====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ udevd/7596 is trying to acquire lock: ffff8880789f9500 (&ima_iint_mutex_key[depth]){+.+.}-{4:4}, at: process_measurement+0x5ab/0x2360 security/integrity/ima/ima_main.c:319 but task is already holding lock: ffff888027294478 (sb_writers#5){.+.+}-{0:0}, at: do_open fs/namei.c:4838 [inline] ffff888027294478 (sb_writers#5){.+.+}-{0:0}, at: path_openat+0x1920/0x23f0 fs/namei.c:5016 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (sb_writers#5){.+.+}-{0:0}: 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+0x6a/0x420 fs/namespace.c:531 lookup_open+0x8e9/0x19e0 fs/namei.c:4459 open_last_lookups fs/namei.c:4774 [inline] path_openat+0xe75/0x23f0 fs/namei.c:5013 do_file_open+0x20e/0x430 fs/namei.c:5045 file_open_name+0x1c3/0x3e0 fs/open.c:1400 filp_open+0x2e/0x50 fs/open.c:1417 fsg_lun_open+0x6b/0x7b0 drivers/usb/gadget/function/storage_common.c:194 fsg_store_file+0x1e7/0x450 drivers/usb/gadget/function/storage_common.c:455 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_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline] __do_fast_syscall_32+0x14b/0x8c0 arch/x86/entry/syscall_32.c:282 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:307 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #3 (&common->filesem){++++}-{4:4}: lock_acquire kernel/locking/lockdep.c:5942 [inline] lock_acquire+0x1d1/0x380 kernel/locking/lockdep.c:5899 down_read+0x94/0x4c0 kernel/locking/rwsem.c:1574 fsg_show_file+0x20/0x180 drivers/usb/gadget/function/storage_common.c:339 fill_read_buffer fs/configfs/file.c:68 [inline] configfs_read_iter+0x426/0x6f0 fs/configfs/file.c:88 __kernel_read+0x397/0xad0 fs/read_write.c:532 integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28 ima_calc_file_hash_tfm+0x25e/0x350 security/integrity/ima/ima_crypto.c:222 ima_calc_file_hash+0x1e3/0x380 security/integrity/ima/ima_crypto.c:280 ima_collect_measurement+0x952/0xb30 security/integrity/ima/ima_api.c:300 process_measurement+0xe04/0x2360 security/integrity/ima/ima_main.c:425 ima_file_check+0xc8/0x120 security/integrity/ima/ima_main.c:686 security_file_post_open+0xc4/0x210 security/security.c:2776 do_open fs/namei.c:4853 [inline] path_openat+0x5d0/0x23f0 fs/namei.c:5016 do_file_open+0x20e/0x430 fs/namei.c:5045 do_sys_openat2+0x163/0x1d0 fs/open.c:1442 do_sys_open fs/open.c:1448 [inline] __do_compat_sys_openat fs/open.c:1510 [inline] __se_compat_sys_openat fs/open.c:1508 [inline] __ia32_compat_sys_openat+0x12d/0x210 fs/open.c:1508 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline] __do_fast_syscall_32+0x14b/0x8c0 arch/x86/entry/syscall_32.c:282 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:307 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #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+0x94/0x4c0 kernel/locking/rwsem.c:1574 fill_read_buffer fs/configfs/file.c:66 [inline] configfs_read_iter+0x346/0x6f0 fs/configfs/file.c:88 __kernel_read+0x397/0xad0 fs/read_write.c:532 integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28 ima_calc_file_hash_tfm+0x25e/0x350 security/integrity/ima/ima_crypto.c:222 ima_calc_file_hash+0x1e3/0x380 security/integrity/ima/ima_crypto.c:280 ima_collect_measurement+0x952/0xb30 security/integrity/ima/ima_api.c:300 process_measurement+0xe04/0x2360 security/integrity/ima/ima_main.c:425 ima_file_check+0xc8/0x120 security/integrity/ima/ima_main.c:686 security_file_post_open+0xc4/0x210 security/security.c:2776 do_open fs/namei.c:4853 [inline] path_openat+0x5d0/0x23f0 fs/namei.c:5016 do_file_open+0x20e/0x430 fs/namei.c:5045 do_sys_openat2+0x163/0x1d0 fs/open.c:1442 do_sys_open fs/open.c:1448 [inline] __do_compat_sys_openat fs/open.c:1510 [inline] __se_compat_sys_openat fs/open.c:1508 [inline] __ia32_compat_sys_openat+0x12d/0x210 fs/open.c:1508 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline] __do_fast_syscall_32+0x14b/0x8c0 arch/x86/entry/syscall_32.c:282 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:307 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #1 (&buffer->mutex){+.+.}-{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+0x19f/0x1c10 kernel/locking/mutex.c:821 configfs_read_iter+0x79/0x6f0 fs/configfs/file.c:86 __kernel_read+0x397/0xad0 fs/read_write.c:532 integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28 ima_calc_file_hash_tfm+0x25e/0x350 security/integrity/ima/ima_crypto.c:222 ima_calc_file_hash+0x1e3/0x380 security/integrity/ima/ima_crypto.c:280 ima_collect_measurement+0x952/0xb30 security/integrity/ima/ima_api.c:300 process_measurement+0xe04/0x2360 security/integrity/ima/ima_main.c:425 ima_file_check+0xc8/0x120 security/integrity/ima/ima_main.c:686 security_file_post_open+0xc4/0x210 security/security.c:2776 do_open fs/namei.c:4853 [inline] path_openat+0x5d0/0x23f0 fs/namei.c:5016 do_file_open+0x20e/0x430 fs/namei.c:5045 do_sys_openat2+0x163/0x1d0 fs/open.c:1442 do_sys_open fs/open.c:1448 [inline] __do_compat_sys_openat fs/open.c:1510 [inline] __se_compat_sys_openat fs/open.c:1508 [inline] __ia32_compat_sys_openat+0x12d/0x210 fs/open.c:1508 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline] __do_fast_syscall_32+0x14b/0x8c0 arch/x86/entry/syscall_32.c:282 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:307 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #0 (&ima_iint_mutex_key[depth]){+.+.}-{4:4}: 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 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x19f/0x1c10 kernel/locking/mutex.c:821 process_measurement+0x5ab/0x2360 security/integrity/ima/ima_main.c:319 ima_file_check+0xc8/0x120 security/integrity/ima/ima_main.c:686 security_file_post_open+0xc4/0x210 security/security.c:2776 do_open fs/namei.c:4853 [inline] path_openat+0x5d0/0x23f0 fs/namei.c:5016 do_file_open+0x20e/0x430 fs/namei.c:5045 do_sys_openat2+0x163/0x1d0 fs/open.c:1442 do_sys_open fs/open.c:1448 [inline] __do_sys_openat fs/open.c:1464 [inline] __se_sys_openat fs/open.c:1459 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1459 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x121/0x770 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: &ima_iint_mutex_key[depth] --> &common->filesem --> sb_writers#5 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(sb_writers#5); lock(&common->filesem); lock(sb_writers#5); lock(&ima_iint_mutex_key[depth]); *** DEADLOCK *** locks held by udevd/7596: 1, last CPU#3: #0: ffff888027294478 (sb_writers#5){.+.+}-{0:0}, at: do_open fs/namei.c:4838 [inline] #0: ffff888027294478 (sb_writers#5){.+.+}-{0:0}, at: path_openat+0x1920/0x23f0 fs/namei.c:5016 stack backtrace: CPU: 3 UID: 0 PID: 7596 Comm: udevd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: __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 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x19f/0x1c10 kernel/locking/mutex.c:821 process_measurement+0x5ab/0x2360 security/integrity/ima/ima_main.c:319 ima_file_check+0xc8/0x120 security/integrity/ima/ima_main.c:686 security_file_post_open+0xc4/0x210 security/security.c:2776 do_open fs/namei.c:4853 [inline] path_openat+0x5d0/0x23f0 fs/namei.c:5016 do_file_open+0x20e/0x430 fs/namei.c:5045 do_sys_openat2+0x163/0x1d0 fs/open.c:1442 do_sys_open fs/open.c:1448 [inline] __do_sys_openat fs/open.c:1464 [inline] __se_sys_openat fs/open.c:1459 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1459 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x121/0x770 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb2632a7407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007fff0a80ad80 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fb263a24880 RCX: 00007fb2632a7407 RDX: 00000000000a0241 RSI: 00007fff0a80ba40 RDI: ffffffffffffff9c RBP: 000055dc20e254e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000124 R11: 0000000000000202 R12: 000055dc20bfc830 R13: 00007fff0a80ba40 R14: 00007fff0a80b640 R15: 00007fff0a80b240