====================================================== WARNING: possible circular locking dependency detected 5.10.0-rc5-next-20201127-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor076/8491 is trying to acquire lock: ffff88801ba842c0 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x363/0x1760 security/integrity/ima/ima_main.c:253 but task is already holding lock: ffff888021da6460 (sb_writers#4){.+.+}-{0:0}, at: do_open fs/namei.c:3245 [inline] ffff888021da6460 (sb_writers#4){.+.+}-{0:0}, at: path_openat+0x1a3d/0x2730 fs/namei.c:3369 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (sb_writers#4){.+.+}-{0:0}: percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1593 [inline] sb_start_write include/linux/fs.h:1663 [inline] mnt_want_write+0x69/0x3d0 fs/namespace.c:354 ovl_maybe_copy_up+0x11f/0x190 fs/overlayfs/copy_up.c:993 ovl_open+0xba/0x270 fs/overlayfs/file.c:154 do_dentry_open+0x4b9/0x11b0 fs/open.c:817 vfs_open fs/open.c:931 [inline] dentry_open+0x132/0x1d0 fs/open.c:947 ima_calc_file_hash+0x32b/0x5a0 security/integrity/ima/ima_crypto.c:557 ima_collect_measurement+0x4ca/0x570 security/integrity/ima/ima_api.c:250 process_measurement+0xca6/0x1760 security/integrity/ima/ima_main.c:330 ima_file_check+0xb9/0x100 security/integrity/ima/ima_main.c:498 do_open fs/namei.c:3254 [inline] path_openat+0x154d/0x2730 fs/namei.c:3369 do_filp_open+0x17e/0x3c0 fs/namei.c:3396 do_sys_openat2+0x16d/0x420 fs/open.c:1168 do_sys_open fs/open.c:1184 [inline] __do_sys_open fs/open.c:1192 [inline] __se_sys_open fs/open.c:1188 [inline] __x64_sys_open+0x119/0x1c0 fs/open.c:1188 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&iint->mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:2868 [inline] check_prevs_add kernel/locking/lockdep.c:2993 [inline] validate_chain kernel/locking/lockdep.c:3608 [inline] __lock_acquire+0x2ade/0x5500 kernel/locking/lockdep.c:4832 lock_acquire kernel/locking/lockdep.c:5437 [inline] lock_acquire+0x29d/0x740 kernel/locking/lockdep.c:5402 __mutex_lock_common kernel/locking/mutex.c:956 [inline] __mutex_lock+0x134/0x1110 kernel/locking/mutex.c:1103 process_measurement+0x363/0x1760 security/integrity/ima/ima_main.c:253 ima_file_check+0xb9/0x100 security/integrity/ima/ima_main.c:498 do_open fs/namei.c:3254 [inline] path_openat+0x154d/0x2730 fs/namei.c:3369 do_filp_open+0x17e/0x3c0 fs/namei.c:3396 do_sys_openat2+0x16d/0x420 fs/open.c:1168 do_sys_open fs/open.c:1184 [inline] __do_sys_openat fs/open.c:1200 [inline] __se_sys_openat fs/open.c:1195 [inline] __x64_sys_openat+0x13f/0x1f0 fs/open.c:1195 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sb_writers#4); lock(&iint->mutex); lock(sb_writers#4); lock(&iint->mutex); *** DEADLOCK *** 1 lock held by syz-executor076/8491: #0: ffff888021da6460 (sb_writers#4){.+.+}-{0:0}, at: do_open fs/namei.c:3245 [inline] #0: ffff888021da6460 (sb_writers#4){.+.+}-{0:0}, at: path_openat+0x1a3d/0x2730 fs/namei.c:3369 stack backtrace: CPU: 1 PID: 8491 Comm: syz-executor076 Not tainted 5.10.0-rc5-next-20201127-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2117 check_prev_add kernel/locking/lockdep.c:2868 [inline] check_prevs_add kernel/locking/lockdep.c:2993 [inline] validate_chain kernel/locking/lockdep.c:3608 [inline] __lock_acquire+0x2ade/0x5500 kernel/locking/lockdep.c:4832 lock_acquire kernel/locking/lockdep.c:5437 [inline] lock_acquire+0x29d/0x740 kernel/locking/lockdep.c:5402 __mutex_lock_common kernel/locking/mutex.c:956 [inline] __mutex_lock+0x134/0x1110 kernel/locking/mutex.c:1103 process_measurement+0x363/0x1760 security/integrity/ima/ima_main.c:253 ima_file_check+0xb9/0x100 security/integrity/ima/ima_main.c:498 do_open fs/namei.c:3254 [inline] path_openat+0x154d/0x2730 fs/namei.c:3369 do_filp_open+0x17e/0x3c0 fs/namei.c:3396 do_sys_openat2+0x16d/0x420 fs/open.c:1168 do_sys_open fs/open.c:1184 [inline] __do_sys_openat fs/open.c:1200 [inline] __se_sys_openat fs/open.c:1195 [inline] __x64_sys_openat+0x13f/0x1f0 fs/open.c:1195 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x446979 Code: e8 5c b3 02 00 48 83 c4 18 c3 0f 1f 80 00 00 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 0f 83 8b 07 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f3ecf002db8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00000000006dbc28 RCX: 0000000000446979 RDX: 000000000000275a RSI: 0000000020000080 RDI: 00000000ffffff9c RBP: 00000000006dbc20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc2c R13: 00007fffc7df550f R14: 00007f3ecf0039c0 R15: 20c49ba5e353f7cf