syzbot


protection_fault: icmp_mtudisc_timeout (4)

Status: upstream: reported on 2025/07/16 23:24
Reported-by: syzbot+5de334298738b60f07ab@syzkaller.appspotmail.com
First crash: 204d, last: 2d05h
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
openbsd protection_fault: icmp_mtudisc_timeout (2) -1 1 513d 513d 0/3 auto-obsoleted due to no activity on 2024/12/10 05:16
openbsd protection_fault: icmp_mtudisc_timeout -1 3 675d 728d 0/3 auto-obsoleted due to no activity on 2024/07/01 04:08
openbsd protection_fault: icmp_mtudisc_timeout (3) -1 1 350d 350d 0/3 auto-obsoleted due to no activity on 2025/05/21 20:37

Sample crash report:
kernel: protection fault trap, code=0
Stopped at      icmp_mtudisc_timeout+0x123:     movq    0(%rax),%rcx
ddb{0}> 
ddb{0}> set $lines = 0
ddb{0}> set $maxwidth = 0
ddb{0}> show panic
the kernel did not panic
ddb{0}> trace
icmp_mtudisc_timeout(fffffd806a843b20,0) at icmp_mtudisc_timeout+0x123 sys/netinet/ip_icmp.c:1102
rt_timer_queue_flush(ffffffff838de900) at rt_timer_queue_flush+0x28d sys/net/route.c:1586
ip_sysctl(ffff80003c481afc,1,200000000600,ffff80003c481b28,200000001640,4) at ip_sysctl+0x84d sys/netinet/ip_input.c:1755
net_sysctl(ffff80003c481af4,3,200000000600,ffff80003c481b28,200000001640,4,d8e057f8db5318ca) at net_sysctl+0x64e sys/kern/uipc_domain.c:260
sys_sysctl(ffff80003c531268,ffff80003c481c60,ffff80003c481bb0) at sys_sysctl+0x3e5 sys/kern/kern_sysctl.c:-1
syscall(ffff80003c481c60) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80003c481c60) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:775
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x8dc91efd810, count: -7
ddb{0}> show registers
rdi                             0x14
rsi                             0x14
rbp               0xffff80003c481930
rbx               0xffff80003c481901
rdx               0xffff800001584940
rcx               0xffff80003c531268
rax               0x45499aab5c77bf1d
r8                0xffffffff816efef0    tcp_mtudisc_increase
r9                                 0
r10               0x20238ee35c8e5b68
r11               0xc9edfd1d8c3252dc
r12               0xffff800000050858
r13                             0x14
r14                                0
r15               0xfffffd806a843b20
rip               0xffffffff81ab8703    icmp_mtudisc_timeout+0x123
cs                               0x8
rflags                       0x10246    __ALIGN_SIZE+0xf246
rsp               0xffff80003c4818e0
ss                              0x10
icmp_mtudisc_timeout+0x123:     movq    0(%rax),%rcx
ddb{0}> show proc
PROC (syz-executor) tid=476777 pid=78345 tcnt=2 stat=onproc
    flags process=0 proc=4000000<THREAD>
    runpri=32, usrpri=81, slppri=32, nice=20
    wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0
    forw=0xffffffffffffffff, list=0xffff80003c530570,0xffff80003c530818
    process=0xffff80003c413058 user=0xffff80003c47c000, vmspace=0xfffffd806c95a5d0
    estcpu=31, cpticks=1, pctcpu=0.0, user=0, sys=1, intr=0
ddb{0}> ps
   PID     TID   PPID    UID  S       FLAGS  WAIT          COMMAND
 85158  447044  20162      0  2           0                syz-executor
 85158   30376  20162      0  3   0x4000080  ttyopn        syz-executor
 65217  229504  64326      0  2           0                syz-executor
 65217   20159  64326      0  3   0x4000080  fsleep        syz-executor
 92524  341799  21758      0  2           0                syz-executor
 92524   34953  21758      0  3   0x4000080  fsleep        syz-executor
 56897  514280  41101      0  2           0                syz-executor
 56897  377581  41101      0  3   0x4000080  sbwait        syz-executor
 56897  502804  41101      0  3   0x4000080  fsleep        syz-executor
 78345  485291  45678      0  2           0                syz-executor
*78345  476777  45678      0  7   0x4000000                syz-executor
 79014  270625   9799      0  2           0                syz-executor
 79014  161068   9799      0  3   0x4000080  fsleep        syz-executor
 66565  171232   8608      0  2           0                syz-executor
 66565   66627   8608      0  3   0x4000080  kqsel         syz-executor
 66565  157435   8608      0  3   0x4000080  kqsel         syz-executor
 66565  180624   8608      0  3   0x4000080  fsleep        syz-executor
 98323  461220      0      0  3     0x14200  acct          acct
 55007  131240      0      0  3     0x14280  nfsidl        nfsio
  5919  199287      0      0  3     0x14280  nfsidl        nfsio
 79077  213771      0      0  3     0x14280  nfsidl        nfsio
 64544  299916      0      0  3     0x14280  nfsidl        nfsio
 23848  450888      0      0  3     0x14280  nfsidl        nfsio
 55899  357389      0      0  3     0x14280  nfsidl        nfsio
 20948  117145      0      0  3     0x14280  nfsidl        nfsio
 70483  426267      0      0  3     0x14280  nfsidl        nfsio
 85737   60098      0      0  3     0x14280  nfsidl        nfsio
 30510  451295      0      0  3     0x14280  nfsidl        nfsio
 78874   67743      0      0  3     0x14280  nfsidl        nfsio
 57454  426574      0      0  3     0x14280  nfsidl        nfsio
 27056  327660      0      0  3     0x14280  nfsidl        nfsio
 94817  410744      0      0  3     0x14280  nfsidl        nfsio
 49530    4310      0      0  3     0x14280  nfsidl        nfsio
 46652  282954      0      0  3     0x14280  nfsidl        nfsio
 75192  418648      0      0  3     0x14280  nfsidl        nfsio
 14674  156062      0      0  3     0x14280  nfsidl        nfsio
 43088  340950      0      0  3     0x14280  nfsidl        nfsio
 61346  412098      0      0  3     0x14280  nfsidl        nfsio
 62596  272809  89728      0  3        0x82  sbwait        sshd-session
 13631  347579  10025      0  2    0x100082                arp
 10025  305389  19230      0  3    0x10008a  sigsusp       sh
 20162  255304  59862      0  3        0x82  nanoslp       syz-executor
 19230   59035  59862      0  3        0x82  wait          syz-executor
 45678  141412  59862      0  3        0x82  nanoslp       syz-executor
  9799   85674  59862      0  3        0x82  nanoslp       syz-executor
 64326   55509  59862      0  3        0x82  nanoslp       syz-executor
  8608  382738  59862      0  3        0x82  nanoslp       syz-executor
 41101  466418  59862      0  3        0x82  nanoslp       syz-executor
 21758  372298  59862      0  3        0x82  nanoslp       syz-executor
 59862  255164  40501      0  3        0x82  kqread        syz-executor
 40501  390807  16978      0  3    0x10008a  sigsusp       ksh
 16978  345694  38357      0  3        0x98  kqread        sshd-session
 38357  433845  89728      0  3        0x92  kqread        sshd-session
 82765  396611      1      0  3    0x100083  ttyopn        getty
 89728  518459      1      0  3        0x88  kqread        sshd
  1700  264756  15395     74  3   0x1100092  bpf           pflogd
 15395  496295      1      0  3        0x80  sbwait        pflogd
 12144   70228  35583     73  3   0x1100090  kqread        syslogd
 35583  385544      1      0  3    0x100082  sbwait        syslogd
 76884  383095      1      0  3    0x100080  kqread        resolvd
 13762   64341  89129     77  3    0x100092  kqread        dhcpleased
 19424  209809  89129     77  3    0x100092  kqread        dhcpleased
 89129  142184      1      0  3        0x80  kqread        dhcpleased
 66547  248206      0      0  3     0x14200  bored         smr
 49961  116630      0      0  2     0x14200                zerothread
 61222  445620      0      0  3     0x14200  aiodoned      aiodoned
 38774  362064      0      0  3     0x14200  syncer        update
 33240   76209      0      0  3     0x14200  cleaner       cleaner
 73157  300443      0      0  3     0x14200  reaper        reaper
 57245  143415      0      0  3     0x14200  pgdaemon      pagedaemon
 18775  510921      0      0  3     0x14200  bored         viomb
 74253  159210      0      0  3  0x40014200  acpi0         acpi0
 35063  381509      0      0  7  0x40014200                idle1
  6900  359966      0      0  3     0x14200  bored         softnet1
 66264  144088      0      0  3     0x14200  bored         softnet0
  8674   48500      0      0  2     0x14200                systqmp
 45940  226467      0      0  3     0x14200  bored         systq
 98038  443597      0      0  3     0x14200  tmoslp        softclockmp
 15995  241474      0      0  3  0x40014200  tmoslp        softclock
 50092   54064      0      0  3  0x40014200                idle0
     1  506320      0      0  3     0x80082  wait          init
     0       0     -1      0  3  0x10010200  scheduler     swapper
ddb{0}> show all locks
Process 78345 (syz-executor) thread 0xffff80003c531268 (476777)
exclusive rwlock netlock r = 0 (0xffffffff838483e0)
#0  witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline]
#0  witness_lock+0x5f1 sys/kern/subr_witness.c:1160
#1  rw_do_enter_write+0x419 sys/kern/kern_rwlock.c:320
#2  ip_sysctl+0x838 sys/netinet/ip_input.c:1754
#3  net_sysctl+0x64e sys/kern/uipc_domain.c:260
#4  sys_sysctl+0x3e5 sys/kern/kern_sysctl.c:-1
#5  syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
#5  syscall+0xbd4 sys/arch/amd64/amd64/trap.c:775
#6  Xsyscall+0x128
ddb{0}> show malloc
           Type InUse  MemUse  HighUse   Limit  Requests Type Lim
         devbuf 11063  12153K   15167K 166960K     13306        0
            pcb    19     14K      15K 166960K       132        0
         rtable   184      9K      10K 166960K       492        0
             pf    28     16K      18K 166960K        95        0
         ifaddr    28      4K       7K 166960K        71        0
        ifgroup    43      2K       2K 166960K       116        0
         sysctl     3      1K       9K 166960K        10        0
       counters    64     36K      37K 166960K       138        0
       ioctlops     0      0K       4K 166960K      1784        0
            iov     1      8K      24K 166960K        42        0
          mount     1      1K       1K 166960K         1        0
            log     0      0K       0K 166960K         4        0
         vnodes  1520     96K      96K 166960K      2090        0
      UFS quota     1     32K      32K 166960K         1        0
      UFS mount     5     36K      36K 166960K         5        0
            shm     2      2K       6K 166960K        10        0
         VM map     2      1K       1K 166960K         2        0
            sem    12      0K       0K 166960K        95        0
        dirhash    12      2K       2K 166960K        24        0
           ACPI  1692    195K     286K 166960K     12470        0
      file desc    19     69K      89K 166960K       651        0
          sigio     0      0K       0K 166960K        19        0
           proc    72    115K     164K 166960K       557        0
        subproc    72      4K       4K 166960K        72        0
    NFS srvsock     1      0K       0K 166960K         1        0
     NFS daemon     1     16K      16K 166960K         1        0
    ip_moptions     0      0K       0K 166960K       193        0
       in_multi    55      4K       6K 166960K       111        0
    ether_multi     1      0K       0K 166960K        12        0
            mrt     1      0K       0K 166960K         9        0
    ISOFS mount     1     32K      32K 166960K         1        0
  MSDOSFS mount     1     16K      16K 166960K         1        0
           ttys    85    387K     387K 166960K        85        0
           exec     0      0K       1K 166960K       430        0
   fusefs mount     1     32K      32K 166960K         1        0
     pfkey data     0      0K       0K 166960K         2        0
            tdb     3      0K       0K 166960K         3        0
        VM swap     8     62K      64K 166960K        10        0
       UVM amap   258    163K     185K 166960K      7790        0
       UVM aobj    49     10K      10K 166960K        50        0
     pinsyscall    47     94K     108K 166960K      1789        0
        memdesc     1      4K       4K 166960K         1        0
    crypto data     1      1K       1K 166960K         1        0
    ip6_options     2      0K       0K 166960K        42        0
            NDP     9      0K       1K 166960K        50        0
           temp    56   8682K    8806K 166960K     27925        0
         kqueue    15     22K      30K 166960K       135        0
      SYN cache     2     16K      16K 166960K         2        0
ddb{0}> show all pools
Name      Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
plcache    128       26    0        0     1     0     1     1     0     8    0
rtpcb      120       68    0       64     1     0     1     1     0     8    0
rtentry    176      118    0       48     5     0     5     5     0     8    0
unpcb      144      713    0      691     9     3     6     6     0     8    5
syncache   336        9    0        9     2     1     1     1     0     8    1
tcpqe       32        1    0        1     1     1     0     1     0     8    0
tcpcb      736      204    0      195     7     0     7     7     0     8    6
arp        136       20    0        8     1     0     1     1     0     8    0
inpcb      328      789    0      774    13     5     8     8     0     8    6
nd6        152       21    0        9     1     0     1     1     0     8    0
pkpcb       40       10    0       10     2     1     1     1     0     8    1
kcovpl      48        8    0        0     1     0     1     1     0     8    0
mppekey    1024       1    0        1     1     1     0     1     0     8    0
ppxss      1192      29    0       29     2     1     1     1     0     8    1
pffrag     232        3    0        0     1     0     1     1     0   482    0
pffrnode    88        3    0        0     1     0     1     1     0     8    0
pffrent     40        6    0        3     1     0     1     1     0     8    0
pfosfp      40     1428    0     1005     5     0     5     5     0     8    0
pfosfpen   112     1428    0      714    21     0    21    21     0     8    0
rttmr      136        4    0        3     1     0     1     1     0     8    0
art_heap8  4096       4    0        0     4     0     4     4     0     8    0
art_heap4  256      470    0      184    28     7    21    28     0     8    1
art_table   40      474    0      184     5     0     5     5     0     8    0
art_node    32      117    0       52     1     0     1     1     0     8    0
sysvmsgpl   40        5    0        2     1     0     1     1     0     8    0
semupl     112        2    0        2     1     1     0     1     0     8    0
semapl     112       92    0       82     1     0     1     1     0     8    0
shmpl      112       42    0        0     2     0     2     2     0     8    0
dirhash    1024      25    0        8     3     0     3     3     0     8    0
dino2pl    256     2738    0     1236    96     0    96    96     0     8    0
ffsino     296     2738    0     1236   118     0   118   118     0     8    0
nchpl      144     3634    0     1934    64     0    64    64     0     8    0
rtmask      32        7    0        7     2     1     1     1     0     8    1
vnodes     216     3216    0        0   179     0   179   179     0     8    0
namei      1024   11881    0    11881     1     0     1     1     0     8    1
percpumem   16       84    0       37     1     0     1     1     0     8    0
vcpupl     3968       4    0        0     1     0     1     1     0     8    0
vmpool     848        5    0        1     1     0     1     1     0     8    0
kstatmem   264       72    0       52     3     1     2     3     0     8    0
scxspl     216    19160    0    19160    10     2     8     8     1     8    8
plimitpl   152      220    0      202     1     0     1     1     0     8    0
sigapl     424     1007    0      936    11     0    11    11     0     8    0
knotepl    120      543    0        0    17     0    17    17     0     8    0
kqueuepl   224      351    0      337     9     4     5     5     0     8    4
pipepl     344      169    0      142     3     0     3     3     0     8    0
fdescpl    528      948    0      914     3     0     3     3     0     8    0
filepl     160     6229    0     6001    23     7    16    17     0     8    5
lockfpl    104      185    0      182     1     0     1     1     0     8    0
lockfspl    48       78    0       75     1     0     1     1     0     8    0
sessionpl  144       26    0       16     1     0     1     1     0     8    0
pgrppl      48       39    0       21     1     0     1     1     0     8    0
ucredpl    104      972    0      959     1     0     1     1     0     8    0
zombiepl   144      936    0      936     1     0     1     1     0     8    1
processpl  1232    1007    0      936     8     0     8     8     0     8    0
procpl     664     1835    0     1754     9     0     9     9     0     8    0
sosppl     176        2    0        2     1     1     0     1     0     8    0
sockpl     752     1594    0     1553    32    19    13    19     0     8    8
mcl64k     65536      4    0        0     1     0     1     1     0     8    0
mcl16k     16384      2    0        0     1     0     1     1     0     8    0
mcl8k      8192       2    0        0     1     0     1     1     0     8    0
mcl4k      4096     122    0        0    16     0    16    16     0     8    0
mcl2k      2048      33    0        0     5     0     5     5     0     8    0
mtagpl      96        3    0        0     1     0     1     1     0     8    0
mbufpl     256      273    0        0    17     0    17    17     0     8    0
bufpl      280     7477    0     1341   439     0   439   439     0     8    0
anonpl      32    10046    0        0    81     0    81    81     0   246    0
amapchunkpl 152   25489    0    24996    39    12    27    34     0   158    6
amappl16   200     3950    0     3917    25    10    15    18     0     8    8
amappl15   192        5    0        5     1     1     0     1     0     8    0
amappl14   184        6    0        6     1     1     0     1     0     8    0
amappl13   176      421    0      419     1     0     1     1     0     8    0
amappl12   168     1315    0     1268     3     0     3     3     0     8    0
amappl11   160        5    0        5     1     1     0     1     0     8    0
amappl10   152       47    0       33     1     0     1     1     0     8    0
amappl9    144      252    0      252     1     1     0     1     0     8    0
amappl8    136       28    0       26     1     0     1     1     0     8    0
amappl7    128       78    0       77     1     0     1     1     0     8    0
amappl6    120      273    0      257     1     0     1     1     0     8    0
amappl5    112       84    0       73     1     0     1     1     0     8    0
amappl4    104      439    0      407     1     0     1     1     0     8    0
amappl3     96     4315    0     4223     4     1     3     3     0     8    0
amappl2     88     1090    0     1004     3     0     3     3     0     8    0
amappl1     80    12157    0    11448    18     0    18    18     0     8    0
amappl      88     6966    0     6797     5     0     5     5     0    92    0
uvmvnodes   80      115    0        0     3     0     3     3     0     8    0
dma4096    4096       1    0        1     1     1     0     1     0     8    0
dma1024    1024       1    0        0     1     0     1     1     0     8    0
dma256     256        6    0        6     1     1     0     1     0     8    0
dma128     128      253    0      253     1     1     0     1     0     8    0
dma64       64        6    0        6     1     1     0     1     0     8    0
dma32       32        7    0        7     1     1     0     1     0     8    0
dma16       16       18    0       17     1     0     1     1     0     8    0
aobjpl      72       49    0        1     1     0     1     1     0     8    0
uaddrrnd    24      948    0      914     1     0     1     1     0     8    0
uaddrbest   32        2    0        0     1     0     1     1     0     8    0
uaddr       24      948    0      914     1     0     1     1     0     8    0
vmmpekpl   168     9906    0     9871     3     0     3     3     0     8    0
vmmpepl    168    68168    0    66035   118    11   107   118     0   357    7
vmsppl     488      947    0      914     5     0     5     5     0     8    0
rwobjpl     80    21736    0    20510    35     0    35    35     0     8    0
pdppl      4096    1914    0     1834   106    26    80    84     0     8    0
pvpl        32    18187    0        0   147     0   147   147     0   265    0
pmappl     256      952    0      915     3     0     3     3     0     8    0
extentpl    40       45    0       27     1     0     1     1     0     8    0
phpool     112      295    0       37     8     0     8     8     0     8    0
ddb{0}> machine ddbcpu 0
Invalid cpu 0
ddb{0}> trace
icmp_mtudisc_timeout(fffffd806a843b20,0) at icmp_mtudisc_timeout+0x123 sys/netinet/ip_icmp.c:1102
rt_timer_queue_flush(ffffffff838de900) at rt_timer_queue_flush+0x28d sys/net/route.c:1586
ip_sysctl(ffff80003c481afc,1,200000000600,ffff80003c481b28,200000001640,4) at ip_sysctl+0x84d sys/netinet/ip_input.c:1755
net_sysctl(ffff80003c481af4,3,200000000600,ffff80003c481b28,200000001640,4,d8e057f8db5318ca) at net_sysctl+0x64e sys/kern/uipc_domain.c:260
sys_sysctl(ffff80003c531268,ffff80003c481c60,ffff80003c481bb0) at sys_sysctl+0x3e5 sys/kern/kern_sysctl.c:-1
syscall(ffff80003c481c60) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80003c481c60) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:775
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x8dc91efd810, count: -7
ddb{0}> machine ddbcpu 1
Stopped at      x86_ipi_db+0x27:        addq    $0x8,%rsp
ddb{1}> trace
x86_ipi_db(ffff8000299ddff0) at x86_ipi_db+0x27 sys/arch/amd64/amd64/db_interface.c:394
x86_ipi_handler() at x86_ipi_handler+0xd9 sys/arch/amd64/amd64/ipi.c:106
Xresume_lapic_ipi() at Xresume_lapic_ipi+0x27
acpicpu_idle() at acpicpu_idle+0x457 sys/dev/acpi/acpicpu_x86.c:1224
sched_idle(ffff8000299ddff0) at sched_idle+0x391 sys/kern/kern_sched.c:191
end trace frame: 0x0, count: -5

Crashes (8):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/04 10:58 openbsd 75991a0e19ad 018ebef2 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore protection_fault: icmp_mtudisc_timeout
2025/11/12 16:07 openbsd 30ee307006ea 07e030de .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore protection_fault: icmp_mtudisc_timeout
2025/11/03 13:58 openbsd 0214ec5c7fc4 e6c64ba8 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore protection_fault: icmp_mtudisc_timeout
2025/08/12 02:52 openbsd 3ae9e49f3bd9 c06e8995 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore protection_fault: icmp_mtudisc_timeout
2025/08/02 09:15 openbsd 4c5c4401a4d8 3cda49cf .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main protection_fault: icmp_mtudisc_timeout
2025/07/27 17:55 openbsd 7b0d12c26b01 3cda49cf .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main protection_fault: icmp_mtudisc_timeout
2025/07/25 17:22 openbsd c5645c128364 3cda49cf .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main protection_fault: icmp_mtudisc_timeout
2025/07/16 23:23 openbsd 9ce74a582983 3cda49cf .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore protection_fault: icmp_mtudisc_timeout
* Struck through repros no longer work on HEAD.