====================================================== WARNING: possible circular locking dependency detected 5.9.0-rc8-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/18285 is trying to acquire lock: ffff888098698450 (sb_writers#4){.+.+}-{0:0}, at: sb_start_write include/linux/fs.h:1643 [inline] ffff888098698450 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x45/0x90 fs/namespace.c:354 but task is already holding lock: ffff8880967bd860 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x66d/0x18e0 security/integrity/ima/ima_main.c:247 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&iint->mutex){+.+.}-{3:3}: lock_acquire+0x148/0x720 kernel/locking/lockdep.c:5029 __mutex_lock_common+0x189/0x2fc0 kernel/locking/mutex.c:956 __mutex_lock kernel/locking/mutex.c:1103 [inline] mutex_lock_nested+0x1a/0x20 kernel/locking/mutex.c:1118 process_measurement+0x66d/0x18e0 security/integrity/ima/ima_main.c:247 ima_file_check+0x9c/0xe0 security/integrity/ima/ima_main.c:492 do_open fs/namei.c:3253 [inline] path_openat+0x27dd/0x3840 fs/namei.c:3368 do_filp_open+0x191/0x3a0 fs/namei.c:3395 do_sys_openat2+0x463/0x830 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+0x1c8/0x1f0 fs/open.c:1195 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (sb_writers#4){.+.+}-{0:0}: check_prev_add kernel/locking/lockdep.c:2496 [inline] check_prevs_add kernel/locking/lockdep.c:2601 [inline] validate_chain+0x1b0c/0x88a0 kernel/locking/lockdep.c:3218 __lock_acquire+0x110b/0x2ae0 kernel/locking/lockdep.c:4441 lock_acquire+0x148/0x720 kernel/locking/lockdep.c:5029 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write+0x14b/0x400 fs/super.c:1672 sb_start_write include/linux/fs.h:1643 [inline] mnt_want_write+0x45/0x90 fs/namespace.c:354 ovl_maybe_copy_up+0x117/0x180 fs/overlayfs/copy_up.c:961 ovl_open+0xa2/0x200 fs/overlayfs/file.c:147 do_dentry_open+0x7c8/0x1010 fs/open.c:817 vfs_open fs/open.c:931 [inline] dentry_open+0xc6/0x120 fs/open.c:947 ima_calc_file_hash+0xfa/0x1f30 security/integrity/ima/ima_crypto.c:557 ima_collect_measurement+0x1fd/0x490 security/integrity/ima/ima_api.c:250 process_measurement+0xddf/0x18e0 security/integrity/ima/ima_main.c:324 ima_file_check+0x9c/0xe0 security/integrity/ima/ima_main.c:492 do_open fs/namei.c:3253 [inline] path_openat+0x27dd/0x3840 fs/namei.c:3368 do_filp_open+0x191/0x3a0 fs/namei.c:3395 do_sys_openat2+0x463/0x830 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+0x1af/0x1e0 fs/open.c:1188 do_syscall_64+0x31/0x70 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(&iint->mutex); lock(sb_writers#4); lock(&iint->mutex); lock(sb_writers#4); *** DEADLOCK *** 1 lock held by syz-executor.0/18285: #0: ffff8880967bd860 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x66d/0x18e0 security/integrity/ima/ima_main.c:247 stack backtrace: CPU: 1 PID: 18285 Comm: syz-executor.0 Not tainted 5.9.0-rc8-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+0x1d6/0x29e lib/dump_stack.c:118 print_circular_bug+0xc72/0xea0 kernel/locking/lockdep.c:1703 check_noncircular+0x1fb/0x3a0 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+0x1b0c/0x88a0 kernel/locking/lockdep.c:3218 __lock_acquire+0x110b/0x2ae0 kernel/locking/lockdep.c:4441 lock_acquire+0x148/0x720 kernel/locking/lockdep.c:5029 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write+0x14b/0x400 fs/super.c:1672 sb_start_write include/linux/fs.h:1643 [inline] mnt_want_write+0x45/0x90 fs/namespace.c:354 ovl_maybe_copy_up+0x117/0x180 fs/overlayfs/copy_up.c:961 ovl_open+0xa2/0x200 fs/overlayfs/file.c:147 do_dentry_open+0x7c8/0x1010 fs/open.c:817 vfs_open fs/open.c:931 [inline] dentry_open+0xc6/0x120 fs/open.c:947 ima_calc_file_hash+0xfa/0x1f30 security/integrity/ima/ima_crypto.c:557 ima_collect_measurement+0x1fd/0x490 security/integrity/ima/ima_api.c:250 process_measurement+0xddf/0x18e0 security/integrity/ima/ima_main.c:324 ima_file_check+0x9c/0xe0 security/integrity/ima/ima_main.c:492 do_open fs/namei.c:3253 [inline] path_openat+0x27dd/0x3840 fs/namei.c:3368 do_filp_open+0x191/0x3a0 fs/namei.c:3395 do_sys_openat2+0x463/0x830 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+0x1af/0x1e0 fs/open.c:1188 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45de29 Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f01f1cc5c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000022180 RCX: 000000000045de29 RDX: 0000000000000000 RSI: 0000000000141183 RDI: 0000000020000300 RBP: 000000000118c008 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bfd4 R13: 00007ffef53da1ff R14: 00007f01f1cc69c0 R15: 000000000118bfd4 ima: Unable to reopen file for reading.