syzbot


INFO: task hung in rtnetlink_rcv_msg (2)

Status: premoderation: reported on 2026/01/21 16:59
Reported-by: syzbot+c8594a8ad43127762feb@syzkaller.appspotmail.com
First crash: 8d18h, last: 7h55m
Similar bugs (16)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: task hung in rtnetlink_rcv_msg 1 1 930d 930d 0/3 auto-obsoleted due to no activity on 2023/10/22 21:13
linux-4.19 INFO: task hung in rtnetlink_rcv_msg (2) 1 14 1472d 1652d 0/1 auto-closed as invalid on 2022/05/18 11:30
linux-4.19 INFO: task hung in rtnetlink_rcv_msg (3) 1 8 1085d 1319d 0/1 upstream: reported on 2022/06/20 23:55
linux-4.19 INFO: task hung in rtnetlink_rcv_msg 1 11 1904d 2226d 0/1 auto-closed as invalid on 2021/03/12 19:03
upstream INFO: task hung in rtnetlink_rcv_msg (2) net 1 C inconclusive 548 311d 520d 0/29 closed as invalid on 2025/04/18 16:40
linux-6.1 INFO: task hung in rtnetlink_rcv_msg (3) origin:upstream 1 C error 20 18d 497d 0/3 upstream: reported C repro on 2024/09/19 14:16
linux-5.15 INFO: task hung in rtnetlink_rcv_msg (3) 1 1 288d 288d 0/3 auto-obsoleted due to no activity on 2025/07/26 04:34
upstream INFO: task hung in rtnetlink_rcv_msg net 1 C inconclusive inconclusive 1970 570d 2533d 26/29 fixed on 2024/07/09 19:14
linux-4.14 INFO: task hung in rtnetlink_rcv_msg 1 1 1065d 1065d 0/1 upstream: reported on 2023/03/01 21:15
linux-5.15 INFO: task hung in rtnetlink_rcv_msg (2) 1 70 440d 732d 0/3 auto-obsoleted due to no activity on 2025/01/24 13:11
linux-6.1 INFO: task hung in rtnetlink_rcv_msg (2) 1 67 570d 734d 0/3 auto-obsoleted due to no activity on 2024/09/17 07:45
linux-6.1 INFO: task hung in rtnetlink_rcv_msg 1 1 855d 855d 0/3 auto-obsoleted due to no activity on 2024/01/09 18:18
android-6-12 INFO: task hung in rtnetlink_rcv_msg 1 265 77d 223d 0/1 auto-obsoleted due to no activity on 2026/01/02 16:22
linux-6.6 INFO: task hung in rtnetlink_rcv_msg 1 2 62d 88d 0/2 upstream: reported on 2025/11/02 14:58
upstream INFO: task hung in rtnetlink_rcv_msg (3) net 1 4 238d 279d 0/29 auto-obsoleted due to no activity on 2025/09/03 19:16
upstream INFO: task hung in cangw_pernet_exit (3) can 1 syz unreliable 290 1494d 1600d 0/29 closed as invalid on 2022/02/08 10:22

Sample crash report:
INFO: task syz-executor:9143 blocked for more than 122 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:0     pid:9143  tgid:9143  ppid:1      flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5996 [inline]
 __schedule+0x134f/0x1ea0 kernel/sched/core.c:7843
 __schedule_loop kernel/sched/core.c:7924 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7939
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7996
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134
 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
 rtnl_lock net/core/rtnetlink.c:79 [inline]
 rtnetlink_rcv_msg+0x79e/0xa40 net/core/rtnetlink.c:6672
 netlink_rcv_skb+0x256/0x4f0 net/netlink/af_netlink.c:2545
 rtnetlink_rcv+0x20/0x30 net/core/rtnetlink.c:6693
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x8c0/0xa60 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x7fe/0xb10 net/netlink/af_netlink.c:1889
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 __sys_sendto+0x718/0x790 net/socket.c:2217
 __do_sys_sendto net/socket.c:2229 [inline]
 __se_sys_sendto net/socket.c:2225 [inline]
 __x64_sys_sendto+0xe9/0x100 net/socket.c:2225
 x64_sys_call+0x2c2c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7fd7b4d560d7
RSP: 002b:00007ffeac3d6410 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000555585c78500 RCX: 00007fd7b4d560d7
RDX: 0000000000000028 RSI: 00007fd7b5b44670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffeac3d6474 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003
R13: 0000000000000000 R14: 00007fd7b5b44670 R15: 0000000000000000
 </TASK>
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 0044b833cf02edb59ee897eae4c42c13324c9de7
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x140/0x1c0 lib/dump_stack.c:120
 dump_stack+0x19/0x20 lib/dump_stack.c:129
 nmi_cpu_backtrace+0x2ba/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:267 [inline]
 watchdog+0xdad/0xf00 kernel/hung_task.c:423
 kthread+0x2c9/0x370 kernel/kthread.c:389
 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 9161 Comm: syz-executor Not tainted syzkaller #0 0044b833cf02edb59ee897eae4c42c13324c9de7
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:87 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:104 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:129 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:161 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0x8c/0x2b0 mm/kasan/generic.c:189
Code: 00 fc ff df 4d 8d 34 19 4d 89 f5 4d 29 dd 49 83 fd 10 7f 29 4d 85 ed 0f 84 46 01 00 00 4c 89 cb 48 f7 d3 4c 01 fb 41 80 3b 00 <0f> 85 9f 01 00 00 49 ff c3 48 ff c3 75 ee e9 26 01 00 00 45 89 dc
RSP: 0018:ffffc9000eaa6dd8 EFLAGS: 00000246
RAX: 1ffff92001d54e01 RBX: ffffffffffffffff RCX: ffffffff81d8735b
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffea0004eb9600
RBP: ffffc9000eaa6e00 R08: ffffea0004eb9607 R09: 1ffffd40009d72c0
R10: dffffc0000000000 R11: fffff940009d72c0 R12: ffffea0004eb9600
R13: 0000000000000001 R14: fffff940009d72c1 R15: 1ffffd40009d72c0
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcc097f84c0 CR3: 000000015c6b2000 CR4: 00000000003526b0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __kasan_check_read+0x15/0x20 mm/kasan/shadow.c:31
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 folio_test_head include/linux/page-flags.h:844 [inline]
 folio_test_large include/linux/page-flags.h:865 [inline]
 folio_order include/linux/mm.h:1221 [inline]
 free_unref_folios+0x15b/0x16a0 mm/page_alloc.c:2898
 folios_put_refs+0x665/0x780 mm/swap.c:1056
 free_pages_and_swap_cache+0x2fd/0x5e0 mm/swap_state.c:336
 __tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline]
 tlb_batch_pages_flush mm/mmu_gather.c:149 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:366 [inline]
 tlb_flush_mmu+0x79a/0xac0 mm/mmu_gather.c:373
 zap_pte_range mm/memory.c:1725 [inline]
 zap_pmd_range mm/memory.c:1764 [inline]
 zap_pud_range mm/memory.c:1793 [inline]
 zap_p4d_range mm/memory.c:1814 [inline]
 unmap_page_range+0x37ec/0x3fa0 mm/memory.c:1835
 unmap_single_vma mm/memory.c:1881 [inline]
 unmap_vmas+0x2d2/0x3f0 mm/memory.c:1925
 exit_mmap+0x29c/0xbc0 mm/mmap.c:1962
 __mmput+0x93/0x320 kernel/fork.c:1353
 mmput+0x55/0x170 kernel/fork.c:1376
 exec_mmap+0x37c/0x410 fs/exec.c:1020
 begin_new_exec+0x11ef/0x1ee0 fs/exec.c:1287
 load_elf_binary+0x81f/0x2b80 fs/binfmt_elf.c:994
 search_binary_handler fs/exec.c:1790 [inline]
 exec_binprm fs/exec.c:1832 [inline]
 bprm_execve+0x6f9/0x1390 fs/exec.c:1884
 do_execveat_common+0x928/0xa80 fs/exec.c:1989
 do_execve fs/exec.c:2063 [inline]
 __do_sys_execve fs/exec.c:2139 [inline]
 __se_sys_execve fs/exec.c:2134 [inline]
 __x64_sys_execve+0x96/0xb0 fs/exec.c:2134
 x64_sys_call+0x12c4/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:60
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f71321c3a17
Code: Unable to access opcode bytes at 0x7f71321c39ed.
RSP: 002b:00007f71323efde8 EFLAGS: 00000206 ORIG_RAX: 000000000000003b
RAX: ffffffffffffffda RBX: 00007ffe51307ef2 RCX: 00007f71321c3a17
RDX: 00007ffe51305860 RSI: 00007ffe51305aa0 RDI: 00007ffe51307ef2
RBP: 00007f71323efe60 R08: 00007ffe51305630 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000206 R12: 00007ffe51305aa0
R13: 00007ffe51305860 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
net_ratelimit: 101656 callbacks suppressed
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:26:0b:0f:8c:b1:f8, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
net_ratelimit: 118736 callbacks suppressed
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:26:0b:0f:8c:b1:f8, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:26:0b:0f:8c:b1:f8, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/30 03:15 android16-6.12 d60ccb82b419 bfa73b7b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/01/29 14:09 android16-6.12 6acc5550e55c aeb6fdd5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/01/29 05:41 android16-6.12 bee827455b83 0adc945e .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/01/27 08:11 android16-6.12 0a08bd027b15 efb3e894 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/01/26 17:44 android16-6.12 132542afc0ef a4c52dd6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/01/25 23:36 android16-6.12 9ca0fde2622c 55756628 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
2026/01/21 16:59 android16-6.12 f33ca06267f8 8fc37797 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust INFO: task hung in rtnetlink_rcv_msg
* Struck through repros no longer work on HEAD.