CVE-2026-23167

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> nfc: nci: Fix race between rfkill and nci_unregister_device().<br /> <br /> syzbot reported the splat below [0] without a repro.<br /> <br /> It indicates that struct nci_dev.cmd_wq had been destroyed before<br /> nci_close_device() was called via rfkill.<br /> <br /> nci_dev.cmd_wq is only destroyed in nci_unregister_device(), which<br /> (I think) was called from virtual_ncidev_close() when syzbot close()d<br /> an fd of virtual_ncidev.<br /> <br /> The problem is that nci_unregister_device() destroys nci_dev.cmd_wq<br /> first and then calls nfc_unregister_device(), which removes the<br /> device from rfkill by rfkill_unregister().<br /> <br /> So, the device is still visible via rfkill even after nci_dev.cmd_wq<br /> is destroyed.<br /> <br /> Let&amp;#39;s unregister the device from rfkill first in nci_unregister_device().<br /> <br /> Note that we cannot call nfc_unregister_device() before<br /> nci_close_device() because<br /> <br /> 1) nfc_unregister_device() calls device_del() which frees<br /> all memory allocated by devm_kzalloc() and linked to<br /> ndev-&gt;conn_info_list<br /> <br /> 2) nci_rx_work() could try to queue nci_conn_info to<br /> ndev-&gt;conn_info_list which could be leaked<br /> <br /> Thus, nfc_unregister_device() is split into two functions so we<br /> can remove rfkill interfaces only before nci_close_device().<br /> <br /> [0]:<br /> DEBUG_LOCKS_WARN_ON(1)<br /> WARNING: kernel/locking/lockdep.c:238 at hlock_class kernel/locking/lockdep.c:238 [inline], CPU#0: syz.0.8675/6349<br /> WARNING: kernel/locking/lockdep.c:238 at check_wait_context kernel/locking/lockdep.c:4854 [inline], CPU#0: syz.0.8675/6349<br /> WARNING: kernel/locking/lockdep.c:238 at __lock_acquire+0x39d/0x2cf0 kernel/locking/lockdep.c:5187, CPU#0: syz.0.8675/6349<br /> Modules linked in:<br /> CPU: 0 UID: 0 PID: 6349 Comm: syz.0.8675 Not tainted syzkaller #0 PREEMPT(full)<br /> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026<br /> RIP: 0010:hlock_class kernel/locking/lockdep.c:238 [inline]<br /> RIP: 0010:check_wait_context kernel/locking/lockdep.c:4854 [inline]<br /> RIP: 0010:__lock_acquire+0x3a4/0x2cf0 kernel/locking/lockdep.c:5187<br /> Code: 18 00 4c 8b 74 24 08 75 27 90 e8 17 f2 fc 02 85 c0 74 1c 83 3d 50 e0 4e 0e 00 75 13 48 8d 3d 43 f7 51 0e 48 c7 c6 8b 3a de 8d 48 0f b9 3a 90 31 c0 0f b6 98 c4 00 00 00 41 8b 45 20 25 ff 1f<br /> RSP: 0018:ffffc9000c767680 EFLAGS: 00010046<br /> RAX: 0000000000000001 RBX: 0000000000040000 RCX: 0000000000080000<br /> RDX: ffffc90013080000 RSI: ffffffff8dde3a8b RDI: ffffffff8ff24ca0<br /> RBP: 0000000000000003 R08: ffffffff8fef35a3 R09: 1ffffffff1fde6b4<br /> R10: dffffc0000000000 R11: fffffbfff1fde6b5 R12: 00000000000012a2<br /> R13: ffff888030338ba8 R14: ffff888030338000 R15: ffff888030338b30<br /> FS: 00007fa5995f66c0(0000) GS:ffff8881256f8000(0000) knlGS:0000000000000000<br /> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033<br /> CR2: 00007f7e72f842d0 CR3: 00000000485a0000 CR4: 00000000003526f0<br /> Call Trace:<br /> <br /> lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868<br /> touch_wq_lockdep_map+0xcb/0x180 kernel/workqueue.c:3940<br /> __flush_workqueue+0x14b/0x14f0 kernel/workqueue.c:3982<br /> nci_close_device+0x302/0x630 net/nfc/nci/core.c:567<br /> nci_dev_down+0x3b/0x50 net/nfc/nci/core.c:639<br /> nfc_dev_down+0x152/0x290 net/nfc/core.c:161<br /> nfc_rfkill_set_block+0x2d/0x100 net/nfc/core.c:179<br /> rfkill_set_block+0x1d2/0x440 net/rfkill/core.c:346<br /> rfkill_fop_write+0x461/0x5a0 net/rfkill/core.c:1301<br /> vfs_write+0x29a/0xb90 fs/read_write.c:684<br /> ksys_write+0x150/0x270 fs/read_write.c:738<br /> do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]<br /> do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94<br /> entry_SYSCALL_64_after_hwframe+0x77/0x7f<br /> RIP: 0033:0x7fa59b39acb9<br /> Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48<br /> RSP: 002b:00007fa5995f6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001<br /> RAX: ffffffffffffffda RBX: 00007fa59b615fa0 RCX: 00007fa59b39acb9<br /> RDX: 0000000000000008 RSI: 0000200000000080 RDI: 0000000000000007<br /> RBP: 00007fa59b408bf7 R08: <br /> ---truncated---