Messages in this thread | | | From | Dmitry Vyukov <> | Date | Mon, 14 Nov 2022 10:48:41 +0100 | Subject | Re: [syzbot] possible deadlock in virtual_nci_close |
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On Mon, 14 Nov 2022 at 04:11, syzbot <syzbot+8040d16d30c215f821de@syzkaller.appspotmail.com> wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: af7a05689189 Merge tag 'mips-fixes_6.1_1' of git://git.ker.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=13d30249880000 > kernel config: https://syzkaller.appspot.com/x/.config?x=9d1d2dd6d424a076 > dashboard link: https://syzkaller.appspot.com/bug?extid=8040d16d30c215f821de > compiler: aarch64-linux-gnu-gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > userspace arch: arm64 > > Unfortunately, I don't have any reproducer for this issue yet. > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+8040d16d30c215f821de@syzkaller.appspotmail.com
This should be fixed by the following commit when/if it's merged. The commit removes nci_mutex.
nfc: Allow to create multiple virtual nci devices https://lore.kernel.org/all/20221104170422.979558-1-dvyukov@google.com/
> nci: __nci_request: wait_for_completion_interruptible_timeout failed 0 > ====================================================== > WARNING: possible circular locking dependency detected > 6.1.0-rc4-syzkaller-00372-gaf7a05689189 #0 Not tainted > ------------------------------------------------------ > syz-executor.1/8551 is trying to acquire lock: > ffff80000e6854c8 (nci_mutex){+.+.}-{3:3}, at: virtual_nci_close+0x2c/0x60 drivers/nfc/virtual_ncidev.c:44 > > but task is already holding lock: > ffff000030115350 (&ndev->req_lock){+.+.}-{3:3}, at: nci_close_device+0x5c/0x360 net/nfc/nci/core.c:560 > > which lock already depends on the new lock. > > > the existing dependency chain (in reverse order) is: > > -> #3 (&ndev->req_lock){+.+.}-{3:3}: > __mutex_lock_common kernel/locking/mutex.c:603 [inline] > __mutex_lock+0x124/0x83c kernel/locking/mutex.c:747 > mutex_lock_nested+0x2c/0x40 kernel/locking/mutex.c:799 > nci_request net/nfc/nci/core.c:148 [inline] > nci_set_local_general_bytes net/nfc/nci/core.c:774 [inline] > nci_start_poll+0x36c/0x624 net/nfc/nci/core.c:838 > nfc_start_poll+0x114/0x270 net/nfc/core.c:225 > nfc_genl_start_poll+0x154/0x3b0 net/nfc/netlink.c:828 > genl_family_rcv_msg_doit+0x1b8/0x2a0 net/netlink/genetlink.c:756 > genl_family_rcv_msg net/netlink/genetlink.c:833 [inline] > genl_rcv_msg+0x2f8/0x594 net/netlink/genetlink.c:850 > netlink_rcv_skb+0x180/0x330 net/netlink/af_netlink.c:2540 > genl_rcv+0x38/0x50 net/netlink/genetlink.c:861 > netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] > netlink_unicast+0x3ec/0x684 net/netlink/af_netlink.c:1345 > netlink_sendmsg+0x690/0xb1c net/netlink/af_netlink.c:1921 > sock_sendmsg_nosec net/socket.c:714 [inline] > sock_sendmsg+0xc0/0xf4 net/socket.c:734 > ____sys_sendmsg+0x534/0x6b0 net/socket.c:2482 > ___sys_sendmsg+0xf0/0x174 net/socket.c:2536 > __sys_sendmsg+0xc4/0x154 net/socket.c:2565 > __do_sys_sendmsg net/socket.c:2574 [inline] > __se_sys_sendmsg net/socket.c:2572 [inline] > __arm64_sys_sendmsg+0x70/0xa0 net/socket.c:2572 > __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] > invoke_syscall+0x6c/0x260 arch/arm64/kernel/syscall.c:52 > el0_svc_common.constprop.0+0xc4/0x254 arch/arm64/kernel/syscall.c:142 > do_el0_svc+0x50/0x14c arch/arm64/kernel/syscall.c:206 > el0_svc+0x54/0x140 arch/arm64/kernel/entry-common.c:637 > el0t_64_sync_handler+0xb8/0xc0 arch/arm64/kernel/entry-common.c:655 > el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581 > > -> #2 (&genl_data->genl_data_mutex){+.+.}-{3:3}: > __mutex_lock_common kernel/locking/mutex.c:603 [inline] > __mutex_lock+0x124/0x83c kernel/locking/mutex.c:747 > mutex_lock_nested+0x2c/0x40 kernel/locking/mutex.c:799 > nfc_urelease_event_work+0x118/0x270 net/nfc/netlink.c:1811 > process_one_work+0x780/0x184c kernel/workqueue.c:2289 > worker_thread+0x3cc/0xc40 kernel/workqueue.c:2436 > kthread+0x23c/0x2a0 kernel/kthread.c:376 > ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860 > > -> #1 (nfc_devlist_mutex){+.+.}-{3:3}: > __mutex_lock_common kernel/locking/mutex.c:603 [inline] > __mutex_lock+0x124/0x83c kernel/locking/mutex.c:747 > mutex_lock_nested+0x2c/0x40 kernel/locking/mutex.c:799 > nfc_register_device+0x34/0x320 net/nfc/core.c:1116 > nci_register_device+0x604/0x8c0 net/nfc/nci/core.c:1256 > virtual_ncidev_open+0x64/0xe0 drivers/nfc/virtual_ncidev.c:146 > misc_open+0x294/0x394 drivers/char/misc.c:143 > chrdev_open+0x1c0/0x54c fs/char_dev.c:414 > do_dentry_open+0x3c4/0xf40 fs/open.c:882 > vfs_open+0x90/0xd0 fs/open.c:1013 > do_open fs/namei.c:3557 [inline] > path_openat+0x1030/0x1fe0 fs/namei.c:3713 > do_filp_open+0x154/0x330 fs/namei.c:3740 > do_sys_openat2+0x124/0x390 fs/open.c:1310 > do_sys_open fs/open.c:1326 [inline] > __do_sys_openat fs/open.c:1342 [inline] > __se_sys_openat fs/open.c:1337 [inline] > __arm64_sys_openat+0x130/0x1c0 fs/open.c:1337 > __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] > invoke_syscall+0x6c/0x260 arch/arm64/kernel/syscall.c:52 > el0_svc_common.constprop.0+0xc4/0x254 arch/arm64/kernel/syscall.c:142 > do_el0_svc+0x50/0x14c arch/arm64/kernel/syscall.c:206 > el0_svc+0x54/0x140 arch/arm64/kernel/entry-common.c:637 > el0t_64_sync_handler+0xb8/0xc0 arch/arm64/kernel/entry-common.c:655 > el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581 > > -> #0 (nci_mutex){+.+.}-{3:3}: > check_prev_add kernel/locking/lockdep.c:3097 [inline] > check_prevs_add kernel/locking/lockdep.c:3216 [inline] > validate_chain kernel/locking/lockdep.c:3831 [inline] > __lock_acquire+0x2788/0x56d0 kernel/locking/lockdep.c:5055 > lock_acquire kernel/locking/lockdep.c:5668 [inline] > lock_acquire+0x58c/0x9a0 kernel/locking/lockdep.c:5633 > __mutex_lock_common kernel/locking/mutex.c:603 [inline] > __mutex_lock+0x124/0x83c kernel/locking/mutex.c:747 > mutex_lock_nested+0x2c/0x40 kernel/locking/mutex.c:799 > virtual_nci_close+0x2c/0x60 drivers/nfc/virtual_ncidev.c:44 > nci_close_device+0x200/0x360 net/nfc/nci/core.c:592 > nci_unregister_device+0x40/0x280 net/nfc/nci/core.c:1291 > virtual_ncidev_close+0x70/0x90 drivers/nfc/virtual_ncidev.c:166 > __fput+0x1ac/0x860 fs/file_table.c:320 > ____fput+0x10/0x1c fs/file_table.c:348 > task_work_run+0x12c/0x220 kernel/task_work.c:179 > resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] > do_notify_resume+0x920/0x2840 arch/arm64/kernel/signal.c:1127 > prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline] > exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline] > el0_svc+0x11c/0x140 arch/arm64/kernel/entry-common.c:638 > el0t_64_sync_handler+0xb8/0xc0 arch/arm64/kernel/entry-common.c:655 > el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581 > > other info that might help us debug this: > > Chain exists of: > nci_mutex --> &genl_data->genl_data_mutex --> &ndev->req_lock > > Possible unsafe locking scenario: > > CPU0 CPU1 > ---- ---- > lock(&ndev->req_lock); > lock(&genl_data->genl_data_mutex); > lock(&ndev->req_lock); > lock(nci_mutex); > > *** DEADLOCK *** > > 1 lock held by syz-executor.1/8551: > #0: ffff000030115350 (&ndev->req_lock){+.+.}-{3:3}, at: nci_close_device+0x5c/0x360 net/nfc/nci/core.c:560 > > stack backtrace: > CPU: 1 PID: 8551 Comm: syz-executor.1 Not tainted 6.1.0-rc4-syzkaller-00372-gaf7a05689189 #0 > Hardware name: linux,dummy-virt (DT) > Call trace: > dump_backtrace+0xe0/0x140 arch/arm64/kernel/stacktrace.c:156 > show_stack+0x18/0x40 arch/arm64/kernel/stacktrace.c:163 > __dump_stack lib/dump_stack.c:88 [inline] > dump_stack_lvl+0x9c/0xd8 lib/dump_stack.c:106 > dump_stack+0x1c/0x38 lib/dump_stack.c:113 > print_circular_bug+0x2d4/0x2ec kernel/locking/lockdep.c:2055 > check_noncircular+0x26c/0x2e0 kernel/locking/lockdep.c:2177 > check_prev_add kernel/locking/lockdep.c:3097 [inline] > check_prevs_add kernel/locking/lockdep.c:3216 [inline] > validate_chain kernel/locking/lockdep.c:3831 [inline] > __lock_acquire+0x2788/0x56d0 kernel/locking/lockdep.c:5055 > lock_acquire kernel/locking/lockdep.c:5668 [inline] > lock_acquire+0x58c/0x9a0 kernel/locking/lockdep.c:5633 > __mutex_lock_common kernel/locking/mutex.c:603 [inline] > __mutex_lock+0x124/0x83c kernel/locking/mutex.c:747 > mutex_lock_nested+0x2c/0x40 kernel/locking/mutex.c:799 > virtual_nci_close+0x2c/0x60 drivers/nfc/virtual_ncidev.c:44 > nci_close_device+0x200/0x360 net/nfc/nci/core.c:592 > nci_unregister_device+0x40/0x280 net/nfc/nci/core.c:1291 > virtual_ncidev_close+0x70/0x90 drivers/nfc/virtual_ncidev.c:166 > __fput+0x1ac/0x860 fs/file_table.c:320 > ____fput+0x10/0x1c fs/file_table.c:348 > task_work_run+0x12c/0x220 kernel/task_work.c:179 > resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] > do_notify_resume+0x920/0x2840 arch/arm64/kernel/signal.c:1127 > prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline] > exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline] > el0_svc+0x11c/0x140 arch/arm64/kernel/entry-common.c:638 > el0t_64_sync_handler+0xb8/0xc0 arch/arm64/kernel/entry-common.c:655 > el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581 > > > --- > 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@googlegroups.com. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/000000000000cceef005ed659943%40google.com.
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