fc9000 RDI: 0000000000000013 RBP: 000000000000006f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006efb08 R13: 00000000ffffffff R14: 00007f6d5889e6d4 R15: 0000000000000000 9pnet_virtio: no channels available for device ./file0 QAT: Invalid ioctl QAT: Invalid ioctl kauditd_printk_skb: 163 callbacks suppressed audit: type=1326 audit(1516426286.653:1301): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 pid=16468 comm="syz-executor3" exe="/root/syz-executor3" sig=0 arch=c000003e syscall=202 compat=0 ip=0x452ee9 code=0x7ffc0000 audit: type=1326 audit(1516426286.654:1302): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 pid=16468 comm="syz-executor3" exe="/root/syz-executor3" sig=0 arch=c000003e syscall=63 compat=0 ip=0x452ee9 code=0x7ffc0000 QAT: Invalid ioctl QAT: Invalid ioctl QAT: Invalid ioctl audit: type=1326 audit(1516426286.654:1303): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 pid=16468 comm="syz-executor3" exe="/root/syz-executor3" sig=0 arch=c000003e syscall=202 compat=0 ip=0x452ee9 code=0x7ffc0000 audit: type=1326 audit(1516426286.654:1304): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 pid=16468 comm="syz-executor3" exe="/root/syz-executor3" sig=0 arch=c000003e syscall=55 compat=0 ip=0x452ee9 code=0x7ffc0000 audit: type=1326 audit(1516426286.654:1305): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 pid=16468 comm="syz-executor3" exe="/root/syz-executor3" sig=0 arch=c000003e syscall=202 compat=0 ip=0x452ee9 code=0x7ffc0000 audit: type=1326 audit(1516426286.654:1306): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 pid=16468 comm="syz-executor3" exe="/root/syz-executor3" sig=0 arch=c000003e syscall=55 compat=0 ip=0x452ee9 code=0x7ffc0000 audit: type=1326 audit(1516426286.654:1307): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 pid=16468 comm="syz-executor3" exe="/root/syz-executor3" sig=0 arch=c000003e syscall=202 compat=0 ip=0x452ee9 code=0x7ffc0000 audit: type=1326 audit(1516426286.654:1308): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 pid=16468 comm="syz-executor3" exe="/root/syz-executor3" sig=0 arch=c000003e syscall=9 compat=0 ip=0x452ee9 code=0x7ffc0000 audit: type=1326 audit(1516426286.654:1309): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 pid=16468 comm="syz-executor3" exe="/root/syz-executor3" sig=0 arch=c000003e syscall=202 compat=0 ip=0x452ee9 code=0x7ffc0000 audit: type=1326 audit(1516426286.654:1310): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 pid=16468 comm="syz-executor3" exe="/root/syz-executor3" sig=0 arch=c000003e syscall=257 compat=0 ip=0x452ee9 code=0x7ffc0000