syzbot


assert "bpfilter_lookup(unit) == NULL" failed in bpf.c

Status: upstream: reported on 2026/01/08 09:03
Reported-by: syzbot+a56d771d60f11124aac0@syzkaller.appspotmail.com
First crash: 18d, last: 18d

Sample crash report:
panic: kernel diagnostic assertion "bpfilter_lookup(unit) == NULL" failed: file "/syzkaller/managers/multicore/kernel/sys/net/bpf.c", line 379
Stopped at      db_enter+0x25:  addq    $0x8,%rsp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
 482649  50950      0           0          0    1  syz-executor
*363093  13112      0           0  0x4000000    0K syz-executor
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
panic(ffffffff833b2fa5) at panic+0x1e5 sys/kern/subr_prf.c:198
__assert(ffffffff833f0741,ffffffff834006bd,17b,ffffffff8340abb9) at __assert+0x29 sys/kern/subr_prf.c:-1
bpfopen(11700,21,2000,ffff80003c41f4e8) at bpfopen+0x2bd bpfilter_lookup sys/net/bpf.c:1832 [inline]
bpfopen(11700,21,2000,ffff80003c41f4e8) at bpfopen+0x2bd sys/net/bpf.c:379
spec_open_clone(ffff80003c44ebe8) at spec_open_clone+0x277 sys/kern/spec_vnops.c:722
spec_open(ffff80003c44ebe8) at spec_open+0x319 sys/kern/spec_vnops.c:148
VOP_OPEN(fffffd8070607630,21,fffffd80097fd5b0,ffff80003c41f4e8) at VOP_OPEN+0x8b sys/kern/vfs_vops.c:138
vn_open(ffff80003c44ee30,21,0) at vn_open+0x6a0 sys/kern/vfs_vnops.c:177
doopenat(ffff80003c41f4e8,ffffff9c,200000000000,20,0,ffff80003c44efe0) at doopenat+0x35b sys/kern/vfs_syscalls.c:1138
syscall(ffff80003c44f090) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80003c44f090) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:775
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x3a3468abde0, 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{0}> 
ddb{0}> set $lines = 0
ddb{0}> set $maxwidth = 0
ddb{0}> show panic
*cpu0: kernel diagnostic assertion "bpfilter_lookup(unit) == NULL" failed: file "/syzkaller/managers/multicore/kernel/sys/net/bpf.c", line 379
ddb{0}> trace
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
panic(ffffffff833b2fa5) at panic+0x1e5 sys/kern/subr_prf.c:198
__assert(ffffffff833f0741,ffffffff834006bd,17b,ffffffff8340abb9) at __assert+0x29 sys/kern/subr_prf.c:-1
bpfopen(11700,21,2000,ffff80003c41f4e8) at bpfopen+0x2bd bpfilter_lookup sys/net/bpf.c:1832 [inline]
bpfopen(11700,21,2000,ffff80003c41f4e8) at bpfopen+0x2bd sys/net/bpf.c:379
spec_open_clone(ffff80003c44ebe8) at spec_open_clone+0x277 sys/kern/spec_vnops.c:722
spec_open(ffff80003c44ebe8) at spec_open+0x319 sys/kern/spec_vnops.c:148
VOP_OPEN(fffffd8070607630,21,fffffd80097fd5b0,ffff80003c41f4e8) at VOP_OPEN+0x8b sys/kern/vfs_vops.c:138
vn_open(ffff80003c44ee30,21,0) at vn_open+0x6a0 sys/kern/vfs_vnops.c:177
doopenat(ffff80003c41f4e8,ffffff9c,200000000000,20,0,ffff80003c44efe0) at doopenat+0x35b sys/kern/vfs_syscalls.c:1138
syscall(ffff80003c44f090) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80003c44f090) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:775
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x3a3468abde0, count: -11
ddb{0}> show registers
rdi                                0
rsi                              0x1
rbp               0xffff80003c44e9c0
rbx               0xffffffff83825e07    cpu_info_full_primary+0x2e07
rdx               0xffff80000155dbc0
rcx               0xffff80003c41f4e8
rax               0xffffffff83824ff0    cpu_info_full_primary+0x1ff0
r8                 0x101010101010101
r9                0x8080808080808080
r10               0xea9b75ce09f6f935
r11                0x394215f31a9d33d
r12               0xffffffff83825c08    cpu_info_full_primary+0x2c08
r13                                0
r14                                0
r15                              0x1
rip               0xffffffff814a31b5    db_enter+0x25
cs                               0x8
rflags                         0x246
rsp               0xffff80003c44e9b0
ss                              0x10
db_enter+0x25:  addq    $0x8,%rsp
ddb{0}> show proc
PROC (syz-executor) tid=363093 pid=13112 tcnt=2 stat=onproc
    flags process=0 proc=4000000<THREAD>
    runpri=32, usrpri=86, slppri=32, nice=20
    wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0
    forw=0xffffffffffffffff, list=0xffff80003c41e028,0xffffffff839f6288
    process=0xffff80003c415d00 user=0xffff80003c44a000, vmspace=0xfffffd806f61c7a8
    estcpu=36, cpticks=1, pctcpu=0.0, user=0, sys=1, intr=0
ddb{0}> ps
   PID     TID   PPID    UID  S       FLAGS  WAIT          COMMAND
 50950  482649  11032      0  7           0                syz-executor
 50950  176513  11032      0  3   0x4000080  fifow         syz-executor
 13112  433693  99365      0  2           0                syz-executor
*13112  363093  99365      0  7   0x4000000                syz-executor
 54438  232498  22826      0  2           0                syz-executor
 54438  344357  22826      0  3   0x4000080  fsleep        syz-executor
 53442  419118   6090      0  2           0                syz-executor
 53442  357095   6090      0  3   0x4000080  fsleep        syz-executor
 42383  111558  57022      0  2           0                syz-executor
 42383   82687  57022      0  3   0x4000080  kqpoll        syz-executor
 30369  108934   3709      0  2           0                syz-executor
 30369  150606   3709      0  3   0x4000080  kqread        syz-executor
 30369  456646   3709      0  3   0x4000080  fsleep        syz-executor
 52420   43439  87645      0  2           0                syz-executor
 52420   75268  87645      0  3   0x4000080  kqsel         syz-executor
 52420  358096  87645      0  3   0x4000080  fsleep        syz-executor
 57022  461466  36962      0  2         0x2                syz-executor
  5837  194132  36962      0  2         0x2                syz-executor
 87645  220075  36962      0  3        0x82  nanoslp       syz-executor
  3709  246299  36962      0  2         0x2                syz-executor
 22826  333119  36962      0  3        0x82  nanoslp       syz-executor
 11032  429387  36962      0  2       0xc82                syz-executor
  6090   71337  36962      0  2         0x2                syz-executor
 99365  453315  36962      0  2       0xc82                syz-executor
 36962  230929  73444      0  3        0x82  kqread        syz-executor
 73444  105058  16100      0  3    0x10008a  sigsusp       ksh
 16100   72038  35284      0  3        0x98  kqread        sshd-session
 35284   12664  67251      0  3        0x92  kqread        sshd-session
 70449  359546      1      0  3    0x100083  ttyopn        getty
 67251  185771      1      0  3        0x88  kqread        sshd
 92737  415840  59161     74  3   0x1100092  bpf           pflogd
 59161   80684      1      0  3        0x80  sbwait        pflogd
 23981  298200  66327     73  3   0x1100090  kqread        syslogd
 66327  130844      1      0  3    0x100082  sbwait        syslogd
 13224   27674      1      0  3    0x100080  kqread        resolvd
 79552  490517  48088     77  3    0x100092  kqread        dhcpleased
 89894  502755  48088     77  3    0x100092  kqread        dhcpleased
 48088   16033      1      0  3        0x80  kqread        dhcpleased
 72137  434885      0      0  3     0x14200  bored         smr
 36189   89256      0      0  2     0x14200                zerothread
 90520  174999      0      0  3     0x14200  aiodoned      aiodoned
 86446  294125      0      0  3     0x14200  syncer        update
 87418  113245      0      0  3     0x14200  cleaner       cleaner
 59248  159464      0      0  3     0x14200  reaper        reaper
 77713  475127      0      0  3     0x14200  pgdaemon      pagedaemon
 54623  304874      0      0  3     0x14200  bored         viomb
 84670  165088      0      0  3  0x40014200  acpi0         acpi0
 87705  279543      0      0  3  0x40014200                idle1
 15998  373148      0      0  3     0x14200  bored         softnet1
 37524  509672      0      0  3     0x14200  bored         softnet0
 35588  449003      0      0  3     0x14200  bored         systqmp
 17311  368435      0      0  3     0x14200  bored         systq
 55025  369349      0      0  3     0x14200  tmoslp        softclockmp
 73414  404177      0      0  3  0x40014200  tmoslp        softclock
 27106    7615      0      0  3  0x40014200                idle0
     1  269318      0      0  3     0x80082  wait          init
     0       0     -1      0  3     0x10200  scheduler     swapper
ddb{0}> show all locks
Process 13112 (syz-executor) thread 0xffff80003c41f4e8 (363093)
exclusive kernel_lock &kernel_lock r = 0 (0xffffffff83903808)
#0  witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline]
#0  witness_lock+0x5f1 sys/kern/subr_witness.c:1160
#1  doopenat+0x345 sys/kern/vfs_syscalls.c:1138
#2  syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
#2  syscall+0xbd4 sys/arch/amd64/amd64/trap.c:775
#3  Xsyscall+0x128
ddb{0}> show malloc
           Type InUse  MemUse  HighUse   Limit  Requests Type Lim
         devbuf 11080  12289K   12510K 166960K     12998        0
            pcb    17     14K      16K 166960K       248        0
         rtable   212      8K       8K 166960K       485        0
             pf    34     17K      18K 166960K        82        0
         ifaddr    41      7K       7K 166960K        78        0
        ifgroup    53      2K       2K 166960K       115        0
         sysctl     3      1K       9K 166960K        13        0
       counters    70     37K      37K 166960K       124        0
       ioctlops     0      0K       4K 166960K      1532        0
            iov     0      0K      28K 166960K        36        0
          mount     1      1K       1K 166960K         1        0
            log     0      0K       0K 166960K         4        0
         vnodes  1378     87K      87K 166960K      1868        0
      UFS quota     1     32K      32K 166960K         1        0
      UFS mount     5     36K      36K 166960K         5        0
            shm     2      1K       5K 166960K         6        0
         VM map     2      1K       1K 166960K         2        0
            sem    12      0K       0K 166960K        35        0
        dirhash    12      2K       2K 166960K        24        0
           ACPI  1692    195K     286K 166960K     12470        0
      file desc    18     65K     236K 166960K       722        0
          sigio     0      0K       0K 166960K         7        0
           proc    72    115K     164K 166960K       641        0
        subproc    72      4K       4K 166960K        90        0
    NFS srvsock     1      0K       0K 166960K         1        0
     NFS daemon     1     16K      16K 166960K         1        0
    ip_moptions     2      0K       0K 166960K        69        0
       in_multi    89      6K       7K 166960K       160        0
    ether_multi     1      0K       0K 166960K        10        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       632        0
   fusefs mount     1     32K      32K 166960K         1        0
     pfkey data     0      0K       0K 166960K         1        0
            tdb     3      0K       0K 166960K         3        0
        VM swap     8     62K      64K 166960K        10        0
       UVM amap   252    151K     173K 166960K      8241        0
       UVM aobj    14      8K       8K 166960K        15        0
     pinsyscall    43     86K     100K 166960K      1912        0
        memdesc     1      4K       4K 166960K         1        0
    crypto data     1      1K       1K 166960K         1        0
    ip6_options     0      0K       0K 166960K        39        0
            NDP    12      0K       2K 166960K        52        0
           temp    52   8673K    8799K 166960K     29065        0
         kqueue    16     26K      32K 166960K       129        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       74    0       71     1     0     1     1     0     8    0
rtentry    176      144    0       55     6     0     6     6     0     8    0
unpcb      144      343    0      319     3     1     2     2     0     8    0
syncache   336       10    0       10     3     2     1     1     0     8    1
tcpcb      736      159    0      153     2     0     2     2     0     8    1
arp        136       22    0        8     1     0     1     1     0     8    0
inpcb      328      669    0      658    11     9     2     7     0     8    1
nd6        152       32    0        9     1     0     1     1     0     8    0
pkpcb       40        7    0        7     2     1     1     1     0     8    1
kcovpl      48       10    0        2     1     0     1     1     0     8    0
mppekey    1024       1    0        1     1     1     0     1     0     8    0
ppxss      1192      20    0       19     2     1     1     1     0     8    0
pffrag     232        6    0        3     1     0     1     1     0   482    0
pffrnode    88        6    0        3     1     0     1     1     0     8    0
pffrent     40       11    0        8     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        2    0        2     1     0     1     1     0     8    1
art_heap8  4096       4    0        0     4     0     4     4     0     8    0
art_heap4  256      646    0      263    33     7    26    29     0     8    1
art_table   40      650    0      263     5     0     5     5     0     8    0
art_node    32      144    0       64     1     0     1     1     0     8    0
sysvmsgpl   40       16    0        2     1     0     1     1     0     8    0
semapl     112       32    0       22     1     0     1     1     0     8    0
shmpl      112        9    0        1     1     0     1     1     0     8    0
dirhash    1024      25    0        8     3     0     3     3     0     8    0
dino2pl    256     2623    0     1110    96     0    96    96     0     8    0
ffsino     296     2623    0     1110   117     0   117   117     0     8    0
nchpl      144     3575    0     1861    64     0    64    64     0     8    0
rtmask      32        3    0        3     2     1     1     1     0     8    1
vnodes     216     2985    0        0   166     0   166   166     0     8    0
namei      1024   12204    0    12204     3     2     1     2     0     8    1
percpumem   16       77    0       27     1     0     1     1     0     8    0
vcpupl     3968       3    0        0     1     0     1     1     0     8    0
vmpool     848        3    0        0     1     0     1     1     0     8    0
kstatmem   264       66    0       40     2     0     2     2     0     8    0
scsiplug    72        1    0        1     1     1     0     1     0     8    0
scxspl     216    19719    0    19719    11     3     8     8     1     8    8
plimitpl   152      177    0      159     1     0     1     1     0     8    0
sigapl     424     1009    0      961     7     1     6     7     0     8    0
knotepl    120      774    0        0    24     0    24    24     0     8    0
kqueuepl   224      185    0      170     2     0     2     2     0     8    0
pipepl     344      185    0      158     3     0     3     3     0     8    0
fdescpl    528      993    0      961     3     0     3     3     0     8    0
filepl     160     5422    0     5192    17     5    12    14     0     8    0
lockfpl    104      245    0      243     1     0     1     1     0     8    0
lockfspl    48       94    0       92     1     0     1     1     0     8    0
sessionpl  144       30    0       21     1     0     1     1     0     8    0
pgrppl      48       55    0       38     1     0     1     1     0     8    0
ucredpl    104      758    0      745     1     0     1     1     0     8    0
zombiepl   144     1099    0     1098     1     0     1     1     0     8    0
processpl  1232    1009    0      961     5     0     5     5     0     8    0
procpl     664     1961    0     1904     6     0     6     6     0     8    0
sosppl     176        5    0        5     3     2     1     1     0     8    1
sockpl     752     1114    0     1076    19    13     6    11     0     8    2
mcl64k     65536      4    0        0     1     0     1     1     0     8    0
mcl16k     16384      1    0        0     1     0     1     1     0     8    0
mcl9k      9216       2    0        0     1     0     1     1     0     8    0
mcl8k      8192       3    0        0     1     0     1     1     0     8    0
mcl4k      4096     125    0        0    16     0    16    16     0     8    0
mcl2k2     2112       1    0        0     1     0     1     1     0     8    0
mcl2k      2048      39    0        0     5     0     5     5     0     8    0
mtagpl      96       75    0        0     2     0     2     2     0     8    0
mbufpl     256      244    0        0    15     0    15    15     0     8    0
bufpl      280     7797    0     1661   439     0   439   439     0     8    0
anonpl      32    11857    0        0    97     1    96    97     0   246    0
amapchunkpl 152   25476    0    24951    38    13    25    33     0   158    4
amappl16   200     2355    0     2322    38    27    11    25     0     8    5
amappl15   192        2    0        2     1     1     0     1     0     8    0
amappl14   184        5    0        4     1     0     1     1     0     8    0
amappl13   176      451    0      450     1     0     1     1     0     8    0
amappl12   168     1381    0     1338     3     1     2     3     0     8    0
amappl11   160       92    0       92     1     1     0     1     0     8    0
amappl10   152       57    0       43     1     0     1     1     0     8    0
amappl9    144      259    0      259     1     1     0     1     0     8    0
amappl8    136       22    0       20     1     0     1     1     0     8    0
amappl7    128       89    0       87     1     0     1     1     0     8    0
amappl6    120      344    0      331     1     0     1     1     0     8    0
amappl5    112       75    0       64     1     0     1     1     0     8    0
amappl4    104      447    0      416     1     0     1     1     0     8    0
amappl3     96     4591    0     4490     4     1     3     3     0     8    0
amappl2     88     1158    0     1080     2     0     2     2     0     8    0
amappl1     80    13200    0    12608    15     1    14    14     0     8    0
amappl      88     7330    0     7155     5     0     5     5     0    92    0
uvmvnodes   80      121    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        7    0        7     2     1     1     1     0     8    1
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       14    0        1     1     0     1     1     0     8    0
uaddrrnd    24      993    0      961     1     0     1     1     0     8    0
uaddrbest   32        2    0        0     1     0     1     1     0     8    0
uaddr       24      993    0      961     1     0     1     1     0     8    0
vmmpekpl   168    10241    0    10197     3     0     3     3     0     8    0
vmmpepl    168    70607    0    68632   118    24    94   107     0   357    4
vmsppl     488      992    0      961     6     1     5     5     0     8    0
rwobjpl     80    21567    0    20497    31     1    30    31     0     8    0
pdppl      4096    1999    0     1925   104    30    74    83     0     8    0
pvpl        32    18302    0        0   148     0   148   148     0   265    0
pmappl     256      995    0      961     3     0     3     3     0     8    0
extentpl    40       45    0       27     1     0     1     1     0     8    0
phpool     112      294    0       44     8     0     8     8     0     8    0
ddb{0}> machine ddbcpu 0
Invalid cpu 0
ddb{0}> trace
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
panic(ffffffff833b2fa5) at panic+0x1e5 sys/kern/subr_prf.c:198
__assert(ffffffff833f0741,ffffffff834006bd,17b,ffffffff8340abb9) at __assert+0x29 sys/kern/subr_prf.c:-1
bpfopen(11700,21,2000,ffff80003c41f4e8) at bpfopen+0x2bd bpfilter_lookup sys/net/bpf.c:1832 [inline]
bpfopen(11700,21,2000,ffff80003c41f4e8) at bpfopen+0x2bd sys/net/bpf.c:379
spec_open_clone(ffff80003c44ebe8) at spec_open_clone+0x277 sys/kern/spec_vnops.c:722
spec_open(ffff80003c44ebe8) at spec_open+0x319 sys/kern/spec_vnops.c:148
VOP_OPEN(fffffd8070607630,21,fffffd80097fd5b0,ffff80003c41f4e8) at VOP_OPEN+0x8b sys/kern/vfs_vops.c:138
vn_open(ffff80003c44ee30,21,0) at vn_open+0x6a0 sys/kern/vfs_vnops.c:177
doopenat(ffff80003c41f4e8,ffffff9c,200000000000,20,0,ffff80003c44efe0) at doopenat+0x35b sys/kern/vfs_syscalls.c:1138
syscall(ffff80003c44f090) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80003c44f090) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:775
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x3a3468abde0, count: -11
ddb{0}> machine ddbcpu 1
Stopped at      x86_ipi_db+0x27:        addq    $0x8,%rsp
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
__sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0xb kd_curproc sys/dev/kcov.c:580 [inline]
__sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0xb sys/dev/kcov.c:153
syscall(ffff80003b3f77c0) at syscall+0xaf4 mi_syscall sys/sys/syscall_mi.h:175 [inline]
syscall(ffff80003b3f77c0) at syscall+0xaf4 sys/arch/amd64/amd64/trap.c:775
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7216ffa7b6b0, count: 9
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
__sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0xb kd_curproc sys/dev/kcov.c:580 [inline]
__sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0xb sys/dev/kcov.c:153
syscall(ffff80003b3f77c0) at syscall+0xaf4 mi_syscall sys/sys/syscall_mi.h:175 [inline]
syscall(ffff80003b3f77c0) at syscall+0xaf4 sys/arch/amd64/amd64/trap.c:775
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7216ffa7b6b0, count: -6

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/08 09:03 openbsd d77c41cf8f5a c1f5c7d0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore assert "bpfilter_lookup(unit) == NULL" failed in bpf.c
* Struck through repros no longer work on HEAD.