syzbot


uvm_fault: pmap_write_protect

Status: upstream: reported on 2026/03/18 00:25
Reported-by: syzbot+e6774d13f7f39738c4ef@syzkaller.appspotmail.com
First crash: 2d23h, last: 2d23h

Sample crash report:
uvm_fault(0xfffffd807e9c1738, 0x7f8315416000, 0, 1) -> e
kernel: page fault trap, code=9
Stopped at      pmap_write_protect+0x410:       movq    0(%r15),%r14
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
*221122  70736      0           0          0    0  syz-executor
pmap_write_protect(fffffd806cfaf290,62a828c1000,62a82cc0000,3) at pmap_write_protect+0x410 sys/arch/amd64/amd64/pmap.c:2208
uvm_map_protect(fffffd807e9c1738,62a828c0000,62a82cc0000,3,0,0,f8cfe4b121bbde51) at uvm_map_protect+0xb95 pmap_protect sys/arch/amd64/compile/SYZKALLER/obj/machine/pmap.h:476 [inline]
uvm_map_protect(fffffd807e9c1738,62a828c0000,62a82cc0000,3,0,0,f8cfe4b121bbde51) at uvm_map_protect+0xb95 sys/uvm/uvm_map.c:3202
sys_mprotect(ffff800033cde2c0,ffff8000374e53a0,ffff8000374e52f0) at sys_mprotect+0x341 sys/uvm/uvm_mmap.c:590
syscall(ffff8000374e53a0) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff8000374e53a0) at syscall+0x962 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x741aadd7dfa0, count: 10
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(0xfffffd807e9c1738, 0x7f8315416000, 0, 1) -> e
ddb> trace
pmap_write_protect(fffffd806cfaf290,62a828c1000,62a82cc0000,3) at pmap_write_protect+0x410 sys/arch/amd64/amd64/pmap.c:2208
uvm_map_protect(fffffd807e9c1738,62a828c0000,62a82cc0000,3,0,0,f8cfe4b121bbde51) at uvm_map_protect+0xb95 pmap_protect sys/arch/amd64/compile/SYZKALLER/obj/machine/pmap.h:476 [inline]
uvm_map_protect(fffffd807e9c1738,62a828c0000,62a82cc0000,3,0,0,f8cfe4b121bbde51) at uvm_map_protect+0xb95 sys/uvm/uvm_map.c:3202
sys_mprotect(ffff800033cde2c0,ffff8000374e53a0,ffff8000374e52f0) at sys_mprotect+0x341 sys/uvm/uvm_mmap.c:590
syscall(ffff8000374e53a0) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff8000374e53a0) at syscall+0x962 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x741aadd7dfa0, count: -5
ddb> show registers
rdi                     0x3fdff03000
rsi               0xffff86aa82c04000
rbp               0xffff8000374e51a0
rbx                    0x62a82cc0000
rdx                      0xfffffffff
rcx                   0x7f8000000000
rax                       0x62a82cc0
r8                                 0
r9                                 0
r10                                0
r11               0xe99310f56cc4922d
r12                   0x7f8315416600
r13                    0x62a82e00000
r14                     0x3fdff03000
r15                   0x7f8315416000
rip               0xffffffff82969b70    pmap_write_protect+0x410
cs                               0x8
rflags                       0x10287    __ALIGN_SIZE+0xf287
rsp               0xffff8000374e5100
ss                              0x10
pmap_write_protect+0x410:       movq    0(%r15),%r14
ddb> show proc
PROC (syz-executor) tid=221122 pid=70736 tcnt=2 stat=onproc
    flags process=0 proc=0
    runpri=86, usrpri=86, slppri=32, nice=20
    wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0
    forw=0xffffffffffffffff, list=0xffff80003c91a560,0xffff800033cdefc8
    process=0xffff80003c904920 user=0xffff8000374e0000, vmspace=0xfffffd807e9c1738
    estcpu=36, cpticks=3, pctcpu=0.0, user=2, sys=1, intr=0
ddb> ps
   PID     TID   PPID    UID  S       FLAGS  WAIT          COMMAND
 30507   91641  46935      0  2           0                syz-executor
 98085  217712  43776      0  2           0                syz-executor
 98085  424571  43776      0  3   0x4000080  kqsel         syz-executor
 68356  403885  64805      0  2           0                syz-executor
 68356    6947  64805      0  3   0x4000080  netcon        syz-executor
*70736  221122  48541      0  7           0                syz-executor
 70736  315314  48541      0  3   0x4000080  fsleep        syz-executor
 46935  374975  38228      0  3        0x82  nanoslp       syz-executor
 43776  369916  38228      0  3        0x82  nanoslp       syz-executor
 67721  215585  38228      0  3        0x82  nanoslp       syz-executor
  9048  112784  38228      0  3        0x82  nanoslp       syz-executor
 94276  175633      0      0  3     0x14280  nfsidl        nfsio
 51945   73884      0      0  3     0x14280  nfsidl        nfsio
 74667  246251      0      0  3     0x14280  nfsidl        nfsio
 20085  167249      0      0  3     0x14280  nfsidl        nfsio
  6351   72116      0      0  3     0x14280  nfsidl        nfsio
 84429  235576      0      0  3     0x14280  nfsidl        nfsio
 61779  275504      0      0  3     0x14280  nfsidl        nfsio
 94625  376845      0      0  3     0x14280  nfsidl        nfsio
 67472   70454      0      0  3     0x14280  nfsidl        nfsio
 80865  493238      0      0  3     0x14280  nfsidl        nfsio
 24789   85529      0      0  3     0x14280  nfsidl        nfsio
 17543  402509      0      0  3     0x14280  nfsidl        nfsio
 59190  268281      0      0  3     0x14280  nfsidl        nfsio
 89405   17324      0      0  3     0x14280  nfsidl        nfsio
 39748  212641      0      0  3     0x14280  nfsidl        nfsio
  7238  113848      0      0  3     0x14280  nfsidl        nfsio
  3220  425667      0      0  3     0x14280  nfsidl        nfsio
 91475  111956      0      0  3     0x14280  nfsidl        nfsio
 98213  100396      0      0  3     0x14280  nfsidl        nfsio
 30811   82935      0      0  3     0x14280  nfsidl        nfsio
 64805  269704  38228      0  3        0x82  nanoslp       syz-executor
 50363  502406  38228      0  3         0x2  biowait       syz-executor
 48541  201598  38228      0  3        0x82  nanoslp       syz-executor
 72381  500623  38228      0  3        0x82  wait          syz-executor
 38228  124117  44774      0  3        0x82  kqread        syz-executor
 44774  456087  51828      0  3    0x10008a  sigsusp       ksh
 51828   22529   8947      0  3        0x98  kqread        sshd-session
  8947  234020  64062      0  3        0x92  kqread        sshd-session
 92283  202682      1      0  3    0x100083  ttyin         getty
 64062  137079      1      0  3        0x88  kqread        sshd
 98788  481428  49484     73  3   0x1100090  kqread        syslogd
 49484  151295      1      0  3    0x100082  sbwait        syslogd
 48021   55439      1      0  3    0x100080  kqread        resolvd
 36900  485992  84958     77  3    0x100092  kqread        dhcpleased
  8094   96727  84958     77  3    0x100092  kqread        dhcpleased
 84958  274863      1      0  3        0x80  kqread        dhcpleased
 84919  271098      0      0  3     0x14200  bored         smr
 62657  230160      0      0  2     0x14200                zerothread
 40452  521826      0      0  3     0x14200  aiodoned      aiodoned
 29127  181640      0      0  3     0x14200  syncer        update
 15974  189837      0      0  3     0x14200  cleaner       cleaner
 96954  250425      0      0  3     0x14200  reaper        reaper
 69532    2517      0      0  3     0x14200  pgdaemon      pagedaemon
 51662  274613      0      0  3     0x14200  bored         viomb
 65668  247692      0      0  3  0x40014200  acpi0         acpi0
 41479  466319      0      0  3     0x14200  bored         softnet0
 24216  482179      0      0  3     0x14200  bored         systqmp
  9425   58044      0      0  3     0x14200  bored         systq
 78929  254948      0      0  3  0x40014200  tmoslp        softclock
 17840  235512      0      0  3  0x40014200                idle0
     1  162588      0      0  3        0x82  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 11068  12113K   13233K 166960K     14281        0
            pcb    17     16K      22K 166960K       535        0
         rtable   241     11K      12K 166960K       761        0
             pf    30     12K      14K 166960K       147        0
         ifaddr    39      7K       8K 166960K       126        0
        ifgroup    48      2K       2K 166960K       205        0
         sysctl     4      1K       9K 166960K        44        0
       counters    33     17K      18K 166960K       146        0
       ioctlops     0      0K       4K 166960K       531        0
            iov     0      0K      32K 166960K       180        0
          mount     1      1K       1K 166960K         1        0
            log     0      0K       0K 166960K         4        0
         vnodes  1388     87K      88K 166960K      2520        0
      UFS quota     1     32K      32K 166960K         1        0
      UFS mount     5     36K      36K 166960K         5        0
            shm     2      1K       9K 166960K        23        0
         VM map     2      1K       1K 166960K         2        0
            sem    12      0K       1K 166960K       164        0
        dirhash    12      2K       2K 166960K        30        0
           ACPI  1692    195K     286K 166960K     12470        0
      file desc    17     61K     102K 166960K      1431        0
          sigio     0      0K       0K 166960K        24        0
           proc    60     59K      83K 166960K       709        0
        subproc    72      4K       4K 166960K       110        0
    NFS srvsock     1      0K       0K 166960K         1        0
     NFS daemon     1     16K      16K 166960K         1        0
    ip_moptions     0      0K       0K 166960K       267        0
       in_multi    88      6K       7K 166960K       201        0
    ether_multi     1      0K       0K 166960K        12        0
            mrt     1      0K       0K 166960K        28        0
    ISOFS mount     1     32K      32K 166960K         1        0
  MSDOSFS mount     1     16K      16K 166960K         1        0
           ttys   253   1129K    1129K 166960K       253        0
           exec     0      0K       1K 166960K       627        0
   fusefs mount     1     32K      32K 166960K         1        0
     pfkey data     0      0K       0K 166960K         2        0
            tdb     3      0K       0K 166960K         3        0
        VM swap     8     62K      64K 166960K        10        0
       UVM amap   211    142K     164K 166960K     14742        0
       UVM aobj    45     16K      16K 166960K        47        0
     pinsyscall    38     76K      92K 166960K      2639        0
        memdesc     1      4K       4K 166960K         1        0
    crypto data     1      1K       1K 166960K         1        0
    ip6_options     0      0K       1K 166960K        71        0
            NDP    11      0K       2K 166960K        88        0
           temp   113   9076K    9142K 166960K     55915        0
         kqueue    13     20K      32K 166960K       263        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      344    0      341     3     0     3     3     0     8    2
rtentry    136      221    0      126     4     0     4     4     0     8    0
unpcb      144     1288    0     1271     6     0     6     6     0     8    5
syncache   336        6    0        6     1     0     1     1     0     8    1
tcpqe       32        6    0        6     1     0     1     1     0     8    1
tcpcb      736      503    0      496     7     0     7     7     0     8    6
arp         96       30    0       14     1     0     1     1     0     8    0
ipq         40        6    0        3     1     0     1     1     0     8    0
ipqe        40       10    0        7     1     0     1     1     0     8    0
inpcb      328     1595    0     1584     7     0     7     7     0     8    5
ip6q        72        4    0        0     1     0     1     1     0     8    0
ip6af       40        4    0        0     1     0     1     1     0     8    0
nd6        112       40    0       17     1     0     1     1     0     8    0
pkpcb       40       77    0       77     1     0     1     1     0     8    1
kcovpl      48       12    0        4     1     0     1     1     0     8    0
mppekey    1024       2    0        2     1     0     1     1     0     8    1
ppxss      1072      94    0       93     1     0     1     1     0     8    0
pppxif     1384       7    0        7     1     0     1     1     0     8    1
art_heap8  4096       3    0        0     3     0     3     3     0     8    0
art_heap4  256      766    0      382    31     0    31    31     0     8    3
art_table   40      769    0      382     5     0     5     5     0     8    0
art_node    32      219    0      136     1     0     1     1     0     8    0
sysvmsgpl   40        8    0        8     1     0     1     1     0     8    1
semupl     112        2    0        2     1     0     1     1     0     8    1
semapl     112      127    0      117     1     0     1     1     0     8    0
shmpl      112       39    0        1     2     0     2     2     0     8    0
dirhash    1024      29    0       12     3     0     3     3     0     8    0
dino2pl    256     4215    0     2759    92     0    92    92     0     8    0
ffsino     256     4215    0     2759    92     0    92    92     0     8    0
nchpl      144     6164    0     4462    64     0    64    64     0     8    0
rtmask      32       10    0       10     1     0     1     1     0     8    1
vnodes     216     4738    0        0   264     0   264   264     0     8    0
namei      1024   24201    0    24201     1     0     1     1     0     8    1
vcpupl     3904       5    0        1     1     0     1     1     0     8    0
vmpool     808        5    0        1     1     0     1     1     0     8    0
kstatmem   264      128    0      106     3     0     3     3     0     8    1
acpiwqpl    32        1    0        1     1     0     1     1     1     8    1
scsiplug    72       11    0       11     1     0     1     1     0     8    1
scxspl     216    21609    0    21608     8     0     8     8     1     8    7
plimitpl   152      407    0      390     1     0     1     1     0     8    0
sigapl     424     1734    0     1672     8     0     8     8     0     8    0
knotepl    120    76853    0    76806    31    21    10    18     0     8    8
kqueuepl   184      686    0      673     4     0     4     4     0     8    3
pipepl     304      222    0      195     3     0     3     3     0     8    0
fdescpl    448     1699    0     1670     4     0     4     4     0     8    0
filepl     120    13441    0    13216    14     0    14    14     0     8    4
lockfpl    104      498    0      495     1     0     1     1     0     8    0
lockfspl    48      172    0      169     1     0     1     1     0     8    0
sessionpl  144       28    0       20     1     0     1     1     0     8    0
pgrppl      48       55    0       39     1     0     1     1     0     8    0
ucredpl    104     2565    0     2552     1     0     1     1     0     8    0
zombiepl   144     1675    0     1672     1     0     1     1     0     8    0
processpl  1152    1734    0     1672     5     0     5     5     0     8    0
procpl     664     3641    0     3576     7     0     7     7     0     8    0
sosppl     176       11    0       11     1     0     1     1     0     8    1
sockpl     552     3496    0     3465    16     5    11    13     0     8    8
mcl64k     65536     61    0       59     1     0     1     1     0     8    0
mcl16k     16384      1    0        1     1     0     1     1     0     8    1
mcl9k      9216       1    0        1     1     0     1     1     0     8    1
mcl8k      8192      20    0       20     1     0     1     1     0     8    1
mcl4k      4096    4152    0     4100    14     0    14    14     0     8    6
mcl2k2     2112       1    0        1     1     0     1     1     0     8    1
mcl2k      2048    1772    0     1769     2     0     2     2     0     8    1
mtagpl      96       10    0       10     1     0     1     1     0     8    1
mbufpl     256    18731    0    18570    19     0    19    19     0     8    4
bufpl      280     6568    0      354   444     0   444   444     0     8    0
anonpl      24   246738    0   243636    58     0    58    58     0   187   25
amapchunkpl 152   50962    0    50533    36     0    36    36     0   158   14
amappl16   200     4198    0     4164    22    10    12    15     0     8    8
amappl15   192        5    0        5     1     0     1     1     0     8    1
amappl14   184      459    0      458     1     0     1     1     0     8    0
amappl13   176      132    0      122     1     0     1     1     0     8    0
amappl12   168     1957    0     1929     2     0     2     2     0     8    0
amappl11   160        2    0        2     1     0     1     1     0     8    1
amappl10   152      152    0      142     1     0     1     1     0     8    0
amappl9    144      257    0      257     1     0     1     1     0     8    1
amappl8    136      120    0      118     1     0     1     1     0     8    0
amappl7    128      156    0      145     1     0     1     1     0     8    0
amappl6    120      190    0      189     1     0     1     1     0     8    0
amappl5    112      101    0       93     1     0     1     1     0     8    0
amappl4    104      283    0      269     1     0     1     1     0     8    0
amappl3     96     9797    0     9697     4     0     4     4     0     8    0
amappl2     88      581    0      526     2     0     2     2     0     8    0
amappl1     80    15877    0    15329    15     0    15    15     0     8    0
amappl      88    13743    0    13595     5     0     5     5     0    92    0
uvmvnodes   80      146    0        0     3     0     3     3     0     8    0
dma4096    4096       2    0        2     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      255    0      255     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       46    0        2     1     0     1     1     0     8    0
uaddrrnd    24     1699    0     1670     1     0     1     1     0     8    0
uaddrbest   32        2    0        0     1     0     1     1     0     8    0
uaddr       24     1699    0     1670     1     0     1     1     0     8    0
vmmpekpl   168    14277    0    14229     3     0     3     3     0     8    0
vmmpepl    168   112327    0   110560    93     0    93    93     0   357   11
vmsppl     368     1698    0     1670     4     0     4     4     0     8    1
rwobjpl     40    30311    0    29290    13     0    13    13     0     8    0
pdppl      4096    3414    0     3346   130    60    70    76     0     8    2
pvpl        32   740078    0   730948   140     0   140   140     0   265   48
pmappl     216     1703    0     1671     2     0     2     2     0     8    0
extentpl    40       45    0       27     1     0     1     1     0     8    0
phpool     112      411    0       60    11     0    11    11     0     8    0
ddb> machine ddbcpu 0
No such command
ddb> trace
pmap_write_protect(fffffd806cfaf290,62a828c1000,62a82cc0000,3) at pmap_write_protect+0x410 sys/arch/amd64/amd64/pmap.c:2208
uvm_map_protect(fffffd807e9c1738,62a828c0000,62a82cc0000,3,0,0,f8cfe4b121bbde51) at uvm_map_protect+0xb95 pmap_protect sys/arch/amd64/compile/SYZKALLER/obj/machine/pmap.h:476 [inline]
uvm_map_protect(fffffd807e9c1738,62a828c0000,62a82cc0000,3,0,0,f8cfe4b121bbde51) at uvm_map_protect+0xb95 sys/uvm/uvm_map.c:3202
sys_mprotect(ffff800033cde2c0,ffff8000374e53a0,ffff8000374e52f0) at sys_mprotect+0x341 sys/uvm/uvm_mmap.c:590
syscall(ffff8000374e53a0) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff8000374e53a0) at syscall+0x962 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x741aadd7dfa0, count: -5
ddb> machine ddbcpu 1
No such command
ddb> trace
pmap_write_protect(fffffd806cfaf290,62a828c1000,62a82cc0000,3) at pmap_write_protect+0x410 sys/arch/amd64/amd64/pmap.c:2208
uvm_map_protect(fffffd807e9c1738,62a828c0000,62a82cc0000,3,0,0,f8cfe4b121bbde51) at uvm_map_protect+0xb95 pmap_protect sys/arch/amd64/compile/SYZKALLER/obj/machine/pmap.h:476 [inline]
uvm_map_protect(fffffd807e9c1738,62a828c0000,62a82cc0000,3,0,0,f8cfe4b121bbde51) at uvm_map_protect+0xb95 sys/uvm/uvm_map.c:3202
sys_mprotect(ffff800033cde2c0,ffff8000374e53a0,ffff8000374e52f0) at sys_mprotect+0x341 sys/uvm/uvm_mmap.c:590
syscall(ffff8000374e53a0) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff8000374e53a0) at syscall+0x962 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x741aadd7dfa0, count: -5

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/18 00:24 openbsd 7b59c65f5490 c8810548 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: pmap_write_protect
* Struck through repros no longer work on HEAD.