====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc2-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.2/23485 is trying to acquire lock: ffff88808b24c080 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x363/0x1760 security/integrity/ima/ima_main.c:247 but task is already holding lock: ffff8880a7be4450 (sb_writers#4){.+.+}-{0:0}, at: sb_start_write include/linux/fs.h:1664 [inline] ffff8880a7be4450 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3a/0xb0 fs/namespace.c:354 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+0x234/0x470 fs/super.c:1672 sb_start_write include/linux/fs.h:1664 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:354 ovl_maybe_copy_up+0x11f/0x190 fs/overlayfs/copy_up.c:961 ovl_open+0xba/0x270 fs/overlayfs/file.c:145 do_dentry_open+0x501/0x1290 fs/open.c:828 vfs_open fs/open.c:942 [inline] dentry_open+0x132/0x1d0 fs/open.c:958 ima_calc_file_hash+0x32b/0x570 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:324 ima_file_check+0xb9/0x100 security/integrity/ima/ima_main.c:492 do_open fs/namei.c:3245 [inline] path_openat+0x156c/0x2750 fs/namei.c:3360 do_filp_open+0x17e/0x3c0 fs/namei.c:3387 do_sys_openat2+0x16f/0x3b0 fs/open.c:1179 do_sys_open fs/open.c:1195 [inline] ksys_open include/linux/syscalls.h:1388 [inline] __do_sys_open fs/open.c:1201 [inline] __se_sys_open fs/open.c:1199 [inline] __x64_sys_open+0x119/0x1c0 fs/open.c:1199 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&iint->mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:2496 [inline] check_prevs_add kernel/locking/lockdep.c:2601 [inline] validate_chain kernel/locking/lockdep.c:3218 [inline] __lock_acquire+0x2acb/0x56e0 kernel/locking/lockdep.c:4380 lock_acquire+0x1f1/0xad0 kernel/locking/lockdep.c:4959 __mutex_lock_common kernel/locking/mutex.c:956 [inline] __mutex_lock+0x134/0x10d0 kernel/locking/mutex.c:1103 process_measurement+0x363/0x1760 security/integrity/ima/ima_main.c:247 ima_file_check+0xb9/0x100 security/integrity/ima/ima_main.c:492 do_open fs/namei.c:3245 [inline] path_openat+0x156c/0x2750 fs/namei.c:3360 do_filp_open+0x17e/0x3c0 fs/namei.c:3387 do_sys_openat2+0x16f/0x3b0 fs/open.c:1179 do_sys_open fs/open.c:1195 [inline] ksys_open include/linux/syscalls.h:1388 [inline] __do_sys_open fs/open.c:1201 [inline] __se_sys_open fs/open.c:1199 [inline] __x64_sys_open+0x119/0x1c0 fs/open.c:1199 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359 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-executor.2/23485: #0: ffff8880a7be4450 (sb_writers#4){.+.+}-{0:0}, at: sb_start_write include/linux/fs.h:1664 [inline] #0: ffff8880a7be4450 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3a/0xb0 fs/namespace.c:354 stack backtrace: CPU: 0 PID: 23485 Comm: syz-executor.2 Not tainted 5.8.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x18f/0x20d lib/dump_stack.c:118 check_noncircular+0x324/0x3e0 kernel/locking/lockdep.c:1827 check_prev_add kernel/locking/lockdep.c:2496 [inline] check_prevs_add kernel/locking/lockdep.c:2601 [inline] validate_chain kernel/locking/lockdep.c:3218 [inline] __lock_acquire+0x2acb/0x56e0 kernel/locking/lockdep.c:4380 lock_acquire+0x1f1/0xad0 kernel/locking/lockdep.c:4959 __mutex_lock_common kernel/locking/mutex.c:956 [inline] __mutex_lock+0x134/0x10d0 kernel/locking/mutex.c:1103 process_measurement+0x363/0x1760 security/integrity/ima/ima_main.c:247 ima_file_check+0xb9/0x100 security/integrity/ima/ima_main.c:492 do_open fs/namei.c:3245 [inline] path_openat+0x156c/0x2750 fs/namei.c:3360 do_filp_open+0x17e/0x3c0 fs/namei.c:3387 do_sys_openat2+0x16f/0x3b0 fs/open.c:1179 do_sys_open fs/open.c:1195 [inline] ksys_open include/linux/syscalls.h:1388 [inline] __do_sys_open fs/open.c:1201 [inline] __se_sys_open fs/open.c:1199 [inline] __x64_sys_open+0x119/0x1c0 fs/open.c:1199 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45cb19 Code: Bad RIP value. RSP: 002b:00007efee40e3c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00000000004f7c40 RCX: 000000000045cb19 RDX: 0000000000000000 RSI: 0000000000000300 RDI: 0000000020000200 RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000799 R14: 0000000000526e5f R15: 00007efee40e46d4