====================================================== WARNING: possible circular locking dependency detected 4.14.216-syzkaller #0 Not tainted binder: 28236:28242 ioctl c0046209 0 returned -22 ------------------------------------------------------ syz-executor.2/28238 is trying to acquire lock: (&sig->cred_guard_mutex){+.+.}, at: [] lock_trace fs/proc/base.c:407 [inline] (&sig->cred_guard_mutex){+.+.}, at: [] proc_pid_stack+0x13f/0x2f0 fs/proc/base.c:457 but task is already holding lock: (&p->lock){+.+.}, at: [] seq_read+0xba/0x1120 fs/seq_file.c:165 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&p->lock){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 seq_read+0xba/0x1120 fs/seq_file.c:165 proc_reg_read+0xee/0x1a0 fs/proc/inode.c:217 do_loop_readv_writev fs/read_write.c:695 [inline] do_loop_readv_writev fs/read_write.c:682 [inline] do_iter_read+0x3eb/0x5b0 fs/read_write.c:919 vfs_readv+0xc8/0x120 fs/read_write.c:981 kernel_readv fs/splice.c:361 [inline] default_file_splice_read+0x418/0x910 fs/splice.c:416 do_splice_to+0xfb/0x140 fs/splice.c:880 splice_direct_to_actor+0x207/0x730 fs/splice.c:952 do_splice_direct+0x164/0x210 fs/splice.c:1061 do_sendfile+0x47f/0xb30 fs/read_write.c:1441 SYSC_sendfile64 fs/read_write.c:1502 [inline] SyS_sendfile64+0xff/0x110 fs/read_write.c:1488 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #2 (sb_writers#3){.+.+}: 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:1549 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:386 ovl_create_object+0x75/0x1d0 fs/overlayfs/dir.c:538 lookup_open+0x77a/0x1750 fs/namei.c:3241 do_last fs/namei.c:3334 [inline] path_openat+0xe08/0x2970 fs/namei.c:3569 do_filp_open+0x179/0x3c0 fs/namei.c:3603 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+0x46/0xbb -> #1 (&ovl_i_mutex_dir_key[depth]){++++}: down_read+0x36/0x80 kernel/locking/rwsem.c:24 inode_lock_shared include/linux/fs.h:729 [inline] do_last fs/namei.c:3333 [inline] path_openat+0x149b/0x2970 fs/namei.c:3569 do_filp_open+0x179/0x3c0 fs/namei.c:3603 do_open_execat+0xd3/0x450 fs/exec.c:849 do_execveat_common+0x711/0x1f30 fs/exec.c:1755 do_execve fs/exec.c:1860 [inline] SYSC_execve fs/exec.c:1941 [inline] SyS_execve+0x3b/0x50 fs/exec.c:1936 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #0 (&sig->cred_guard_mutex){+.+.}: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 lock_trace fs/proc/base.c:407 [inline] proc_pid_stack+0x13f/0x2f0 fs/proc/base.c:457 proc_single_show+0xe7/0x150 fs/proc/base.c:761 seq_read+0x4cf/0x1120 fs/seq_file.c:237 __vfs_read+0xe4/0x620 fs/read_write.c:411 vfs_read+0x139/0x340 fs/read_write.c:447 SYSC_read fs/read_write.c:574 [inline] SyS_read+0xf2/0x210 fs/read_write.c:567 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb other info that might help us debug this: Chain exists of: &sig->cred_guard_mutex --> sb_writers#3 --> &p->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&p->lock); lock(sb_writers#3); lock(&p->lock); lock(&sig->cred_guard_mutex); *** DEADLOCK *** 2 locks held by syz-executor.2/28238: #0: (&f->f_pos_lock){+.+.}, at: [] __fdget_pos+0x1fb/0x2b0 fs/file.c:769 #1: (&p->lock){+.+.}, at: [] seq_read+0xba/0x1120 fs/seq_file.c:165 stack backtrace: CPU: 0 PID: 28238 Comm: syz-executor.2 Not tainted 4.14.216-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 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 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 lock_trace fs/proc/base.c:407 [inline] proc_pid_stack+0x13f/0x2f0 fs/proc/base.c:457 proc_single_show+0xe7/0x150 fs/proc/base.c:761 seq_read+0x4cf/0x1120 fs/seq_file.c:237 __vfs_read+0xe4/0x620 fs/read_write.c:411 vfs_read+0x139/0x340 fs/read_write.c:447 SYSC_read fs/read_write.c:574 [inline] SyS_read+0xf2/0x210 fs/read_write.c:567 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45e219 RSP: 002b:00007f6903e00c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045e219 RDX: 00000000000000dd RSI: 0000000020000880 RDI: 0000000000000006 RBP: 000000000119bfc0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119bf8c R13: 00007ffdfa6b9c4f R14: 00007f6903e019c0 R15: 000000000119bf8c EXT4-fs error (device loop5): ext4_quota_enable:5713: comm syz-executor.5: inode #239: comm syz-executor.5: iget: illegal inode # EXT4-fs error (device loop5): ext4_quota_enable:5715: comm syz-executor.5: Bad quota inode # 239 EXT4-fs warning (device loop5): ext4_enable_quotas:5755: Failed to enable quota tracking (type=-1, err=-117). Please run e2fsck to fix. EXT4-fs (loop5): mount failed print_req_error: 237 callbacks suppressed print_req_error: I/O error, dev loop5, sector 0 buffer_io_error: 211 callbacks suppressed Buffer I/O error on dev loop5, logical block 0, async page read print_req_error: I/O error, dev loop5, sector 6 Buffer I/O error on dev loop5, logical block 3, async page read print_req_error: I/O error, dev loop5, sector 0 Buffer I/O error on dev loop5, logical block 0, async page read print_req_error: I/O error, dev loop5, sector 6 Buffer I/O error on dev loop5, logical block 3, async page read EXT4-fs error (device loop5): ext4_quota_enable:5713: comm syz-executor.5: inode #239: comm syz-executor.5: iget: illegal inode # EXT4-fs error (device loop5): ext4_quota_enable:5715: comm syz-executor.5: Bad quota inode # 239 EXT4-fs warning (device loop5): ext4_enable_quotas:5755: Failed to enable quota tracking (type=-1, err=-117). Please run e2fsck to fix. EXT4-fs (loop5): mount failed EXT4-fs (loop2): ext4_check_descriptors: Checksum for group 0 failed (60729!=0) EXT4-fs (loop2): group descriptors corrupted! EXT4-fs (loop2): ext4_check_descriptors: Checksum for group 0 failed (60729!=0) EXT4-fs (loop2): group descriptors corrupted! nla_parse: 2 callbacks suppressed netlink: 60 bytes leftover after parsing attributes in process `syz-executor.1'. netlink: 60 bytes leftover after parsing attributes in process `syz-executor.1'. netlink: 80 bytes leftover after parsing attributes in process `syz-executor.2'. IPVS: ftp: loaded support on port[0] = 21 IPVS: ftp: loaded support on port[0] = 21