syzbot

======================================================
WARNING: possible circular locking dependency detected
6.14.0-rc6-syzkaller-00253-gcb82ca153949 #0 Not tainted
------------------------------------------------------
udevd/5306 is trying to acquire lock:
ffff888043fb6878 (kn->active#5){++++}-{0:0}, at: __kernfs_remove+0x400/0x870 fs/kernfs/dir.c:1487

but task is already holding lock:
ffff888032ec74c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x17e/0x700 block/bdev.c:1086

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&disk->open_mutex){+.+.}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
       bdev_open+0xf0/0xc50 block/bdev.c:903
       bdev_file_open_by_dev+0x1b0/0x220 block/bdev.c:1017
       disk_scan_partitions+0x1be/0x2b0 block/genhd.c:374
       add_disk_fwnode+0xcc1/0xfc0 block/genhd.c:526
       pmem_attach_disk+0xe01/0x10e0 drivers/nvdimm/pmem.c:576
       nvdimm_bus_probe+0x147/0x4e0 drivers/nvdimm/bus.c:94
       really_probe+0x2b9/0xad0 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:678
       driver_register+0x23a/0x320 drivers/base/driver.c:249
       do_one_initcall+0x248/0x930 init/main.c:1257
       do_initcall_level+0x157/0x210 init/main.c:1319
       do_initcalls+0x71/0xd0 init/main.c:1335
       kernel_init_freeable+0x435/0x5d0 init/main.c:1568
       kernel_init+0x1d/0x2b0 init/main.c:1457
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #1 (&nvdimm_namespace_key){+.+.}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
       device_lock include/linux/device.h:1030 [inline]
       uevent_show+0x17d/0x340 drivers/base/core.c:2730
       dev_attr_show+0x55/0xc0 drivers/base/core.c:2424
       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:484 [inline]
       vfs_read+0x975/0xb40 fs/read_write.c:565
       ksys_read+0x18f/0x2b0 fs/read_write.c:708
       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:3163 [inline]
       check_prevs_add kernel/locking/lockdep.c:3282 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
       __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       kernfs_drain+0x31c/0x6d0 fs/kernfs/dir.c:500
       __kernfs_remove+0x400/0x870 fs/kernfs/dir.c:1487
       kernfs_remove_by_name_ns+0xdc/0x160 fs/kernfs/dir.c:1695
       sysfs_remove_file include/linux/sysfs.h:794 [inline]
       device_remove_file drivers/base/core.c:3048 [inline]
       device_del+0x56a/0x9b0 drivers/base/core.c:3853
       drop_partition+0x11b/0x180 block/partitions/core.c:278
       bdev_disk_changed+0x2c8/0x14d0 block/partitions/core.c:674
       __loop_clr_fd drivers/block/loop.c:1191 [inline]
       lo_release+0x535/0x840 drivers/block/loop.c:1758
       bdev_release+0x5dd/0x700
       blkdev_release+0x15/0x20 block/fops.c:660
       __fput+0x3e9/0x9f0 fs/file_table.c:464
       __do_sys_close fs/open.c:1580 [inline]
       __se_sys_close fs/open.c:1565 [inline]
       __x64_sys_close+0x7f/0x110 fs/open.c:1565
       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

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 udevd/5306:
 #0: ffff888032ec74c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x17e/0x700 block/bdev.c:1086

stack backtrace:
CPU: 0 UID: 0 PID: 5306 Comm: udevd Not tainted 6.14.0-rc6-syzkaller-00253-gcb82ca153949 #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:
 <TASK>
 __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:2076
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2208
 check_prev_add kernel/locking/lockdep.c:3163 [inline]
 check_prevs_add kernel/locking/lockdep.c:3282 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
 kernfs_drain+0x31c/0x6d0 fs/kernfs/dir.c:500
 __kernfs_remove+0x400/0x870 fs/kernfs/dir.c:1487
 kernfs_remove_by_name_ns+0xdc/0x160 fs/kernfs/dir.c:1695
 sysfs_remove_file include/linux/sysfs.h:794 [inline]
 device_remove_file drivers/base/core.c:3048 [inline]
 device_del+0x56a/0x9b0 drivers/base/core.c:3853
 drop_partition+0x11b/0x180 block/partitions/core.c:278
 bdev_disk_changed+0x2c8/0x14d0 block/partitions/core.c:674
 __loop_clr_fd drivers/block/loop.c:1191 [inline]
 lo_release+0x535/0x840 drivers/block/loop.c:1758
 bdev_release+0x5dd/0x700
 blkdev_release+0x15/0x20 block/fops.c:660
 __fput+0x3e9/0x9f0 fs/file_table.c:464
 __do_sys_close fs/open.c:1580 [inline]
 __se_sys_close fs/open.c:1565 [inline]
 __x64_sys_close+0x7f/0x110 fs/open.c:1565
 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
RIP: 0033:0x7f9fe65170a8
Code: 48 8b 05 83 9d 0d 00 64 c7 00 16 00 00 00 83 c8 ff 48 83 c4 20 5b c3 64 8b 04 25 18 00 00 00 85 c0 75 20 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 5b 48 8b 15 51 9d 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffc7d8d62a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00007f9fe68f10e0 RCX: 00007f9fe65170a8
RDX: 0000558276767fa5 RSI: 00007ffc7d8d5aa8 RDI: 0000000000000008
RBP: 000055872e02e980 R08: 0000000000000006 R09: 9de3d388d0cb96d8
R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000002
R13: 000055872e02d9c0 R14: 0000000000000008 R15: 000055872e024910
 </TASK>
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
udevd[5306]: inotify_add_watch(7, /dev/loop0p2, 10) failed: No such file or directory
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
udevd[5306]: inotify_add_watch(7, /dev/loop0p2, 10) failed: No such file or directory
udevd[5306]: inotify_add_watch(7, /dev/loop0p2, 10) failed: No such file or directory
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
udevd[5306]: inotify_add_watch(7, /dev/loop0p2, 10) failed: No such file or directory
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
udevd[5306]: inotify_add_watch(7, /dev/loop0p2, 10) failed: No such file or directory
udevd[5306]: inotify_add_watch(7, /dev/loop0p2, 10) failed: No such file or directory
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7
Alternate GPT is invalid, using primary GPT.
 loop0: p2 p3 p7