====================================================== WARNING: possible circular locking dependency detected 4.19.211-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.3/17720 is trying to acquire lock: 00000000c876719d (&sig->cred_guard_mutex){+.+.}, at: lock_trace fs/proc/base.c:402 [inline] 00000000c876719d (&sig->cred_guard_mutex){+.+.}, at: proc_pid_syscall+0xb8/0x2f0 fs/proc/base.c:635 but task is already holding lock: 000000008147ccb9 (&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 proc_reg_read+0x1bd/0x2d0 fs/proc/inode.c:231 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_create_object+0x96/0x290 fs/overlayfs/dir.c:602 lookup_open+0x893/0x1a20 fs/namei.c:3235 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 -> #2 (&ovl_i_mutex_dir_key[depth]){++++}: iterate_dir+0x409/0x5c0 fs/readdir.c:43 ovl_dir_read fs/overlayfs/readdir.c:312 [inline] ovl_dir_read_merged+0x367/0x4e0 fs/overlayfs/readdir.c:387 ovl_check_empty_dir+0xac/0x4c0 fs/overlayfs/readdir.c:929 ovl_do_remove+0xd2/0xdb0 fs/overlayfs/dir.c:840 vfs_rmdir.part.0+0x10f/0x3d0 fs/namei.c:3882 vfs_rmdir fs/namei.c:3868 [inline] do_rmdir+0x3fd/0x490 fs/namei.c:3943 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]#3){++++}: inode_lock_shared include/linux/fs.h:758 [inline] do_last fs/namei.c:3326 [inline] path_openat+0x17ec/0x2df0 fs/namei.c:3537 do_filp_open+0x18c/0x3f0 fs/namei.c:3567 do_open_execat+0x11d/0x5b0 fs/exec.c:853 __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){+.+.}: __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 __vfs_read+0xf7/0x750 fs/read_write.c:416 vfs_read+0x194/0x3c0 fs/read_write.c:452 ksys_read+0x12b/0x2a0 fs/read_write.c:579 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 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.3/17720: #0: 00000000c14ce51f (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767 #1: 000000008147ccb9 (&p->lock){+.+.}, at: seq_read+0x6b/0x11c0 fs/seq_file.c:164 stack backtrace: CPU: 1 PID: 17720 Comm: syz-executor.3 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 __vfs_read+0xf7/0x750 fs/read_write.c:416 vfs_read+0x194/0x3c0 fs/read_write.c:452 ksys_read+0x12b/0x2a0 fs/read_write.c:579 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7ff57efb6059 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:00007ff57d92b168 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007ff57f0c8f60 RCX: 00007ff57efb6059 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007ff57f01008d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffefc34a91f R14: 00007ff57d92b300 R15: 0000000000022000 audit: type=1326 audit(1644926216.729:14840): auid=4294967295 uid=0 gid=0 ses=4294967295 subj==unconfined pid=17732 comm="syz-executor.2" exe="/root/syz-executor.2" sig=31 arch=c000003e syscall=202 compat=0 ip=0x7fa5f2b4a059 code=0x0 kvm [17759]: vcpu0, guest rIP: 0xfff0 disabled perfctr wrmsr: 0xc2 data 0x3ad6e37883b8e6ec audit: type=1326 audit(1644926217.989:14841): auid=4294967295 uid=0 gid=0 ses=4294967295 subj==unconfined pid=17826 comm="syz-executor.3" exe="/root/syz-executor.3" sig=9 arch=c000003e syscall=231 compat=0 ip=0x7ff57efb6059 code=0x0 audit: type=1326 audit(1644926218.869:14842): auid=4294967295 uid=0 gid=0 ses=4294967295 subj==unconfined pid=17964 comm="syz-executor.0" exe="/root/syz-executor.0" sig=9 arch=c000003e syscall=231 compat=0 ip=0x7fe87c285059 code=0x0 netlink: 24 bytes leftover after parsing attributes in process `syz-executor.1'. netlink: 12 bytes leftover after parsing attributes in process `syz-executor.2'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.1'. netlink: 12 bytes leftover after parsing attributes in process `syz-executor.2'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.1'. audit: type=1326 audit(1644926221.249:14843): auid=4294967295 uid=0 gid=0 ses=4294967295 subj==unconfined pid=17995 comm="syz-executor.0" exe="/root/syz-executor.0" sig=9 arch=c000003e syscall=231 compat=0 ip=0x7fe87c285059 code=0x0 netlink: 12 bytes leftover after parsing attributes in process `syz-executor.2'. SQUASHFS error: lzo decompression failed, data probably corrupt SQUASHFS error: squashfs_read_data failed to read block 0x60 SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f audit: type=1326 audit(1644926224.289:14844): auid=4294967295 uid=0 gid=0 ses=4294967295 subj==unconfined pid=18144 comm="syz-executor.0" exe="/root/syz-executor.0" sig=9 arch=c000003e syscall=231 compat=0 ip=0x7fe87c285059 code=0x0 SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f audit: type=1800 audit(1644926224.329:14845): pid=18155 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed comm="syz-executor.2" name="file1" dev="loop2" ino=5 res=0 SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f netlink: 12 bytes leftover after parsing attributes in process `syz-executor.2'. audit: type=1804 audit(1644926224.579:14846): pid=18219 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.1" name="/root/syzkaller-testdir183401948/syzkaller.ExtD18/1002/bus" dev="sda1" ino=14997 res=1 netlink: 12 bytes leftover after parsing attributes in process `syz-executor.1'. audit: type=1800 audit(1644926224.579:14847): pid=18219 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.1" name="bus" dev="sda1" ino=14997 res=0 audit: type=1804 audit(1644926224.789:14848): pid=18234 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.1" name="/root/syzkaller-testdir183401948/syzkaller.ExtD18/1003/bus" dev="sda1" ino=14985 res=1 audit: type=1800 audit(1644926224.789:14849): pid=18234 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.1" name="bus" dev="sda1" ino=14985 res=0 netlink: 12 bytes leftover after parsing attributes in process `syz-executor.1'. audit: type=1804 audit(1644926224.869:14850): pid=18251 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=ToMToU comm="syz-executor.1" name="/root/syzkaller-testdir183401948/syzkaller.ExtD18/1003/bus" dev="sda1" ino=14985 res=1 audit: type=1804 audit(1644926224.889:14851): pid=18254 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.1" name="/root/syzkaller-testdir183401948/syzkaller.ExtD18/1003/bus" dev="sda1" ino=14985 res=1 netlink: 12 bytes leftover after parsing attributes in process `syz-executor.1'. audit: type=1800 audit(1644926224.889:14852): pid=18254 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.1" name="bus" dev="sda1" ino=14985 res=0 SQUASHFS error: lzo decompression failed, data probably corrupt SQUASHFS error: squashfs_read_data failed to read block 0x60 SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f SQUASHFS error: Unable to read fragment cache entry [60] SQUASHFS error: Unable to read page, block 60, size 1f