====================================================== WARNING: possible circular locking dependency detected 4.14.218-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.3/14908 is trying to acquire lock: (&sig->cred_guard_mutex){+.+.}, at: [] lock_trace syzkaller/managers/linux-4-14/kernel/fs/proc/base.c:407 [inline] (&sig->cred_guard_mutex){+.+.}, at: [] proc_pid_stack+0x13f/0x2f0 syzkaller/managers/linux-4-14/kernel/fs/proc/base.c:457 but task is already holding lock: (&p->lock){+.+.}, at: [] seq_read+0xba/0x1120 syzkaller/managers/linux-4-14/kernel/fs/seq_file.c:165 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&p->lock){+.+.}: __mutex_lock_common syzkaller/managers/linux-4-14/kernel/kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 syzkaller/managers/linux-4-14/kernel/kernel/locking/mutex.c:893 seq_read+0xba/0x1120 syzkaller/managers/linux-4-14/kernel/fs/seq_file.c:165 proc_reg_read+0xee/0x1a0 syzkaller/managers/linux-4-14/kernel/fs/proc/inode.c:217 do_loop_readv_writev syzkaller/managers/linux-4-14/kernel/fs/read_write.c:695 [inline] do_loop_readv_writev syzkaller/managers/linux-4-14/kernel/fs/read_write.c:682 [inline] do_iter_read+0x3eb/0x5b0 syzkaller/managers/linux-4-14/kernel/fs/read_write.c:919 vfs_readv+0xc8/0x120 syzkaller/managers/linux-4-14/kernel/fs/read_write.c:981 kernel_readv syzkaller/managers/linux-4-14/kernel/fs/splice.c:361 [inline] default_file_splice_read+0x418/0x910 syzkaller/managers/linux-4-14/kernel/fs/splice.c:416 do_splice_to+0xfb/0x140 syzkaller/managers/linux-4-14/kernel/fs/splice.c:880 splice_direct_to_actor+0x207/0x730 syzkaller/managers/linux-4-14/kernel/fs/splice.c:952 do_splice_direct+0x164/0x210 syzkaller/managers/linux-4-14/kernel/fs/splice.c:1061 do_sendfile+0x47f/0xb30 syzkaller/managers/linux-4-14/kernel/fs/read_write.c:1441 SYSC_sendfile64 syzkaller/managers/linux-4-14/kernel/fs/read_write.c:1502 [inline] SyS_sendfile64+0xff/0x110 syzkaller/managers/linux-4-14/kernel/fs/read_write.c:1488 do_syscall_64+0x1d5/0x640 syzkaller/managers/linux-4-14/kernel/arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #2 (sb_writers#3){.+.+}: percpu_down_read_preempt_disable syzkaller/managers/linux-4-14/kernel/./include/linux/percpu-rwsem.h:36 [inline] percpu_down_read syzkaller/managers/linux-4-14/kernel/./include/linux/percpu-rwsem.h:59 [inline] __sb_start_write+0x64/0x260 syzkaller/managers/linux-4-14/kernel/fs/super.c:1342 sb_start_write syzkaller/managers/linux-4-14/kernel/./include/linux/fs.h:1549 [inline] mnt_want_write+0x3a/0xb0 syzkaller/managers/linux-4-14/kernel/fs/namespace.c:386 ovl_do_remove+0x67/0xb90 syzkaller/managers/linux-4-14/kernel/fs/overlayfs/dir.c:759 vfs_rmdir.part.0+0x144/0x390 syzkaller/managers/linux-4-14/kernel/fs/namei.c:3908 vfs_rmdir syzkaller/managers/linux-4-14/kernel/fs/namei.c:3893 [inline] do_rmdir+0x334/0x3c0 syzkaller/managers/linux-4-14/kernel/fs/namei.c:3968 do_syscall_64+0x1d5/0x640 syzkaller/managers/linux-4-14/kernel/arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #1 (&ovl_i_mutex_dir_key[depth]#2){++++}: down_read+0x36/0x80 syzkaller/managers/linux-4-14/kernel/kernel/locking/rwsem.c:24 inode_lock_shared syzkaller/managers/linux-4-14/kernel/./include/linux/fs.h:729 [inline] do_last syzkaller/managers/linux-4-14/kernel/fs/namei.c:3333 [inline] path_openat+0x149b/0x2970 syzkaller/managers/linux-4-14/kernel/fs/namei.c:3569 do_filp_open+0x179/0x3c0 syzkaller/managers/linux-4-14/kernel/fs/namei.c:3603 do_open_execat+0xd3/0x450 syzkaller/managers/linux-4-14/kernel/fs/exec.c:849 do_execveat_common+0x711/0x1f30 syzkaller/managers/linux-4-14/kernel/fs/exec.c:1755 do_execve syzkaller/managers/linux-4-14/kernel/fs/exec.c:1860 [inline] SYSC_execve syzkaller/managers/linux-4-14/kernel/fs/exec.c:1941 [inline] SyS_execve+0x3b/0x50 syzkaller/managers/linux-4-14/kernel/fs/exec.c:1936 do_syscall_64+0x1d5/0x640 syzkaller/managers/linux-4-14/kernel/arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #0 (&sig->cred_guard_mutex){+.+.}: lock_acquire+0x170/0x3f0 syzkaller/managers/linux-4-14/kernel/kernel/locking/lockdep.c:3998 __mutex_lock_common syzkaller/managers/linux-4-14/kernel/kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 syzkaller/managers/linux-4-14/kernel/kernel/locking/mutex.c:893 lock_trace syzkaller/managers/linux-4-14/kernel/fs/proc/base.c:407 [inline] proc_pid_stack+0x13f/0x2f0 syzkaller/managers/linux-4-14/kernel/fs/proc/base.c:457 proc_single_show+0xe7/0x150 syzkaller/managers/linux-4-14/kernel/fs/proc/base.c:761 seq_read+0x4cf/0x1120 syzkaller/managers/linux-4-14/kernel/fs/seq_file.c:237 do_loop_readv_writev syzkaller/managers/linux-4-14/kernel/fs/read_write.c:695 [inline] do_loop_readv_writev syzkaller/managers/linux-4-14/kernel/fs/read_write.c:682 [inline] do_iter_read+0x3eb/0x5b0 syzkaller/managers/linux-4-14/kernel/fs/read_write.c:919 vfs_readv+0xc8/0x120 syzkaller/managers/linux-4-14/kernel/fs/read_write.c:981 do_preadv syzkaller/managers/linux-4-14/kernel/fs/read_write.c:1065 [inline] SYSC_preadv syzkaller/managers/linux-4-14/kernel/fs/read_write.c:1115 [inline] SyS_preadv+0x15a/0x200 syzkaller/managers/linux-4-14/kernel/fs/read_write.c:1110 do_syscall_64+0x1d5/0x640 syzkaller/managers/linux-4-14/kernel/arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb 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.3/14908: #0: (&p->lock){+.+.}, at: [] seq_read+0xba/0x1120 syzkaller/managers/linux-4-14/kernel/fs/seq_file.c:165 stack backtrace: CPU: 1 PID: 14908 Comm: syz-executor.3 Not tainted 4.14.218-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack syzkaller/managers/linux-4-14/kernel/lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 syzkaller/managers/linux-4-14/kernel/lib/dump_stack.c:58 print_circular_bug.constprop.0.cold+0x2d7/0x41e syzkaller/managers/linux-4-14/kernel/kernel/locking/lockdep.c:1258 check_prev_add syzkaller/managers/linux-4-14/kernel/kernel/locking/lockdep.c:1905 [inline] check_prevs_add syzkaller/managers/linux-4-14/kernel/kernel/locking/lockdep.c:2022 [inline] validate_chain syzkaller/managers/linux-4-14/kernel/kernel/locking/lockdep.c:2464 [inline] __lock_acquire+0x2e0e/0x3f20 syzkaller/managers/linux-4-14/kernel/kernel/locking/lockdep.c:3491 lock_acquire+0x170/0x3f0 syzkaller/managers/linux-4-14/kernel/kernel/locking/lockdep.c:3998 __mutex_lock_common syzkaller/managers/linux-4-14/kernel/kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 syzkaller/managers/linux-4-14/kernel/kernel/locking/mutex.c:893 lock_trace syzkaller/managers/linux-4-14/kernel/fs/proc/base.c:407 [inline] proc_pid_stack+0x13f/0x2f0 syzkaller/managers/linux-4-14/kernel/fs/proc/base.c:457 proc_single_show+0xe7/0x150 syzkaller/managers/linux-4-14/kernel/fs/proc/base.c:761 seq_read+0x4cf/0x1120 syzkaller/managers/linux-4-14/kernel/fs/seq_file.c:237 do_loop_readv_writev syzkaller/managers/linux-4-14/kernel/fs/read_write.c:695 [inline] do_loop_readv_writev syzkaller/managers/linux-4-14/kernel/fs/read_write.c:682 [inline] do_iter_read+0x3eb/0x5b0 syzkaller/managers/linux-4-14/kernel/fs/read_write.c:919 vfs_readv+0xc8/0x120 syzkaller/managers/linux-4-14/kernel/fs/read_write.c:981 do_preadv syzkaller/managers/linux-4-14/kernel/fs/read_write.c:1065 [inline] SYSC_preadv syzkaller/managers/linux-4-14/kernel/fs/read_write.c:1115 [inline] SyS_preadv+0x15a/0x200 syzkaller/managers/linux-4-14/kernel/fs/read_write.c:1110 do_syscall_64+0x1d5/0x640 syzkaller/managers/linux-4-14/kernel/arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x465b09 RSP: 002b:00007f9fb1de0188 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000465b09 RDX: 0000000000000375 RSI: 00000000200017c0 RDI: 0000000000000005 RBP: 00000000004b069f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007ffcb0f35daf R14: 00007f9fb1de0300 R15: 0000000000022000 ptrace attach of "/root/syz-executor.3"[15057] was attempted by "/root/syz-executor.3"[15058] SQUASHFS error: squashfs_read_data failed to read block 0x0 squashfs: SQUASHFS error: unable to read squashfs_super_block SQUASHFS error: squashfs_read_data failed to read block 0x0 squashfs: SQUASHFS error: unable to read squashfs_super_block SQUASHFS error: squashfs_read_data failed to read block 0x0 squashfs: SQUASHFS error: unable to read squashfs_super_block SQUASHFS error: squashfs_read_data failed to read block 0x0 squashfs: SQUASHFS error: unable to read squashfs_super_block SQUASHFS error: squashfs_read_data failed to read block 0x0 squashfs: SQUASHFS error: unable to read squashfs_super_block Unknown ioctl -2143791862 Unknown ioctl -1072147198 Unknown ioctl -2143791862 Unknown ioctl -1072147198 IPVS: ftp: loaded support on port[0] = 21 IPVS: ftp: loaded support on port[0] = 21