syzbot


uvm_fault: amap_lookups

Status: upstream: reported on 2026/07/14 00:24
Reported-by: syzbot+7651266b7ef13d67cc1a@syzkaller.appspotmail.com
First crash: 4d20h, last: 2h25m

Sample crash report:
uvm_fault(0xfffff9806d09e7c8, 0x100000010, 0, 1) -> e
kernel: page fault trap, code=0
Stopped at      amap_lookups+0x1e0:     movl    0x10(%r15),%r14d
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
* 93348  24691  32767        0x10          0    0  syz-executor
 522590  90844      0     0x14000      0x200    1  reaper
amap_lookups(fffff9806cdb4298,1000,ffff80002a2ce2f0,8) at amap_lookups+0x1e0 amap_chunk_get sys/uvm/uvm_amap.c:118 [inline]
amap_lookups(fffff9806cdb4298,1000,ffff80002a2ce2f0,8) at amap_lookups+0x1e0 sys/uvm/uvm_amap.c:1168
uvm_fault_check(ffff80002a2ce3f0,ffff80002a2ce428,ffff80002a2ce460,0) at uvm_fault_check+0x8d2 sys/uvm/uvm_fault.c:840
uvm_fault(fffff9806d09e7c8,ea8e38b0000,0,1) at uvm_fault+0x106 sys/uvm/uvm_fault.c:627
upageflttrap(ffff80002a2ce590,ea8e38b0f50) at upageflttrap+0xa9 sys/arch/amd64/amd64/trap.c:192
usertrap(ffff80002a2ce590) at usertrap+0x430 sys/arch/amd64/amd64/trap.c:640
recall_trap() at recall_trap+0x8
end of kernel
end trace frame: 0x718665ac72e0, 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{0}> 
ddb{0}> set $lines = 0
ddb{0}> set $maxwidth = 0
ddb{0}> show panic
*cpu0: uvm_fault(0xfffff9806d09e7c8, 0x100000010, 0, 1) -> e
ddb{0}> show kasan
No such command
ddb{0}> trace
amap_lookups(fffff9806cdb4298,1000,ffff80002a2ce2f0,8) at amap_lookups+0x1e0 amap_chunk_get sys/uvm/uvm_amap.c:118 [inline]
amap_lookups(fffff9806cdb4298,1000,ffff80002a2ce2f0,8) at amap_lookups+0x1e0 sys/uvm/uvm_amap.c:1168
uvm_fault_check(ffff80002a2ce3f0,ffff80002a2ce428,ffff80002a2ce460,0) at uvm_fault_check+0x8d2 sys/uvm/uvm_fault.c:840
uvm_fault(fffff9806d09e7c8,ea8e38b0000,0,1) at uvm_fault+0x106 sys/uvm/uvm_fault.c:627
upageflttrap(ffff80002a2ce590,ea8e38b0f50) at upageflttrap+0xa9 sys/arch/amd64/amd64/trap.c:192
usertrap(ffff80002a2ce590) at usertrap+0x430 sys/arch/amd64/amd64/trap.c:640
recall_trap() at recall_trap+0x8
end of kernel
end trace frame: 0x718665ac72e0, count: -6
ddb{0}> show registers
rdi                             0x11
rsi                             0x20
rbp               0xffff80002a2ce240
rbx                                0
rdx                                0
rcx                                0
rax               0xffff800000c43ea0
r8                0xffffffff81d97110    uvm_map_inentry_sp
r9                                 0
r10                                0
r11               0x48af2429fdc34da8
r12                              0x9
r13                                0
r14                             0x20
r15                      0x100000000
rip               0xffffffff82e31e00    amap_lookups+0x1e0
cs                               0x8
rflags                       0x10206    __ALIGN_SIZE+0xf206
rsp               0xffff80002a2ce1b0
ss                                 0
amap_lookups+0x1e0:     movl    0x10(%r15),%r14d
ddb{0}> show proc
PROC (syz-executor) tid=93348 pid=24691 tcnt=1 stat=onproc
    flags process=10<SUGID> proc=0
    runpri=60, usrpri=61, slppri=16, nice=20
    wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0
    forw=0xffffffffffffffff, list=0xffff800045fe7248,0xffffffff83b42ca8
    process=0xffff80003b3cd360 user=0xffff80002a2c9000, vmspace=0xfffff9806d09e7c8
    estcpu=11, cpticks=1, pctcpu=0.0, user=0, sys=1, intr=0
ddb{0}> ps
   PID     TID   PPID   UID  S      PRLAGS     PFLAGS WAIT      COMMAND
*24691   93348  36523 32767  7        0x10          0           syz-executor
 18940  486115  39508 32767  2        0x10          0           syz-executor
 89374  279623  86333 32767  2        0x10          0           syz-executor
 89374  191788  86333 32767  2        0x10  0x4000000           syz-executor
 89864  109503   8599 32767  2        0x10          0           syz-executor
 77741  173147  94542     0  2         0x2          0           syz-executor
 13379  257276  22738 32767  3        0x10       0x80 piperd    syz-executor
 40452   80047  81417 32767  2        0x10      0xc80           syz-executor
 70965  462216   3294 32767  3        0x10       0x80 piperd    syz-executor
 36523  497199  46202 32767  3        0x10       0x80 nanoslp   syz-executor
 39508  519284  10296 32767  2        0x10      0xc80           syz-executor
 86333  490989  32485 32767  2        0x10      0xc80           syz-executor
  8599    3749   5013 32767  3        0x10       0x80 nanoslp   syz-executor
 22738  496119  94542     0  3         0x2       0x80 wait      syz-executor
 46202  219744  94542     0  3         0x2       0x80 wait      syz-executor
 81417    4896  94542     0  3         0x2       0x80 wait      syz-executor
  3294  396710  94542     0  3         0x2       0x80 wait      syz-executor
 10296  482612  94542     0  3         0x2       0x80 wait      syz-executor
 32485  513052  94542     0  3         0x2       0x80 wait      syz-executor
  5013  498702  94542     0  3         0x2       0x80 wait      syz-executor
 94542  177084  17299     0  2         0x2          0           syz-executor
 17299  393543  16847     0  3    0x100002       0x88 sigsusp   ksh
 16847  138347  70884     0  3        0x10       0x88 kqread    sshd-session
 70884  215354   2797     0  3        0x12       0x80 kqread    sshd-session
 33777   52268      1     0  3    0x100003       0x80 ttyin     getty
  2797    2308      1     0  3           0       0x88 kqread    sshd
  2035  420667  88037    73  3   0x1100010       0x80 kqread    syslogd
 88037  313724      1     0  3    0x100002       0x80 sbwait    syslogd
 59708  384832      1     0  3    0x100000       0x80 kqread    resolvd
 84972  172351  92054    77  3    0x100012       0x80 kqread    dhcpleased
  6232  510443  92054    77  3    0x100012       0x80 kqread    dhcpleased
 92054  495593      1     0  3           0       0x80 kqread    dhcpleased
 77306  104958      0     0  3     0x14000      0x200 bored     smr
 14436  455884      0     0  2     0x14000      0x200           zerothread
 64853  459171      0     0  3     0x14000      0x200 aiodoned  aiodoned
 15663  436752      0     0  3     0x14000      0x200 syncer    update
 84641  327573      0     0  3     0x14000      0x200 cleaner   cleaner
 90844  522590      0     0  7     0x14000      0x200           reaper
 77996  220733      0     0  3     0x14000      0x200 pgdaemon  pagedaemon
 73319  243276      0     0  3     0x14000      0x200 bored     viomb
 40229  400530      0     0  3     0x14000 0x40000200 acpi0     acpi0
 29064  161909      0     0  3     0x14000 0x40000200           idle1
 59220  191504      0     0  3     0x14000      0x200 bored     softnet1
 93383  304617      0     0  3     0x14000      0x200 bored     softnet0
 29886  297032      0     0  3     0x14000      0x200 bored     systqmp
 10586  411624      0     0  3     0x14000      0x200 bored     systq
 33080  307086      0     0  3     0x14000      0x200 tmoslp    softclockmp
   983  516703      0     0  3     0x14000 0x40000200 tmoslp    softclock
 60934  355623      0     0  3     0x14000 0x40000200           idle0
     1  441923      0     0  3         0x2       0x80 wait      init
     0       0     -1     0  3     0x10000      0x200 scheduler swapper
ddb{0}> show all locks
Process 24691 (syz-executor) thread 0xffff800045fe6550 (93348)
shared rwlock amaplk r = 0 (0xfffff9806e0bde58)
#0  witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline]
#0  witness_lock+0x5f1 sys/kern/subr_witness.c:1160
#1  rw_do_enter_read+0x3e8 sys/kern/kern_rwlock.c:413
#2  uvm_fault_check+0x8a9 sys/uvm/uvm_fault.c:834
#3  uvm_fault+0x106 sys/uvm/uvm_fault.c:627
#4  upageflttrap+0xa9 sys/arch/amd64/amd64/trap.c:192
#5  usertrap+0x430 sys/arch/amd64/amd64/trap.c:640
#6  recall_trap+0x8
shared rwlock vmmaplk r = 0 (0xfffff9806d09e8c8)
#0  witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline]
#0  witness_lock+0x5f1 sys/kern/subr_witness.c:1160
#1  rw_do_enter_read+0x3e8 sys/kern/kern_rwlock.c:413
#2  uvmfault_lookup+0x122 sys/uvm/uvm_fault.c:1880
#3  uvm_fault_check+0x4f sys/uvm/uvm_fault.c:693
#4  uvm_fault+0x106 sys/uvm/uvm_fault.c:627
#5  upageflttrap+0xa9 sys/arch/amd64/amd64/trap.c:192
#6  usertrap+0x430 sys/arch/amd64/amd64/trap.c:640
#7  recall_trap+0x8
ddb{0}> show malloc
           Type InUse  MemUse  HighUse   Limit  Requests Type Lim
         devbuf 11049  12016K   12034K 166960K     12143        0
            pcb    17     12K      12K 166960K        17        0
         rtable   215      6K       7K 166960K       362        0
             pf    29     16K      16K 166960K        31        0
         ifaddr    38      6K       7K 166960K        44        0
        ifgroup    46      2K       2K 166960K        50        0
         sysctl     1      1K       9K 166960K         5        0
       counters    68     36K      37K 166960K        70        0
       ioctlops     0      0K       2K 166960K        33        0
            iov     0      0K       8K 166960K         8        0
          mount     1      1K       1K 166960K         1        0
            log     0      0K       0K 166960K         4        0
         vnodes  1288     81K      81K 166960K      1467        0
      UFS quota     1     32K      32K 166960K         1        0
      UFS mount     5     36K      36K 166960K         5        0
            shm     2      1K       5K 166960K         5        0
         VM map     2      1K       1K 166960K         2        0
            sem    12      0K       0K 166960K        86        0
        dirhash    12      2K       2K 166960K        15        0
           ACPI  1734    201K     291K 166960K     11964        0
      file desc    21     77K     117K 166960K       394        0
           proc    58     99K     147K 166960K       531        0
        subproc    64      4K       4K 166960K       163        0
    NFS srvsock     1      0K       0K 166960K         1        0
     NFS daemon     1     16K      16K 166960K         1        0
    ip_moptions     0      0K       0K 166960K        53        0
       in_multi    88      6K       7K 166960K       106        0
    ether_multi     1      0K       0K 166960K         2        0
            mrt     0      0K       0K 166960K        14        0
    ISOFS mount     1     32K      32K 166960K         1        0
  MSDOSFS mount     1     16K      16K 166960K         1        0
           ttys    73    334K     334K 166960K        73        0
           exec     0      0K       1K 166960K       389        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   193    142K     151K 166960K      4848        0
       UVM aobj     9      2K       2K 166960K         9        0
     pinsyscall    42     84K     110K 166960K      1494        0
        memdesc     1      4K       4K 166960K         1        0
    crypto data     1      1K       1K 166960K         1        0
    ip6_options     0      0K       0K 166960K        12        0
            NDP    10      0K       2K 166960K        27        0
           temp    35   9118K    9178K 166960K      4384        0
         kqueue    13     20K      26K 166960K        62        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       28    0        0     1     0     1     1     0     8    0
rtpcb      120       85    0       82     2     0     2     2     0     8    1
rtentry    176      113    0       14     6     0     6     6     0     8    1
unpcb      144      163    0      148     1     0     1     1     0     8    0
syncache   336        4    0        4     1     1     0     1     0     8    0
tcpcb      736      156    0      152     7     0     7     7     0     8    6
arp        136       18    0        2     1     0     1     1     0     8    0
ipq         40        2    0        0     1     0     1     1     0     8    0
ipqe        40        2    0        0     1     0     1     1     0     8    0
inpcb      328      378    0      371     7     0     7     7     0     8    6
nd6        152       26    0        5     1     0     1     1     0     8    0
kcovpl      48       18    0       11     1     0     1     1     0     8    0
art_heap8  4096       1    0        0     1     0     1     1     0     8    0
art_heap4  256      469    0       61    30     0    30    30     0     8    2
art_table   40      470    0       61     5     0     5     5     0     8    0
art_node    32      113    0       23     1     0     1     1     0     8    0
sysvmsgpl   40        4    0        3     1     0     1     1     0     8    0
semapl      72       84    0       74     1     0     1     1     0     8    0
shmpl      112        6    0        0     1     0     1     1     0     8    0
dirhash    1024      19    0        2     3     0     3     3     0     8    0
dino2pl    256     1869    0      392    93     0    93    93     0     8    0
ffsino     296     1869    0      392   114     0   114   114     0     8    0
nchpl      144     2352    0      652    64     0    64    64     0     8    0
vnodes     216     2041    0        0   114     0   114   114     0     8    0
namei      1024    7316    0     7316     1     0     1     1     0     8    1
percpumem   16       51    0        1     1     0     1     1     0     8    0
kstatmem   264       25    0        2     2     0     2     2     0     8    0
scxspl     216     7882    0     7882     4     3     1     3     1     8    1
plimitpl   152       77    0       54     2     0     2     2     0     8    1
sigapl     424      670    0      620     7     0     7     7     0     8    0
knotepl    120      319    0        0    10     0    10    10     0     8    0
kqueuepl   224       78    0       69     1     0     1     1     0     8    0
pipepl     344      237    0      210     9     0     9     9     0     8    6
fdescpl    528      654    0      621     3     0     3     3     0     8    0
filepl     160     3027    0     2833    14     0    14    14     0     8    5
lockfpl    104       84    0       82     1     0     1     1     0     8    0
lockfspl    48       22    0       20     1     0     1     1     0     8    0
sessionpl  144       46    0       31     1     0     1     1     0     8    0
pgrppl      48       68    0       45     1     0     1     1     0     8    0
ucredpl    104      404    0      386     1     0     1     1     0     8    0
zombiepl   144      621    0      620     1     0     1     1     0     8    0
processpl  1232     670    0      620     5     0     5     5     0     8    0
procpl     664     1031    0      980     7     0     7     7     0     8    2
sockpl     752      632    0      607    11     0    11    11     0     8    8
mcl64k     65536      2    0        0     1     0     1     1     0     8    0
mcl8k      8192       4    0        0     1     0     1     1     0     8    0
mcl4k      4096     122    0        0    16     0    16    16     0     8    1
mcl2k      2048      20    0        0     3     0     3     3     0     8    0
mextrefs    64       16    0        0     1     0     1     1     0     8    0
mtagpl      96        1    0        0     1     0     1     1     0     8    0
mbufpl     256      249    0        0    16     0    16    16     0     8    0
bufpl      272     2610    0      102   168     0   168   168     0     8    0
anonpl      32    11447    0        0    93     0    93    93     0   247    0
amapchunkpl 152   14621    0    14239    27     0    27    27     0   158    9
amappl16   200     2429    0     2411    23    13    10    23     0     8    8
amappl15   192       10    0       10     1     1     0     1     0     8    0
amappl14   184      412    0      411     1     0     1     1     0     8    0
amappl13   176      117    0      107     1     0     1     1     0     8    0
amappl12   168      890    0      859     2     0     2     2     0     8    0
amappl11   160        4    0        4     1     1     0     1     0     8    0
amappl10   152       60    0       50     1     0     1     1     0     8    0
amappl9    144      285    0      285     1     1     0     1     0     8    0
amappl8    136       94    0       93     1     0     1     1     0     8    0
amappl7    128      143    0      132     1     0     1     1     0     8    0
amappl6    120      148    0      147     1     0     1     1     0     8    0
amappl5    112       97    0       90     1     0     1     1     0     8    0
amappl4    104      266    0      249     1     0     1     1     0     8    0
amappl3     96     2840    0     2746     5     1     4     4     0     8    0
amappl2     88      524    0      469     2     0     2     2     0     8    0
amappl1     80    11261    0    10697    14     0    14    14     0     8    0
amappl      88     4124    0     3993     5     0     5     5     0    92    0
uvmvnodes   80      101    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        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        8    0        0     1     0     1     1     0     8    0
uaddrrnd    24      654    0      621     1     0     1     1     0     8    0
uaddrbest   32        2    0        0     1     0     1     1     0     8    0
uaddr       24      654    0      621     1     0     1     1     0     8    0
vmmpekpl   168     7448    0     7405     3     0     3     3     0     8    0
vmmpepl    168    50225    0    48421   109     0   109   109     0   357   23
vmsppl     488      653    0      621     7     1     6     6     0     8    1
rwobjpl     80    17061    0    16168    28     0    28    28     0     8    6
pdppl      4096    1315    0     1242   109    30    79    93     0     8    6
pvpl        32    18251    0        0   148     0   148   148     0   265    0
pmappl     256      653    0      621     4     1     3     3     0     8    0
extentpl    40       46    0       28     1     0     1     1     0     8    0
phpool     112      457    0       34    13     0    13    13     0     8    0
ddb{0}> machine ddbcpu 0
Invalid cpu 0
ddb{0}> trace
amap_lookups(fffff9806cdb4298,1000,ffff80002a2ce2f0,8) at amap_lookups+0x1e0 amap_chunk_get sys/uvm/uvm_amap.c:118 [inline]
amap_lookups(fffff9806cdb4298,1000,ffff80002a2ce2f0,8) at amap_lookups+0x1e0 sys/uvm/uvm_amap.c:1168
uvm_fault_check(ffff80002a2ce3f0,ffff80002a2ce428,ffff80002a2ce460,0) at uvm_fault_check+0x8d2 sys/uvm/uvm_fault.c:840
uvm_fault(fffff9806d09e7c8,ea8e38b0000,0,1) at uvm_fault+0x106 sys/uvm/uvm_fault.c:627
upageflttrap(ffff80002a2ce590,ea8e38b0f50) at upageflttrap+0xa9 sys/arch/amd64/amd64/trap.c:192
usertrap(ffff80002a2ce590) at usertrap+0x430 sys/arch/amd64/amd64/trap.c:640
recall_trap() at recall_trap+0x8
end of kernel
end trace frame: 0x718665ac72e0, count: -6
ddb{0}> machine ddbcpu 1
Stopped at      x86_ipi_db+0x27:        addq    $0x8,%rsp
x86_ipi_db(ffff80002999dff0) 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
__mp_lock(ffffffff83a3e980) at __mp_lock+0x192 __mp_lock_spin sys/kern/kern_lock.c:142 [inline]
__mp_lock(ffffffff83a3e980) at __mp_lock+0x192 sys/kern/kern_lock.c:173
reaper(ffff800045ffd9f8) at reaper+0x211 sys/kern/kern_exit.c:507
end trace frame: 0x0, count: 10

Crashes (10):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/18 18:52 openbsd bc321d44d2f5 72524a66 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-setuid uvm_fault: amap_lookups
2026/07/18 06:35 openbsd 97f4e10dc0be 72524a66 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore uvm_fault: amap_lookups
2026/07/17 15:08 openbsd 94b919120046 7f27c57a .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: amap_lookups
2026/07/15 23:01 openbsd 5b4a77182f82 27a8bd60 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore uvm_fault: amap_lookups
2026/07/15 20:58 openbsd 5b4a77182f82 27a8bd60 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: amap_lookups
2026/07/15 15:12 openbsd af68cf7bb0f1 a4ed0f4f .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: amap_lookups
2026/07/15 07:15 openbsd c070732167b6 2130f682 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: amap_lookups
2026/07/15 02:23 openbsd c070732167b6 2130f682 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-setuid uvm_fault: amap_lookups
2026/07/14 02:47 openbsd 925b83c94733 2130f682 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-setuid uvm_fault: amap_lookups
2026/07/14 00:24 openbsd 925b83c94733 2130f682 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-setuid uvm_fault: amap_lookups
* Struck through repros no longer work on HEAD.