syzbot


uvm_fault: ufs_direnter (6)

Status: upstream: reported on 2026/04/01 04:53
Reported-by: syzbot+ea762fbfc40d721c3e07@syzkaller.appspotmail.com
First crash: 113d, last: 30d
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
openbsd uvm_fault: ufs_direnter (2) -1 1 852d 852d 0/4 auto-obsoleted due to no activity on 2024/06/20 10:15
openbsd uvm_fault: ufs_direnter -1 1 1392d 1392d 0/4 auto-obsoleted due to no activity on 2022/12/28 17:05
openbsd uvm_fault: ufs_direnter (4) -1 1 532d 532d 0/4 auto-obsoleted due to no activity on 2025/05/07 09:55
openbsd uvm_fault: ufs_direnter (3) -1 3 676d 678d 0/4 auto-obsoleted due to no activity on 2024/12/14 08:05
openbsd uvm_fault: ufs_direnter (5) -1 1 313d 313d 0/4 auto-obsoleted due to no activity on 2025/12/12 09:01

Sample crash report:
login: uvm_fault(0xffffffff83a71ae8, 0xffff80002454200c, 0, 1) -> d
kernel: page fault trap, code=0
Stopped at      ufs_direnter+0x23b:     movl    0(%r14),%r15d
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
*503132  89684      0         0x2          0    0  syz-executor
ufs_direnter(fffff8806b448bf8,fffff88068112980,ffff8000318ad580,ffff8000318ad8b0,fffff88067310aa0) at ufs_direnter+0x23b sys/ufs/ufs/ufs_lookup.c:764
ufs_mkdir(ffff8000318ad720) at ufs_mkdir+0x5d5 sys/ufs/ufs/ufs_vnops.c:1179
VOP_MKDIR(fffff8806b448bf8,ffff8000318ad880,ffff8000318ad8b0,ffff8000318ad7b0) at VOP_MKDIR+0x101 sys/kern/vfs_vops.c:394
domkdirat(ffff80003c8eaa80,ffffff9c,7bb1ed93c140,1ff) at domkdirat+0x179 sys/kern/vfs_syscalls.c:3062
syscall(ffff8000318ada20) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff8000318ada20) at syscall+0x962 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7bb1ed93c1e0, count: 9
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(0xffffffff83a71ae8, 0xffff80002454200c, 0, 1) -> d
ddb> trace
ufs_direnter(fffff8806b448bf8,fffff88068112980,ffff8000318ad580,ffff8000318ad8b0,fffff88067310aa0) at ufs_direnter+0x23b sys/ufs/ufs/ufs_lookup.c:764
ufs_mkdir(ffff8000318ad720) at ufs_mkdir+0x5d5 sys/ufs/ufs/ufs_vnops.c:1179
VOP_MKDIR(fffff8806b448bf8,ffff8000318ad880,ffff8000318ad8b0,ffff8000318ad7b0) at VOP_MKDIR+0x101 sys/kern/vfs_vops.c:394
domkdirat(ffff80003c8eaa80,ffffff9c,7bb1ed93c140,1ff) at domkdirat+0x179 sys/kern/vfs_syscalls.c:3062
syscall(ffff8000318ada20) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff8000318ada20) at syscall+0x962 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7bb1ed93c1e0, count: -6
ddb> show registers
rdi                                0
rsi                                0
rbp               0xffff8000318ad570
rbx               0xfffff88007ffd750
rdx                                0
rcx               0xfffff8806bafed00
rax               0xffff80003c8eaa80
r8                0xffffffffffffffff
r9                                 0
r10               0x4c1183680060f9ce
r11               0x43bc4b800fd64b02
r12               0xfffff8806b9ce500
r13               0xfffff8806b9cf200
r14               0xffff80002454200c
r15                                0
rip               0xffffffff8227188b    ufs_direnter+0x23b
cs                               0x8
rflags                       0x10246    __ALIGN_SIZE+0xf246
rsp               0xffff8000318ad4d0
ss                                 0
ufs_direnter+0x23b:     movl    0(%r14),%r15d
ddb> show proc
PROC (syz-executor) tid=503132 pid=89684 tcnt=1 stat=onproc
    flags process=2<EXEC> proc=0
    runpri=17, usrpri=81, slppri=17, nice=20
    wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0
    forw=0xffffffffffffffff, list=0xffff80002a756a70,0xffff80003c8ead28
    process=0xffff807fffffb198 user=0xffff8000318a8000, vmspace=0xfffff88076067cf0
    estcpu=36, cpticks=1, pctcpu=0.0, user=0, sys=1, intr=0
ddb> ps
   PID     TID   PPID    UID  S       FLAGS  WAIT          COMMAND
 18375   85850  30467      0  2           0                syz-executor
 18375  210530  30467      0  3   0x4000080  fsleep        syz-executor
 90800  230706  90458     -1  2        0x10                syz-executor
 90800  382635  90458     -1  3   0x4000090  ttyretype     syz-executor
 90800  367015  90458     -1  3   0x4000090  msgwait       syz-executor
 42329   76398  56834      0  3        0x80  nanoslp       syz-executor
 42329  316283  56834      0  3   0x4000080  lockf         syz-executor
 42329   16410  56834      0  3   0x4000080  lockf         syz-executor
 42329  393573  56834      0  3   0x4000080  fsleep        syz-executor
*89684  503132  34809      0  7         0x2                syz-executor
  2322  396920      1      0  3    0x100083  ttyin         getty
 72792  129693      0      0  3     0x14200  acct          acct
 24813  211857      0      0  3     0x14280  nfsidl        nfsio
  7327  317191      0      0  3     0x14280  nfsidl        nfsio
 51448  453847      0      0  3     0x14280  nfsidl        nfsio
 43249    5155      0      0  3     0x14280  nfsidl        nfsio
 35836  335369      0      0  3     0x14280  nfsidl        nfsio
 62728  250206      0      0  3     0x14280  nfsidl        nfsio
 89216  183948      0      0  3     0x14280  nfsidl        nfsio
 13673  281918      0      0  3     0x14280  nfsidl        nfsio
 32161  356906      0      0  3     0x14280  nfsidl        nfsio
 72618  447378      0      0  3     0x14280  nfsidl        nfsio
 86441  100464      0      0  3     0x14280  nfsidl        nfsio
 85553  336167      0      0  3     0x14280  nfsidl        nfsio
 73399  275677      0      0  3     0x14280  nfsidl        nfsio
 94516  369917      0      0  3     0x14280  nfsidl        nfsio
 53316  353266      0      0  3     0x14280  nfsidl        nfsio
  7626   83119      0      0  3     0x14280  nfsidl        nfsio
  2343  121211      0      0  3     0x14280  nfsidl        nfsio
 29022  112206      0      0  3     0x14280  nfsidl        nfsio
 65987  460513      0      0  3     0x14280  nfsidl        nfsio
 90589   64907      0      0  3     0x14280  nfsidl        nfsio
 94368  299880  34809      0  3        0x82  wait          syz-executor
 30467   57569  34809      0  3        0x82  nanoslp       syz-executor
 61210  295838  34809      0  3        0x82  nanoslp       syz-executor
 56834  472463  34809      0  3        0x82  nanoslp       syz-executor
 90458  493100  34809      0  3        0x82  nanoslp       syz-executor
 15571  364622  34809      0  3        0x82  wait          syz-executor
 34809  366242      1      0  3        0x82  wait          syz-executor
 20434  111530  38479      0  3        0x98  kqread        sshd-session
 38479  240443      1      0  3        0x92  kqread        sshd-session
 44600  180290      1     73  2   0x1100090                syslogd
 67564  395558      0      0  3     0x14200  bored         smr
 90293  343579      0      0  2     0x14200                zerothread
 29029  338546      0      0  3     0x14200  aiodoned      aiodoned
 83688  344473      0      0  3     0x14200  syncer        update
  5028  114684      0      0  3     0x14200  cleaner       cleaner
 72892   38251      0      0  3     0x14200  reaper        reaper
  8970  119250      0      0  3     0x14200  pgdaemon      pagedaemon
 17532   36315      0      0  3     0x14200  bored         viomb
 33400  309790      0      0  3  0x40014200  acpi0         acpi0
 51175  157032      0      0  3     0x14200  bored         softnet0
 48750  286679      0      0  3     0x14200  smrbar        systqmp
 37638  262908      0      0  3     0x14200  bored         systq
 20917   44428      0      0  3  0x40014200  tmoslp        softclock
 29117  246954      0      0  3  0x40014200                idle0
     1  269127      0      0  3        0x82  wait          init
     0       0     -1      0  3     0x10200  scheduler     swapper
ddb> show all locks
No such command
ddb> show malloc
           Type InUse  MemUse  HighUse   Limit  Requests Type Lim
         devbuf 11058  12168K   12412K 166960K     12695        0
            pcb    17     14K      16K 166960K       154        0
         rtable   239      7K       7K 166960K       771        0
             pf    34     13K      18K 166960K        96        0
         ifaddr    41      7K       7K 166960K       110        0
        ifgroup    55      2K       2K 166960K       133        0
         sysctl     3      1K       9K 166960K        10        0
       counters    34     17K      18K 166960K        60        0
       ioctlops     0      0K       4K 166960K       151        0
            iov     0      0K      12K 166960K        14        0
          mount     1      1K       1K 166960K         1        0
            log     0      0K       0K 166960K         4        0
         vnodes  1386     87K      88K 166960K      2095        0
      UFS quota     1     32K      32K 166960K         1        0
      UFS mount     5     36K      36K 166960K         5        0
            shm     2     10K      14K 166960K         9        0
         VM map     2      1K       1K 166960K         2        0
            sem    12      0K       1K 166960K        23        0
        dirhash    12      2K       2K 166960K        18        0
           ACPI  1692    195K     286K 166960K     12470        0
      file desc    16     57K     240K 166960K       689        0
          sigio     0      0K       0K 166960K        83        0
           proc    20     25K      91K 166960K       877        0
        subproc    72      4K       4K 166960K       181        0
    NFS srvsock     1      0K       0K 166960K         1        0
     NFS daemon     1     16K      16K 166960K         1        0
    ip_moptions     0      0K       0K 166960K        32        0
       in_multi    89      6K       7K 166960K       247        0
    ether_multi     1      0K       0K 166960K         3        0
            mrt     0      0K       0K 166960K        19        0
    ISOFS mount     1     32K      32K 166960K         1        0
  MSDOSFS mount     1     16K      16K 166960K         1        0
           ttys   217    970K     970K 166960K       217        0
           exec     0      0K       1K 166960K       603        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   157     92K     160K 166960K      6938        0
       UVM aobj    15      2K       2K 166960K        15        0
     pinsyscall    24     48K      94K 166960K      2102        0
        memdesc     1      4K       4K 166960K         1        0
    crypto data     1      1K       1K 166960K         1        0
    ip6_options     0      0K       0K 166960K        14        0
            NDP    14      0K       2K 166960K        77        0
           temp    51   9114K    9175K 166960K     16212        0
         kqueue     6     10K      26K 166960K        78        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       81    0       81     1     0     1     1     0     8    1
rtentry    136      258    0      152     4     0     4     4     0     8    0
unpcb      144      224    0      217     2     0     2     2     0     8    1
syncache   336        7    0        7     1     0     1     1     0     8    1
tcpcb      736      194    0      192     7     0     7     7     0     8    6
arp         96       45    0       26     1     0     1     1     0     8    0
inpcb      328      643    0      638     7     0     7     7     0     8    5
ip6q        72        2    0        0     1     0     1     1     0     8    0
ip6af       40        2    0        0     1     0     1     1     0     8    0
nd6        112       65    0       43     1     0     1     1     0     8    0
pkpcb       40        6    0        6     1     0     1     1     0     8    1
kcovpl      48       20    0       12     1     0     1     1     0     8    0
ppxss      1072      12    0       12     1     0     1     1     0     8    1
pfstscr     40        1    0        1     1     0     1     1     0     8    1
pfsrclim   320        1    0        1     1     0     1     1     0     8    1
pftag       88        1    0        0     1     0     1     1     0     8    0
pfstkey    128        2    0        2     1     0     1     1     0     8    1
pfstate    384        1    0        1     1     0     1     1     0     8    1
pfrule     1360       4    0        4     1     0     1     1     0     8    1
rttmr      136        1    0        1     1     0     1     1     0     8    1
art_heap8  4096       2    0        0     2     0     2     2     0     8    0
art_heap4  256     1082    0      643    32     0    32    32     0     8    4
art_table   40     1084    0      643     6     0     6     6     0     8    0
art_node    32      258    0      160     1     0     1     1     0     8    0
sysvmsgpl   40        5    0        3     1     0     1     1     0     8    0
semupl     112        2    0        2     1     0     1     1     0     8    1
semapl      72       19    0        9     1     0     1     1     0     8    0
shmpl      112       12    0        0     1     0     1     1     0     8    0
dirhash    1024      21    0        4     3     0     3     3     0     8    0
dino2pl    256     2483    0      995    94     0    94    94     0     8    0
ffsino     256     2483    0      995    94     0    94    94     0     8    0
nchpl      144     3231    0     1496    65     0    65    65     0     8    0
vnodes     216     2943    0        0   164     0   164   164     0     8    0
namei      1024   11785    0    11784     2     0     2     2     0     8    1
acpiwqpl    32        1    0        1     1     0     1     1     1     8    1
kstatmem   264       73    0       48     2     0     2     2     0     8    0
scsiplug    72        1    0        1     1     0     1     1     0     8    1
scxspl     216    15409    0    15409     8     0     8     8     1     8    8
plimitpl   152      128    0      113     1     0     1     1     0     8    0
sigapl     424      972    0      917     8     0     8     8     0     8    0
knotepl    120    16230    0    16202    10     0    10    10     0     8    8
kqueuepl   184      150    0      144     1     0     1     1     0     8    0
pipepl     304      191    0      164     3     0     3     3     0     8    0
fdescpl    448      938    0      917     5     0     5     5     0     8    1
filepl     120     5097    0     4903    10     0    10    10     0     8    2
lockfpl    104      194    0      190     1     0     1     1     0     8    0
lockfspl    48       88    0       86     1     0     1     1     0     8    0
sessionpl  144       52    0       47     1     0     1     1     0     8    0
pgrppl      48       79    0       66     1     0     1     1     0     8    0
ucredpl    104     1268    0     1258     1     0     1     1     0     8    0
zombiepl   144      921    0      917     1     0     1     1     0     8    0
processpl  1152     972    0      917     5     0     5     5     0     8    0
procpl     664     1521    0     1460     7     0     7     7     0     8    0
sosppl     176        5    0        5     1     0     1     1     0     8    1
sockpl     552      962    0      950     8     0     8     8     0     8    6
mcl64k     65536     33    0       31     1     0     1     1     0     8    0
mcl16k     16384      2    0        2     1     0     1     1     0     8    1
mcl8k      8192      72    0       71     1     0     1     1     0     8    0
mcl4k      4096    3019    0     2966    14     0    14    14     0     8    6
mcl2k      2048     615    0      614     1     0     1     1     0     8    0
mtagpl      96       10    0        6     1     0     1     1     0     8    0
mbufpl     256     8899    0     8723    18     0    18    18     0     8    5
bufpl      272     6619    0      404   415     0   415   415     0     8    0
anonpl      24   148090    0   145855    59     0    59    59     0    88   22
amapchunkpl 152   21603    0    21219    29     0    29    29     0   158   13
amappl16   200     2321    0     2300    22    10    12    16     0     8    8
amappl15   192        5    0        5     1     0     1     1     0     8    1
amappl14   184      554    0      554     1     0     1     1     0     8    1
amappl13   176      140    0      136     1     0     1     1     0     8    0
amappl12   168     1231    0     1211     2     0     2     2     0     8    0
amappl11   160        6    0        6     1     0     1     1     0     8    1
amappl10   152       62    0       60     1     0     1     1     0     8    0
amappl9    144      274    0      273     1     0     1     1     0     8    0
amappl8    136      142    0      142     1     0     1     1     0     8    1
amappl7    128      167    0      162     1     0     1     1     0     8    0
amappl6    120      300    0      300     1     0     1     1     0     8    1
amappl5    112       91    0       87     1     0     1     1     0     8    0
amappl4    104      298    0      289     1     0     1     1     0     8    0
amappl3     96     4201    0     4119     3     0     3     3     0     8    0
amappl2     88      628    0      599     2     0     2     2     0     8    0
amappl1     80    13282    0    12974    13     0    13    13     0     8    2
amappl      88     5928    0     5799     4     0     4     4     0    92    0
uvmvnodes   80      112    0        0     3     0     3     3     0     8    0
dma4096    4096       1    0        1     1     0     1     1     0     8    1
dma1024    1024       1    0        0     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       14    0        0     1     0     1     1     0     8    0
uaddrrnd    24      938    0      917     1     0     1     1     0     8    0
uaddrbest   32        2    0        0     1     0     1     1     0     8    0
uaddr       24      938    0      917     1     0     1     1     0     8    0
vmmpekpl   168     8966    0     8926     3     0     3     3     0     8    0
vmmpepl    168    67221    0    66034    91     0    91    91     0   357   27
vmsppl     368      937    0      917     4     0     4     4     0     8    1
rwobjpl     40    20760    0    20139    13     0    13    13     0     8    0
pdppl      4096    1882    0     1834   104    50    54    80     0     8    6
pvpl        32   403784    0   397152   130     0   130   130     0   265   52
pmappl     216      937    0      917     3     0     3     3     0     8    1
extentpl    40       45    0       27     1     0     1     1     0     8    0
phpool     112      803    0       50    22     0    22    22     0     8    0
ddb> machine ddbcpu 0
No such command
ddb> trace
ufs_direnter(fffff8806b448bf8,fffff88068112980,ffff8000318ad580,ffff8000318ad8b0,fffff88067310aa0) at ufs_direnter+0x23b sys/ufs/ufs/ufs_lookup.c:764
ufs_mkdir(ffff8000318ad720) at ufs_mkdir+0x5d5 sys/ufs/ufs/ufs_vnops.c:1179
VOP_MKDIR(fffff8806b448bf8,ffff8000318ad880,ffff8000318ad8b0,ffff8000318ad7b0) at VOP_MKDIR+0x101 sys/kern/vfs_vops.c:394
domkdirat(ffff80003c8eaa80,ffffff9c,7bb1ed93c140,1ff) at domkdirat+0x179 sys/kern/vfs_syscalls.c:3062
syscall(ffff8000318ada20) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff8000318ada20) at syscall+0x962 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7bb1ed93c1e0, count: -6
ddb> machine ddbcpu 1
No such command
ddb> trace
ufs_direnter(fffff8806b448bf8,fffff88068112980,ffff8000318ad580,ffff8000318ad8b0,fffff88067310aa0) at ufs_direnter+0x23b sys/ufs/ufs/ufs_lookup.c:764
ufs_mkdir(ffff8000318ad720) at ufs_mkdir+0x5d5 sys/ufs/ufs/ufs_vnops.c:1179
VOP_MKDIR(fffff8806b448bf8,ffff8000318ad880,ffff8000318ad8b0,ffff8000318ad7b0) at VOP_MKDIR+0x101 sys/kern/vfs_vops.c:394
domkdirat(ffff80003c8eaa80,ffffff9c,7bb1ed93c140,1ff) at domkdirat+0x179 sys/kern/vfs_syscalls.c:3062
syscall(ffff8000318ada20) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff8000318ada20) at syscall+0x962 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7bb1ed93c1e0, count: -6

Crashes (10):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/23 05:58 openbsd aa0f58e8a9e2 62cc6db3 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: ufs_direnter
2026/06/11 20:19 openbsd 28cce1e713d0 d93a6ab6 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: ufs_direnter
2026/05/24 01:16 openbsd 19a448b47c50 c69befb3 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore uvm_fault: ufs_direnter
2026/05/01 16:54 openbsd bedf3632bee6 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: ufs_direnter
2026/05/01 04:03 openbsd d15801fa3705 340bcdf0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: ufs_direnter
2026/04/27 16:30 openbsd 80ba1745ccfd 0f700595 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore uvm_fault: ufs_direnter
2026/04/23 12:50 openbsd 7a2e62a4900c 4c3406dc .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: ufs_direnter
2026/04/22 23:22 openbsd 18dcbfb1f230 b10da5ec .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore uvm_fault: ufs_direnter
2026/04/08 09:55 openbsd 7ed665c6a362 4b3d9a38 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: ufs_direnter
2026/04/01 04:53 openbsd 9f2496a89535 4b3d9a38 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore uvm_fault: ufs_direnter
* Struck through repros no longer work on HEAD.