====================================================== WARNING: possible circular locking dependency detected 6.15.0-rc2-syzkaller #0 Not tainted ------------------------------------------------------ syz.3.589/8431 is trying to acquire lock: ffff88804d27df08 (kn->active#5){++++}-{0:0}, at: __kernfs_remove+0x271/0x890 fs/kernfs/dir.c:1506 but task is already holding lock: ffff888043590358 (&disk->open_mutex){+.+.}-{4:4}, at: loop_reread_partitions+0x47/0x140 drivers/block/loop.c:512 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&disk->open_mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:601 [inline] __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:746 bdev_open+0x41a/0xe40 block/bdev.c:907 bdev_file_open_by_dev block/bdev.c:1021 [inline] bdev_file_open_by_dev+0x17d/0x210 block/bdev.c:996 disk_scan_partitions+0x1ed/0x320 block/genhd.c:374 add_disk_fwnode+0x1060/0x13a0 block/genhd.c:526 pmem_attach_disk+0x981/0x1350 drivers/nvdimm/pmem.c:574 nd_pmem_probe+0x1a9/0x1f0 drivers/nvdimm/pmem.c:647 nvdimm_bus_probe+0x169/0x5d0 drivers/nvdimm/bus.c:94 call_driver_probe drivers/base/dd.c:579 [inline] really_probe+0x23e/0xa90 drivers/base/dd.c:658 __driver_probe_device+0x1de/0x440 drivers/base/dd.c:800 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:830 __driver_attach+0x283/0x580 drivers/base/dd.c:1216 bus_for_each_dev+0x13b/0x1d0 drivers/base/bus.c:370 bus_add_driver+0x2e9/0x690 drivers/base/bus.c:678 driver_register+0x15c/0x4b0 drivers/base/driver.c:249 __nd_driver_register+0x103/0x1a0 drivers/nvdimm/bus.c:622 do_one_initcall+0x120/0x6e0 init/main.c:1257 do_initcall_level init/main.c:1319 [inline] do_initcalls init/main.c:1335 [inline] do_basic_setup init/main.c:1354 [inline] kernel_init_freeable+0x5c2/0x900 init/main.c:1567 kernel_init+0x1c/0x2b0 init/main.c:1457 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #1 (&nvdimm_namespace_key){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:601 [inline] __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:746 device_lock include/linux/device.h:922 [inline] uevent_show+0x187/0x3b0 drivers/base/core.c:2730 dev_attr_show+0x53/0xe0 drivers/base/core.c:2424 sysfs_kf_seq_show+0x213/0x3e0 fs/sysfs/file.c:65 seq_read_iter+0x506/0x12c0 fs/seq_file.c:230 kernfs_fop_read_iter+0x40f/0x5a0 fs/kernfs/file.c:279 new_sync_read fs/read_write.c:489 [inline] vfs_read+0x8c8/0xc70 fs/read_write.c:570 ksys_read+0x12a/0x240 fs/read_write.c:713 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (kn->active#5){++++}-{0:0}: check_prev_add kernel/locking/lockdep.c:3166 [inline] check_prevs_add kernel/locking/lockdep.c:3285 [inline] validate_chain kernel/locking/lockdep.c:3909 [inline] __lock_acquire+0x1173/0x1ba0 kernel/locking/lockdep.c:5235 lock_acquire kernel/locking/lockdep.c:5866 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5823 kernfs_drain+0x4af/0x570 fs/kernfs/dir.c:511 __kernfs_remove+0x271/0x890 fs/kernfs/dir.c:1506 kernfs_remove_by_name_ns+0x68/0x110 fs/kernfs/dir.c:1714 sysfs_remove_file include/linux/sysfs.h:794 [inline] device_remove_file drivers/base/core.c:3048 [inline] device_remove_file drivers/base/core.c:3044 [inline] device_del+0x381/0x9f0 drivers/base/core.c:3853 drop_partition+0x109/0x1c0 block/partitions/core.c:278 bdev_disk_changed+0x24f/0x1520 block/partitions/core.c:674 loop_reread_partitions+0x70/0x140 drivers/block/loop.c:513 loop_change_fd drivers/block/loop.c:666 [inline] lo_ioctl+0x20e5/0x26d0 drivers/block/loop.c:1569 lo_compat_ioctl+0xb9/0x170 drivers/block/loop.c:1726 compat_blkdev_ioctl+0x2eb/0x7a0 block/ioctl.c:754 __do_compat_sys_ioctl+0x1cb/0x2c0 fs/ioctl.c:1004 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e 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.3.589/8431: #0: ffff888043590358 (&disk->open_mutex){+.+.}-{4:4}, at: loop_reread_partitions+0x47/0x140 drivers/block/loop.c:512 stack backtrace: CPU: 0 UID: 0 PID: 8431 Comm: syz.3.589 Not tainted 6.15.0-rc2-syzkaller #0 PREEMPT(full) 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+0x116/0x1f0 lib/dump_stack.c:120 print_circular_bug+0x275/0x350 kernel/locking/lockdep.c:2079 check_noncircular+0x14c/0x170 kernel/locking/lockdep.c:2211 check_prev_add kernel/locking/lockdep.c:3166 [inline] check_prevs_add kernel/locking/lockdep.c:3285 [inline] validate_chain kernel/locking/lockdep.c:3909 [inline] __lock_acquire+0x1173/0x1ba0 kernel/locking/lockdep.c:5235 lock_acquire kernel/locking/lockdep.c:5866 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5823 kernfs_drain+0x4af/0x570 fs/kernfs/dir.c:511 __kernfs_remove+0x271/0x890 fs/kernfs/dir.c:1506 kernfs_remove_by_name_ns+0x68/0x110 fs/kernfs/dir.c:1714 sysfs_remove_file include/linux/sysfs.h:794 [inline] device_remove_file drivers/base/core.c:3048 [inline] device_remove_file drivers/base/core.c:3044 [inline] device_del+0x381/0x9f0 drivers/base/core.c:3853 drop_partition+0x109/0x1c0 block/partitions/core.c:278 bdev_disk_changed+0x24f/0x1520 block/partitions/core.c:674 loop_reread_partitions+0x70/0x140 drivers/block/loop.c:513 loop_change_fd drivers/block/loop.c:666 [inline] lo_ioctl+0x20e5/0x26d0 drivers/block/loop.c:1569 lo_compat_ioctl+0xb9/0x170 drivers/block/loop.c:1726 compat_blkdev_ioctl+0x2eb/0x7a0 block/ioctl.c:754 __do_compat_sys_ioctl+0x1cb/0x2c0 fs/ioctl.c:1004 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7f83579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f50a655c EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000004c06 RDX: 0000000000000006 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 loop9: [CUMANA/ADFS] p1 [ADFS] p1 loop9: partition table partially beyond EOD, truncated loop9: p1 size 81768186 extends beyond EOD, truncated ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi