audit: type=1800 audit(1642328473.702:584): pid=2800 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.5" name="file0" dev="loop5" ino=17 res=0 ====================================================== WARNING: possible circular locking dependency detected 4.14.262-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/2799 is trying to acquire lock: (&ovl_i_mutex_dir_key[depth]){++++}, at: [] inode_lock_shared include/linux/fs.h:729 [inline] (&ovl_i_mutex_dir_key[depth]){++++}, at: [] do_last fs/namei.c:3333 [inline] (&ovl_i_mutex_dir_key[depth]){++++}, at: [] path_openat+0x149b/0x2970 fs/namei.c:3569 but task is already holding lock: (&sig->cred_guard_mutex){+.+.}, at: [] prepare_bprm_creds fs/exec.c:1404 [inline] (&sig->cred_guard_mutex){+.+.}, at: [] do_execveat_common+0x319/0x1f30 fs/exec.c:1748 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&sig->cred_guard_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 do_io_accounting fs/proc/base.c:2738 [inline] proc_tid_io_accounting+0x184/0x290 fs/proc/base.c:2781 proc_single_show+0xe7/0x150 fs/proc/base.c:761 seq_read+0x4e4/0x1180 fs/seq_file.c:240 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 do_preadv fs/read_write.c:1065 [inline] SYSC_preadv fs/read_write.c:1115 [inline] SyS_preadv+0x15a/0x200 fs/read_write.c:1110 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #2 (&p->lock){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 seq_read+0xba/0x1180 fs/seq_file.c:168 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 -> #1 (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:1551 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:386 ovl_xattr_set+0x4d/0x290 fs/overlayfs/inode.c:214 __vfs_setxattr+0xdc/0x130 fs/xattr.c:150 __vfs_setxattr_noperm+0xfd/0x3d0 fs/xattr.c:181 __vfs_setxattr_locked+0x14d/0x250 fs/xattr.c:239 vfs_setxattr+0xcf/0x230 fs/xattr.c:256 setxattr+0x1a9/0x300 fs/xattr.c:523 path_setxattr+0x118/0x130 fs/xattr.c:542 SYSC_lsetxattr fs/xattr.c:564 [inline] SyS_lsetxattr+0x33/0x40 fs/xattr.c:560 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #0 (&ovl_i_mutex_dir_key[depth]){++++}: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 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 other info that might help us debug this: Chain exists of: &ovl_i_mutex_dir_key[depth] --> &p->lock --> &sig->cred_guard_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sig->cred_guard_mutex); lock(&p->lock); lock(&sig->cred_guard_mutex); lock(&ovl_i_mutex_dir_key[depth]); *** DEADLOCK *** 1 lock held by syz-executor.0/2799: #0: (&sig->cred_guard_mutex){+.+.}, at: [] prepare_bprm_creds fs/exec.c:1404 [inline] #0: (&sig->cred_guard_mutex){+.+.}, at: [] do_execveat_common+0x319/0x1f30 fs/exec.c:1748 stack backtrace: CPU: 1 PID: 2799 Comm: syz-executor.0 Not tainted 4.14.262-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 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 RIP: 0033:0x7f3c64c87fe9 RSP: 002b:00007f3c635fd168 EFLAGS: 00000246 ORIG_RAX: 000000000000003b RAX: ffffffffffffffda RBX: 00007f3c64d9af60 RCX: 00007f3c64c87fe9 RDX: 0000000020000900 RSI: 0000000020000500 RDI: 0000000020000000 RBP: 00007f3c64ce208d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffeb3597f3f R14: 00007f3c635fd300 R15: 0000000000022000 overlayfs: failed to resolve '.#ôq8ÓjÅ': -2 EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue audit: type=1800 audit(1642328474.663:585): pid=2833 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.5" name="file0" dev="loop5" ino=17 res=0 overlayfs: failed to resolve '.#ôq8ÓjÅ': -2 audit: type=1800 audit(1642328474.743:586): pid=2860 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.4" name="bus" dev="sda1" ino=13958 res=0 overlayfs: failed to resolve '.#ôq8ÓjÅ': -2 kvm: vcpu 0: requested 128 ns lapic timer period limited to 500000 ns EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue audit: type=1800 audit(1642328475.033:587): pid=2925 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.5" name="file0" dev="loop5" ino=17 res=0 audit: type=1800 audit(1642328476.533:588): pid=3034 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.3" name="bus" dev="sda1" ino=14196 res=0 audit: type=1800 audit(1642328476.533:589): pid=3036 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.4" name="bus" dev="sda1" ino=14214 res=0 unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 audit: type=1800 audit(1642328476.853:590): pid=3116 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.4" name="bus" dev="sda1" ino=14201 res=0 EXT4-fs (loop1): Unrecognized mount option "bha" or missing value EXT4-fs (loop1): Unrecognized mount option "bha" or missing value print_req_error: I/O error, dev loop1, sector 0 Buffer I/O error on dev loop1, logical block 0, async page read print_req_error: I/O error, dev loop1, sector 4 Buffer I/O error on dev loop1, logical block 2, async page read print_req_error: I/O error, dev loop1, sector 6 Buffer I/O error on dev loop1, logical block 3, async page read ip6_tables: ip6tables: counters copy to user failed while replacing table audit: type=1800 audit(1642328477.723:591): pid=3200 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.4" name="bus" dev="sda1" ino=14295 res=0 ip6_tables: ip6tables: counters copy to user failed while replacing table audit: type=1800 audit(1642328478.563:592): pid=3233 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.4" name="bus" dev="sda1" ino=14103 res=0 audit: type=1800 audit(1642328481.674:593): pid=3273 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.5" name="bus" dev="sda1" ino=14597 res=0 ip6_tables: ip6tables: counters copy to user failed while replacing table audit: type=1800 audit(1642328481.674:594): pid=3274 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.4" name="bus" dev="sda1" ino=14613 res=0 netlink: 28 bytes leftover after parsing attributes in process `syz-executor.5'. audit: type=1800 audit(1642328481.914:595): pid=3326 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.4" name="bus" dev="sda1" ino=14485 res=0 netlink: 28 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 28 bytes leftover after parsing attributes in process `syz-executor.5'. EXT4-fs (loop1): Unrecognized mount option "ÿÿÿÿ" or missing value EXT4-fs (loop1): Unrecognized mount option "ÿÿÿÿ" or missing value audit: type=1800 audit(1642328482.784:596): pid=3456 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.4" name="bus" dev="sda1" ino=14321 res=0 audit: type=1800 audit(1642328483.004:597): pid=3496 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.5" name="bus" dev="sda1" ino=14551 res=0 audit: type=1800 audit(1642328483.664:598): pid=3528 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.4" name="bus" dev="sda1" ino=14202 res=0