====================================================== WARNING: possible circular locking dependency detected 4.19.109-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.2/1115 is trying to acquire lock: 00000000f6d1a25f (&sig->cred_guard_mutex){+.+.}, at: lock_trace+0x45/0xe0 fs/proc/base.c:402 but task is already holding lock: 00000000add9c74f (&p->lock){+.+.}, at: seq_read+0x6b/0x10f0 fs/seq_file.c:161 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&p->lock){+.+.}: seq_read+0x6b/0x10f0 fs/seq_file.c:161 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x46b/0x640 fs/read_write.c:925 vfs_readv+0xf0/0x160 fs/read_write.c:987 kernel_readv fs/splice.c:362 [inline] default_file_splice_read+0x478/0x970 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+0x1a8/0x270 fs/splice.c:1068 do_sendfile+0x549/0xc10 fs/read_write.c:1447 __do_sys_sendfile64 fs/read_write.c:1508 [inline] __se_sys_sendfile64 fs/read_write.c:1494 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1494 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #2 (sb_writers#4){.+.+}: sb_start_write include/linux/fs.h:1578 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:360 ovl_create_object+0x96/0x290 fs/overlayfs/dir.c:600 lookup_open+0x11f6/0x19b0 fs/namei.c:3235 do_last fs/namei.c:3327 [inline] path_openat+0x13cb/0x4200 fs/namei.c:3537 do_filp_open+0x1a1/0x280 fs/namei.c:3567 do_sys_open+0x3c0/0x500 fs/open.c:1088 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]){++++}: inode_lock_shared include/linux/fs.h:757 [inline] do_last fs/namei.c:3326 [inline] path_openat+0x1d18/0x4200 fs/namei.c:3537 do_filp_open+0x1a1/0x280 fs/namei.c:3567 do_open_execat+0x124/0x5b0 fs/exec.c:853 __do_execve_file.isra.0+0x1577/0x2110 fs/exec.c:1755 do_execveat_common fs/exec.c:1866 [inline] do_execve fs/exec.c:1883 [inline] __do_sys_execve fs/exec.c:1964 [inline] __se_sys_execve fs/exec.c:1959 [inline] __x64_sys_execve+0x8a/0xb0 fs/exec.c:1959 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&sig->cred_guard_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:925 [inline] __mutex_lock+0xf7/0x1300 kernel/locking/mutex.c:1072 lock_trace+0x45/0xe0 fs/proc/base.c:402 proc_pid_syscall+0x94/0x240 fs/proc/base.c:635 proc_single_show+0xeb/0x170 fs/proc/base.c:755 seq_read+0x4b9/0x10f0 fs/seq_file.c:229 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x46b/0x640 fs/read_write.c:925 vfs_readv+0xf0/0x160 fs/read_write.c:987 do_preadv+0x1b6/0x270 fs/read_write.c:1071 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#4 --> &p->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&p->lock); lock(sb_writers#4); lock(&p->lock); lock(&sig->cred_guard_mutex); *** DEADLOCK *** 1 lock held by syz-executor.2/1115: #0: 00000000add9c74f (&p->lock){+.+.}, at: seq_read+0x6b/0x10f0 fs/seq_file.c:161 stack backtrace: CPU: 0 PID: 1115 Comm: syz-executor.2 Not tainted 4.19.109-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+0x188/0x20d lib/dump_stack.c:118 print_circular_bug.isra.0.cold+0x1c4/0x282 kernel/locking/lockdep.c:1221 check_prev_add kernel/locking/lockdep.c:1861 [inline] check_prevs_add kernel/locking/lockdep.c:1974 [inline] validate_chain kernel/locking/lockdep.c:2415 [inline] __lock_acquire+0x2e19/0x49c0 kernel/locking/lockdep.c:3411 lock_acquire+0x170/0x400 kernel/locking/lockdep.c:3903 __mutex_lock_common kernel/locking/mutex.c:925 [inline] __mutex_lock+0xf7/0x1300 kernel/locking/mutex.c:1072 lock_trace+0x45/0xe0 fs/proc/base.c:402 proc_pid_syscall+0x94/0x240 fs/proc/base.c:635 proc_single_show+0xeb/0x170 fs/proc/base.c:755 seq_read+0x4b9/0x10f0 fs/seq_file.c:229 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x46b/0x640 fs/read_write.c:925 vfs_readv+0xf0/0x160 fs/read_write.c:987 do_preadv+0x1b6/0x270 fs/read_write.c:1071 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c849 Code: ad b6 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f38f619cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00007f38f619d6d4 RCX: 000000000045c849 RDX: 000000000000037d RSI: 0000000020000500 RDI: 0000000000000005 RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000857 R14: 00000000004cb187 R15: 000000000076bf0c overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir CIFS VFS: Malformed UNC in devname. overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir kauditd_printk_skb: 25 callbacks suppressed audit: type=1804 audit(1584296226.949:1163): pid=1147 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=open_writers comm="syz-executor.3" name="/root/syzkaller-testdir937745331/syzkaller.oQjpkn/451/bus/bus" dev="overlay" ino=16642 res=1 overlayfs: unrecognized mount option "wfile1" or missing value audit: type=1804 audit(1584296227.219:1164): pid=1183 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=open_writers comm="syz-executor.3" name="/root/syzkaller-testdir937745331/syzkaller.oQjpkn/452/bus/bus" dev="sda1" ino=16548 res=1 overlayfs: unrecognized mount option "wfile1" or missing value audit: type=1804 audit(1584296227.319:1165): pid=1183 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=open_writers comm="syz-executor.3" name="/root/syzkaller-testdir937745331/syzkaller.oQjpkn/452/bus/bus" dev="sda1" ino=16548 res=1 overlayfs: filesystem on './file0' not supported as upperdir audit: type=1804 audit(1584296227.469:1166): pid=1188 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=ToMToU comm="syz-executor.1" name="/root/syzkaller-testdir034915272/syzkaller.YSprrg/2427/bus/bus" dev="overlay" ino=16643 res=1 audit: type=1804 audit(1584296227.479:1167): pid=1187 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=open_writers comm="syz-executor.1" name="/root/syzkaller-testdir034915272/syzkaller.YSprrg/2427/bus/bus" dev="overlay" ino=16643 res=1 overlayfs: unrecognized mount option "lowegdir=./bus" or missing value overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore audit: type=1804 audit(1584296227.599:1168): pid=1201 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=open_writers comm="syz-executor.3" name="/root/syzkaller-testdir937745331/syzkaller.oQjpkn/453/bus/bus" dev="sda1" ino=16539 res=1 overlayfs: at least 2 lowerdir are needed while upperdir nonexistent audit: type=1804 audit(1584296227.659:1169): pid=1206 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=open_writers comm="syz-executor.1" name="/root/syzkaller-testdir034915272/syzkaller.YSprrg/2428/bus/bus" dev="sda1" ino=16580 res=1 overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore audit: type=1804 audit(1584296227.809:1170): pid=1224 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=open_writers comm="syz-executor.1" name="/root/syzkaller-testdir034915272/syzkaller.YSprrg/2428/bus/bus" dev="sda1" ino=16580 res=1 overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: option "workdir=./fihR2vHdiile0G5S w.@m瑛ꬆ" is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent audit: type=1804 audit(1584296227.889:1171): pid=1223 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=open_writers comm="syz-executor.3" name="/root/syzkaller-testdir937745331/syzkaller.oQjpkn/454/bus/bus" dev="sda1" ino=16626 res=1 overlayfs: unrecognized mount option "worHKа}G#kdir=./file1" or missing value overlayfs: option "workdir=./fihR2vHdiile0G5S w.@m瑛ꬆ" is useless in a non-upper mount, ignore audit: type=1804 audit(1584296228.109:1172): pid=1241 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=open_writers comm="syz-executor.1" name="/root/syzkaller-testdir034915272/syzkaller.YSprrg/2429/bus/bus" dev="sda1" ino=16596 res=1 overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: unrecognized mount option "worHKа}G#kdir=./file1" or missing value overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: unrecognized mount option "00000000000000000003" or missing value overlayfs: unrecognized mount option "wor5kdir=./file1" or missing value overlayfs: unrecognized mount option "00000000000000000003" or missing value overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: filesystem on './file0' not supported as upperdir overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: './bus' not a directory overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore IPVS: Error connecting to the multicast addr overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: filesystem on './file0' not supported as upperdir IPVS: Error connecting to the multicast addr overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: unrecognized mount option "workdi=./file1" or missing value overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: unrecognized mount option "workdi=./file1" or missing value overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: filesystem on './file0' not supported as upperdir overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: filesystem on './file0' not supported as upperdir overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: filesystem on './file0' not supported as upperdir kauditd_printk_skb: 45 callbacks suppressed audit: type=1804 audit(1584296232.179:1218): pid=1505 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=open_writers comm="syz-executor.1" name="/root/syzkaller-testdir034915272/syzkaller.YSprrg/2438/bus/bus" dev="overlay" ino=16626 res=1 overlayfs: option "workdir=./r=./file0" is useless in a non-upper mount, ignore overlayfs: at least 2 lowerdir are needed while upperdir nonexistent overlayfs: unrecognized mount option "workd r=./file1" or missing value audit: type=1804 audit(1584296232.699:1219): pid=1549 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=open_writers comm="syz-executor.1" name="/root/syzkaller-testdir034915272/syzkaller.YSprrg/2439/bus/bus" dev="sda1" ino=16544 res=1 overlayfs: failed to resolve './file0': -2 overlayfs: failed to resolve './file0': -2 overlayfs: failed to resolve './file0': -2 overlayfs: unrecognized mount option "workd r=./file1" or missing value audit: type=1804 audit(1584296233.489:1220): pid=1549 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=ToMToU comm="syz-executor.1" name="/root/syzkaller-testdir034915272/syzkaller.YSprrg/2439/bus/bus" dev="sda1" ino=16544 res=1 overlayfs: missing 'lowerdir' overlayfs: unrecognized mount option "low dir=./bus" or missing value overlayfs: failed to resolve './file1': -2 audit: type=1804 audit(1584296233.979:1221): pid=1616 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=open_writers comm="syz-executor.1" name="/root/syzkaller-testdir034915272/syzkaller.YSprrg/2441/bus/bus" dev="sda1" ino=16541 res=1 overlayfs: missing 'lowerdir' overlayfs: failed to resolve './file1': -2 overlayfs: missing 'lowerdir' overlayfs: unrecognized mount option "low dir=./bus" or missing value audit: type=1804 audit(1584296234.159:1222): pid=1643 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=open_writers comm="syz-executor.1" name="/root/syzkaller-testdir034915272/syzkaller.YSprrg/2441/bus/bus" dev="sda1" ino=16541 res=1 overlayfs: failed to resolve './file1': -2 audit: type=1800 audit(1584296234.199:1223): pid=1643 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=collect_data cause=failed comm="syz-executor.1" name="bus" dev="sda1" ino=16541 res=0 overlayfs: missing 'lowerdir' overlayfs: filesystem on './file0' not supported as upperdir overlayfs: failed to resolve './file1': -2 overlayfs: missing 'lowerdir' overlayfs: failed to resolve './file1': -2 overlayfs: missing 'lowerdir' overlayfs: failed to resolve './file1': -2 overlayfs: missing 'lowerdir' overlayfs: missing 'lowerdir' overlayfs: missing 'lowerdir' overlayfs: option "workdir=." is useless in a non-upper mount, ignore overlayfs: failed to resolve './Rnworkdir=./file1erdir=./file0V[z $o;': -2 overlayfs: at least 2 lowerdir are needed while upperdir nonexistent audit: type=1804 audit(1584296235.119:1224): pid=1727 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=open_writers comm="syz-executor.1" name="/root/syzkaller-testdir034915272/syzkaller.YSprrg/2443/bus/bus" dev="sda1" ino=16753 res=1 overlayfs: failed to resolve './file0': -2 overlayfs: unrecognized mount option "l" or missing value overlayfs: failed to resolve './Rnworkdir=./file1erdir=./file0V[z $o;': -2 audit: type=1804 audit(1584296235.299:1225): pid=1727 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=open_writers comm="syz-executor.1" name="/root/syzkaller-testdir034915272/syzkaller.YSprrg/2443/bus/bus" dev="sda1" ino=16753 res=1 overlayfs: unrecognized mount option "l" or missing value overlayfs: failed to resolve './file0': -2 audit: type=1804 audit(1584296235.469:1226): pid=1758 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=open_writers comm="syz-executor.1" name="/root/syzkaller-testdir034915272/syzkaller.YSprrg/2444/bus/bus" dev="overlay" ino=17009 res=1 overlayfs: failed to resolve './file0': -2 overlayfs: unrecognized mount option "l" or missing value overlayfs: filesystem on './file0' not supported as upperdir audit: type=1804 audit(1584296235.639:1227): pid=1758 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=open_writers comm="syz-executor.1" name="/root/syzkaller-testdir034915272/syzkaller.YSprrg/2444/bus/bus" dev="overlay" ino=17009 res=1