====================================================== WARNING: possible circular locking dependency detected 4.14.291-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.3/9665 is trying to acquire lock: ((&strp->work)){+.+.}, at: [] flush_work+0x88/0x770 kernel/workqueue.c:2887 but task is already holding lock: (sk_lock-AF_INET){+.+.}, at: [] lock_sock include/net/sock.h:1473 [inline] (sk_lock-AF_INET){+.+.}, at: [] kcm_attach net/kcm/kcmsock.c:1390 [inline] (sk_lock-AF_INET){+.+.}, at: [] kcm_attach_ioctl net/kcm/kcmsock.c:1490 [inline] (sk_lock-AF_INET){+.+.}, at: [] kcm_ioctl+0x328/0xfb0 net/kcm/kcmsock.c:1701 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (sk_lock-AF_INET){+.+.}: lock_sock_nested+0xb7/0x100 net/core/sock.c:2813 do_strp_work net/strparser/strparser.c:415 [inline] strp_work+0x3e/0x100 net/strparser/strparser.c:434 process_one_work+0x793/0x14a0 kernel/workqueue.c:2117 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 -> #0 ((&strp->work)){+.+.}: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 flush_work+0xad/0x770 kernel/workqueue.c:2890 __cancel_work_timer+0x321/0x460 kernel/workqueue.c:2965 strp_done+0x53/0xd0 net/strparser/strparser.c:519 kcm_attach net/kcm/kcmsock.c:1429 [inline] kcm_attach_ioctl net/kcm/kcmsock.c:1490 [inline] kcm_ioctl+0x828/0xfb0 net/kcm/kcmsock.c:1701 sock_do_ioctl net/socket.c:974 [inline] sock_ioctl+0x2cc/0x4c0 net/socket.c:1071 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 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: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sk_lock-AF_INET); lock((&strp->work)); lock(sk_lock-AF_INET); lock((&strp->work)); *** DEADLOCK *** 1 lock held by syz-executor.3/9665: #0: (sk_lock-AF_INET){+.+.}, at: [] lock_sock include/net/sock.h:1473 [inline] #0: (sk_lock-AF_INET){+.+.}, at: [] kcm_attach net/kcm/kcmsock.c:1390 [inline] #0: (sk_lock-AF_INET){+.+.}, at: [] kcm_attach_ioctl net/kcm/kcmsock.c:1490 [inline] #0: (sk_lock-AF_INET){+.+.}, at: [] kcm_ioctl+0x328/0xfb0 net/kcm/kcmsock.c:1701 stack backtrace: CPU: 0 PID: 9665 Comm: syz-executor.3 Not tainted 4.14.291-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 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 flush_work+0xad/0x770 kernel/workqueue.c:2890 __cancel_work_timer+0x321/0x460 kernel/workqueue.c:2965 strp_done+0x53/0xd0 net/strparser/strparser.c:519 kcm_attach net/kcm/kcmsock.c:1429 [inline] kcm_attach_ioctl net/kcm/kcmsock.c:1490 [inline] kcm_ioctl+0x828/0xfb0 net/kcm/kcmsock.c:1701 sock_do_ioctl net/socket.c:974 [inline] sock_ioctl+0x2cc/0x4c0 net/socket.c:1071 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7fdaff8a6279 RSP: 002b:00007fdafe1b8168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fdaff9b91f0 RCX: 00007fdaff8a6279 RDX: 0000000020000180 RSI: 00000000000089e0 RDI: 0000000000000087 RBP: 00007fdaff900189 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffcd68a952f R14: 00007fdafe1b8300 R15: 0000000000022000 syz-executor.0 (9664) used greatest stack depth: 24576 bytes left overlayfs: unrecognized mount option "up¶©›Ù!œåB‘\*perdir=./bus" or missing value Zero length message leads to an empty skb overlayfs: unrecognized mount option "up¶©›Ù!œåB‘\*perdir=./bus" or missing value audit: type=1804 audit(1661707640.126:2): pid=10019 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.1" name="/root/syzkaller-testdir1901479587/syzkaller.bxDfDa/13/bus" dev="sda1" ino=13914 res=1 audit: type=1804 audit(1661707640.156:3): pid=10019 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="ToMToU" comm="syz-executor.1" name="/root/syzkaller-testdir1901479587/syzkaller.bxDfDa/13/bus" dev="sda1" ino=13914 res=1 audit: type=1804 audit(1661707640.156:4): pid=10019 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="ToMToU" comm="syz-executor.1" name="/root/syzkaller-testdir1901479587/syzkaller.bxDfDa/13/bus" dev="sda1" ino=13914 res=1 audit: type=1804 audit(1661707640.346:5): pid=10051 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.1" name="/root/syzkaller-testdir1901479587/syzkaller.bxDfDa/14/bus" dev="sda1" ino=13917 res=1 ip_tables: iptables: counters copy to user failed while replacing table audit: type=1804 audit(1661707640.376:6): pid=10051 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="ToMToU" comm="syz-executor.1" name="/root/syzkaller-testdir1901479587/syzkaller.bxDfDa/14/bus" dev="sda1" ino=13917 res=1 audit: type=1804 audit(1661707640.376:7): pid=10051 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="ToMToU" comm="syz-executor.1" name="/root/syzkaller-testdir1901479587/syzkaller.bxDfDa/14/bus" dev="sda1" ino=13917 res=1 ip_tables: iptables: counters copy to user failed while replacing table audit: type=1804 audit(1661707640.476:8): pid=10085 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.1" name="/root/syzkaller-testdir1901479587/syzkaller.bxDfDa/15/bus" dev="sda1" ino=13917 res=1 ip_tables: iptables: counters copy to user failed while replacing table audit: type=1804 audit(1661707640.476:9): pid=10085 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="ToMToU" comm="syz-executor.1" name="/root/syzkaller-testdir1901479587/syzkaller.bxDfDa/15/bus" dev="sda1" ino=13917 res=1 audit: type=1804 audit(1661707640.476:10): pid=10085 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="ToMToU" comm="syz-executor.1" name="/root/syzkaller-testdir1901479587/syzkaller.bxDfDa/15/bus" dev="sda1" ino=13917 res=1 audit: type=1800 audit(1661707640.896:11): pid=10154 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.4" name="file0" dev="sda1" ino=13882 res=0 kvm: vcpu 0: requested 128 ns lapic timer period limited to 500000 ns kvm: vcpu 0: requested 128 ns lapic timer period limited to 500000 ns kvm: vcpu 0: requested 128 ns lapic timer period limited to 500000 ns kvm: vcpu 0: requested 128 ns lapic timer period limited to 500000 ns kvm: vcpu 0: requested 128 ns lapic timer period limited to 500000 ns kvm: vcpu 0: requested 128 ns lapic timer period limited to 500000 ns