EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback. ext4 filesystem being mounted at /45/file2 supports timestamps until 2038-01-19 (0x7fffffff) ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.0.2820/16538 is trying to acquire lock: ffff8880594ca418 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:412 but task is already holding lock: ffff888059061128 (&common->filesem){++++}-{3:3}, at: fsg_store_file+0x178/0x530 drivers/usb/gadget/function/storage_common.c:452 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&common->filesem){++++}-{3:3}: down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520 fsg_show_file+0x2d/0x130 drivers/usb/gadget/function/storage_common.c:339 fill_read_buffer fs/configfs/file.c:68 [inline] configfs_read_iter+0x29d/0x570 fs/configfs/file.c:88 __kernel_read+0x2e5/0x730 fs/read_write.c:428 integrity_kernel_read+0x8a/0xd0 security/integrity/iint.c:221 ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:485 [inline] ima_calc_file_shash security/integrity/ima/ima_crypto.c:516 [inline] ima_calc_file_hash+0xb1f/0x1960 security/integrity/ima/ima_crypto.c:573 ima_collect_measurement+0x4d4/0xa30 security/integrity/ima/ima_api.c:290 process_measurement+0x123a/0x1d50 security/integrity/ima/ima_main.c:370 ima_file_check+0xcc/0x110 security/integrity/ima/ima_main.c:568 do_open fs/namei.c:3685 [inline] path_openat+0x2910/0x3270 fs/namei.c:3844 do_filp_open+0x1f2/0x430 fs/namei.c:3871 do_sys_openat2+0x134/0x1d0 fs/open.c:1422 do_sys_open fs/open.c:1437 [inline] __do_sys_openat fs/open.c:1453 [inline] __se_sys_openat fs/open.c:1448 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1448 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #3 (&p->frag_sem){.+.+}-{3:3}: down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520 fill_read_buffer fs/configfs/file.c:66 [inline] configfs_read_iter+0x1a5/0x570 fs/configfs/file.c:88 __kernel_read+0x2e5/0x730 fs/read_write.c:428 integrity_kernel_read+0x8a/0xd0 security/integrity/iint.c:221 ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:485 [inline] ima_calc_file_shash security/integrity/ima/ima_crypto.c:516 [inline] ima_calc_file_hash+0xb1f/0x1960 security/integrity/ima/ima_crypto.c:573 ima_collect_measurement+0x4d4/0xa30 security/integrity/ima/ima_api.c:290 process_measurement+0x123a/0x1d50 security/integrity/ima/ima_main.c:370 ima_file_check+0xcc/0x110 security/integrity/ima/ima_main.c:568 do_open fs/namei.c:3685 [inline] path_openat+0x2910/0x3270 fs/namei.c:3844 do_filp_open+0x1f2/0x430 fs/namei.c:3871 do_sys_openat2+0x134/0x1d0 fs/open.c:1422 do_sys_open fs/open.c:1437 [inline] __do_sys_openat fs/open.c:1453 [inline] __se_sys_openat fs/open.c:1448 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1448 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #2 (&buffer->mutex#2){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x135/0xc80 kernel/locking/mutex.c:747 configfs_read_iter+0x72/0x570 fs/configfs/file.c:86 __kernel_read+0x2e5/0x730 fs/read_write.c:428 integrity_kernel_read+0x8a/0xd0 security/integrity/iint.c:221 ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:485 [inline] ima_calc_file_shash security/integrity/ima/ima_crypto.c:516 [inline] ima_calc_file_hash+0xb1f/0x1960 security/integrity/ima/ima_crypto.c:573 ima_collect_measurement+0x4d4/0xa30 security/integrity/ima/ima_api.c:290 process_measurement+0x123a/0x1d50 security/integrity/ima/ima_main.c:370 ima_file_check+0xcc/0x110 security/integrity/ima/ima_main.c:568 do_open fs/namei.c:3685 [inline] path_openat+0x2910/0x3270 fs/namei.c:3844 do_filp_open+0x1f2/0x430 fs/namei.c:3871 do_sys_openat2+0x134/0x1d0 fs/open.c:1422 do_sys_open fs/open.c:1437 [inline] __do_sys_openat fs/open.c:1453 [inline] __se_sys_openat fs/open.c:1448 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1448 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #1 (&iint_mutex_key[depth]){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x135/0xc80 kernel/locking/mutex.c:747 process_measurement+0x739/0x1d50 security/integrity/ima/ima_main.c:275 ima_file_check+0xcc/0x110 security/integrity/ima/ima_main.c:568 do_open fs/namei.c:3685 [inline] path_openat+0x2910/0x3270 fs/namei.c:3844 do_filp_open+0x1f2/0x430 fs/namei.c:3871 do_sys_openat2+0x134/0x1d0 fs/open.c:1422 do_sys_open fs/open.c:1437 [inline] __do_sys_open fs/open.c:1445 [inline] __se_sys_open fs/open.c:1441 [inline] __x64_sys_open+0x11f/0x140 fs/open.c:1441 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #0 (sb_writers#4){.+.+}-{0:0}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x37ef/0x7d80 kernel/locking/lockdep.c:5137 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1633 [inline] sb_start_write+0x4d/0x1c0 include/linux/fs.h:1708 mnt_want_write+0x41/0x90 fs/namespace.c:412 open_last_lookups fs/namei.c:3596 [inline] path_openat+0x768/0x3270 fs/namei.c:3841 do_filp_open+0x1f2/0x430 fs/namei.c:3871 file_open_name fs/open.c:1367 [inline] filp_open+0x180/0x1e0 fs/open.c:1387 fsg_lun_open+0x67/0xec0 drivers/usb/gadget/function/storage_common.c:194 fsg_store_file+0x1a9/0x530 drivers/usb/gadget/function/storage_common.c:455 flush_write_buffer fs/configfs/file.c:207 [inline] configfs_write_iter+0x312/0x400 fs/configfs/file.c:229 call_write_iter include/linux/fs.h:2018 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x474/0x9a0 fs/read_write.c:584 ksys_write+0x151/0x260 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 other info that might help us debug this: Chain exists of: sb_writers#4 --> &p->frag_sem --> &common->filesem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&common->filesem); lock(&p->frag_sem); lock(&common->filesem); rlock(sb_writers#4); *** DEADLOCK *** 5 locks held by syz.0.2820/16538: #0: ffff8880243c54c8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2a3/0x330 fs/file.c:1040 #1: ffff888018bac418 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x21e/0x9a0 fs/read_write.c:580 #2: ffff88802f499488 (&buffer->mutex#2){+.+.}-{3:3}, at: configfs_write_iter+0x81/0x400 fs/configfs/file.c:226 #3: ffff8880256afa78 (&p->frag_sem){.+.+}-{3:3}, at: flush_write_buffer fs/configfs/file.c:205 [inline] #3: ffff8880256afa78 (&p->frag_sem){.+.+}-{3:3}, at: configfs_write_iter+0x215/0x400 fs/configfs/file.c:229 #4: ffff888059061128 (&common->filesem){++++}-{3:3}, at: fsg_store_file+0x178/0x530 drivers/usb/gadget/function/storage_common.c:452 stack backtrace: CPU: 1 PID: 16538 Comm: syz.0.2820 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 check_noncircular+0x2fc/0x400 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x37ef/0x7d80 kernel/locking/lockdep.c:5137 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1633 [inline] sb_start_write+0x4d/0x1c0 include/linux/fs.h:1708 mnt_want_write+0x41/0x90 fs/namespace.c:412 open_last_lookups fs/namei.c:3596 [inline] path_openat+0x768/0x3270 fs/namei.c:3841 do_filp_open+0x1f2/0x430 fs/namei.c:3871 file_open_name fs/open.c:1367 [inline] filp_open+0x180/0x1e0 fs/open.c:1387 fsg_lun_open+0x67/0xec0 drivers/usb/gadget/function/storage_common.c:194 fsg_store_file+0x1a9/0x530 drivers/usb/gadget/function/storage_common.c:455 flush_write_buffer fs/configfs/file.c:207 [inline] configfs_write_iter+0x312/0x400 fs/configfs/file.c:229 call_write_iter include/linux/fs.h:2018 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x474/0x9a0 fs/read_write.c:584 ksys_write+0x151/0x260 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7eff1a59e0d9 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:00007eff1b3ed028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007eff1a825fa0 RCX: 00007eff1a59e0d9 RDX: 0000000000000005 RSI: 0000200000000380 RDI: 0000000000000004 RBP: 00007eff1a635024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007eff1a826038 R14: 00007eff1a825fa0 R15: 00007ffffd5edd58 mass_storage.0/lun.0: unable to open backing file: file0 EXT4-fs (loop0): unmounting filesystem 00000000-0000-0000-0000-000000000000.