loop0: detected capacity change from 0 to 4096
=======================================================
WARNING: The mand mount option has been deprecated and
         and is ignored by this kernel. Remove the mand
         option from the mount to silence this warning.
=======================================================
nvmet: adding nsid 1 to subsystem testnqn

======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.0/5320 is trying to acquire lock:
ffff88804446d798 (&ima_iint_mutex_key[depth]){+.+.}-{4:4}, at: process_measurement+0x7d0/0x1c10 security/integrity/ima/ima_main.c:319

but task is already holding lock:
ffff888052d3c068 (&subsys->lock){+.+.}-{4:4}, at: nvmet_ns_enable+0x4d/0x780 drivers/nvme/target/core.c:583

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&subsys->lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821
       nvmet_ns_device_path_store+0x54/0x160 drivers/nvme/target/configfs.c:536
       flush_write_buffer fs/configfs/file.c:207 [inline]
       configfs_write_iter+0x337/0x430 fs/configfs/file.c:229
       new_sync_write fs/read_write.c:595 [inline]
       vfs_write+0x612/0xba0 fs/read_write.c:687
       ksys_write+0x150/0x270 fs/read_write.c:739
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&p->frag_sem){.+.+}-{4:4}:
       down_read+0x4a/0x330 kernel/locking/rwsem.c:1574
       fill_read_buffer fs/configfs/file.c:66 [inline]
       configfs_read_iter+0x1cc/0x620 fs/configfs/file.c:88
       __kernel_read+0x4ca/0x960 fs/read_write.c:532
       integrity_kernel_read+0x89/0xd0 security/integrity/iint.c:28
       ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:222 [inline]
       ima_calc_file_hash+0x451/0x890 security/integrity/ima/ima_crypto.c:280
       ima_collect_measurement+0x51b/0xa00 security/integrity/ima/ima_api.c:300
       process_measurement+0x1272/0x1c10 security/integrity/ima/ima_main.c:425
       ima_file_check+0xe1/0x130 security/integrity/ima/ima_main.c:685
       security_file_post_open+0xb3/0x260 security/security.c:2755
       do_open fs/namei.c:4702 [inline]
       path_openat+0x2e90/0x3830 fs/namei.c:4863
       do_file_open+0x23e/0x4a0 fs/namei.c:4892
       do_sys_openat2+0x115/0x200 fs/open.c:1368
       do_sys_open fs/open.c:1374 [inline]
       __do_sys_openat fs/open.c:1390 [inline]
       __se_sys_openat fs/open.c:1385 [inline]
       __x64_sys_openat+0x138/0x170 fs/open.c:1385
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&buffer->mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821
       configfs_read_iter+0x70/0x620 fs/configfs/file.c:86
       __kernel_read+0x4ca/0x960 fs/read_write.c:532
       integrity_kernel_read+0x89/0xd0 security/integrity/iint.c:28
       ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:222 [inline]
       ima_calc_file_hash+0x451/0x890 security/integrity/ima/ima_crypto.c:280
       ima_collect_measurement+0x51b/0xa00 security/integrity/ima/ima_api.c:300
       process_measurement+0x1272/0x1c10 security/integrity/ima/ima_main.c:425
       ima_file_check+0xe1/0x130 security/integrity/ima/ima_main.c:685
       security_file_post_open+0xb3/0x260 security/security.c:2755
       do_open fs/namei.c:4702 [inline]
       path_openat+0x2e90/0x3830 fs/namei.c:4863
       do_file_open+0x23e/0x4a0 fs/namei.c:4892
       do_sys_openat2+0x115/0x200 fs/open.c:1368
       do_sys_open fs/open.c:1374 [inline]
       __do_sys_openat fs/open.c:1390 [inline]
       __se_sys_openat fs/open.c:1385 [inline]
       __x64_sys_openat+0x138/0x170 fs/open.c:1385
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&ima_iint_mutex_key[depth]){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3165 [inline]
       check_prevs_add kernel/locking/lockdep.c:3284 [inline]
       validate_chain kernel/locking/lockdep.c:3908 [inline]
       __lock_acquire+0x1520/0x2cf0 kernel/locking/lockdep.c:5237
       lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821
       process_measurement+0x7d0/0x1c10 security/integrity/ima/ima_main.c:319
       ima_file_check+0xe1/0x130 security/integrity/ima/ima_main.c:685
       security_file_post_open+0xb3/0x260 security/security.c:2755
       do_open fs/namei.c:4702 [inline]
       path_openat+0x2e90/0x3830 fs/namei.c:4863
       do_file_open+0x23e/0x4a0 fs/namei.c:4892
       file_open_name fs/open.c:1326 [inline]
       filp_open+0x16d/0x1d0 fs/open.c:1343
       nvmet_file_ns_enable+0x74/0x350 drivers/nvme/target/io-cmd-file.c:41
       nvmet_ns_enable+0xaa/0x780 drivers/nvme/target/core.c:596
       nvmet_ns_enable_store+0xd7/0x170 drivers/nvme/target/configfs.c:735
       flush_write_buffer fs/configfs/file.c:207 [inline]
       configfs_write_iter+0x337/0x430 fs/configfs/file.c:229
       new_sync_write fs/read_write.c:595 [inline]
       vfs_write+0x612/0xba0 fs/read_write.c:687
       ksys_write+0x150/0x270 fs/read_write.c:739
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  &ima_iint_mutex_key[depth] --> &p->frag_sem --> &subsys->lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&subsys->lock);
                               lock(&p->frag_sem);
                               lock(&subsys->lock);
  lock(&ima_iint_mutex_key[depth]);

 *** DEADLOCK ***

6 locks held by syz.0.0/5320:
 #0: ffff88803e9709b0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
 #1: ffff8880316e6450 (sb_writers#13){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline]
 #1: ffff8880316e6450 (sb_writers#13){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
 #2: ffff88801328b880 (&buffer->mutex){+.+.}-{4:4}, at: configfs_write_iter+0x7e/0x430 fs/configfs/file.c:226
 #3: ffff888042eff370 (&p->frag_sem){.+.+}-{4:4}, at: flush_write_buffer fs/configfs/file.c:205 [inline]
 #3: ffff888042eff370 (&p->frag_sem){.+.+}-{4:4}, at: configfs_write_iter+0x238/0x430 fs/configfs/file.c:229
 #4: ffffffff8f6dbfa8 (nvmet_config_sem){+.+.}-{4:4}, at: nvmet_ns_enable_store+0xc8/0x170 drivers/nvme/target/configfs.c:733
 #5: ffff888052d3c068 (&subsys->lock){+.+.}-{4:4}, at: nvmet_ns_enable+0x4d/0x780 drivers/nvme/target/core.c:583

stack backtrace:
CPU: 0 UID: 0 PID: 5320 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043
 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175
 check_prev_add kernel/locking/lockdep.c:3165 [inline]
 check_prevs_add kernel/locking/lockdep.c:3284 [inline]
 validate_chain kernel/locking/lockdep.c:3908 [inline]
 __lock_acquire+0x1520/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
 __mutex_lock_common kernel/locking/mutex.c:646 [inline]
 __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821
 process_measurement+0x7d0/0x1c10 security/integrity/ima/ima_main.c:319
 ima_file_check+0xe1/0x130 security/integrity/ima/ima_main.c:685
 security_file_post_open+0xb3/0x260 security/security.c:2755
 do_open fs/namei.c:4702 [inline]
 path_openat+0x2e90/0x3830 fs/namei.c:4863
 do_file_open+0x23e/0x4a0 fs/namei.c:4892
 file_open_name fs/open.c:1326 [inline]
 filp_open+0x16d/0x1d0 fs/open.c:1343
 nvmet_file_ns_enable+0x74/0x350 drivers/nvme/target/io-cmd-file.c:41
 nvmet_ns_enable+0xaa/0x780 drivers/nvme/target/core.c:596
 nvmet_ns_enable_store+0xd7/0x170 drivers/nvme/target/configfs.c:735
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x337/0x430 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x612/0xba0 fs/read_write.c:687
 ksys_write+0x150/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbeaed9e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fbeafc3dfe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fbeaf025fa0 RCX: 00007fbeaed9e0d9
RDX: 0000000000000001 RSI: 0000200000000580 RDI: 000000000000000a
RBP: 00007fbeaee35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbeaf026038 R14: 00007fbeaf025fa0 R15: 00007ffc7b3acbe8
 </TASK>