====================================================== WARNING: possible circular locking dependency detected 4.14.307-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.1/31022 is trying to acquire lock: (&bdev->bd_mutex){+.+.}, at: [] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192 but task is already holding lock: (&nbd->config_lock){+.+.}, at: [] nbd_ioctl+0x11f/0xad0 drivers/block/nbd.c:1369 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&nbd->config_lock){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 nbd_open+0x1ac/0x370 drivers/block/nbd.c:1422 __blkdev_get+0x306/0x1090 fs/block_dev.c:1470 blkdev_get+0x88/0x890 fs/block_dev.c:1611 blkdev_open+0x1cc/0x250 fs/block_dev.c:1772 do_dentry_open+0x44b/0xec0 fs/open.c:777 vfs_open+0x105/0x220 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0x628/0x2970 fs/namei.c:3571 do_filp_open+0x179/0x3c0 fs/namei.c:3605 do_sys_open+0x296/0x410 fs/open.c:1081 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x5e/0xd3 -> #1 (nbd_index_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 nbd_open+0x1e/0x370 drivers/block/nbd.c:1409 __blkdev_get+0x306/0x1090 fs/block_dev.c:1470 blkdev_get+0x88/0x890 fs/block_dev.c:1611 blkdev_open+0x1cc/0x250 fs/block_dev.c:1772 do_dentry_open+0x44b/0xec0 fs/open.c:777 vfs_open+0x105/0x220 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0x628/0x2970 fs/namei.c:3571 do_filp_open+0x179/0x3c0 fs/namei.c:3605 do_sys_open+0x296/0x410 fs/open.c:1081 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x5e/0xd3 -> #0 (&bdev->bd_mutex){+.+.}: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 blkdev_reread_part+0x1b/0x40 block/ioctl.c:192 nbd_bdev_reset drivers/block/nbd.c:1076 [inline] nbd_clear_sock_ioctl drivers/block/nbd.c:1282 [inline] __nbd_ioctl drivers/block/nbd.c:1306 [inline] nbd_ioctl+0x802/0xad0 drivers/block/nbd.c:1376 __blkdev_driver_ioctl block/ioctl.c:297 [inline] blkdev_ioctl+0x540/0x1830 block/ioctl.c:594 block_ioctl+0xd9/0x120 fs/block_dev.c:1893 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x5e/0xd3 other info that might help us debug this: Chain exists of: &bdev->bd_mutex --> nbd_index_mutex --> &nbd->config_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&nbd->config_lock); lock(nbd_index_mutex); lock(&nbd->config_lock); base_sock_release(ffff88807e2160c0) sk=ffff88809d3388c0 lock(&bdev->bd_mutex); *** DEADLOCK *** 1 lock held by syz-executor.1/31022: #0: (&nbd->config_lock){+.+.}, at: [] nbd_ioctl+0x11f/0xad0 drivers/block/nbd.c:1369 stack backtrace: CPU: 0 PID: 31022 Comm: syz-executor.1 Not tainted 4.14.307-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1905 [inline] check_prevs_add kernel/locking/lockdep.c:2022 [inline] validate_chain kernel/locking/lockdep.c:2464 [inline] __lock_acquire+0x2e0e/0x3f20 kernel/locking/lockdep.c:3491 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 blkdev_reread_part+0x1b/0x40 block/ioctl.c:192 nbd_bdev_reset drivers/block/nbd.c:1076 [inline] nbd_clear_sock_ioctl drivers/block/nbd.c:1282 [inline] __nbd_ioctl drivers/block/nbd.c:1306 [inline] nbd_ioctl+0x802/0xad0 drivers/block/nbd.c:1376 __blkdev_driver_ioctl block/ioctl.c:297 [inline] blkdev_ioctl+0x540/0x1830 block/ioctl.c:594 block_ioctl+0xd9/0x120 fs/block_dev.c:1893 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x5e/0xd3 RIP: 0033:0x7f9bc31870f9 RSP: 002b:00007f9bc16f9168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f9bc32a6f80 RCX: 00007f9bc31870f9 RDX: 0000000000000000 RSI: 000000000000ab04 RDI: 0000000000000009 RBP: 00007f9bc31e2ae9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff600e566f R14: 00007f9bc16f9300 R15: 0000000000022000 base_sock_release(ffff88807b105540) sk=ffff8880b5682940 base_sock_release(ffff88807b3d7600) sk=ffff8880ae8fc480 base_sock_release(ffff88807c926080) sk=ffff888096bc8c80 base_sock_release(ffff88807f9e7600) sk=ffff8880b4b35400 base_sock_release(ffff88807e21ab00) sk=ffff8880a829e100 base_sock_release(ffff88807e88a940) sk=ffff888084cd0ec0 base_sock_release(ffff88807f851480) sk=ffff8880b33d8140 base_sock_release(ffff88807f817180) sk=ffff8880a975f300 base_sock_release(ffff88807fac9900) sk=ffff8880991d9680 base_sock_release(ffff88807e21a200) sk=ffff8880b0a9e480 base_sock_release(ffff88807e8b9680) sk=ffff8880aa43d380 base_sock_release(ffff88807c8ef040) sk=ffff88809321d380 base_sock_release(ffff88807b125040) sk=ffff8880af556c40 base_sock_release(ffff88808eae31c0) sk=ffff88809543e540 base_sock_release(ffff88807e15fa40) sk=ffff8880af9c82c0 base_sock_release(ffff88807c8e1980) sk=ffff8880a0019600 base_sock_release(ffff88807f96f200) sk=ffff8880b36de1c0 base_sock_release(ffff88808e35f980) sk=ffff8880af868400 base_sock_release(ffff88807b006200) sk=ffff88807f110380 base_sock_release(ffff88807caa9140) sk=ffff8880a2309200 base_sock_release(ffff88807fb9e4c0) sk=ffff8880a4bbd3c0 base_sock_release(ffff88807caf3980) sk=ffff8880962b2880 base_sock_release(ffff88807b35f200) sk=ffff88809a8771c0 base_sock_release(ffff88807e951200) sk=ffff8880af4144c0 base_sock_release(ffff88807e0a80c0) sk=ffff88808f4eee00 base_sock_release(ffff88807fba3680) sk=ffff8880ae65aa40 base_sock_release(ffff88807eb2ba80) sk=ffff88809705c500 base_sock_release(ffff88807b1e54c0) sk=ffff8880a9014140 base_sock_release(ffff88807fa19180) sk=ffff8880ab0c16c0 base_sock_release(ffff88807e900580) sk=ffff8880aa0a4ac0 base_sock_release(ffff88808ea5ea40) sk=ffff8880a1b7f200 base_sock_release(ffff88807fbf2540) sk=ffff88807a944400 base_sock_release(ffff88807b39c140) sk=ffff888097069540 base_sock_release(ffff88807b39c5c0) sk=ffff88809c86d680 base_sock_release(ffff88807f940a40) sk=ffff8880aef1d340 base_sock_release(ffff88807fb76200) sk=ffff8880979a6d80 base_sock_release(ffff88807f9c79c0) sk=ffff8880aae4c3c0 base_sock_release(ffff88807fb3e100) sk=ffff8880969ba480 base_sock_release(ffff88807f8c91c0) sk=ffff8880a3878c40 base_sock_release(ffff88807e947080) sk=ffff8880a8ef4bc0 base_sock_release(ffff88809f4a3600) sk=ffff8880912a3200 base_sock_release(ffff88807b0dc480) sk=ffff88809a4ee4c0 base_sock_release(ffff88807b3d2980) sk=ffff8880ac66ca80 base_sock_release(ffff88807cb1b480) sk=ffff8880ab431740 base_sock_release(ffff88807c8fea00) sk=ffff888092d70480 base_sock_release(ffff88807c813ac0) sk=ffff88808f4ee580 base_sock_release(ffff88807eb855c0) sk=ffff888081058440 base_sock_release(ffff88807eb85140) sk=ffff88809bffebc0 base_sock_release(ffff88807e873a00) sk=ffff88809e30b400 base_sock_release(ffff88807c9521c0) sk=ffff88809310a2c0 can: request_module (can-proto-0) failed. base_sock_release(ffff88807e25c580) sk=ffff8880a9afcb80 can: request_module (can-proto-0) failed. base_sock_release(ffff88807e110100) sk=ffff88808d9f82c0 can: request_module (can-proto-0) failed. base_sock_release(ffff88807e0885c0) sk=ffff8880a8e3b4c0 base_sock_release(ffff88807b32bb00) sk=ffff888096cbb240 base_sock_release(ffff88807b14ba40) sk=ffff8880b517d540 base_sock_release(ffff88807e922100) sk=ffff8880987936c0 base_sock_release(ffff88807b125940) sk=ffff888092e10600 base_sock_release(ffff888085c7b600) sk=ffff888090020c40 base_sock_release(ffff888085c7b180) sk=ffff888091365540 base_sock_release(ffff88807fa5e640) sk=ffff88809a4ba500 base_sock_release(ffff88807caec100) sk=ffff88809a4ef5c0 base_sock_release(ffff88807e8c49c0) sk=ffff88807fe80980 base_sock_release(ffff88807e0c70c0) sk=ffff8880afb50b00 base_sock_release(ffff88807fa3f600) sk=ffff8880b5008e80 base_sock_release(ffff88807c9ec640) sk=ffff888092eba4c0 base_sock_release(ffff88807e931980) sk=ffff8880954963c0 base_sock_release(ffff88807f8629c0) sk=ffff8880b4aca300 base_sock_release(ffff88807e381500) sk=ffff8880abf72d40