uvm_fault: ifa_ifwithaddr

Status: upstream: reported on 2026/08/21 14:34
Reported-by: syzbot+deef8ed9109497738e5c@syzkaller.appspotmail.com
First crash: 9d02h, last: 9d02h

Sample crash report:
uvm_fault(0xffffffff839fdaf8, 0xffff800000004001, 0, 1) -> e
kernel: page fault trap, code=0
Stopped at      ifa_ifwithaddr+0x144:   movzbl  0x1(%r13),%ebx
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
* 30583   5358      0           0  0x4000000    0  syz-executor
ifa_ifwithaddr(ffff800000c5df78,5) at ifa_ifwithaddr+0x144 sys/net/if.c:1634
ifa_ifwithroute(fe101c21,ffff800000c5df60,ffff800000c5df78,5) at ifa_ifwithroute+0xe9 sys/net/rtsock.c:-1
rtm_getifa(ffff80003c95ae40,5) at rtm_getifa+0x2dd sys/net/rtsock.c:-1
rtm_output(ffff800000c5df00,ffff80003c95aee8,ffff80003c95ae40,7,5) at rtm_output+0x7e4 sys/net/rtsock.c:952
route_output(fffffa806ea7e100,ffff800010fe17c0) at route_output+0xa6a sys/net/rtsock.c:862
route_send(ffff800010fe17c0,fffffa806ea7e100,0,0) at route_send+0xd7 sys/net/rtsock.c:322
sosend(ffff800010fe17c0,0,ffff80003c95b098,0,0,2) at sosend+0x804 sys/kern/uipc_socket.c:-1
sendit(ffff800031cb1240,5,ffff80003c95b190,2,ffff80003c95b230) at sendit+0x5a5 sys/kern/uipc_syscalls.c:785
sys_sendto(ffff800031cb1240,ffff80003c95b2e0,ffff80003c95b230) at sys_sendto+0x8d sys/kern/uipc_syscalls.c:563
syscall(ffff80003c95b2e0) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80003c95b2e0) at syscall+0x962 sys/arch/amd64/amd64/trap.c:791
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xcc2b9f51db0, count: 4
https://www.openbsd.org/ddb.html describes the minimum info required in bug
reports.  Insufficient info makes it difficult to find and fix bugs.
ddb> 
ddb> set $lines = 0
ddb> set $maxwidth = 0
ddb> show panic
*cpu0: uvm_fault(0xffffffff839fdaf8, 0xffff800000004001, 0, 1) -> e
ddb> show kasan
No such command
ddb> trace
ifa_ifwithaddr(ffff800000c5df78,5) at ifa_ifwithaddr+0x144 sys/net/if.c:1634
ifa_ifwithroute(fe101c21,ffff800000c5df60,ffff800000c5df78,5) at ifa_ifwithroute+0xe9 sys/net/rtsock.c:-1
rtm_getifa(ffff80003c95ae40,5) at rtm_getifa+0x2dd sys/net/rtsock.c:-1
rtm_output(ffff800000c5df00,ffff80003c95aee8,ffff80003c95ae40,7,5) at rtm_output+0x7e4 sys/net/rtsock.c:952
route_output(fffffa806ea7e100,ffff800010fe17c0) at route_output+0xa6a sys/net/rtsock.c:862
route_send(ffff800010fe17c0,fffffa806ea7e100,0,0) at route_send+0xd7 sys/net/rtsock.c:322
sosend(ffff800010fe17c0,0,ffff80003c95b098,0,0,2) at sosend+0x804 sys/kern/uipc_socket.c:-1
sendit(ffff800031cb1240,5,ffff80003c95b190,2,ffff80003c95b230) at sendit+0x5a5 sys/kern/uipc_syscalls.c:785
sys_sendto(ffff800031cb1240,ffff80003c95b2e0,ffff80003c95b230) at sys_sendto+0x8d sys/kern/uipc_syscalls.c:563
syscall(ffff80003c95b2e0) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80003c95b2e0) at syscall+0x962 sys/arch/amd64/amd64/trap.c:791
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xcc2b9f51db0, count: -11
ddb> show registers
rdi               0xffff8000380ca000
rsi                            0x1da
rbp               0xffff80003c95ace0
rbx                              0x2
rdx               0xffff8000380ca000
rcx                            0x1d9
rax               0xffffffff82656954    ifa_ifwithaddr+0x1c4
r8                               0x5
r9                               0x2
r10               0x97b4b51e699e54f5
r11               0x6d8e74ef068b1f7c
r12               0xffff800001618000
r13               0xffff800000004000
r14               0xffff800000c5df78
r15                              0x1
rip               0xffffffff826568d4    ifa_ifwithaddr+0x144
cs                               0x8
rflags                       0x10246    __ALIGN_SIZE+0xf246
rsp               0xffff80003c95ac90
ss                              0x10
ifa_ifwithaddr+0x144:   movzbl  0x1(%r13),%ebx
ddb> show proc
PROC (syz-executor) tid=30583 pid=5358 tcnt=2 stat=onproc
    flags process=0 proc=4000000<THREAD>
    runpri=32, usrpri=50, slppri=32, nice=20
    wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0
    forw=0xffffffffffffffff, list=0xffff80003c8fb4e0,0xffff800031cb0fb8
    process=0xffff800045ffba98 user=0xffff80003c956000, vmspace=0xfffffa807f1c1738
    estcpu=36, cpticks=2, pctcpu=0.0, user=1, sys=1, intr=0
ddb> ps
   PID     TID   PPID   UID  S      PRLAGS     PFLAGS WAIT      COMMAND
 13979  404285  72093     0  2           0          0           syz-executor
 13979  136162  72093     0  3           0  0x4000080 fsleep    syz-executor
  5358  284594  78974     0  2           0          0           syz-executor
* 5358   30583  78974     0  7           0  0x4000000           syz-executor
 20924   43219  72455     0  2           0          0           syz-executor
 20924  371307  72455     0  3           0  0x4000080 bell      syz-executor
 20924  124489  72455     0  3           0  0x4000080 fsleep    syz-executor
 98674   74619  64423     0  2           0          0           syz-executor
 98674   90125  64423     0  3           0  0x4000080 fsleep    syz-executor
 98674  356984  64423     0  3           0  0x4000080 fsleep    syz-executor
  1326  273401  83195     0  2           0          0           syz-executor
  1326    6261  83195     0  3           0  0x4000080 fsleep    syz-executor
  1326   62486  83195     0  3           0  0x4000080 fsleep    syz-executor
 40737  128676      0     0  3     0x14000      0x280 nfsidl    nfsio
 24387  101632      0     0  3     0x14000      0x280 nfsidl    nfsio
 86443  514895      0     0  3     0x14000      0x280 nfsidl    nfsio
 12710  471008      0     0  3     0x14000      0x280 nfsidl    nfsio
 18173  456129      0     0  3     0x14000      0x280 nfsidl    nfsio
    88  267357      0     0  3     0x14000      0x280 nfsidl    nfsio
 32808  235885      0     0  3     0x14000      0x280 nfsidl    nfsio
 53587  166374      0     0  3     0x14000      0x280 nfsidl    nfsio
 71700  373554      0     0  3     0x14000      0x280 nfsidl    nfsio
 75014   89338      0     0  3     0x14000      0x280 nfsidl    nfsio
 36286    4580      0     0  3     0x14000      0x280 nfsidl    nfsio
 19598  120794      0     0  3     0x14000      0x280 nfsidl    nfsio
 32183  324934      0     0  3     0x14000      0x280 nfsidl    nfsio
 93850  262148      0     0  3     0x14000      0x280 nfsidl    nfsio
 26566  451277      0     0  3     0x14000      0x280 nfsidl    nfsio
 58563  412109      0     0  3     0x14000      0x280 nfsidl    nfsio
  9373   37544      0     0  3     0x14000      0x280 nfsidl    nfsio
 19551   97312      0     0  3     0x14000      0x280 nfsidl    nfsio
 15687  392417      0     0  3     0x14000      0x280 nfsidl    nfsio
 17325   68392      0     0  3     0x14000      0x280 nfsidl    nfsio
 66241  484628      0     0  3     0x14000      0x200 acct      acct
 10724  462693      1     0  3    0x100003       0x80 ttyin     getty
 78974  340694  72190     0  3         0x2       0x80 nanoslp   syz-executor
 72455   93533  72190     0  2         0x2      0xc80           syz-executor
 72093  174604  72190     0  3         0x2       0x80 nanoslp   syz-executor
 83195  241781  72190     0  3         0x2       0x80 nanoslp   syz-executor
 64423   55527  72190     0  2         0x2      0xc80           syz-executor
 37859  311036  72190     0  3         0x2       0x80 nanoslp   syz-executor
 53329  336807  72190     0  2         0x2          0           syz-executor
 34385  229150  72190     0  2         0x2          0           syz-executor
 72190  256938      1     0  3         0x2       0x80 kqread    syz-executor
  6903   89297      0     0  3     0x14000      0x200 bored     smr
 92669  503182      0     0  2     0x14000      0x200           zerothread
 68376  278740      0     0  3     0x14000      0x200 aiodoned  aiodoned
 19807  464706      0     0  3     0x14000      0x200 syncer    update
  2367  512618      0     0  3     0x14000      0x200 cleaner   cleaner
 65280  523979      0     0  3     0x14000      0x200 reaper    reaper
 65488  138115      0     0  3     0x14000      0x200 pgdaemon  pagedaemon
 81236  144559      0     0  3     0x14000      0x200 bored     viomb
 99862  151587      0     0  3     0x14000 0x40000200 acpi0     acpi0
  1527  329851      0     0  3     0x14000      0x200 bored     softnet0
 55384  511544      0     0  3     0x14000      0x200 bored     systqmp
 10639  492795      0     0  3     0x14000      0x200 bored     systq
 45157  185155      0     0  3     0x14000 0x40000200 tmoslp    softclock
 30866  330822      0     0  3     0x14000 0x40000200           idle0
     1  331338      0     0  3         0x2       0x80 wait      init
     0       0     -1     0  3     0x10000      0x200 scheduler swapper
ddb> show all locks
No such command
ddb> show malloc
           Type InUse  MemUse  HighUse   Limit  Requests Type Lim
         devbuf 11077  12699K   12699K 166960K     12355        0
            pcb    17     13K      13K 166960K        58        0
         rtable   238      8K       8K 166960K       413        0
             pf    29     12K      16K 166960K        58        0
         ifaddr    40      7K       7K 166960K        54        0
        ifgroup    47      1K       2K 166960K        73        0
         sysctl     3      1K       9K 166960K         7        0
       counters    33     17K      18K 166960K        45        0
       ioctlops     0      0K       4K 166960K        96        0
            iov     0      0K      16K 166960K         7        0
          mount     1      1K       1K 166960K         1        0
            log     1      0K       0K 166960K         5        0
         vnodes  1366     86K      86K 166960K      1656        0
      UFS quota     1     32K      32K 166960K         1        0
      UFS mount     5     36K      36K 166960K         5        0
            shm     2      1K       1K 166960K         2        0
         VM map     2      1K       1K 166960K         2        0
            sem     7      0K       0K 166960K        11        0
        dirhash    12      2K       2K 166960K        15        0
           ACPI  1734    201K     291K 166960K     11964        0
      file desc    15     57K     232K 166960K       296        0
          sigio     0      0K       0K 166960K         1        0
           proc    20     25K     124K 166960K       532        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        21        0
       in_multi    89      6K       6K 166960K       108        0
    ether_multi     1      0K       0K 166960K         3        0
            mrt     1      0K       0K 166960K        11        0
    ISOFS mount     1     32K      32K 166960K         1        0
  MSDOSFS mount     1     16K      16K 166960K         1        0
           ttys    97    440K     440K 166960K        97        0
           exec     0      0K       1K 166960K       376        0
   fusefs mount     1     32K      32K 166960K         1        0
            tdb     3      0K       0K 166960K         3        0
        VM swap     8     62K      64K 166960K        10        0
       UVM amap   128     82K     167K 166960K      4171        0
       UVM aobj     3      2K       4K 166960K         4        0
     pinsyscall    18     36K      96K 166960K      1387        0
        memdesc     1      4K       4K 166960K         1        0
    crypto data     1      1K       1K 166960K         1        0
    ip6_options     0      0K       0K 166960K        11        0
            NDP    11      0K       1K 166960K        34        0
           temp    36   9106K    9154K 166960K     10861        0
         kqueue     1      2K      22K 166960K        55        0
      SYN cache     2     16K      16K 166960K         2        0
ddb> show all pools
Name      Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
rtpcb      120       54    0       52     1     0     1     1     0     8    0
rtentry    136      121    0       17     4     0     4     4     0     8    0
unpcb      144      235    0      235     5     0     5     5     0     8    5
syncache   336        4    0        4     1     0     1     1     0     8    1
tcpcb      736       31    0       30     1     0     1     1     0     8    0
arp         96       20    0        2     1     0     1     1     0     8    0
ipq         40        2    0        0     1     0     1     1     0     8    0
ipqe        40        2    0        0     1     0     1     1     0     8    0
inpcb      328      328    0      326     6     0     6     6     0     8    5
ip6q        80        1    0        0     1     0     1     1     0     8    0
ip6af       40        1    0        0     1     0     1     1     0     8    0
nd6        112       25    0        4     1     0     1     1     0     8    0
pkpcb       40        4    0        4     1     0     1     1     0     8    1
kcovpl      48        8    0        0     1     0     1     1     0     8    0
ppxss      1072       9    0        9     1     0     1     1     0     8    1
pppxif     1416       1    0        1     1     0     1     1     0     8    1
pfrktable  1344       3    0        3     1     0     1     1     0     8    1
pfanchor   1288       1    0        1     1     0     1     1     0     8    1
pfrule     1360       3    0        3     1     0     1     1     0     8    1
art_heap8  4096       2    0        0     2     0     2     2     0     8    0
art_heap4  256      468    0       57    27     0    27    27     0     8    1
art_table   40      470    0       57     5     0     5     5     0     8    0
art_node    32      121    0       26     1     0     1     1     0     8    0
sysvmsgpl   40        1    0        0     1     0     1     1     0     8    0
semapl      72        9    0        4     1     0     1     1     0     8    0
shmpl      112        1    0        1     1     0     1     1     0     8    1
dirhash    1024      19    0        2     3     0     3     3     0     8    0
dino2pl    256     1898    0      437    92     0    92    92     0     8    0
ffsino     256     1898    0      437    92     0    92    92     0     8    0
nchpl      144     2282    0      590    64     0    64    64     0     8    0
rtmask      32        3    0        3     1     0     1     1     0     8    1
vnodes     216     2158    0        0   120     0   120   120     0     8    0
namei      1024    7615    0     7614     2     0     2     2     0     8    1
pfiaddrpl  120        1    0        1     1     0     1     1     0     8    1
kstatmem   264       37    0       14     2     0     2     2     0     8    0
scsiplug    72        1    0        1     1     0     1     1     0     8    1
scxspl     216     7357    0     7357     5     0     5     5     1     8    5
plimitpl   152       87    0       75     1     0     1     1     0     8    0
sigapl     424      600    0      548     7     0     7     7     0     8    0
knotepl    120     8472    0     8455     8     0     8     8     0     8    6
kqueuepl   184      100    0       99     2     0     2     2     0     8    1
pipepl     304      128    0      101     3     0     3     3     0     8    0
fdescpl    448      566    0      548     5     0     5     5     0     8    1
filepl     120     3173    0     3006    14     0    14    14     0     8    5
lockfpl    104       59    0       58     1     0     1     1     0     8    0
lockfspl    48       27    0       26     1     0     1     1     0     8    0
sessionpl  144       33    0       30     1     0     1     1     0     8    0
pgrppl      48       41    0       30     1     0     1     1     0     8    0
ucredpl    104      486    0      483     1     0     1     1     0     8    0
zombiepl   144      549    0      548     1     0     1     1     0     8    0
processpl  1152     600    0      548     4     0     4     4     0     8    0
procpl     664      835    0      775     6     0     6     6     0     8    0
sosppl     176        2    0        2     1     0     1     1     0     8    1
sockpl     552      624    0      620    11     0    11    11     0     8   10
mcl64k     65536     76    0       75     1     0     1     1     0     8    0
mcl9k128   9344       2    0        2     1     0     1     1     0     8    1
mcl8k      8192       8    0        8     1     0     1     1     0     8    1
mcl4k      4096    2712    0     2659    14     0    14    14     0     8    6
mcl2k      2048     231    0      230     2     0     2     2     0     8    1
mextrefs    64      112    0      111     1     0     1     1     0     8    0
mtagpl      96        4    0        4     1     0     1     1     0     8    1
mbufpl     256     5942    0     5772    18     0    18    18     0     8    5
bufpl      272     2576    0      103   165     0   165   165     0     8    0
anonpl      24    91749    0    90213    23     0    23    23     0   187    6
amapchunkpl 152   12167    0    11825    26     0    26    26     0   158   10
amappl16   200     1199    0     1179     4     0     4     4     0     8    2
amappl15   192       44    0       44     1     0     1     1     0     8    1
amappl14   184      409    0      409     1     0     1     1     0     8    1
amappl13   176      130    0      129     1     0     1     1     0     8    0
amappl12   168      879    0      862     2     0     2     2     0     8    0
amappl11   160        6    0        6     1     0     1     1     0     8    1
amappl10   152       55    0       55     1     0     1     1     0     8    1
amappl9    144      280    0      280     1     0     1     1     0     8    1
amappl8    136      108    0      107     1     0     1     1     0     8    0
amappl7    128      144    0      141     1     0     1     1     0     8    0
amappl6    120      147    0      147     1     0     1     1     0     8    1
amappl5    112       92    0       91     1     0     1     1     0     8    0
amappl4    104      260    0      256     1     0     1     1     0     8    0
amappl3     96     2169    0     2111     3     0     3     3     0     8    0
amappl2     88      683    0      660     2     0     2     2     0     8    0
amappl1     80    10732    0    10616    13     0    13    13     0     8    7
amappl      88     3447    0     3333     4     0     4     4     0    92    0
uvmvnodes   80      101    0        0     3     0     3     3     0     8    0
dma4096    4096       1    0        1     1     0     1     1     0     8    1
dma1024    1024       2    0        1     1     0     1     1     0     8    0
dma256     256        6    0        6     1     0     1     1     0     8    1
dma128     128      254    0      254     1     0     1     1     0     8    1
dma64       64        6    0        6     1     0     1     1     0     8    1
dma32       32        7    0        7     1     0     1     1     0     8    1
dma16       16       18    0       17     1     0     1     1     0     8    0
aobjpl      72        3    0        1     1     0     1     1     0     8    0
uaddrrnd    24      566    0      548     1     0     1     1     0     8    0
uaddrbest   32        2    0        0     1     0     1     1     0     8    0
uaddr       24      566    0      548     1     0     1     1     0     8    0
vmmpekpl   168     6407    0     6374     2     0     2     2     0     8    0
vmmpepl    168    43964    0    43171    78     0    78    78     0   357   38
vmsppl     368      565    0      548     4     0     4     4     0     8    1
rwobjpl     40    14985    0    14576    11     0    11    11     0     8    1
pdppl      4096    1138    0     1096   100    54    46    82     0     8    4
pvpl        32   248379    0   244268    70     0    70    70     0   265   27
pmappl     216      565    0      548     3     0     3     3     0     8    0
extentpl    40       46    0       28     1     0     1     1     0     8    0
phpool     112      534    0       54    15     0    15    15     0     8    0
ddb> machine ddbcpu 0
No such command
ddb> trace
ifa_ifwithaddr(ffff800000c5df78,5) at ifa_ifwithaddr+0x144 sys/net/if.c:1634
ifa_ifwithroute(fe101c21,ffff800000c5df60,ffff800000c5df78,5) at ifa_ifwithroute+0xe9 sys/net/rtsock.c:-1
rtm_getifa(ffff80003c95ae40,5) at rtm_getifa+0x2dd sys/net/rtsock.c:-1
rtm_output(ffff800000c5df00,ffff80003c95aee8,ffff80003c95ae40,7,5) at rtm_output+0x7e4 sys/net/rtsock.c:952
route_output(fffffa806ea7e100,ffff800010fe17c0) at route_output+0xa6a sys/net/rtsock.c:862
route_send(ffff800010fe17c0,fffffa806ea7e100,0,0) at route_send+0xd7 sys/net/rtsock.c:322
sosend(ffff800010fe17c0,0,ffff80003c95b098,0,0,2) at sosend+0x804 sys/kern/uipc_socket.c:-1
sendit(ffff800031cb1240,5,ffff80003c95b190,2,ffff80003c95b230) at sendit+0x5a5 sys/kern/uipc_syscalls.c:785
sys_sendto(ffff800031cb1240,ffff80003c95b2e0,ffff80003c95b230) at sys_sendto+0x8d sys/kern/uipc_syscalls.c:563
syscall(ffff80003c95b2e0) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80003c95b2e0) at syscall+0x962 sys/arch/amd64/amd64/trap.c:791
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xcc2b9f51db0, count: -11
ddb> machine ddbcpu 1
No such command
ddb> 

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/21 14:33 openbsd 073728865af4 1e72964b .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: ifa_ifwithaddr
* Struck through repros no longer work on HEAD.