On Thu, 2024-06-13 at 12:38 -0700, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 2ccbdf43d5e7 Merge tag 'for-linus' of > git://git.kernel.org.. > git tree: upstream > console output: > https://syzkaller.appspot.com/x/log.txt?x=158e5256980000 > kernel config: > https://syzkaller.appspot.com/x/.config?x=c79815c08cc14227 > dashboard link: > https://syzkaller.appspot.com/bug?extid=e9820daec56bcb4c41b5 > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for > Debian) 2.40 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: > https://storage.googleapis.com/syzbot-assets/9fb20954c51e/disk-2ccbdf43.raw.xz > vmlinux: > https://storage.googleapis.com/syzbot-assets/06d78b3cf960/vmlinux-2ccbdf43.xz > kernel image: > https://storage.googleapis.com/syzbot-assets/15e5b0a8df77/bzImage-2ccbdf43.xz > > IMPORTANT: if you fix the issue, please add the following tag to the > commit: > Reported-by: syzbot+e9820daec56bcb4c41b5@xxxxxxxxxxxxxxxxxxxxxxxxx > > INFO: task syz-executor.1:7517 blocked for more than 143 seconds. > Not tainted 6.10.0-rc3-syzkaller-00044-g2ccbdf43d5e7 #0 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this > message. > task:syz-executor.1 state:D stack:23800 pid:7517 tgid:7515 > ppid:6054 flags:0x00000006 > Call Trace: > <TASK> > context_switch kernel/sched/core.c:5408 [inline] > __schedule+0x1796/0x49d0 kernel/sched/core.c:6745 > __schedule_loop kernel/sched/core.c:6822 [inline] > schedule+0x14b/0x320 kernel/sched/core.c:6837 > schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6894 > __mutex_lock_common kernel/locking/mutex.c:684 [inline] > __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752 > nfsd_nl_rpc_status_get_start+0x8d/0xe0 fs/nfsd/nfsctl.c:1476 > genl_start+0x4d6/0x6d0 net/netlink/genetlink.c:1005 > __netlink_dump_start+0x45c/0x780 net/netlink/af_netlink.c:2445 > genl_family_rcv_msg_dumpit net/netlink/genetlink.c:1076 [inline] > genl_family_rcv_msg net/netlink/genetlink.c:1192 [inline] > genl_rcv_msg+0x88c/0xec0 net/netlink/genetlink.c:1210 > netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2564 > genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 > netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline] > netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1361 > netlink_sendmsg+0x8db/0xcb0 net/netlink/af_netlink.c:1905 > sock_sendmsg_nosec net/socket.c:730 [inline] > __sock_sendmsg+0x221/0x270 net/socket.c:745 > ____sys_sendmsg+0x525/0x7d0 net/socket.c:2585 > ___sys_sendmsg net/socket.c:2639 [inline] > __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2668 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > RIP: 0033:0x7f182b67cea9 > RSP: 002b:00007f182c48a0c8 EFLAGS: 00000246 ORIG_RAX: > 000000000000002e > RAX: ffffffffffffffda RBX: 00007f182b7b3f80 RCX: 00007f182b67cea9 > RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000003 > RBP: 00007f182b6ebff4 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 > R13: 000000000000000b R14: 00007f182b7b3f80 R15: 00007ffd83adb8d8 > </TASK> > > Showing all locks held in the system: > 5 locks held by kworker/u8:1/12: > #0: ffff888015ed3148 ((wq_completion)netns){+.+.}-{0:0}, at: > process_one_work kernel/workqueue.c:3206 [inline] > #0: ffff888015ed3148 ((wq_completion)netns){+.+.}-{0:0}, at: > process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312 > #1: ffffc90000117d00 (net_cleanup_work){+.+.}-{0:0}, at: > process_one_work kernel/workqueue.c:3207 [inline] > #1: ffffc90000117d00 (net_cleanup_work){+.+.}-{0:0}, at: > process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312 > #2: ffffffff8f5c8cd0 (pernet_ops_rwsem){++++}-{3:3}, at: > cleanup_net+0x16a/0xcc0 net/core/net_namespace.c:594 > #3: ffff8880237ed408 (&wg->device_update_lock){+.+.}-{3:3}, at: > wg_destruct+0x110/0x2e0 drivers/net/wireguard/device.c:249 > #4: ffffffff8e339240 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: > rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:4448 > 1 lock held by khungtaskd/30: > #0: ffffffff8e333fa0 (rcu_read_lock){....}-{1:2}, at: > rcu_lock_acquire include/linux/rcupdate.h:329 [inline] > #0: ffffffff8e333fa0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock > include/linux/rcupdate.h:781 [inline] > #0: ffffffff8e333fa0 (rcu_read_lock){....}-{1:2}, at: > debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6614 > 3 locks held by kworker/u8:4/61: > #0: ffff8880b953e798 (&rq->__lock){-.-.}-{2:2}, at: > raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:559 > #1: ffff8880b9528948 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}- > {0:0}, at: psi_task_switch+0x441/0x770 kernel/sched/psi.c:988 > #2: ffff8880b953e798 (&rq->__lock){-.-.}-{2:2}, at: > raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:559 > 3 locks held by kworker/0:2/1156: > #0: ffff888015080948 ((wq_completion)events){+.+.}-{0:0}, at: > process_one_work kernel/workqueue.c:3206 [inline] > #0: ffff888015080948 ((wq_completion)events){+.+.}-{0:0}, at: > process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312 > #1: ffffc90004627d00 ((linkwatch_work).work){+.+.}-{0:0}, at: > process_one_work kernel/workqueue.c:3207 [inline] > #1: ffffc90004627d00 ((linkwatch_work).work){+.+.}-{0:0}, at: > process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312 > #2: ffffffff8f5d5508 (rtnl_mutex){+.+.}-{3:3}, at: > linkwatch_event+0xe/0x60 net/core/link_watch.c:276 > 2 locks held by kworker/u8:9/2839: > 2 locks held by getty/4842: > #0: ffff88802b04c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: > tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 > #1: ffffc90002f162f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: > n_tty_read+0x6b5/0x1e10 drivers/tty/n_tty.c:2201 > 2 locks held by syz-fuzzer/5088: > 3 locks held by kworker/0:6/5164: > #0: ffff888015080948 ((wq_completion)events){+.+.}-{0:0}, at: > process_one_work kernel/workqueue.c:3206 [inline] > #0: ffff888015080948 ((wq_completion)events){+.+.}-{0:0}, at: > process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312 > #1: ffffc90004577d00 (free_ipc_work){+.+.}-{0:0}, at: > process_one_work kernel/workqueue.c:3207 [inline] > #1: ffffc90004577d00 (free_ipc_work){+.+.}-{0:0}, at: > process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312 > #2: ffffffff8e339378 (rcu_state.exp_mutex){+.+.}-{3:3}, at: > exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline] > #2: ffffffff8e339378 (rcu_state.exp_mutex){+.+.}-{3:3}, at: > synchronize_rcu_expedited+0x381/0x830 kernel/rcu/tree_exp.h:939 > 2 locks held by syz-executor.4/7353: > #0: ffffffff8f63b9d0 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 > net/netlink/genetlink.c:1218 > #1: ffffffff8e600748 (nfsd_mutex){+.+.}-{3:3}, at: > nfsd_nl_listener_set_doit+0x12d/0x1a90 fs/nfsd/nfsctl.c:1966 > 3 locks held by syz-executor.1/7517: > #0: ffffffff8f63b9d0 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 > net/netlink/genetlink.c:1218 > #1: ffff888052998678 (nlk_cb_mutex-GENERIC){+.+.}-{3:3}, at: > __netlink_dump_start+0x119/0x780 net/netlink/af_netlink.c:2418 > #2: ffffffff8e600748 (nfsd_mutex){+.+.}-{3:3}, at: > nfsd_nl_rpc_status_get_start+0x8d/0xe0 fs/nfsd/nfsctl.c:1476 > 2 locks held by syz-executor.1/10475: > #0: ffffffff8f5d5508 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock > net/core/rtnetlink.c:79 [inline] > #0: ffffffff8f5d5508 (rtnl_mutex){+.+.}-{3:3}, at: > rtnetlink_rcv_msg+0x842/0x1180 net/core/rtnetlink.c:6632 > > > --- > 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. > > If the report is already addressed, let syzbot know by replying with: > #syz fix: exact-commit-title > > If you want to overwrite report's subsystems, reply with: > #syz set subsystems: new-subsystem > (See the list of subsystem names on the web dashboard) > > If the report is a duplicate of another one, reply with: > #syz dup: exact-subject-of-another-report > > If you want to undo deduplication, reply with: > #syz undup nfsd_nl_rpc_status_get_dumpit grabs the nfsd_mutex in the ->start netlink op, and then releases it in the ->done op. Is it possible that something is causing ->done to not happen after ->start has? -- Jeff Layton <jlayton@xxxxxxxxxx>
