KASAN: null-ptr-deref Read in netlink_has_listeners

Status: upstream: reported C repro on 2026/10/26 18:43
Subsystems: net
Labels: prio:normal
[Documentation on labels]
Reported-by: syzbot+1269fe6cc2016008124e@syzkaller.appspotmail.com
First crash: 28d, last: 1d00h
▶ ▼ ✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
c7c813c4 repro-c Reproduced: ✅ ❓ KASAN: null-ptr-deref Read in netlink_has_listeners 2026/10/19 23:22 2026/10/19 23:23 2026/10/20 00:32 e931f328
5cef6e5f assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ KASAN: null-ptr-deref Read in netlink_has_listeners 2026/09/30 08:11 2026/09/30 08:11 2026/09/30 09:13 7808aef4
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[PATCH net] netdev-genl: ignore NETDEV_UNREGISTER rebroadcasts 2 (2) 2026/10/26 22:28
[syzbot] [net?] KASAN: null-ptr-deref Read in netlink_has_listeners 1 (2) 2026/10/26 21:15
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2026/10/20 00:34 17m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git c03c1a14507dfaf8b856c2608f9ac216021fc222 report job log log

Sample crash report:
==================================================================
BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:82 [inline]
BUG: KASAN: null-ptr-deref in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
BUG: KASAN: null-ptr-deref in netlink_is_kernel net/netlink/af_netlink.c:88 [inline]
BUG: KASAN: null-ptr-deref in netlink_has_listeners+0x3d/0x3f0 net/netlink/af_netlink.c:1390
Read of size 8 at addr 0000000000000578 by task syz-executor333/5617

CPU: 0 UID: 0 PID: 5617 Comm: syz-executor333 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200
 instrument_atomic_read include/linux/instrumented.h:82 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 netlink_is_kernel net/netlink/af_netlink.c:88 [inline]
 netlink_has_listeners+0x3d/0x3f0 net/netlink/af_netlink.c:1390
 genl_has_listeners include/net/genetlink.h:644 [inline]
 devlink_nl_notify_need net/devlink/devl_internal.h:238 [inline]
 devlink_port_notify+0x18c/0x520 net/devlink/port.c:559
 __devlink_port_type_set+0x5f1/0x7a0 net/devlink/port.c:1237
 devlink_port_netdevice_event+0x25d/0x3a0 net/devlink/port.c:-1
 notifier_call_chain+0x1a5/0x3d0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2313 [inline]
 call_netdevice_notifiers net/core/dev.c:2327 [inline]
 unregister_netdevice_many_notify+0x1a76/0x2140 net/core/dev.c:12580
 unregister_netdevice_many net/core/dev.c:12635 [inline]
 unregister_netdevice_queue+0x2f5/0x340 net/core/dev.c:12436
 unregister_netdevice include/linux/netdevice.h:3490 [inline]
 nsim_destroy+0x275/0x800 drivers/net/netdevsim/netdev.c:1198
 __nsim_dev_port_del+0x14e/0x200 drivers/net/netdevsim/dev.c:1472
 nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1486 [inline]
 nsim_dev_reload_destroy+0x288/0x490 drivers/net/netdevsim/dev.c:1710
 nsim_drv_remove+0x58/0x170 drivers/net/netdevsim/dev.c:1725
 device_remove drivers/base/dd.c:616 [inline]
 __device_release_driver drivers/base/dd.c:1349 [inline]
 device_release_driver_internal+0x48b/0x880 drivers/base/dd.c:1372
 bus_remove_device+0x444/0x560 drivers/base/bus.c:664
 device_del+0x524/0x8f0 drivers/base/core.c:3965
 device_unregister+0x21/0xf0 drivers/base/core.c:4006
 nsim_bus_dev_del drivers/net/netdevsim/bus.c:488 [inline]
 del_device_store+0x2b5/0x370 drivers/net/netdevsim/bus.c:244
 kernfs_fop_write_iter+0x3a4/0x540 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x612/0xba0 fs/read_write.c:687
 ksys_write+0x150/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb10e25df77
Code: 48 89 fa 4c 89 df e8 98 1e 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffd1f1777c0 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000555587f6f400 RCX: 00007fb10e25df77
RDX: 0000000000000003 RSI: 00007fb10e29d08b RDI: 0000000000000003
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffd1f177938
R13: 0000000000000002 R14: 00007fb10e2c5c80 R15: 0000000000000002
 </TASK>
==================================================================

Crashes (44):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/20 00:51 git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git c03c1a14507d 432c0077 .config console log report C ci-snapshot-upstream-root KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/22 20:01 upstream 4403278e4ea2 4ba27f85 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/22 04:56 upstream 9ba46df34488 61c200c7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/21 23:51 upstream 9ba46df34488 61c200c7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/21 02:25 upstream f47d223627f8 df8746fb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/20 19:40 upstream f47d223627f8 df8746fb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/20 09:10 upstream f47d223627f8 72cdc28d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/20 09:00 upstream f47d223627f8 72cdc28d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/19 13:56 upstream c03c1a14507d 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/19 08:52 upstream 8486d3571291 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/19 06:41 upstream 8486d3571291 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/19 02:41 upstream 8486d3571291 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/18 23:52 upstream 8486d3571291 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/18 13:05 upstream 32c52ec87d62 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/18 13:04 upstream 32c52ec87d62 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/18 13:04 upstream 32c52ec87d62 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/18 02:50 upstream 58161ead29e5 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/17 19:05 upstream 58161ead29e5 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/17 14:27 upstream 70dd4ee72eb2 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/17 08:00 upstream 70dd4ee72eb2 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/17 07:58 upstream 70dd4ee72eb2 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/17 06:53 upstream 70dd4ee72eb2 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/16 18:07 upstream 2f2f7eeef8b0 b1757810 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/16 06:22 upstream 2f2f7eeef8b0 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/16 06:00 upstream 045958acaa75 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/16 03:10 upstream 0fcb05b72344 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/15 18:21 upstream 0fcb05b72344 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/15 18:17 upstream 0fcb05b72344 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/15 18:11 upstream 0fcb05b72344 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/15 13:14 upstream 0fcb05b72344 8fb0ae89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/23 05:43 upstream 2a08195e4db5 4ba27f85 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/21 08:04 upstream 9e947d96915a 61c200c7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/21 05:02 upstream f47d223627f8 df8746fb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/18 19:32 upstream 32c52ec87d62 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/16 05:27 upstream 045958acaa75 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/16 05:16 upstream 045958acaa75 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/15 23:43 upstream 045958acaa75 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/15 23:31 upstream 045958acaa75 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/25 22:01 upstream 21a7f44fd076 1d9ca40b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: null-ptr-deref Read in netlink_has_listeners
2026/09/28 10:50 upstream 72d3fcf802c4 a3c7249d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: null-ptr-deref Read in netlink_has_listeners
2026/10/23 04:14 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad 4ba27f85 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: unable to handle kernel paging request in netlink_has_listeners
2026/10/22 21:26 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 7be4bc52fd9e b55fad29 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte BUG: unable to handle kernel NULL pointer dereference in netlink_has_listeners
2026/10/16 02:03 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 045958acaa75 3f2522c6 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 BUG: unable to handle kernel NULL pointer dereference in netlink_has_listeners
* Struck through repros no longer work on HEAD.