====================================================== WARNING: possible circular locking dependency detected 4.14.298-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor269/7982 is trying to acquire lock: (sb_writers#3){.+.+}, at: [] sb_start_write include/linux/fs.h:1551 [inline] (sb_writers#3){.+.+}, at: [] mnt_want_write+0x3a/0xb0 fs/namespace.c:386 but task is already holding lock: (&iint->mutex){+.+.}, at: [] process_measurement+0x270/0xb20 security/integrity/ima/ima_main.c:225 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&iint->mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 process_measurement+0x270/0xb20 security/integrity/ima/ima_main.c:225 do_last fs/namei.c:3435 [inline] path_openat+0x10ad/0x2970 fs/namei.c:3571 do_filp_open+0x179/0x3c0 fs/namei.c:3605 do_sys_open+0x296/0x410 fs/open.c:1081 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x5e/0xd3 -> #0 (sb_writers#3){.+.+}: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline] percpu_down_read include/linux/percpu-rwsem.h:59 [inline] __sb_start_write+0x64/0x260 fs/super.c:1342 sb_start_write include/linux/fs.h:1551 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:386 ovl_open_maybe_copy_up+0xcf/0x130 fs/overlayfs/inode.c:344 ovl_d_real+0xbc/0x350 fs/overlayfs/super.c:88 d_real include/linux/dcache.h:587 [inline] vfs_open+0x19e/0x220 fs/open.c:882 dentry_open+0xa7/0x210 fs/open.c:905 ima_calc_file_hash+0x51c/0x780 security/integrity/ima/ima_crypto.c:452 ima_collect_measurement+0x39d/0x430 security/integrity/ima/ima_api.c:227 process_measurement+0x78b/0xb20 security/integrity/ima/ima_main.c:264 do_last fs/namei.c:3435 [inline] path_openat+0x10ad/0x2970 fs/namei.c:3571 do_filp_open+0x179/0x3c0 fs/namei.c:3605 do_sys_open+0x296/0x410 fs/open.c:1081 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x5e/0xd3 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&iint->mutex); lock(sb_writers#3); lock(&iint->mutex); lock(sb_writers#3); *** DEADLOCK *** 1 lock held by syz-executor269/7982: #0: (&iint->mutex){+.+.}, at: [] process_measurement+0x270/0xb20 security/integrity/ima/ima_main.c:225 stack backtrace: CPU: 1 PID: 7982 Comm: syz-executor269 Not tainted 4.14.298-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1905 [inline] check_prevs_add kernel/locking/lockdep.c:2022 [inline] validate_chain kernel/locking/lockdep.c:2464 [inline] __lock_acquire+0x2e0e/0x3f20 kernel/locking/lockdep.c:3491 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline] percpu_down_read include/linux/percpu-rwsem.h:59 [inline] __sb_start_write+0x64/0x260 fs/super.c:1342 sb_start_write include/linux/fs.h:1551 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:386 ovl_open_maybe_copy_up+0xcf/0x130 fs/overlayfs/inode.c:344 ovl_d_real+0xbc/0x350 fs/overlayfs/super.c:88 d_real include/linux/dcache.h:587 [inline] vfs_open+0x19e/0x220 fs/open.c:882 dentry_open+0xa7/0x210 fs/open.c:905 ima_calc_file_hash+0x51c/0x780 security/integrity/ima/ima_crypto.c:452 ima_collect_measurement+0x39d/0x430 security/integrity/ima/ima_api.c:227 process_measurement+0x78b/0xb20 security/integrity/ima/ima_main.c:264 do_last fs/namei.c:3435 [inline] path_openat+0x10ad/0x2970 fs/namei.c:3571 do_filp_open+0x179/0x3c0 fs/namei.c:3605