====================================================== WARNING: possible circular locking dependency detected 6.10.0-rc5-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/5226 is trying to acquire lock: ffff88801ec770f8 (kn->active#5){++++}-{0:0}, at: __kernfs_remove+0x281/0x670 fs/kernfs/dir.c:1486 but task is already holding lock: ffff888021eec4c8 (&disk->open_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x62b/0x850 drivers/block/loop.c:1207 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&disk->open_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752 bdev_open+0x41a/0xe50 block/bdev.c:897 bdev_file_open_by_dev block/bdev.c:1011 [inline] bdev_file_open_by_dev+0x17d/0x210 block/bdev.c:986 disk_scan_partitions+0x1ed/0x320 block/genhd.c:367 device_add_disk+0xe97/0x1250 block/genhd.c:510 pmem_attach_disk+0x9fe/0x1400 drivers/nvdimm/pmem.c:578 nd_pmem_probe+0x1a9/0x1f0 drivers/nvdimm/pmem.c:651 nvdimm_bus_probe+0x169/0x5d0 drivers/nvdimm/bus.c:91 call_driver_probe drivers/base/dd.c:578 [inline] really_probe+0x23e/0xa90 drivers/base/dd.c:656 __driver_probe_device+0x1de/0x440 drivers/base/dd.c:798 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:828 __driver_attach+0x283/0x580 drivers/base/dd.c:1214 bus_for_each_dev+0x13c/0x1d0 drivers/base/bus.c:368 bus_add_driver+0x2e9/0x690 drivers/base/bus.c:673 driver_register+0x15c/0x4b0 drivers/base/driver.c:246 __nd_driver_register+0x103/0x1a0 drivers/nvdimm/bus.c:619 do_one_initcall+0x128/0x700 init/main.c:1267 do_initcall_level init/main.c:1329 [inline] do_initcalls init/main.c:1345 [inline] do_basic_setup init/main.c:1364 [inline] kernel_init_freeable+0x69d/0xca0 init/main.c:1578 kernel_init+0x1c/0x2b0 init/main.c:1467 ret_from_fork+0x45/0x80 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}: __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752 device_lock include/linux/device.h:1009 [inline] uevent_show+0x188/0x3b0 drivers/base/core.c:2743 dev_attr_show+0x53/0xe0 drivers/base/core.c:2437 sysfs_kf_seq_show+0x23e/0x410 fs/sysfs/file.c:59 seq_read_iter+0x4fa/0x12c0 fs/seq_file.c:230 kernfs_fop_read_iter+0x41a/0x590 fs/kernfs/file.c:279 new_sync_read fs/read_write.c:395 [inline] vfs_read+0x869/0xbd0 fs/read_write.c:476 ksys_read+0x12f/0x260 fs/read_write.c:619 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 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:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719 kernfs_drain+0x48f/0x590 fs/kernfs/dir.c:500 __kernfs_remove+0x281/0x670 fs/kernfs/dir.c:1486 kernfs_remove_by_name_ns+0xb2/0x130 fs/kernfs/dir.c:1694 sysfs_remove_file include/linux/sysfs.h:773 [inline] device_remove_file drivers/base/core.c:3061 [inline] device_remove_file drivers/base/core.c:3057 [inline] device_del+0x381/0x9f0 drivers/base/core.c:3866 drop_partition+0x109/0x1c0 block/partitions/core.c:273 bdev_disk_changed+0x24d/0x14f0 block/partitions/core.c:664 __loop_clr_fd+0x654/0x850 drivers/block/loop.c:1208 loop_clr_fd drivers/block/loop.c:1276 [inline] lo_ioctl+0x5dc/0x1950 drivers/block/loop.c:1578 blkdev_ioctl+0x27c/0x6e0 block/ioctl.c:676 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl fs/ioctl.c:893 [inline] __x64_sys_ioctl+0x193/0x220 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 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-executor.0/5226: #0: ffff888021eec4c8 (&disk->open_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x62b/0x850 drivers/block/loop.c:1207 stack backtrace: CPU: 0 PID: 5226 Comm: syz-executor.0 Not tainted 6.10.0-rc5-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719 kernfs_drain+0x48f/0x590 fs/kernfs/dir.c:500 __kernfs_remove+0x281/0x670 fs/kernfs/dir.c:1486 kernfs_remove_by_name_ns+0xb2/0x130 fs/kernfs/dir.c:1694 sysfs_remove_file include/linux/sysfs.h:773 [inline] device_remove_file drivers/base/core.c:3061 [inline] device_remove_file drivers/base/core.c:3057 [inline] device_del+0x381/0x9f0 drivers/base/core.c:3866 drop_partition+0x109/0x1c0 block/partitions/core.c:273 bdev_disk_changed+0x24d/0x14f0 block/partitions/core.c:664 __loop_clr_fd+0x654/0x850 drivers/block/loop.c:1208 loop_clr_fd drivers/block/loop.c:1276 [inline] lo_ioctl+0x5dc/0x1950 drivers/block/loop.c:1578 blkdev_ioctl+0x27c/0x6e0 block/ioctl.c:676 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl fs/ioctl.c:893 [inline] __x64_sys_ioctl+0x193/0x220 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f79dee7cc4b Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00 RSP: 002b:00007ffc211531f0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f79dee7cc4b RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000003 RBP: 00007ffc211532ac R08: 0000000000000000 R09: 00007ffc21152f97 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000032 R13: 0000000000018e4b R14: 0000000000018ad6 R15: 0000000000000012