======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G S                 
------------------------------------------------------
syz.5.1357/11683 is trying to acquire lock:
ffff88807b7dc460 (sb_writers#6){.+.+}-{0:0}, at: lookup_open+0x150/0x1990 fs/namei.c:4480

but task is already holding lock:
ffff888034da2068 (&subsys->lock){+.+.}-{4:4}, at: nvmet_ns_enable+0x4f/0x660 drivers/nvme/target/core.c:590

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&subsys->lock){+.+.}-{4:4}:
       lock_acquire kernel/locking/lockdep.c:5942 [inline]
       lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821
       nvmet_ns_buffered_io_store+0xc0/0x1e0 drivers/nvme/target/configfs.c:764
       flush_write_buffer fs/configfs/file.c:207 [inline]
       configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
       new_sync_write fs/read_write.c:595 [inline]
       vfs_write+0x6af/0x1050 fs/read_write.c:687
       ksys_write+0x12a/0x250 fs/read_write.c:739
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&p->frag_sem){.+.+}-{4:4}:
       lock_acquire kernel/locking/lockdep.c:5942 [inline]
       lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899
       down_read+0x99/0x4c0 kernel/locking/rwsem.c:1574
       __configfs_open_file+0xe8/0x9c0 fs/configfs/file.c:304
       do_dentry_open+0x6ab/0x14d0 fs/open.c:996
       vfs_open+0x82/0x3f0 fs/open.c:1101
       dentry_open+0x71/0xd0 fs/open.c:1124
       ima_calc_file_hash+0xe1/0x380 security/integrity/ima/ima_crypto.c:269
       ima_collect_measurement+0x94f/0xb30 security/integrity/ima/ima_api.c:300
       process_measurement+0xdfe/0x2350 security/integrity/ima/ima_main.c:425
       ima_file_check+0xc3/0x110 security/integrity/ima/ima_main.c:685
       security_file_post_open+0xc4/0x210 security/security.c:2755
       do_open fs/namei.c:4868 [inline]
       path_openat+0x5cd/0x2440 fs/namei.c:5029
       do_file_open+0x20e/0x430 fs/namei.c:5058
       do_sys_openat2+0x10f/0x1e0 fs/open.c:1417
       do_sys_open fs/open.c:1423 [inline]
       __do_sys_openat fs/open.c:1439 [inline]
       __se_sys_openat fs/open.c:1434 [inline]
       __x64_sys_openat+0x12d/0x210 fs/open.c:1434
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&ima_iint_mutex_key[depth]){+.+.}-{4:4}:
       lock_acquire kernel/locking/lockdep.c:5942 [inline]
       lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821
       process_measurement+0x5ab/0x2350 security/integrity/ima/ima_main.c:319
       ima_file_check+0xc3/0x110 security/integrity/ima/ima_main.c:685
       security_file_post_open+0xc4/0x210 security/security.c:2755
       do_open fs/namei.c:4868 [inline]
       path_openat+0x5cd/0x2440 fs/namei.c:5029
       do_file_open+0x20e/0x430 fs/namei.c:5058
       do_sys_openat2+0x10f/0x1e0 fs/open.c:1417
       do_sys_open fs/open.c:1423 [inline]
       __do_sys_openat fs/open.c:1439 [inline]
       __se_sys_openat fs/open.c:1434 [inline]
       __x64_sys_openat+0x12d/0x210 fs/open.c:1434
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (sb_writers#6){.+.+}-{0:0}:
       check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3209
       check_prevs_add kernel/locking/lockdep.c:3328 [inline]
       validate_chain kernel/locking/lockdep.c:3952 [inline]
       __lock_acquire+0x1528/0x1f40 kernel/locking/lockdep.c:5288
       lock_acquire kernel/locking/lockdep.c:5942 [inline]
       lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899
       percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline]
       percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
       __sb_start_write include/linux/fs/super.h:19 [inline]
       sb_start_write include/linux/fs/super.h:125 [inline]
       mnt_want_write+0x6f/0x420 fs/namespace.c:527
       lookup_open+0x150/0x1990 fs/namei.c:4480
       open_last_lookups fs/namei.c:4796 [inline]
       path_openat+0xa2c/0x2440 fs/namei.c:5026
       do_file_open+0x20e/0x430 fs/namei.c:5058
       file_open_name+0x1c3/0x3e0 fs/open.c:1375
       filp_open+0x2e/0x50 fs/open.c:1392
       nvmet_file_ns_enable+0x95/0x420 drivers/nvme/target/io-cmd-file.c:41
       nvmet_ns_enable+0x44e/0x660 drivers/nvme/target/core.c:608
       nvmet_ns_enable_store+0x11e/0x160 drivers/nvme/target/configfs.c:740
       flush_write_buffer fs/configfs/file.c:207 [inline]
       configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
       new_sync_write fs/read_write.c:595 [inline]
       vfs_write+0x6af/0x1050 fs/read_write.c:687
       ksys_write+0x12a/0x250 fs/read_write.c:739
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  sb_writers#6 --> &p->frag_sem --> &subsys->lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&subsys->lock);
                               lock(&p->frag_sem);
                               lock(&subsys->lock);
  rlock(sb_writers#6);

 *** DEADLOCK ***

locks held by syz.5.1357/11683: 6, last CPU#1:
 #0: ffff888079a07b30 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
 #1: ffff88801f374460 (sb_writers#16){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
 #2: ffff888031717480 (&buffer->mutex){+.+.}-{4:4}, at: configfs_write_iter+0x76/0x4e0 fs/configfs/file.c:226
 #3: ffff8880352e0470 (&p->frag_sem){.+.+}-{4:4}, at: flush_write_buffer fs/configfs/file.c:205 [inline]
 #3: ffff8880352e0470 (&p->frag_sem){.+.+}-{4:4}, at: configfs_write_iter+0x218/0x4e0 fs/configfs/file.c:229
 #4: ffffffff90f5cea8 (nvmet_config_sem){+.+.}-{4:4}, at: nvmet_ns_enable_store+0xa5/0x160 drivers/nvme/target/configfs.c:738
 #5: ffff888034da2068 (&subsys->lock){+.+.}-{4:4}, at: nvmet_ns_enable+0x4f/0x660 drivers/nvme/target/core.c:590

stack backtrace:
CPU: 1 UID: 0 PID: 11683 Comm: syz.5.1357 Tainted: G S                  syzkaller #0 PREEMPT(full) 
Tainted: [S]=CPU_OUT_OF_SPEC
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_circular_bug.cold+0x178/0x1be kernel/locking/lockdep.c:2087
 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2219
 check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3209
 check_prevs_add kernel/locking/lockdep.c:3328 [inline]
 validate_chain kernel/locking/lockdep.c:3952 [inline]
 __lock_acquire+0x1528/0x1f40 kernel/locking/lockdep.c:5288
 lock_acquire kernel/locking/lockdep.c:5942 [inline]
 lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899
 percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline]
 percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
 __sb_start_write include/linux/fs/super.h:19 [inline]
 sb_start_write include/linux/fs/super.h:125 [inline]
 mnt_want_write+0x6f/0x420 fs/namespace.c:527
 lookup_open+0x150/0x1990 fs/namei.c:4480
 open_last_lookups fs/namei.c:4796 [inline]
 path_openat+0xa2c/0x2440 fs/namei.c:5026
 do_file_open+0x20e/0x430 fs/namei.c:5058
 file_open_name+0x1c3/0x3e0 fs/open.c:1375
 filp_open+0x2e/0x50 fs/open.c:1392
 nvmet_file_ns_enable+0x95/0x420 drivers/nvme/target/io-cmd-file.c:41
 nvmet_ns_enable+0x44e/0x660 drivers/nvme/target/core.c:608
 nvmet_ns_enable_store+0x11e/0x160 drivers/nvme/target/configfs.c:740
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6af/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f628799e1d9
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:00007f628881d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f6287c25fa0 RCX: 00007f628799e1d9
RDX: 0000000000000001 RSI: 00002000000004c0 RDI: 0000000000000009
RBP: 00007f6287a35888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6287c26038 R14: 00007f6287c25fa0 R15: 00007ffdb491b138
 </TASK>
nvmet: failed to open file ./file0: (-2)