Mass Storage Function, version: 2009/09/11
LUN: removable file: (no medium)
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.6.365/5819 is trying to acquire lock:
ffff88805aa9a460 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386

but task is already holding lock:
ffff88807c229928 (&common->filesem){++++}-{3:3}, at: fsg_store_file+0x174/0x530 drivers/usb/gadget/function/storage_common.c:451

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&common->filesem){++++}-{3:3}:
       down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498
       fsg_store_cdrom+0xc4/0x1a0 drivers/usb/gadget/function/storage_common.c:477
       flush_write_buffer fs/configfs/file.c:207 [inline]
       configfs_write_iter+0x30b/0x400 fs/configfs/file.c:229
       call_write_iter include/linux/fs.h:2173 [inline]
       new_sync_write fs/read_write.c:507 [inline]
       vfs_write+0x748/0xd70 fs/read_write.c:594
       ksys_write+0x153/0x260 fs/read_write.c:647
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #2 (&p->frag_sem){.+.+}-{3:3}:
       down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498
       __configfs_open_file+0xd5/0x7d0 fs/configfs/file.c:304
       do_dentry_open+0x7f7/0xf90 fs/open.c:826
       vfs_open fs/open.c:958 [inline]
       dentry_open+0xc6/0x120 fs/open.c:974
       ima_calc_file_hash+0x18c/0x1940 security/integrity/ima/ima_crypto.c:558
       ima_collect_measurement+0x335/0x7e0 security/integrity/ima/ima_api.c:255
       process_measurement+0x1185/0x1c20 security/integrity/ima/ima_main.c:351
       ima_file_check+0xc7/0x110 security/integrity/ima/ima_main.c:533
       do_open fs/namei.c:3618 [inline]
       path_openat+0x27cf/0x2fb0 fs/namei.c:3750
       do_filp_open+0x1df/0x400 fs/namei.c:3777
       do_sys_openat2+0x14b/0x500 fs/open.c:1255
       do_sys_open fs/open.c:1271 [inline]
       __do_sys_openat fs/open.c:1287 [inline]
       __se_sys_openat fs/open.c:1282 [inline]
       __x64_sys_openat+0x135/0x160 fs/open.c:1282
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #1 (&iint_mutex_key[depth]){+.+.}-{3:3}:
       __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       process_measurement+0x724/0x1c20 security/integrity/ima/ima_main.c:261
       ima_file_check+0xc7/0x110 security/integrity/ima/ima_main.c:533
       do_open fs/namei.c:3618 [inline]
       path_openat+0x27cf/0x2fb0 fs/namei.c:3750
       do_filp_open+0x1df/0x400 fs/namei.c:3777
       do_sys_openat2+0x14b/0x500 fs/open.c:1255
       do_sys_open fs/open.c:1271 [inline]
       __do_sys_openat fs/open.c:1287 [inline]
       __se_sys_openat fs/open.c:1282 [inline]
       __x64_sys_openat+0x135/0x160 fs/open.c:1282
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #0 (sb_writers#3){.+.+}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3788 [inline]
       __lock_acquire+0x2c66/0x7b50 kernel/locking/lockdep.c:5012
       lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1811 [inline]
       sb_start_write+0x4f/0x1c0 include/linux/fs.h:1881
       mnt_want_write+0x3d/0x90 fs/namespace.c:386
       open_last_lookups fs/namei.c:3529 [inline]
       path_openat+0x795/0x2fb0 fs/namei.c:3747
       do_filp_open+0x1df/0x400 fs/namei.c:3777
       file_open_name fs/open.c:1200 [inline]
       filp_open+0x17c/0x1e0 fs/open.c:1220
       fsg_lun_open+0x63/0xee0 drivers/usb/gadget/function/storage_common.c:193
       fsg_store_file+0x1a5/0x530 drivers/usb/gadget/function/storage_common.c:454
       flush_write_buffer fs/configfs/file.c:207 [inline]
       configfs_write_iter+0x30b/0x400 fs/configfs/file.c:229
       call_write_iter include/linux/fs.h:2173 [inline]
       new_sync_write fs/read_write.c:507 [inline]
       vfs_write+0x748/0xd70 fs/read_write.c:594
       ksys_write+0x153/0x260 fs/read_write.c:647
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

other info that might help us debug this:

Chain exists of:
  sb_writers#3 --> &p->frag_sem --> &common->filesem

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&common->filesem);
                               lock(&p->frag_sem);
                               lock(&common->filesem);
  lock(sb_writers#3);

 *** DEADLOCK ***

5 locks held by syz.6.365/5819:
 #0: ffff888076de5c70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056
 #1: ffff88801dba2460 (sb_writers#27){.+.+}-{0:0}, at: vfs_write+0x296/0xd70 fs/read_write.c:590
 #2: ffff88805dfe4e88 (&buffer->mutex){+.+.}-{3:3}, at: configfs_write_iter+0x7d/0x400 fs/configfs/file.c:226
 #3: ffff888060736678 (&p->frag_sem){.+.+}-{3:3}, at: flush_write_buffer fs/configfs/file.c:205 [inline]
 #3: ffff888060736678 (&p->frag_sem){.+.+}-{3:3}, at: configfs_write_iter+0x20e/0x400 fs/configfs/file.c:229
 #4: ffff88807c229928 (&common->filesem){++++}-{3:3}, at: fsg_store_file+0x174/0x530 drivers/usb/gadget/function/storage_common.c:451

stack backtrace:
CPU: 1 PID: 5819 Comm: syz.6.365 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3788 [inline]
 __lock_acquire+0x2c66/0x7b50 kernel/locking/lockdep.c:5012
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
 __sb_start_write include/linux/fs.h:1811 [inline]
 sb_start_write+0x4f/0x1c0 include/linux/fs.h:1881
 mnt_want_write+0x3d/0x90 fs/namespace.c:386
 open_last_lookups fs/namei.c:3529 [inline]
 path_openat+0x795/0x2fb0 fs/namei.c:3747
 do_filp_open+0x1df/0x400 fs/namei.c:3777
 file_open_name fs/open.c:1200 [inline]
 filp_open+0x17c/0x1e0 fs/open.c:1220
 fsg_lun_open+0x63/0xee0 drivers/usb/gadget/function/storage_common.c:193
 fsg_store_file+0x1a5/0x530 drivers/usb/gadget/function/storage_common.c:454
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x30b/0x400 fs/configfs/file.c:229
 call_write_iter include/linux/fs.h:2173 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x748/0xd70 fs/read_write.c:594
 ksys_write+0x153/0x260 fs/read_write.c:647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f4cd8cc90d9
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:00007f4cd6f21028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f4cd8f50fa0 RCX: 00007f4cd8cc90d9
RDX: 0000000000000001 RSI: 0000200000000f00 RDI: 0000000000000003
RBP: 00007f4cd8d60024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4cd8f51038 R14: 00007f4cd8f50fa0 R15: 00007ffea7f22878
 </TASK>
mass_storage.usb0/lun.0: unable to open backing file: f