uvm_fault: dtioctl

Status: upstream: reported on 2026/07/14 19:18
Reported-by: syzbot+465d761472d27f70d7a8@syzkaller.appspotmail.com
First crash: 37d, last: 7h50m

Sample crash report:
uvm_fault(0xffffef006d18d2f0, 0x8621, 0, 1) -> e
kernel: page fault trap, code=0
Stopped at      dtioctl+0x489:  movl    0x28(%r12),%r13d
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
*507721  95923      0           0  0x4000000    0  syz-executor
dtioctl(11e5f,80184404,ffff80002a7a5040,81,ffff80003c8fba10) at dtioctl+0x489 dt_ioctl_probe_enable sys/dev/dt/dt_dev.c:613 [inline]
dtioctl(11e5f,80184404,ffff80002a7a5040,81,ffff80003c8fba10) at dtioctl+0x489 sys/dev/dt/dt_dev.c:328
VOP_IOCTL(ffffef005ddf0cf8,80184404,ffff80002a7a5040,81,ffffef0007ffd680,ffff80003c8fba10) at VOP_IOCTL+0xa3 sys/kern/vfs_vops.c:264
vn_ioctl(ffffef006d480108,80184404,ffff80002a7a5040,ffff80003c8fba10) at vn_ioctl+0xea sys/kern/vfs_vnops.c:537
sys_ioctl(ffff80003c8fba10,ffff80002a7a5210,ffff80002a7a5160) at sys_ioctl+0x660 sys/kern/sys_generic.c:-1
syscall(ffff80002a7a5210) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80002a7a5210) at syscall+0x962 sys/arch/amd64/amd64/trap.c:791
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7b1a0e9f0a0, 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(0xffffef006d18d2f0, 0x8621, 0, 1) -> e
ddb> show kasan
No such command
ddb> trace
dtioctl(11e5f,80184404,ffff80002a7a5040,81,ffff80003c8fba10) at dtioctl+0x489 dt_ioctl_probe_enable sys/dev/dt/dt_dev.c:613 [inline]
dtioctl(11e5f,80184404,ffff80002a7a5040,81,ffff80003c8fba10) at dtioctl+0x489 sys/dev/dt/dt_dev.c:328
VOP_IOCTL(ffffef005ddf0cf8,80184404,ffff80002a7a5040,81,ffffef0007ffd680,ffff80003c8fba10) at VOP_IOCTL+0xa3 sys/kern/vfs_vops.c:264
vn_ioctl(ffffef006d480108,80184404,ffff80002a7a5040,ffff80003c8fba10) at vn_ioctl+0xea sys/kern/vfs_vnops.c:537
sys_ioctl(ffff80003c8fba10,ffff80002a7a5210,ffff80002a7a5160) at sys_ioctl+0x660 sys/kern/sys_generic.c:-1
syscall(ffff80002a7a5210) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80002a7a5210) at syscall+0x962 sys/arch/amd64/amd64/trap.c:791
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7b1a0e9f0a0, count: -6
ddb> show registers
rdi                                0
rsi                                0
rbp               0xffff80002a7a4e70
rbx                            0x15f
rdx                                0
rcx                             0x81
rax               0xffff80003c8fba10
r8                0xffff80003c8fba10
r9                0xffff80003c8fba10
r10               0xf78746da806b4e74
r11               0x9be2e233111a69bc
r12                           0x85f9    __ALIGN_SIZE+0x75f9
r13                       0x6a87192e
r14               0xffff80002a7a5040
r15               0xffff8000016f1d00
rip               0xffffffff81fb9419    dtioctl+0x489
cs                               0x8
rflags                       0x10206    __ALIGN_SIZE+0xf206
rsp               0xffff80002a7a4df0
ss                              0x10
dtioctl+0x489:  movl    0x28(%r12),%r13d
ddb> show proc
PROC (syz-executor) tid=507721 pid=95923 tcnt=3 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=0xffff80003c8fad18,0xffff80003c8fbcb8
    process=0xffff800045ff8918 user=0xffff80002a7a0000, vmspace=0xffffef006d18d2f0
    estcpu=36, cpticks=1, pctcpu=0.0, user=0, sys=1, intr=0
ddb> ps
   PID     TID   PPID   UID  S      PRLAGS     PFLAGS WAIT      COMMAND
 95923  338321  58432     0  2           0          0           syz-executor
*95923  507721  58432     0  7           0  0x4000000           syz-executor
 95923  518813  58432     0  3           0  0x4000080 fsleep    syz-executor
  4261  362099      1     0  3           0       0x80 nanoslp   init
 21080   40283  34241     0  3           0       0x80 nanoslp   syz-executor
 21080  120270  34241     0  3           0  0x4000080 lockf     syz-executor
 21080  344571  34241     0  3           0  0x4000080 lockf     syz-executor
 21080  257676  34241     0  3           0  0x4000080 kqsel     syz-executor
 21080   93519  34241     0  3           0  0x4000080 fsleep    syz-executor
 61178  428457  30815     0  3           0       0x80 nanoslp   syz-executor
 61178  419305  30815     0  3           0  0x4000080 netacc    syz-executor
 61178   72974  30815     0  3           0  0x4000080 fsleep    syz-executor
 61637  148973  61180     0  3           0       0x80 nanoslp   syz-executor
 61637   53263  61180     0  3           0  0x4000080 kqpoll    syz-executor
 61637  308531  61180     0  3           0  0x4000080 fsleep    syz-executor
 61637  143483  61180     0  3           0  0x4000080 fsleep    syz-executor
 53616  199869  73508     0  3         0x2       0x80 nanoslp   syz-executor
 58795   37093      0     0  3     0x14000      0x200 acct      acct
 61180  194916  73508     0  3         0x2       0x80 nanoslp   syz-executor
 58432  471590  73508     0  3         0x2       0x80 nanoslp   syz-executor
 34241  361124  73508     0  3         0x2       0x80 nanoslp   syz-executor
 34150  437227  73508     0  3         0x2       0x80 wait      syz-executor
  1280    1331  73508     0  3         0x2       0x80 wait      syz-executor
 30815  214735  73508     0  3         0x2       0x80 nanoslp   syz-executor
 50199  489763  73508     0  3         0x2       0x80 wait      syz-executor
 73508  383786      1     0  3         0x2       0x80 kqread    syz-executor
 76108  343992      0     0  3     0x14000      0x200 bored     smr
 12755  483933      0     0  2     0x14000      0x200           zerothread
 91666  325954      0     0  3     0x14000      0x200 aiodoned  aiodoned
  2194  151487      0     0  3     0x14000      0x200 syncer    update
 20320   12772      0     0  3     0x14000      0x200 cleaner   cleaner
 29403  230736      0     0  3     0x14000      0x200 reaper    reaper
 16683   85400      0     0  3     0x14000      0x200 pgdaemon  pagedaemon
 71199  213107      0     0  3     0x14000      0x200 bored     viomb
 74597  372850      0     0  3     0x14000 0x40000200 acpi0     acpi0
 15586  370466      0     0  3     0x14000      0x200 bored     softnet0
 25098  263596      0     0  3     0x14000      0x200 smrbar    systqmp
  5156   74119      0     0  3     0x14000      0x200 bored     systq
 26708   70332      0     0  3     0x14000 0x40000200 tmoslp    softclock
 47196  269476      0     0  3     0x14000 0x40000200           idle0
     1  471644      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 11057  12124K   12627K 166960K     12988        0
            pcb    18     13K      14K 166960K       135        0
         rtable   224      7K      10K 166960K       511        0
             pf    30     12K      72K 166960K       125        0
         ifaddr    38      6K       8K 166960K        71        0
        ifgroup    48      2K       2K 166960K       103        0
         sysctl     3      1K       9K 166960K        11        0
       counters    33     17K      18K 166960K        57        0
       ioctlops     0      0K       4K 166960K       212        0
            iov     0      0K      16K 166960K        16        0
          mount     1      1K       1K 166960K         1        0
            log     2      0K       0K 166960K         6        0
         vnodes  1351     85K      85K 166960K      1873        0
      UFS quota     1     32K      32K 166960K         1        0
      UFS mount     5     36K      36K 166960K         5        0
            shm     2      1K       5K 166960K         8        0
         VM map     2      1K       1K 166960K         2        0
            sem    12      0K       0K 166960K        22        0
        dirhash    12      2K       3K 166960K        30        0
           ACPI  1734    201K     291K 166960K     11964        0
      file desc    17     65K      97K 166960K       543        0
          sigio     0      0K       0K 166960K         5        0
           proc    11     17K     124K 166960K       598        0
        subproc    72      4K       4K 166960K        91        0
    NFS srvsock     1      0K       0K 166960K         1        0
     NFS daemon     1     16K      16K 166960K         1        0
    ip_moptions     0      0K       0K 166960K        51        0
       in_multi    84      5K       6K 166960K       129        0
    ether_multi     1      0K       0K 166960K         4        0
            mrt     0      0K       0K 166960K        24        0
    ISOFS mount     1     32K      32K 166960K         1        0
  MSDOSFS mount     1     16K      16K 166960K         1        0
           ttys   229   1023K    1023K 166960K       229        0
           exec     0      0K       1K 166960K       450        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   160     80K     156K 166960K      6422        0
       UVM aobj    17      2K       2K 166960K        17        0
     pinsyscall    19     38K      96K 166960K      1700        0
        memdesc     1      4K       4K 166960K         1        0
    crypto data     1      1K       1K 166960K         1        0
    ip6_options     0      0K       0K 166960K        10        0
            NDP    11      0K       2K 166960K        48        0
           temp    44   9111K    9186K 166960K     18823        0
         kqueue     2      4K      28K 166960K       105        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       63    0       63     1     0     1     1     0     8    1
rtentry    136      152    0       54     5     0     5     5     0     8    0
unpcb      144      221    0      219     1     0     1     1     0     8    0
syncache   336        9    0        9     1     0     1     1     0     8    1
tcpcb      736      168    0      165     7     0     7     7     0     8    6
arp         96       24    0        8     1     0     1     1     0     8    0
ipq         40        9    0        0     1     0     1     1     0     8    0
ipqe        40       44    0       35     1     0     1     1     0     8    0
inpcb      328      466    0      461     6     0     6     6     0     8    5
ip6q        80        3    0        1     1     0     1     1     0     8    0
ip6af       40        4    0        2     1     0     1     1     0     8    0
nd6        112       33    0       12     1     0     1     1     0     8    0
pkpcb       40        4    0        4     1     0     1     1     0     8    1
kcovpl      48       10    0        2     1     0     1     1     0     8    0
mppekey    1024       1    0        1     1     0     1     1     0     8    1
ppxss      1072      17    0       17     1     0     1     1     0     8    1
pppxif     1416       1    0        1     1     0     1     1     0     8    1
pfrktable  1344      15    0       15     1     0     1     1     0     8    1
pfanchor   1288       8    0        3     1     0     1     1     0     8    0
pftag       88        4    0        2     1     0     1     1     0     8    0
pfrule     1360      71    0       70     1     0     1     1     0     8    0
rttmr      136        4    0        4     1     0     1     1     0     8    1
art_heap8  4096       1    0        0     1     0     1     1     0     8    0
art_heap4  256      621    0      190    31     0    31    31     0     8    4
art_table   40      622    0      190     5     0     5     5     0     8    0
art_node    32      150    0       60     1     0     1     1     0     8    0
sysvmsgpl   40        2    0        2     1     0     1     1     0     8    1
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       14    0        0     1     0     1     1     0     8    0
dirhash    1024      29    0       12     3     0     3     3     0     8    0
dino2pl    256     2352    0      897    92     0    92    92     0     8    0
ffsino     256     2352    0      897    92     0    92    92     0     8    0
nchpl      144     3039    0     1338    64     0    64    64     0     8    0
rtmask      32        1    0        1     1     0     1     1     0     8    1
vnodes     216     2771    0        0   154     0   154   154     0     8    0
namei      1024    9904    0     9904     2     0     2     2     0     8    2
pfiaddrpl  120        4    0        4     1     0     1     1     0     8    1
kstatmem   264       57    0       34     2     0     2     2     0     8    0
scxspl     216    10329    0    10329     3     0     3     3     1     8    3
plimitpl   152      251    0      241     1     0     1     1     0     8    0
sigapl     424      837    0      803     6     0     6     6     0     8    0
knotepl    120    19831    0    19814    25    15    10    25     0     8    8
kqueuepl   184      143    0      137     1     0     1     1     0     8    0
pipepl     304      216    0      189     8     0     8     8     0     8    5
fdescpl    448      823    0      803     5     0     5     5     0     8    1
filepl     120     4341    0     4162    11     0    11    11     0     8    3
lockfpl    104      189    0      186     1     0     1     1     0     8    0
lockfspl    48       87    0       86     1     0     1     1     0     8    0
sessionpl  144       48    0       46     1     0     1     1     0     8    0
pgrppl      48       60    0       50     1     0     1     1     0     8    0
ucredpl    104      691    0      687     1     0     1     1     0     8    0
zombiepl   144      807    0      803     1     0     1     1     0     8    0
processpl  1152     837    0      803     4     0     4     4     0     8    0
procpl     664     1425    0     1380     6     0     6     6     0     8    0
sosppl     176        3    0        3     1     0     1     1     0     8    1
sockpl     552      841    0      834     5     0     5     5     0     8    4
mcl64k     65536    130    0      126     1     0     1     1     0     8    0
mcl16k     16384      1    0        1     1     0     1     1     0     8    1
mcl9k128   9344      67    0       67     1     0     1     1     0     8    1
mcl8k      8192      74    0       74     1     0     1     1     0     8    1
mcl4k      4096    3006    0     2953    14     0    14    14     0     8    7
mcl2k2     2112       2    0        2     1     0     1     1     0     8    1
mcl2k      2048     507    0      506     2     0     2     2     0     8    1
mextrefs    64      228    0      228     1     0     1     1     0     8    1
mtagpl      96        8    0        8     1     0     1     1     0     8    1
mbufpl     256     9034    0     8870    15     0    15    15     0     8    2
bufpl      272     3394    0      103   220     0   220   220     0     8    0
anonpl      24   118558    0   116862    45     0    45    45     0   187   25
amapchunkpl 152   20084    0    19627    27     0    27    27     0   158    5
amappl16   200     1738    0     1712    15     4    11    15     0     8    8
amappl15   192       31    0       31     1     0     1     1     0     8    1
amappl14   184      435    0      435     1     0     1     1     0     8    1
amappl13   176      118    0      118     1     0     1     1     0     8    1
amappl12   168     1084    0     1066     2     0     2     2     0     8    0
amappl11   160        4    0        4     1     0     1     1     0     8    1
amappl10   152      101    0      101     1     0     1     1     0     8    1
amappl9    144      274    0      273     1     0     1     1     0     8    0
amappl8    136      100    0      100     1     0     1     1     0     8    1
amappl7    128      148    0      146     1     0     1     1     0     8    0
amappl6    120      166    0      166     1     0     1     1     0     8    1
amappl5    112       92    0       91     1     0     1     1     0     8    0
amappl4    104      278    0      275     1     0     1     1     0     8    0
amappl3     96     3528    0     3450     3     0     3     3     0     8    0
amappl2     88      942    0      918     2     0     2     2     0     8    0
amappl1     80    11833    0    11736    14     1    13    14     0     8    8
amappl      88     5610    0     5462     5     0     5     5     0    92    0
uvmvnodes   80      116    0        0     3     0     3     3     0     8    0
dma65536   65536      1    0        1     1     0     1     1     0     8    1
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        7    0        7     1     0     1     1     0     8    1
dma128     128      253    0      253     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       16    0        0     1     0     1     1     0     8    0
uaddrrnd    24      823    0      803     1     0     1     1     0     8    0
uaddrbest   32        2    0        0     1     0     1     1     0     8    0
uaddr       24      823    0      803     1     0     1     1     0     8    0
vmmpekpl   168     8350    0     8310     3     0     3     3     0     8    0
vmmpepl    168    58830    0    57913    90     0    90    90     0   357   48
vmsppl     368      822    0      803     4     0     4     4     0     8    1
rwobjpl     40    18110    0    17654    12     0    12    12     0     8    1
pdppl      4096    1652    0     1606    98    48    50    82     0     8    4
pvpl        32   345677    0   341056   112     0   112   112     0   265   63
pmappl     216      822    0      803     3     0     3     3     0     8    0
extentpl    40       46    0       28     1     0     1     1     0     8    0
phpool     112      596    0       48    16     0    16    16     0     8    0
ddb> machine ddbcpu 0
No such command
ddb> trace
dtioctl(11e5f,80184404,ffff80002a7a5040,81,ffff80003c8fba10) at dtioctl+0x489 dt_ioctl_probe_enable sys/dev/dt/dt_dev.c:613 [inline]
dtioctl(11e5f,80184404,ffff80002a7a5040,81,ffff80003c8fba10) at dtioctl+0x489 sys/dev/dt/dt_dev.c:328
VOP_IOCTL(ffffef005ddf0cf8,80184404,ffff80002a7a5040,81,ffffef0007ffd680,ffff80003c8fba10) at VOP_IOCTL+0xa3 sys/kern/vfs_vops.c:264
vn_ioctl(ffffef006d480108,80184404,ffff80002a7a5040,ffff80003c8fba10) at vn_ioctl+0xea sys/kern/vfs_vnops.c:537
sys_ioctl(ffff80003c8fba10,ffff80002a7a5210,ffff80002a7a5160) at sys_ioctl+0x660 sys/kern/sys_generic.c:-1
syscall(ffff80002a7a5210) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80002a7a5210) at syscall+0x962 sys/arch/amd64/amd64/trap.c:791
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7b1a0e9f0a0, count: -6
ddb> machine ddbcpu 1
No such command
ddb> trace
dtioctl(11e5f,80184404,ffff80002a7a5040,81,ffff80003c8fba10) at dtioctl+0x489 dt_ioctl_probe_enable sys/dev/dt/dt_dev.c:613 [inline]
dtioctl(11e5f,80184404,ffff80002a7a5040,81,ffff80003c8fba10) at dtioctl+0x489 sys/dev/dt/dt_dev.c:328
VOP_IOCTL(ffffef005ddf0cf8,80184404,ffff80002a7a5040,81,ffffef0007ffd680,ffff80003c8fba10) at VOP_IOCTL+0xa3 sys/kern/vfs_vops.c:264
vn_ioctl(ffffef006d480108,80184404,ffff80002a7a5040,ffff80003c8fba10) at vn_ioctl+0xea sys/kern/vfs_vnops.c:537
sys_ioctl(ffff80003c8fba10,ffff80002a7a5210,ffff80002a7a5160) at sys_ioctl+0x660 sys/kern/sys_generic.c:-1
syscall(ffff80002a7a5210) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80002a7a5210) at syscall+0x962 sys/arch/amd64/amd64/trap.c:791
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7b1a0e9f0a0, count: -6
ddb> 

Crashes (8):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/20 15:12 openbsd 1a498b6f2b58 1e72964b .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: dtioctl
2026/08/17 04:37 openbsd 3b8d610e537f 746171ee .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: dtioctl
2026/08/15 08:46 openbsd a536f3ad0739 746171ee .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: dtioctl
2026/08/13 23:05 openbsd 52741ec3fdca b13552fe .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: dtioctl
2026/07/22 05:20 openbsd e524649e2c66 b561ce9c .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: dtioctl
2026/07/20 13:56 openbsd 3406bb49e583 4763fed7 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: dtioctl
2026/07/15 20:58 openbsd 5b4a77182f82 27a8bd60 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: dtioctl
2026/07/14 19:17 openbsd ddde2be8d3c6 2130f682 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: dtioctl
* Struck through repros no longer work on HEAD.