====================================================== WARNING: possible circular locking dependency detected 6.12.0-rc6-syzkaller-00192-gf1dce1f09380 #0 Not tainted ------------------------------------------------------ syz.0.0/5324 is trying to acquire lock: ffff88804ff14a58 (kn->active#5){++++}-{0:0}, at: __kernfs_remove+0x400/0x870 fs/kernfs/dir.c:1486 but task is already holding lock: ffff88801fb2b4c8 (&disk->open_mutex){+.+.}-{3:3}, at: bdev_release+0x17e/0x700 block/bdev.c:1087 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&disk->open_mutex){+.+.}-{3:3}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752 bdev_open+0xf0/0xc50 block/bdev.c:904 bdev_file_open_by_dev+0x1b0/0x220 block/bdev.c:1018 disk_scan_partitions+0x1be/0x2b0 block/genhd.c:367 device_add_disk+0xd02/0x1000 block/genhd.c:510 pmem_attach_disk+0xdf7/0x10e0 drivers/nvdimm/pmem.c:576 nvdimm_bus_probe+0x147/0x4e0 drivers/nvdimm/bus.c:94 really_probe+0x2b8/0xad0 drivers/base/dd.c:658 __driver_probe_device+0x1a2/0x390 drivers/base/dd.c:800 driver_probe_device+0x50/0x430 drivers/base/dd.c:830 __driver_attach+0x45f/0x710 drivers/base/dd.c:1216 bus_for_each_dev+0x239/0x2b0 drivers/base/bus.c:370 bus_add_driver+0x346/0x670 drivers/base/bus.c:675 driver_register+0x23a/0x320 drivers/base/driver.c:246 do_one_initcall+0x248/0x880 init/main.c:1269 do_initcall_level+0x157/0x210 init/main.c:1331 do_initcalls+0x3f/0x80 init/main.c:1347 kernel_init_freeable+0x435/0x5d0 init/main.c:1580 kernel_init+0x1d/0x2b0 init/main.c:1469 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #1 (&nvdimm_namespace_key){+.+.}-{3:3}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752 device_lock include/linux/device.h:1014 [inline] uevent_show+0x17d/0x340 drivers/base/core.c:2736 dev_attr_show+0x55/0xc0 drivers/base/core.c:2430 sysfs_kf_seq_show+0x331/0x4c0 fs/sysfs/file.c:59 seq_read_iter+0x43f/0xd70 fs/seq_file.c:230 new_sync_read fs/read_write.c:488 [inline] vfs_read+0x991/0xb70 fs/read_write.c:569 ksys_read+0x183/0x2b0 fs/read_write.c:712 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (kn->active#5){++++}-{0:0}: check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 kernfs_drain+0x31c/0x6d0 fs/kernfs/dir.c:500 __kernfs_remove+0x400/0x870 fs/kernfs/dir.c:1486 kernfs_remove_by_name_ns+0xdc/0x160 fs/kernfs/dir.c:1694 sysfs_remove_file include/linux/sysfs.h:773 [inline] device_remove_file drivers/base/core.c:3054 [inline] device_del+0x56a/0x9b0 drivers/base/core.c:3859 drop_partition+0x11b/0x180 block/partitions/core.c:273 bdev_disk_changed+0x2bf/0x13f0 block/partitions/core.c:666 __loop_clr_fd drivers/block/loop.c:1182 [inline] lo_release+0x53e/0x850 drivers/block/loop.c:1739 bdev_release+0x5dd/0x700 blkdev_release+0x15/0x20 block/fops.c:639 __fput+0x23f/0x880 fs/file_table.c:431 task_work_run+0x24f/0x310 kernel/task_work.c:239 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x168/0x370 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: kn->active#5 --> &nvdimm_namespace_key --> &disk->open_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&disk->open_mutex); lock(&nvdimm_namespace_key); lock(&disk->open_mutex); lock(kn->active#5); *** DEADLOCK *** 1 lock held by syz.0.0/5324: #0: ffff88801fb2b4c8 (&disk->open_mutex){+.+.}-{3:3}, at: bdev_release+0x17e/0x700 block/bdev.c:1087 stack backtrace: CPU: 0 UID: 0 PID: 5324 Comm: syz.0.0 Not tainted 6.12.0-rc6-syzkaller-00192-gf1dce1f09380 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2206 check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 kernfs_drain+0x31c/0x6d0 fs/kernfs/dir.c:500 __kernfs_remove+0x400/0x870 fs/kernfs/dir.c:1486 kernfs_remove_by_name_ns+0xdc/0x160 fs/kernfs/dir.c:1694 sysfs_remove_file include/linux/sysfs.h:773 [inline] device_remove_file drivers/base/core.c:3054 [inline] device_del+0x56a/0x9b0 drivers/base/core.c:3859 drop_partition+0x11b/0x180 block/partitions/core.c:273 bdev_disk_changed+0x2bf/0x13f0 block/partitions/core.c:666 __loop_clr_fd drivers/block/loop.c:1182 [inline] lo_release+0x53e/0x850 drivers/block/loop.c:1739 bdev_release+0x5dd/0x700 blkdev_release+0x15/0x20 block/fops.c:639 __fput+0x23f/0x880 fs/file_table.c:431 task_work_run+0x24f/0x310 kernel/task_work.c:239 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x168/0x370 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7faffaf7e719 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fffc81cc548 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 0000000000010b03 RCX: 00007faffaf7e719 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007faffb137a80 R08: 0000000000000001 R09: 00007fffc81cc83f R10: 00007faffadff030 R11: 0000000000000246 R12: 0000000000010c4b R13: 00007fffc81cc650 R14: 00000000000000fa R15: ffffffffffffffff