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* [syzbot] possible deadlock in virtual_nci_close
@ 2022-11-14  3:11 syzbot
  2022-11-14  9:48 ` Dmitry Vyukov
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: syzbot @ 2022-11-14  3:11 UTC (permalink / raw)
  To: bongsu.jeon, krzysztof.kozlowski, linux-kernel, netdev, syzkaller-bugs

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

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.

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [syzbot] possible deadlock in virtual_nci_close
  2022-11-14  3:11 [syzbot] possible deadlock in virtual_nci_close syzbot
@ 2022-11-14  9:48 ` Dmitry Vyukov
  2022-11-14 14:55 ` syzbot
  2022-11-16  5:58 ` syzbot
  2 siblings, 0 replies; 6+ messages in thread
From: Dmitry Vyukov @ 2022-11-14  9:48 UTC (permalink / raw)
  To: syzbot
  Cc: bongsu.jeon, krzysztof.kozlowski, linux-kernel, netdev, syzkaller-bugs

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.
>
> --
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^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [syzbot] possible deadlock in virtual_nci_close
  2022-11-14  3:11 [syzbot] possible deadlock in virtual_nci_close syzbot
  2022-11-14  9:48 ` Dmitry Vyukov
@ 2022-11-14 14:55 ` syzbot
  2022-11-16  5:58 ` syzbot
  2 siblings, 0 replies; 6+ messages in thread
From: syzbot @ 2022-11-14 14:55 UTC (permalink / raw)
  To: bongsu.jeon, dvyukov, krzysztof.kozlowski, linux-kernel, netdev,
	syzkaller-bugs

syzbot has found a reproducer for the following issue on:

HEAD commit:    1621b6eaebf7 Merge branch 'for-next/fixes' into for-kernelci
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=108bcd85880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=606e57fd25c5c6cc
dashboard link: https://syzkaller.appspot.com/bug?extid=8040d16d30c215f821de
compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11b08dd1880000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14fcee02880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/82aa7741098d/disk-1621b6ea.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f6be08c4e4c2/vmlinux-1621b6ea.xz
kernel image: https://storage.googleapis.com/syzbot-assets/296b6946258a/Image-1621b6ea.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8040d16d30c215f821de@syzkaller.appspotmail.com

nci: nci_start_poll: failed to set local general bytes
nci: __nci_request: wait_for_completion_interruptible_timeout failed 0
======================================================
WARNING: possible circular locking dependency detected
6.1.0-rc4-syzkaller-31872-g1621b6eaebf7 #0 Not tainted
------------------------------------------------------
syz-executor424/3032 is trying to acquire lock:
ffff80000d5fac10 (nci_mutex){+.+.}-{3:3}, at: virtual_nci_close+0x28/0x58 drivers/nfc/virtual_ncidev.c:44

but task is already holding lock:
ffff0000cb900350 (&ndev->req_lock){+.+.}-{3:3}, at: nci_close_device+0x74/0x2b4 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+0xd4/0xca8 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
       nci_request net/nfc/nci/core.c:148 [inline]
       nci_set_local_general_bytes+0xbc/0x480 net/nfc/nci/core.c:774
       nci_start_poll+0x1e8/0x474 net/nfc/nci/core.c:838
       nfc_start_poll+0xfc/0x170 net/nfc/core.c:225
       nfc_genl_start_poll+0xd4/0x174 net/nfc/netlink.c:828
       genl_family_rcv_msg_doit net/netlink/genetlink.c:756 [inline]
       genl_family_rcv_msg net/netlink/genetlink.c:833 [inline]
       genl_rcv_msg+0x458/0x4f4 net/netlink/genetlink.c:850
       netlink_rcv_skb+0xe8/0x1d4 net/netlink/af_netlink.c:2540
       genl_rcv+0x38/0x50 net/netlink/genetlink.c:861
       netlink_unicast_kernel+0xfc/0x1dc net/netlink/af_netlink.c:1319
       netlink_unicast+0x164/0x248 net/netlink/af_netlink.c:1345
       netlink_sendmsg+0x484/0x584 net/netlink/af_netlink.c:1921
       sock_sendmsg_nosec net/socket.c:714 [inline]
       sock_sendmsg net/socket.c:734 [inline]
       ____sys_sendmsg+0x2f8/0x440 net/socket.c:2482
       ___sys_sendmsg net/socket.c:2536 [inline]
       __sys_sendmsg+0x1ac/0x228 net/socket.c:2565
       __do_sys_sendmsg net/socket.c:2574 [inline]
       __se_sys_sendmsg net/socket.c:2572 [inline]
       __arm64_sys_sendmsg+0x2c/0x3c net/socket.c:2572
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
       el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206
       el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584

-> #2 (&genl_data->genl_data_mutex){+.+.}-{3:3}:
       __mutex_lock_common+0xd4/0xca8 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
       nfc_urelease_event_work+0x88/0x16c net/nfc/netlink.c:1811
       process_one_work+0x2d8/0x504 kernel/workqueue.c:2289
       worker_thread+0x340/0x610 kernel/workqueue.c:2436
       kthread+0x12c/0x158 kernel/kthread.c:376
       ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:863

-> #1 (nfc_devlist_mutex){+.+.}-{3:3}:
       __mutex_lock_common+0xd4/0xca8 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
       nfc_register_device+0x34/0x208 net/nfc/core.c:1116
       nci_register_device+0x338/0x3b0 net/nfc/nci/core.c:1256
       virtual_ncidev_open+0x6c/0xd8 drivers/nfc/virtual_ncidev.c:146
       misc_open+0x1b8/0x200 drivers/char/misc.c:143
       chrdev_open+0x2b4/0x2e8 fs/char_dev.c:414
       do_dentry_open+0x364/0x748 fs/open.c:882
       vfs_open+0x38/0x48 fs/open.c:1013
       do_open fs/namei.c:3557 [inline]
       path_openat+0xe34/0x11c4 fs/namei.c:3713
       do_filp_open+0xdc/0x1b8 fs/namei.c:3740
       do_sys_openat2+0xb8/0x22c 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+0xb0/0xe0 fs/open.c:1337
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
       el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206
       el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:637
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584

-> #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+0x1530/0x3084 kernel/locking/lockdep.c:5055
       lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5668
       __mutex_lock_common+0xd4/0xca8 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
       virtual_nci_close+0x28/0x58 drivers/nfc/virtual_ncidev.c:44
       nci_close_device+0x188/0x2b4 net/nfc/nci/core.c:592
       nci_unregister_device+0x3c/0x100 net/nfc/nci/core.c:1291
       virtual_ncidev_close+0x70/0xb0 drivers/nfc/virtual_ncidev.c:166
       __fput+0x198/0x3e4 fs/file_table.c:320
       ____fput+0x20/0x30 fs/file_table.c:348
       task_work_run+0x100/0x148 kernel/task_work.c:179
       exit_task_work include/linux/task_work.h:38 [inline]
       do_exit+0x2dc/0xcac kernel/exit.c:820
       do_group_exit+0x98/0xcc kernel/exit.c:950
       get_signal+0xabc/0xb2c kernel/signal.c:2858
       do_signal+0x128/0x438 arch/arm64/kernel/signal.c:1071
       do_notify_resume+0xc0/0x1f0 arch/arm64/kernel/signal.c:1124
       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+0x9c/0x150 arch/arm64/kernel/entry-common.c:638
       el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
       el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584

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-executor424/3032:
 #0: ffff0000cb900350 (&ndev->req_lock){+.+.}-{3:3}, at: nci_close_device+0x74/0x2b4 net/nfc/nci/core.c:560

stack backtrace:
CPU: 0 PID: 3032 Comm: syz-executor424 Not tainted 6.1.0-rc4-syzkaller-31872-g1621b6eaebf7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/30/2022
Call trace:
 dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:156
 show_stack+0x2c/0x54 arch/arm64/kernel/stacktrace.c:163
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x104/0x16c lib/dump_stack.c:106
 dump_stack+0x1c/0x58 lib/dump_stack.c:113
 print_circular_bug+0x2c4/0x2c8 kernel/locking/lockdep.c:2055
 check_noncircular+0x14c/0x154 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+0x1530/0x3084 kernel/locking/lockdep.c:5055
 lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5668
 __mutex_lock_common+0xd4/0xca8 kernel/locking/mutex.c:603
 __mutex_lock kernel/locking/mutex.c:747 [inline]
 mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
 virtual_nci_close+0x28/0x58 drivers/nfc/virtual_ncidev.c:44
 nci_close_device+0x188/0x2b4 net/nfc/nci/core.c:592
 nci_unregister_device+0x3c/0x100 net/nfc/nci/core.c:1291
 virtual_ncidev_close+0x70/0xb0 drivers/nfc/virtual_ncidev.c:166
 __fput+0x198/0x3e4 fs/file_table.c:320
 ____fput+0x20/0x30 fs/file_table.c:348
 task_work_run+0x100/0x148 kernel/task_work.c:179
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0x2dc/0xcac kernel/exit.c:820
 do_group_exit+0x98/0xcc kernel/exit.c:950
 get_signal+0xabc/0xb2c kernel/signal.c:2858
 do_signal+0x128/0x438 arch/arm64/kernel/signal.c:1071
 do_notify_resume+0xc0/0x1f0 arch/arm64/kernel/signal.c:1124
 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+0x9c/0x150 arch/arm64/kernel/entry-common.c:638
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584


^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [syzbot] possible deadlock in virtual_nci_close
  2022-11-14  3:11 [syzbot] possible deadlock in virtual_nci_close syzbot
  2022-11-14  9:48 ` Dmitry Vyukov
  2022-11-14 14:55 ` syzbot
@ 2022-11-16  5:58 ` syzbot
  2022-11-22 13:08   ` Dmitry Vyukov
  2 siblings, 1 reply; 6+ messages in thread
From: syzbot @ 2022-11-16  5:58 UTC (permalink / raw)
  To: bongsu.jeon, clement.perrochaud, davem, dvyukov, hdanton,
	krzysztof.kozlowski, kuba, linux-kernel, michael.thalmeier,
	netdev, r.baldyga, robert.dolca, sameo, shikha.singh,
	syzkaller-bugs, thierry.escande

syzbot has bisected this issue to:

commit e624e6c3e777fb3dfed036b9da4d433aee3608a5
Author: Bongsu Jeon <bongsu.jeon@samsung.com>
Date:   Wed Jan 27 13:08:28 2021 +0000

    nfc: Add a virtual nci device driver

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1093fb59880000
start commit:   094226ad94f4 Linux 6.1-rc5
git tree:       upstream
final oops:     https://syzkaller.appspot.com/x/report.txt?x=1293fb59880000
console output: https://syzkaller.appspot.com/x/log.txt?x=1493fb59880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=7d516a992a8757b5
dashboard link: https://syzkaller.appspot.com/bug?extid=8040d16d30c215f821de
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1360e2f1880000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14a95659880000

Reported-by: syzbot+8040d16d30c215f821de@syzkaller.appspotmail.com
Fixes: e624e6c3e777 ("nfc: Add a virtual nci device driver")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [syzbot] possible deadlock in virtual_nci_close
  2022-11-16  5:58 ` syzbot
@ 2022-11-22 13:08   ` Dmitry Vyukov
  0 siblings, 0 replies; 6+ messages in thread
From: Dmitry Vyukov @ 2022-11-22 13:08 UTC (permalink / raw)
  To: syzbot
  Cc: bongsu.jeon, clement.perrochaud, davem, hdanton,
	krzysztof.kozlowski, kuba, linux-kernel, michael.thalmeier,
	netdev, r.baldyga, robert.dolca, sameo, shikha.singh,
	syzkaller-bugs, thierry.escande

On Wed, 16 Nov 2022 at 06:58, syzbot
<syzbot+8040d16d30c215f821de@syzkaller.appspotmail.com> wrote:
>
> syzbot has bisected this issue to:
>
> commit e624e6c3e777fb3dfed036b9da4d433aee3608a5
> Author: Bongsu Jeon <bongsu.jeon@samsung.com>
> Date:   Wed Jan 27 13:08:28 2021 +0000
>
>     nfc: Add a virtual nci device driver
>
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1093fb59880000
> start commit:   094226ad94f4 Linux 6.1-rc5
> git tree:       upstream
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=1293fb59880000
> console output: https://syzkaller.appspot.com/x/log.txt?x=1493fb59880000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=7d516a992a8757b5
> dashboard link: https://syzkaller.appspot.com/bug?extid=8040d16d30c215f821de
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1360e2f1880000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14a95659880000
>
> Reported-by: syzbot+8040d16d30c215f821de@syzkaller.appspotmail.com
> Fixes: e624e6c3e777 ("nfc: Add a virtual nci device driver")
>
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection

#syz fix: NFC: nci: Allow to create multiple virtual nci devices

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [syzbot] possible deadlock in virtual_nci_close
       [not found] <20221115102048.2433-1-hdanton@sina.com>
@ 2022-11-15 10:50 ` syzbot
  0 siblings, 0 replies; 6+ messages in thread
From: syzbot @ 2022-11-15 10:50 UTC (permalink / raw)
  To: hdanton, linux-kernel, syzkaller-bugs

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+8040d16d30c215f821de@syzkaller.appspotmail.com

Tested on:

commit:         1621b6ea Merge branch 'for-next/fixes' into for-kernelci
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=120ddf69880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9aff35d9bd592994
dashboard link: https://syzkaller.appspot.com/bug?extid=8040d16d30c215f821de
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
patch:          https://syzkaller.appspot.com/x/patch.diff?x=11685d35880000

Note: testing is done by a robot and is best-effort only.

^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-11-22 13:08 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-11-14  3:11 [syzbot] possible deadlock in virtual_nci_close syzbot
2022-11-14  9:48 ` Dmitry Vyukov
2022-11-14 14:55 ` syzbot
2022-11-16  5:58 ` syzbot
2022-11-22 13:08   ` Dmitry Vyukov
     [not found] <20221115102048.2433-1-hdanton@sina.com>
2022-11-15 10:50 ` syzbot

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