syzbot


uvm_fault: ufsdirhash_build

Status: upstream: reported on 2025/12/09 04:14
Reported-by: syzbot+68feee2e572938a63147@syzkaller.appspotmail.com
First crash: 7d11h, last: 7d11h

Sample crash report:
uvm_fault(0xffffffff839b9bc0, 0xffff800026982004, 0, 1) -> d
kernel: page fault trap, code=0
Stopped at      ufsdirhash_build+0x9e8: movzwl  0x4(%rax,%r14,1),%r15d
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
*174923  38534      0           0  0x4000000    0  syz-executor
ufsdirhash_build(fffffd807e910800) at ufsdirhash_build+0x9e8 sys/ufs/ufs/ufs_dirhash.c:213
ufs_lookup() at ufs_lookup+0x388 sys/ufs/ufs/ufs_lookup.c:198
VOP_LOOKUP(fffffd806c2a3e80,ffff80003ca256e8,ffff80003ca25718) at VOP_LOOKUP+0x6e sys/kern/vfs_vops.c:85
vfs_lookup(ffff80003ca256b8) at vfs_lookup+0x921 sys/kern/vfs_lookup.c:566
namei(ffff80003ca256b8) at namei+0x7ca sys/kern/vfs_lookup.c:250
domknodat(ffff80002a8134f0,ffffff9c,200000000280,2000,1e5f) at domknodat+0xb4 sys/kern/vfs_syscalls.c:1592
syscall(ffff80003ca258a0) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80003ca258a0) at syscall+0x962 sys/arch/amd64/amd64/trap.c:775
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xe83e5d1c2e0, count: 7
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(0xffffffff839b9bc0, 0xffff800026982004, 0, 1) -> d
ddb> trace
ufsdirhash_build(fffffd807e910800) at ufsdirhash_build+0x9e8 sys/ufs/ufs/ufs_dirhash.c:213
ufs_lookup() at ufs_lookup+0x388 sys/ufs/ufs/ufs_lookup.c:198
VOP_LOOKUP(fffffd806c2a3e80,ffff80003ca256e8,ffff80003ca25718) at VOP_LOOKUP+0x6e sys/kern/vfs_vops.c:85
vfs_lookup(ffff80003ca256b8) at vfs_lookup+0x921 sys/kern/vfs_lookup.c:566
namei(ffff80003ca256b8) at namei+0x7ca sys/kern/vfs_lookup.c:250
domknodat(ffff80002a8134f0,ffffff9c,200000000280,2000,1e5f) at domknodat+0xb4 sys/kern/vfs_syscalls.c:1592
syscall(ffff80003ca258a0) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80003ca258a0) at syscall+0x962 sys/arch/amd64/amd64/trap.c:775
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xe83e5d1c2e0, count: -8
ddb> show registers
rdi                                0
rsi                                0
rbp               0xffff80003ca25350
rbx                           0x3fff    __ALIGN_SIZE+0x2fff
rdx                                0
rcx               0xfffffd806bb1ae60
rax               0xffff800026982000
r8                0xffffffffffffffff
r9                0xfffffd8007bfd820
r10               0xf54c8f46c140b576
r11               0x994e9d9bce42af7b
r12               0xffff800026982000
r13               0xffff8000014f5600
r14                                0
r15                                0
rip               0xffffffff81bfbc68    ufsdirhash_build+0x9e8
cs                               0x8
rflags                       0x10246    __ALIGN_SIZE+0xf246
rsp               0xffff80003ca252b0
ss                              0x10
ufsdirhash_build+0x9e8: movzwl  0x4(%rax,%r14,1),%r15d
ddb> show proc
PROC (syz-executor) tid=174923 pid=38534 tcnt=2 stat=onproc
    flags process=0 proc=4000000<THREAD>
    runpri=50, usrpri=50, slppri=32, nice=20
    wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0
    forw=0xffffffffffffffff, list=0xffff80003c53a550,0xffffffff8395f738
    process=0xffff8000ffff9b18 user=0xffff80003ca20000, vmspace=0xfffffd806d2515d8
    estcpu=36, cpticks=1, pctcpu=0.0, user=0, sys=1, intr=0
ddb> ps
   PID     TID   PPID    UID  S       FLAGS  WAIT          COMMAND
 38534  327227  12863      0  2           0                syz-executor
*38534  174923  12863      0  7   0x4000000                syz-executor
 87251  316479  30168      0  2           0                syz-executor
 87251  310031  30168      0  3   0x4000080  fsleep        syz-executor
 60569  235832  72330      0  2       0xc80                syz-executor
 60569  227840  72330      0  3   0x4000080  fsleep        syz-executor
 60569  499419  72330      0  3   0x4000080  fsleep        syz-executor
 60569   51073  72330      0  2   0x4000000                syz-executor
 37206  247059  85240     -1  3        0x90  nanoslp       syz-executor
 37206  118771  85240     -1  3   0x4000090  fsleep        syz-executor
 37206  365986  85240     -1  2   0x4000010                syz-executor
 68373   28740      1      0  3    0x100083  ttyin         getty
 51647  196964      0      0  3     0x14280  nfsidl        nfsio
 14817  238540      0      0  3     0x14280  nfsidl        nfsio
 86999  356449      0      0  3     0x14280  nfsidl        nfsio
  9122  407583      0      0  3     0x14280  nfsidl        nfsio
 90311  165712      0      0  3     0x14280  nfsidl        nfsio
 97824  113730      0      0  3     0x14280  nfsidl        nfsio
 17203  429380      0      0  3     0x14280  nfsidl        nfsio
 47226  216848      0      0  3     0x14280  nfsidl        nfsio
 72896  127977      0      0  3     0x14280  nfsidl        nfsio
 87481  452644      0      0  3     0x14280  nfsidl        nfsio
 82737  171552      0      0  3     0x14280  nfsidl        nfsio
 87175  258838      0      0  3     0x14280  nfsidl        nfsio
 98917  464089      0      0  3     0x14280  nfsidl        nfsio
 31389  321744      0      0  3     0x14280  nfsidl        nfsio
 52881  221446      0      0  3     0x14280  nfsidl        nfsio
 51751  326280      0      0  3     0x14280  nfsidl        nfsio
 46731  156426      0      0  3     0x14280  nfsidl        nfsio
 78684  441595      0      0  3     0x14280  nfsidl        nfsio
 34873  493895      0      0  3     0x14280  nfsidl        nfsio
 17536  360466      0      0  3     0x14280  nfsidl        nfsio
 85240   64125  40159      0  3        0x82  nanoslp       syz-executor
 93963  475294  40159      0  3        0x82  nanoslp       syz-executor
 72330   70911  40159      0  3        0x82  nanoslp       syz-executor
 30168  456748  40159      0  2       0xc82                syz-executor
 12863  463057  40159      0  2       0xc82                syz-executor
 40159  102875  99021      0  3        0x82  wait          syz-executor
 99021  190372  81816      0  3    0x10008a  sigsusp       ksh
 81816  381894  83762      0  3        0x98  kqread        sshd-session
 83762  179738   3114      0  3        0x92  kqread        sshd-session
  3114  441467      1      0  3        0x88  kqread        sshd
 19024  202575  51930     73  3   0x1100090  kqread        syslogd
 51930  431972      1      0  3    0x100082  sbwait        syslogd
  5647  283061      1      0  3    0x100080  kqread        resolvd
 71375  142827  89351     77  3    0x100092  kqread        dhcpleased
 28831  440458  89351     77  3    0x100092  kqread        dhcpleased
 89351  383620      1      0  3        0x80  kqread        dhcpleased
 29751  443132      0      0  3     0x14200  bored         smr
 65617  475742      0      0  2     0x14200                zerothread
 14893  510591      0      0  3     0x14200  aiodoned      aiodoned
 54765   23891      0      0  3     0x14200  syncer        update
  5027  109561      0      0  3     0x14200  cleaner       cleaner
 84386  321354      0      0  3     0x14200  reaper        reaper
 43670  349819      0      0  3     0x14200  pgdaemon      pagedaemon
 22391  123642      0      0  3     0x14200  bored         viomb
 90830  497855      0      0  3  0x40014200  acpi0         acpi0
 78023  424603      0      0  3     0x14200  bored         softnet0
 78657  158226      0      0  3     0x14200  bored         systqmp
 97649  207169      0      0  3     0x14200  bored         systq
 50078  390155      0      0  3  0x40014200  tmoslp        softclock
 43411  252336      0      0  3  0x40014200                idle0
     1  201175      0      0  3     0x80082  wait          init
     0       0     -1      0  3  0x10010200  scheduler     swapper
ddb> show all locks
No such command
ddb> show malloc
           Type InUse  MemUse  HighUse   Limit  Requests Type Lim
         devbuf 10205  11054K   12679K 166960K     13971        0
            pcb    18     16K      19K 166960K       597        0
         rtable   195      9K       9K 166960K       530        0
             pf    36     14K      17K 166960K       183        0
         ifaddr    37      6K       7K 166960K       128        0
        ifgroup    52      2K       2K 166960K       211        0
         sysctl     4      1K       9K 166960K        12        0
       counters    35     18K      18K 166960K       134        0
       ioctlops     0      0K       4K 166960K       393        0
            iov     0      0K      16K 166960K        52        0
          mount     1      1K       1K 166960K         1        0
            log     0      0K       0K 166960K         4        0
         vnodes  1496     94K      95K 166960K      2650        0
      UFS quota     1     32K      32K 166960K         1        0
      UFS mount     5     36K      36K 166960K         5        0
            shm     2      2K       6K 166960K        15        0
         VM map     2      1K       1K 166960K         2        0
            sem    12      0K       0K 166960K       112        0
        dirhash    63     11K      14K 166960K       999        0
           ACPI  1692    195K     286K 166960K     12470        0
      file desc    15     53K      81K 166960K      1375        0
          sigio     0      0K       0K 166960K        20        0
           proc    61     59K      75K 166960K       629        0
        subproc    72      4K       4K 166960K        83        0
    NFS srvsock     1      0K       0K 166960K         1        0
     NFS daemon     1     16K      16K 166960K         1        0
    ip_moptions     0      0K       0K 166960K       213        0
       in_multi    76      5K       7K 166960K       176        0
    ether_multi     1      0K       0K 166960K        16        0
            mrt     1      0K       0K 166960K        23        0
    ISOFS mount     1     32K      32K 166960K         1        0
  MSDOSFS mount     1     16K      16K 166960K         1        0
           ttys   223    996K     996K 166960K       223        0
           exec     0      0K       1K 166960K       657        0
   fusefs mount     1     32K      32K 166960K         1        0
     pfkey data     0      0K       0K 166960K         5        0
            tdb     3      0K       0K 166960K         3        0
        VM swap     8     62K      64K 166960K        10        0
       UVM amap   215    150K     173K 166960K     14786        0
       UVM aobj    69      7K       7K 166960K        73        0
     pinsyscall    36     72K      89K 166960K      2566        0
        memdesc     1      4K       4K 166960K         1        0
    crypto data     1      1K       1K 166960K         1        0
    ip6_options     0      0K       0K 166960K       117        0
            NDP    12      0K       1K 166960K        89        0
           temp    75   8672K    8800K 166960K     61420        0
         kqueue    13     20K      32K 166960K       321        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      181    0      177     3     0     3     3     0     8    2
rtentry    136      157    0       80     4     0     4     4     0     8    0
unpcb      144     1114    0     1099     9     5     4     6     0     8    3
syncache   336       22    0       22     2     1     1     1     0     8    1
tcpqe       32       15    0       15     1     0     1     1     0     8    1
tcpcb      736      707    0      701     8     0     8     8     0     8    7
arp         96       22    0        7     1     0     1     1     0     8    0
ipq         40        9    0        9     1     0     1     1     0     8    1
ipqe        40       11    0       11     1     0     1     1     0     8    1
inpcb      328     1831    0     1821    13     4     9    13     0     8    7
ip6q        72        3    0        2     1     0     1     1     0     8    0
ip6af       40        4    0        3     1     0     1     1     0     8    0
nd6        112       33    0       17     1     0     1     1     0     8    0
pkpcb       40       11    0       11     1     0     1     1     0     8    1
kcovpl      48        9    0        1     1     0     1     1     0     8    0
mppekey    1024       2    0        2     1     0     1     1     0     8    1
ppxss      1072      84    0       82     2     1     1     1     0     8    0
pppxif     1384      12    0       12     1     0     1     1     0     8    1
pfstscr     40        1    0        1     1     0     1     1     0     8    1
pfstitem    24        6    0        2     1     0     1     1     0     8    0
pfstkey    128        8    0        2     1     0     1     1     0     8    0
pfstate    384        5    0        3     1     0     1     1     0     8    0
pfrule     1344       6    0        6     1     0     1     1     0     8    1
rttmr      136        6    0        6     1     0     1     1     0     8    1
art_heap8  4096       3    0        0     3     0     3     3     0     8    0
art_heap4  256      786    0      445    31     1    30    31     0     8    5
art_table   40      789    0      445     5     0     5     5     0     8    0
art_node    32      157    0       87     1     0     1     1     0     8    0
sysvmsgpl   40        9    0        7     1     0     1     1     0     8    0
semupl     112        2    0        2     2     1     1     1     0     8    1
semapl     112      108    0       98     1     0     1     1     0     8    0
shmpl      112       68    0        4     2     0     2     2     0     8    0
dirhash    1024     347    0      313     5     0     5     5     0     8    0
dino2pl    256     3898    0     2404    95     0    95    95     0     8    0
ffsino     256     3898    0     2404    95     0    95    95     0     8    0
nchpl      144     5834    0     4143    64     0    64    64     0     8    0
rtmask      32       15    0       14     2     1     1     1     0     8    0
vnodes     216     4790    0        0   267     0   267   267     0     8    0
namei      1024   19952    0    19951     2     1     1     1     0     8    0
vcpupl     3904       2    0        0     1     0     1     1     0     8    0
vmpool     800        2    0        0     1     0     1     1     0     8    0
kstatmem   264      138    0      114     3     0     3     3     0     8    1
acpiwqpl    32        2    0        2     1     0     1     1     1     8    1
scsiplug    72        8    0        8     1     0     1     1     0     8    1
scxspl     216    20177    0    20177    10     2     8     8     1     8    8
plimitpl   152      494    0      478     1     0     1     1     0     8    0
sigapl     424     1702    0     1642     9     1     8     8     0     8    0
knotepl    120    84742    0    84695    32    21    11    17     0     8    8
kqueuepl   184      574    0      565     3     0     3     3     0     8    2
pipepl     304      253    0      226     3     0     3     3     0     8    0
fdescpl    448     1666    0     1639     4     0     4     4     0     8    0
filepl     120    11380    0    11176    21     6    15    17     0     8    7
lockfpl    104      694    0      692     2     0     2     2     0     8    1
lockfspl    48      197    0      195     1     0     1     1     0     8    0
sessionpl  144       42    0       34     1     0     1     1     0     8    0
pgrppl      48       59    0       43     1     0     1     1     0     8    0
ucredpl    104     1834    0     1822     1     0     1     1     0     8    0
zombiepl   144     2552    0     2547     1     0     1     1     0     8    0
processpl  1152    1702    0     1642     5     0     5     5     0     8    0
procpl     664     3959    0     3891     9     0     9     9     0     8    2
sosppl     176       10    0       10     1     0     1     1     0     8    1
sockpl     552     3247    0     3218    21    11    10    12     0     8    7
mcl64k     65536    158    0      158     2     1     1     1     0     8    1
mcl16k     16384      8    0        8     1     0     1     1     0     8    1
mcl12k     12288      3    0        3     1     0     1     1     0     8    1
mcl9k      9216       3    0        3     1     0     1     1     0     8    1
mcl8k      8192      55    0       55     2     1     1     1     0     8    1
mcl4k      4096    4400    0     4345    14     6     8    14     0     8    0
mcl2k      2048    1858    0     1857     6     3     3     3     0     8    2
mtagpl      96       38    0       24     1     0     1     1     0     8    0
mbufpl     256    18711    0    18615    30     9    21    27     0     8    8
bufpl      280     8465    0     2244   445     0   445   445     0     8    0
anonpl      24   265642    0   261732    62    11    51    51     0   187   14
amapchunkpl 152   56766    0    56301    41     5    36    36     0   158   13
amappl16   200     4745    0     4709    33    19    14    15     0     8    8
amappl15   192        5    0        5     2     1     1     1     0     8    1
amappl14   184        6    0        6     2     1     1     1     0     8    1
amappl13   176      416    0      415     1     0     1     1     0     8    0
amappl12   168     2124    0     2087     2     0     2     2     0     8    0
amappl11   160        9    0        9     1     1     0     1     0     8    0
amappl10   152       43    0       32     1     0     1     1     0     8    0
amappl9    144      255    0      255     1     1     0     1     0     8    0
amappl8    136       22    0       20     1     0     1     1     0     8    0
amappl7    128       99    0       98     1     0     1     1     0     8    0
amappl6    120      296    0      285     1     0     1     1     0     8    0
amappl5    112       92    0       84     1     0     1     1     0     8    0
amappl4    104      476    0      450     1     0     1     1     0     8    0
amappl3     96     9970    0     9880     4     0     4     4     0     8    1
amappl2     88      686    0      631     2     0     2     2     0     8    0
amappl1     80    18629    0    18103    13     0    13    13     0     8    0
amappl      88    13726    0    13579     5     0     5     5     0    92    0
uvmvnodes   80      134    0        0     3     0     3     3     0     8    0
dma65536   65536      2    0        2     1     0     1     1     0     8    1
dma8192    8192       2    0        2     1     0     1     1     0     8    1
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      257    0      257     2     1     1     1     0     8    1
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       72    0        4     2     0     2     2     0     8    0
uaddrrnd    24     1666    0     1639     1     0     1     1     0     8    0
uaddrbest   32        2    0        0     1     0     1     1     0     8    0
uaddr       24     1666    0     1639     1     0     1     1     0     8    0
vmmpekpl   168    16888    0    16845     3     0     3     3     0     8    0
vmmpepl    168   116738    0   115058    96     1    95    95     0   357   10
vmsppl     368     1665    0     1639     4     1     3     4     0     8    0
rwobjpl     40    34397    0    33366    14     0    14    14     0     8    1
pdppl      4096    3343    0     3280   120    51    69    75     0     8    6
pvpl        32   756396    0   747372   140    15   125   125     0   265   32
pmappl     216     1667    0     1639     2     0     2     2     0     8    0
extentpl    40       45    0       27     1     0     1     1     0     8    0
phpool     112      430    0       77    11     0    11    11     0     8    0
ddb> machine ddbcpu 0
No such command
ddb> trace
ufsdirhash_build(fffffd807e910800) at ufsdirhash_build+0x9e8 sys/ufs/ufs/ufs_dirhash.c:213
ufs_lookup() at ufs_lookup+0x388 sys/ufs/ufs/ufs_lookup.c:198
VOP_LOOKUP(fffffd806c2a3e80,ffff80003ca256e8,ffff80003ca25718) at VOP_LOOKUP+0x6e sys/kern/vfs_vops.c:85
vfs_lookup(ffff80003ca256b8) at vfs_lookup+0x921 sys/kern/vfs_lookup.c:566
namei(ffff80003ca256b8) at namei+0x7ca sys/kern/vfs_lookup.c:250
domknodat(ffff80002a8134f0,ffffff9c,200000000280,2000,1e5f) at domknodat+0xb4 sys/kern/vfs_syscalls.c:1592
syscall(ffff80003ca258a0) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80003ca258a0) at syscall+0x962 sys/arch/amd64/amd64/trap.c:775
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xe83e5d1c2e0, count: -8
ddb> machine ddbcpu 1
No such command
ddb> trace
ufsdirhash_build(fffffd807e910800) at ufsdirhash_build+0x9e8 sys/ufs/ufs/ufs_dirhash.c:213
ufs_lookup() at ufs_lookup+0x388 sys/ufs/ufs/ufs_lookup.c:198
VOP_LOOKUP(fffffd806c2a3e80,ffff80003ca256e8,ffff80003ca25718) at VOP_LOOKUP+0x6e sys/kern/vfs_vops.c:85
vfs_lookup(ffff80003ca256b8) at vfs_lookup+0x921 sys/kern/vfs_lookup.c:566
namei(ffff80003ca256b8) at namei+0x7ca sys/kern/vfs_lookup.c:250
domknodat(ffff80002a8134f0,ffffff9c,200000000280,2000,1e5f) at domknodat+0xb4 sys/kern/vfs_syscalls.c:1592
syscall(ffff80003ca258a0) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80003ca258a0) at syscall+0x962 sys/arch/amd64/amd64/trap.c:775
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xe83e5d1c2e0, count: -8

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/09 04:14 openbsd bf8f637750de fc20f974 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: ufsdirhash_build
* Struck through repros no longer work on HEAD.