syzbot has found a reproducer for the following issue on: HEAD commit: 454c576c Add linux-next specific files for 20210401 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=1616e07ed00000 kernel config: https://syzkaller.appspot.com/x/.config?x=920cc274cae812a5 dashboard link: https://syzkaller.appspot.com/bug?extid=c18f2f6a7b08c51e3025 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13da365ed00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13ca9d16d00000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+c18f2f6a7b08c51e3025@xxxxxxxxxxxxxxxxxxxxxxxxx ====================================================== WARNING: possible circular locking dependency detected 5.12.0-rc5-next-20210401-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor144/9166 is trying to acquire lock: ffff888144cf0460 (sb_writers#5){.+.+}-{0:0}, at: ovl_maybe_copy_up+0x11f/0x190 fs/overlayfs/copy_up.c:995 but task is already holding lock: ffff8880256d42c0 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x3a8/0x17e0 security/integrity/ima/ima_main.c:253 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&iint->mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:949 [inline] __mutex_lock+0x139/0x1120 kernel/locking/mutex.c:1096 process_measurement+0x3a8/0x17e0 security/integrity/ima/ima_main.c:253 ima_file_check+0xb9/0x100 security/integrity/ima/ima_main.c:499 do_open fs/namei.c:3361 [inline] path_openat+0x15b5/0x27e0 fs/namei.c:3492 do_filp_open+0x17e/0x3c0 fs/namei.c:3519 do_sys_openat2+0x16d/0x420 fs/open.c:1187 do_sys_open fs/open.c:1203 [inline] __do_sys_open fs/open.c:1211 [inline] __se_sys_open fs/open.c:1207 [inline] __x64_sys_open+0x119/0x1c0 fs/open.c:1207 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #0 (sb_writers#5){.+.+}-{0:0}: check_prev_add kernel/locking/lockdep.c:2938 [inline] check_prevs_add kernel/locking/lockdep.c:3061 [inline] validate_chain kernel/locking/lockdep.c:3676 [inline] __lock_acquire+0x2a17/0x5230 kernel/locking/lockdep.c:4902 lock_acquire kernel/locking/lockdep.c:5512 [inline] lock_acquire+0x1ab/0x740 kernel/locking/lockdep.c:5477 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1758 [inline] sb_start_write include/linux/fs.h:1828 [inline] mnt_want_write+0x6e/0x3e0 fs/namespace.c:375 ovl_maybe_copy_up+0x11f/0x190 fs/overlayfs/copy_up.c:995 ovl_open+0xba/0x270 fs/overlayfs/file.c:149 do_dentry_open+0x4b9/0x11b0 fs/open.c:826 vfs_open fs/open.c:940 [inline] dentry_open+0x132/0x1d0 fs/open.c:956 ima_calc_file_hash+0x2d2/0x4b0 security/integrity/ima/ima_crypto.c:557 ima_collect_measurement+0x4ca/0x570 security/integrity/ima/ima_api.c:252 process_measurement+0xd1c/0x17e0 security/integrity/ima/ima_main.c:330 ima_file_check+0xb9/0x100 security/integrity/ima/ima_main.c:499 do_open fs/namei.c:3361 [inline] path_openat+0x15b5/0x27e0 fs/namei.c:3492 do_filp_open+0x17e/0x3c0 fs/namei.c:3519 do_sys_openat2+0x16d/0x420 fs/open.c:1187 do_sys_open fs/open.c:1203 [inline] __do_sys_open fs/open.c:1211 [inline] __se_sys_open fs/open.c:1207 [inline] __x64_sys_open+0x119/0x1c0 fs/open.c:1207 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&iint->mutex); lock(sb_writers#5); lock(&iint->mutex); lock(sb_writers#5); *** DEADLOCK *** 1 lock held by syz-executor144/9166: #0: ffff8880256d42c0 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x3a8/0x17e0 security/integrity/ima/ima_main.c:253 stack backtrace: CPU: 1 PID: 9166 Comm: syz-executor144 Not tainted 5.12.0-rc5-next-20210401-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+0x141/0x1d7 lib/dump_stack.c:120 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2129 check_prev_add kernel/locking/lockdep.c:2938 [inline] check_prevs_add kernel/locking/lockdep.c:3061 [inline] validate_chain kernel/locking/lockdep.c:3676 [inline] __lock_acquire+0x2a17/0x5230 kernel/locking/lockdep.c:4902 lock_acquire kernel/locking/lockdep.c:5512 [inline] lock_acquire+0x1ab/0x740 kernel/locking/lockdep.c:5477 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1758 [inline] sb_start_write include/linux/fs.h:1828 [inline] mnt_want_write+0x6e/0x3e0 fs/namespace.c:375 ovl_maybe_copy_up+0x11f/0x190 fs/overlayfs/copy_up.c:995 ovl_open+0xba/0x270 fs/overlayfs/file.c:149 do_dentry_open+0x4b9/0x11b0 fs/open.c:826 vfs_open fs/open.c:940 [inline] dentry_open+0x132/0x1d0 fs/open.c:956 ima_calc_file_hash+0x2d2/0x4b0 security/integrity/ima/ima_crypto.c:557 ima_collect_measurement+0x4ca/0x570 security/integrity/ima/ima_api.c:252 process_measurement+0xd1c/0x17e0 security/integrity/ima/ima_main.c:330 ima_file_check+0xb9/0x100 security/integrity/ima/ima_main.c:499 do_open fs/namei.c:3361 [inline] path_openat+0x15b5/0x27e0 fs/namei.c:3492 do_filp_open+0x17e/0x3c0 fs/namei.c:3519 do_sys_openat2+0x16d/0x420 fs/open.c:1187 do_sys_open fs/open.c:1203 [inline] __do_sys_open fs/open.c:1211 [inline] __se_sys_open fs/open.c:1207 [inline] __x64_sys_open+0x119/0x1c0 fs/open.c:1207 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x446109 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 15 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe4412f12f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00000000004cb4c0 RCX: 0000000000446109 RDX: 0000000000000000 RSI: 0000000000000007 RDI: 00000000200001c0 RBP: 000000000049b06c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 69662f7375622f2e R13: 79706f636174656d R14: 0079616c7265766f R15: 00000000004cb4c8
