Hello, syzbot found the following issue on: HEAD commit: 95d10484d66e Add linux-next specific files for 20220817 git tree: linux-next console+strace: https://syzkaller.appspot.com/x/log.txt?x=11b3b2f3080000 kernel config: https://syzkaller.appspot.com/x/.config?x=2f5fa747986be53a dashboard link: https://syzkaller.appspot.com/bug?extid=e696806ef96cdd2d87cd compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1778e50d080000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1379e5e3080000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+e696806ef96cdd2d87cd@xxxxxxxxxxxxxxxxxxxxxxxxx ====================================================== WARNING: possible circular locking dependency detected 6.0.0-rc1-next-20220817-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor769/3613 is trying to acquire lock: ffff88801cb5c0f8 ((work_completion)(&strp->work)){+.+.}-{0:0}, at: __flush_work+0xdd/0xae0 kernel/workqueue.c:3066 but task is already holding lock: ffff88801d5b0fb0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1687 [inline] ffff88801d5b0fb0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: kcm_attach net/kcm/kcmsock.c:1390 [inline] ffff88801d5b0fb0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: kcm_attach_ioctl net/kcm/kcmsock.c:1490 [inline] ffff88801d5b0fb0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: kcm_ioctl+0x396/0x1180 net/kcm/kcmsock.c:1696 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (sk_lock-AF_INET6){+.+.}-{0:0}: lock_sock_nested+0x36/0xf0 net/core/sock.c:3391 do_strp_work net/strparser/strparser.c:398 [inline] strp_work+0x40/0x130 net/strparser/strparser.c:415 process_one_work+0x991/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 -> #0 ((work_completion)(&strp->work)){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3829 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5053 lock_acquire kernel/locking/lockdep.c:5666 [inline] lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631 __flush_work+0x105/0xae0 kernel/workqueue.c:3069 __cancel_work_timer+0x3f9/0x570 kernel/workqueue.c:3160 strp_done+0x64/0xf0 net/strparser/strparser.c:513 kcm_attach net/kcm/kcmsock.c:1429 [inline] kcm_attach_ioctl net/kcm/kcmsock.c:1490 [inline] kcm_ioctl+0x913/0x1180 net/kcm/kcmsock.c:1696 sock_do_ioctl+0xcc/0x230 net/socket.c:1169 sock_ioctl+0x2f1/0x640 net/socket.c:1286 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sk_lock-AF_INET6); lock((work_completion)(&strp->work)); lock(sk_lock-AF_INET6); lock((work_completion)(&strp->work)); *** DEADLOCK *** 1 lock held by syz-executor769/3613: #0: ffff88801d5b0fb0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1687 [inline] #0: ffff88801d5b0fb0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: kcm_attach net/kcm/kcmsock.c:1390 [inline] #0: ffff88801d5b0fb0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: kcm_attach_ioctl net/kcm/kcmsock.c:1490 [inline] #0: ffff88801d5b0fb0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: kcm_ioctl+0x396/0x1180 net/kcm/kcmsock.c:1696 stack backtrace: CPU: 0 PID: 3613 Comm: syz-executor769 Not tainted 6.0.0-rc1-next-20220817-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3829 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5053 lock_acquire kernel/locking/lockdep.c:5666 [inline] lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631 __flush_work+0x105/0xae0 kernel/workqueue.c:3069 __cancel_work_timer+0x3f9/0x570 kernel/workqueue.c:3160 strp_done+0x64/0xf0 net/strparser/strparser.c:513 kcm_attach net/kcm/kcmsock.c:1429 [inline] kcm_attach_ioctl net/kcm/kcmsock.c:1490 [inline] kcm_ioctl+0x913/0x1180 net/kcm/kcmsock.c:1696 sock_do_ioctl+0xcc/0x230 net/socket.c:1169 sock_ioctl+0x2f1/0x640 net/socket.c:1286 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fc907a73f09 Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 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 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc5f76b0d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc907a73f09 RDX: 00000000200000c0 RSI: 00000000000089e0 RDI: 0000000000000003 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches
