====================================================== WARNING: possible circular locking dependency detected 4.19.211-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.4/1921 is trying to acquire lock: 0000000063dde468 (&sig->cred_guard_mutex){+.+.}, at: lock_trace fs/proc/base.c:402 [inline] 0000000063dde468 (&sig->cred_guard_mutex){+.+.}, at: proc_pid_syscall+0xb8/0x2f0 fs/proc/base.c:635 but task is already holding lock: 00000000fa104b99 (&p->lock){+.+.}, at: seq_read+0x6b/0x11c0 fs/seq_file.c:164 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&p->lock){+.+.}: seq_read+0x6b/0x11c0 fs/seq_file.c:164 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x471/0x630 fs/read_write.c:925 vfs_readv+0xe5/0x150 fs/read_write.c:987 kernel_readv fs/splice.c:362 [inline] default_file_splice_read+0x457/0xa00 fs/splice.c:417 do_splice_to+0x10e/0x160 fs/splice.c:881 splice_direct_to_actor+0x2b9/0x8d0 fs/splice.c:959 do_splice_direct+0x1a7/0x270 fs/splice.c:1068 do_sendfile+0x550/0xc30 fs/read_write.c:1447 __do_sys_sendfile64 fs/read_write.c:1508 [inline] __se_sys_sendfile64+0x147/0x160 fs/read_write.c:1494 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #3 (sb_writers#3){.+.+}: sb_start_write include/linux/fs.h:1579 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:360 ovl_setattr+0xdd/0x920 fs/overlayfs/inode.c:30 notify_change+0x70b/0xfc0 fs/attr.c:334 chown_common+0x4a9/0x550 fs/open.c:651 do_fchownat+0x126/0x1e0 fs/open.c:681 __do_sys_lchown fs/open.c:706 [inline] __se_sys_lchown fs/open.c:704 [inline] __x64_sys_lchown+0x7a/0xc0 fs/open.c:704 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #2 (&ovl_i_mutex_dir_key[depth]){++++}: inode_lock_shared include/linux/fs.h:758 [inline] lookup_slow fs/namei.c:1688 [inline] lookup_one_len_unlocked+0x111/0x140 fs/namei.c:2573 ovl_lookup_single+0x60/0x920 fs/overlayfs/namei.c:206 ovl_lookup_layer+0x3bd/0x440 fs/overlayfs/namei.c:292 ovl_lookup+0x729/0x1a00 fs/overlayfs/namei.c:903 lookup_open+0x698/0x1a20 fs/namei.c:3214 do_last fs/namei.c:3327 [inline] path_openat+0x1094/0x2df0 fs/namei.c:3537 do_filp_open+0x18c/0x3f0 fs/namei.c:3567 do_sys_open+0x3b3/0x520 fs/open.c:1085 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #1 (&ovl_i_mutex_dir_key[depth]#2){++++}: inode_lock_shared include/linux/fs.h:758 [inline] do_last fs/namei.c:3326 [inline] path_openat+0x17ec/0x2df0 fs/namei.c:3537 netlink: 'syz-executor.1': attribute type 4 has an invalid length. do_filp_open+0x18c/0x3f0 fs/namei.c:3567 do_open_execat+0x11d/0x5b0 fs/exec.c:853 netlink: 'syz-executor.1': attribute type 4 has an invalid length. __do_execve_file+0x1a8b/0x2360 fs/exec.c:1770 do_execveat_common fs/exec.c:1879 [inline] do_execve+0x35/0x50 fs/exec.c:1896 __do_sys_execve fs/exec.c:1977 [inline] __se_sys_execve fs/exec.c:1972 [inline] __x64_sys_execve+0x7c/0xa0 fs/exec.c:1972 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&sig->cred_guard_mutex){+.+.}: netlink: 'syz-executor.1': attribute type 4 has an invalid length. __mutex_lock_common kernel/locking/mutex.c:937 [inline] __mutex_lock+0xd7/0x1190 kernel/locking/mutex.c:1078 lock_trace fs/proc/base.c:402 [inline] proc_pid_syscall+0xb8/0x2f0 fs/proc/base.c:635 proc_single_show+0xeb/0x170 fs/proc/base.c:755 netlink: 'syz-executor.1': attribute type 4 has an invalid length. seq_read+0x4e0/0x11c0 fs/seq_file.c:232 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x471/0x630 fs/read_write.c:925 vfs_readv+0xe5/0x150 fs/read_write.c:987 netlink: 'syz-executor.1': attribute type 4 has an invalid length. do_readv+0x136/0x330 fs/read_write.c:1020 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Chain exists of: &sig->cred_guard_mutex --> sb_writers#3 --> &p->lock audit: type=1800 audit(1646532949.731:25482): pid=1922 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="file0" dev="loop0" ino=2513 res=0 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.4/1921: #0: 00000000df3fe6af (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767 #1: 00000000fa104b99 (&p->lock){+.+.}, at: seq_read+0x6b/0x11c0 fs/seq_file.c:164 stack backtrace: CPU: 0 PID: 1921 Comm: syz-executor.4 Not tainted 4.19.211-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+0x1fc/0x2ef lib/dump_stack.c:118 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1222 check_prev_add kernel/locking/lockdep.c:1866 [inline] check_prevs_add kernel/locking/lockdep.c:1979 [inline] validate_chain kernel/locking/lockdep.c:2420 [inline] __lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3416 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908 __mutex_lock_common kernel/locking/mutex.c:937 [inline] __mutex_lock+0xd7/0x1190 kernel/locking/mutex.c:1078 lock_trace fs/proc/base.c:402 [inline] proc_pid_syscall+0xb8/0x2f0 fs/proc/base.c:635 proc_single_show+0xeb/0x170 fs/proc/base.c:755 seq_read+0x4e0/0x11c0 fs/seq_file.c:232 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x471/0x630 fs/read_write.c:925 vfs_readv+0xe5/0x150 fs/read_write.c:987 do_readv+0x136/0x330 fs/read_write.c:1020 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f3613263049 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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:00007f3611bd8168 EFLAGS: 00000246 ORIG_RAX: 0000000000000013 RAX: ffffffffffffffda RBX: 00007f3613375f60 RCX: 00007f3613263049 RDX: 0000000000000001 RSI: 0000000020000840 RDI: 0000000000000003 RBP: 00007f36132bd08d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffcad21259f R14: 00007f3611bd8300 R15: 0000000000022000 validate_nla: 61 callbacks suppressed netlink: 'syz-executor.1': attribute type 4 has an invalid length. audit: type=1800 audit(1646532951.631:25483): pid=1952 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="file0" dev="loop0" ino=2514 res=0 netlink: 'syz-executor.1': attribute type 4 has an invalid length. audit: type=1800 audit(1646532951.781:25484): pid=2014 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="file0" dev="loop0" ino=2515 res=0 netlink: 40 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 'syz-executor.1': attribute type 4 has an invalid length. audit: type=1800 audit(1646532952.511:25485): pid=2034 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="file0" dev="loop0" ino=2516 res=0 audit: type=1800 audit(1646532952.741:25486): pid=2062 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="file0" dev="loop0" ino=2517 res=0 audit: type=1800 audit(1646532953.601:25487): pid=2108 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="file0" dev="loop0" ino=2518 res=0 audit: type=1800 audit(1646532953.861:25488): pid=2138 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="file0" dev="loop0" ino=2519 res=0 netlink: 'syz-executor.1': attribute type 4 has an invalid length. netlink: 'syz-executor.1': attribute type 4 has an invalid length. audit: type=1800 audit(1646532954.111:25489): pid=2178 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="file0" dev="loop0" ino=2520 res=0 netlink: 'syz-executor.1': attribute type 4 has an invalid length. audit: type=1800 audit(1646532954.351:25490): pid=2227 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="file0" dev="loop0" ino=2521 res=0 audit: type=1800 audit(1646532954.561:25491): pid=2255 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="file0" dev="loop0" ino=2522 res=0 kauditd_printk_skb: 1 callbacks suppressed audit: type=1800 audit(1646532955.001:25493): pid=2321 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="file0" dev="loop0" ino=2524 res=0 audit: type=1800 audit(1646532955.231:25494): pid=2350 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="file0" dev="loop0" ino=2525 res=0 audit: type=1800 audit(1646532955.501:25495): pid=2378 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="file0" dev="loop0" ino=2526 res=0 audit: type=1800 audit(1646532955.741:25496): pid=2412 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="file0" dev="loop0" ino=2527 res=0 netlink: 20 bytes leftover after parsing attributes in process `syz-executor.5'. audit: type=1400 audit(1646532955.991:25497): apparmor="DENIED" operation="change_hat" info="unconfined can not change_hat" error=-1 profile="unconfined" pid=2461 comm="syz-executor.2" audit: type=1800 audit(1646532956.021:25498): pid=2453 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="file0" dev="loop0" ino=2528 res=0 base_sock_release(00000000dcbc6523) sk=0000000095f9f624 audit: type=1800 audit(1646532956.191:25499): pid=2482 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="file0" dev="loop0" ino=2529 res=0 audit: type=1800 audit(1646532956.871:25500): pid=2501 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="file0" dev="loop0" ino=2530 res=0 audit: type=1800 audit(1646532957.131:25501): pid=2534 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="file0" dev="loop0" ino=2531 res=0 audit: type=1800 audit(1646532957.302:25502): pid=2564 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="file0" dev="loop0" ino=2532 res=0 dccp_invalid_packet: invalid packet type