====================================================== WARNING: possible circular locking dependency detected 4.19.211-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.2/5277 is trying to acquire lock: 00000000f54f1684 (&sig->cred_guard_mutex){+.+.}, at: lock_trace fs/proc/base.c:402 [inline] 00000000f54f1684 (&sig->cred_guard_mutex){+.+.}, at: proc_pid_syscall+0xb8/0x2f0 fs/proc/base.c:635 but task is already holding lock: 00000000cafe9fb9 (&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: -> #3 (&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 -> #2 (sb_writers#3){.+.+}: sb_start_write include/linux/fs.h:1579 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:360 ovl_xattr_set+0x53/0x600 fs/overlayfs/inode.c:338 ovl_posix_acl_xattr_set+0x347/0x9a0 fs/overlayfs/super.c:917 __vfs_setxattr+0x10e/0x170 fs/xattr.c:149 __vfs_setxattr_noperm+0x11a/0x420 fs/xattr.c:180 __vfs_setxattr_locked+0x176/0x250 fs/xattr.c:238 vfs_setxattr+0xe5/0x270 fs/xattr.c:255 setxattr+0x23d/0x330 fs/xattr.c:520 path_setxattr+0x170/0x190 fs/xattr.c:539 __do_sys_lsetxattr fs/xattr.c:561 [inline] __se_sys_lsetxattr fs/xattr.c:557 [inline] __x64_sys_lsetxattr+0xbd/0x150 fs/xattr.c:557 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: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 traverse.part.0+0xcf/0x5f0 fs/seq_file.c:116 traverse fs/seq_file.c:106 [inline] seq_read+0x99d/0x11c0 fs/seq_file.c:191 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_preadv fs/read_write.c:1071 [inline] __do_sys_preadv fs/read_write.c:1121 [inline] __se_sys_preadv fs/read_write.c:1116 [inline] __x64_sys_preadv+0x22b/0x310 fs/read_write.c:1116 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 *** 1 lock held by syz-executor.2/5277: #0: 00000000cafe9fb9 (&p->lock){+.+.}, at: seq_read+0x6b/0x11c0 fs/seq_file.c:164 stack backtrace: CPU: 0 PID: 5277 Comm: syz-executor.2 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 traverse.part.0+0xcf/0x5f0 fs/seq_file.c:116 traverse fs/seq_file.c:106 [inline] seq_read+0x99d/0x11c0 fs/seq_file.c:191 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_preadv fs/read_write.c:1071 [inline] __do_sys_preadv fs/read_write.c:1121 [inline] __se_sys_preadv fs/read_write.c:1116 [inline] __x64_sys_preadv+0x22b/0x310 fs/read_write.c:1116 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7feb3e363059 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:00007feb3ccd8168 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00007feb3e475f60 RCX: 00007feb3e363059 RDX: 0000000000000005 RSI: 0000000020000400 RDI: 0000000000000003 RBP: 00007feb3e3bd08d R08: 0000000040000006 R09: 0000000000000000 R10: 0000000000000400 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc30a4825f R14: 00007feb3ccd8300 R15: 0000000000022000 audit: type=1800 audit(1643521544.095:664): pid=5348 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.2" name="file0" dev="sda1" ino=15374 res=0 audit: type=1804 audit(1643521544.125:665): pid=5348 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.2" name="/root/syzkaller-testdir029504306/syzkaller.pmRWJj/90/file0" dev="sda1" ino=15374 res=1 mac80211_hwsim: wmediumd released netlink socket, switching to perfect channel medium audit: type=1800 audit(1643521544.485:666): pid=5372 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.2" name="file0" dev="sda1" ino=15370 res=0 mac80211_hwsim: wmediumd released netlink socket, switching to perfect channel medium audit: type=1800 audit(1643521545.455:667): pid=5419 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.2" name="file0" dev="sda1" ino=14388 res=0 mac80211_hwsim: wmediumd released netlink socket, switching to perfect channel medium audit: type=1804 audit(1643521545.475:668): pid=5419 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.2" name="/root/syzkaller-testdir029504306/syzkaller.pmRWJj/92/file0" dev="sda1" ino=14388 res=1 sp0: Synchronizing with TNC UDF-fs: INFO Mounting volume 'LinuxUDF', timestamp 2020/09/19 18:44 (1000) sp0: Synchronizing with TNC mac80211_hwsim: wmediumd released netlink socket, switching to perfect channel medium UDF-fs: INFO Mounting volume 'LinuxUDF', timestamp 2020/09/19 18:44 (1000) sp0: Synchronizing with TNC nla_parse: 31 callbacks suppressed netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'. x_tables: ip_tables: .0 target: invalid size 8 (kernel) != (user) 6 UDF-fs: INFO Mounting volume 'LinuxUDF', timestamp 2020/09/19 18:44 (1000) ISO 9660 Extensions: Microsoft Joliet Level 0 netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'. ISOFS: File unit size != 0 for ISO file (1792). x_tables: ip_tables: .0 target: invalid size 8 (kernel) != (user) 6 mac80211_hwsim: wmediumd released netlink socket, switching to perfect channel medium netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'. x_tables: ip_tables: .0 target: invalid size 8 (kernel) != (user) 6 netlink: 4 bytes leftover after parsing attributes in process `syz-executor.3'. x_tables: ip_tables: .0 target: invalid size 8 (kernel) != (user) 6 ISO 9660 Extensions: Microsoft Joliet Level 0 ISOFS: File unit size != 0 for ISO file (1792). mac80211_hwsim: wmediumd released netlink socket, switching to perfect channel medium ISO 9660 Extensions: Microsoft Joliet Level 0 ISOFS: File unit size != 0 for ISO file (1792). netlink: 4 bytes leftover after parsing attributes in process `syz-executor.3'. x_tables: ip_tables: .0 target: invalid size 8 (kernel) != (user) 6 MTD: Attempt to mount non-MTD device "/dev/loop4" cramfs: wrong magic netlink: 4 bytes leftover after parsing attributes in process `syz-executor.3'. x_tables: ip_tables: .0 target: invalid size 8 (kernel) != (user) 6 netlink: 4 bytes leftover after parsing attributes in process `syz-executor.3'. x_tables: ip_tables: .0 target: invalid size 8 (kernel) != (user) 6 MTD: Attempt to mount non-MTD device "/dev/loop4" cramfs: wrong magic mac80211_hwsim: wmediumd released netlink socket, switching to perfect channel medium MTD: Attempt to mount non-MTD device "/dev/loop4" cramfs: wrong magic XFS (loop1): unknown mount option [loéom=./file1]. befs: Unrecognized mount option "xfs" or missing value befs: (loop1): cannot parse mount options MTD: Attempt to mount non-MTD device "/dev/loop4" cramfs: wrong magic MTD: Attempt to mount non-MTD device "/dev/loop4" cramfs: wrong magic XFS (loop1): unknown mount option [loéom=./file1]. MTD: Attempt to mount non-MTD device "/dev/loop4" cramfs: wrong magic mac80211_hwsim: wmediumd released netlink socket, switching to perfect channel medium befs: Unrecognized mount option "xfs" or missing value befs: (loop1): cannot parse mount options XFS (loop1): unknown mount option [loéom=./file1]. MTD: Attempt to mount non-MTD device "/dev/loop4" mac80211_hwsim: wmediumd released netlink socket, switching to perfect channel medium cramfs: wrong magic MTD: Attempt to mount non-MTD device "/dev/loop4" cramfs: wrong magic MTD: Attempt to mount non-MTD device "/dev/loop4" cramfs: wrong magic MTD: Attempt to mount non-MTD device "/dev/loop4" cramfs: wrong magic