syzbot


panic: chgproccnt: procs < NUM

Status: upstream: reported on 2025/02/22 06:58
Reported-by: syzbot+265d5006dac2f45c9e9d@syzkaller.appspotmail.com
First crash: 366d, last: 29d

Sample crash report:
panic: chgproccnt: procs < 0
Stopped at      db_enter+0x25:  addq    $0x8,%rsp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
*476109  23390      0        0x10  0x4000000    0  syz-executor
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
panic(ffffffff83404581) at panic+0x1cf sys/kern/subr_prf.c:198
chgproccnt(212a200,ffffffff) at chgproccnt+0xcc
sys_setreuid(ffff800031903a30,ffff80003c930f50,ffff80003c930ea0) at sys_setreuid+0x563 sys/kern/kern_prot.c:688
syscall(ffff80003c930f50) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80003c930f50) at syscall+0x962 sys/arch/amd64/amd64/trap.c:775
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x3a64a5bc120, 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: chgproccnt: procs < 0
ddb> trace
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
panic(ffffffff83404581) at panic+0x1cf sys/kern/subr_prf.c:198
chgproccnt(212a200,ffffffff) at chgproccnt+0xcc
sys_setreuid(ffff800031903a30,ffff80003c930f50,ffff80003c930ea0) at sys_setreuid+0x563 sys/kern/kern_prot.c:688
syscall(ffff80003c930f50) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80003c930f50) at syscall+0x962 sys/arch/amd64/amd64/trap.c:775
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x3a64a5bc120, count: -6
ddb> show registers
rdi                                0
rsi                              0x1
rbp               0xffff80003c930d30
rbx                        0x212a200    __kernel_phys_base+0x112a200
rdx               0xffff800001573c40
rcx                                0
rax               0xffff800031903a30
r8                 0x101010101010101
r9                0x8080808080808080
r10               0x3fa2cd41b3f80d56
r11               0x7c8128c3121f82de
r12                                0
r13               0xfffffd8007bfd4e0
r14                                0
r15                              0x1
rip               0xffffffff81df8255    db_enter+0x25
cs                               0x8
rflags                         0x246
rsp               0xffff80003c930d20
ss                              0x10
db_enter+0x25:  addq    $0x8,%rsp
ddb> show proc
PROC (syz-executor) tid=476109 pid=23390 tcnt=4 stat=onproc
    flags process=10<SUGID> proc=4000000<THREAD>
    runpri=82, usrpri=82, slppri=32, nice=20
    wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0
    forw=0xffffffffffffffff, list=0xffff80003c93b248,0xffff8000319037a8
    process=0xffff8000ffff9b18 user=0xffff80003c92c000, vmspace=0xfffffd806cafbe78
    estcpu=32, cpticks=0, pctcpu=0.0, user=0, sys=0, intr=0
ddb> ps
   PID     TID   PPID    UID  S       FLAGS  WAIT          COMMAND
 66273  342514  51225      0  2           0                syz-executor
 87799   13456  54381     -1  2        0x10                syz-executor
 87799  375669  54381     -1  3   0x4000090  fsleep        syz-executor
 95728  248302  82148      0  2           0                syz-executor
 95728   63558  82148      0  2   0x4000000                syz-executor
  1170  238501  22237      0  2           0                syz-executor
  1170  122688  22237      0  2   0x4000000                syz-executor
  1170  109515  22237      0  2   0x4000000                syz-executor
  1170  384935  22237      0  2   0x4000000                syz-executor
 52992   62085  26045      0  3        0x80  nanoslp       syz-executor
 52992  496242  26045      0  2   0x4000000                syz-executor
 52992   14160  26045      0  3   0x4000080  fsleep        syz-executor
 52992   43768  26045      0  2   0x4000000                syz-executor
 23390   44865  24159      0  2        0x10                syz-executor
 23390  469747  24159      0  2   0x4000010                syz-executor
*23390  476109  24159      0  7   0x4000010                syz-executor
 23390  468473  24159      0  3   0x4000090  fsleep        syz-executor
 45551  181004      0      0  3     0x14280  nfsidl        nfsio
  1252  405378      0      0  3     0x14280  nfsidl        nfsio
 46014  238512      0      0  3     0x14280  nfsidl        nfsio
 71629  469681      0      0  3     0x14280  nfsidl        nfsio
 39946  380879      0      0  3     0x14280  nfsidl        nfsio
 37301  446439      0      0  3     0x14280  nfsidl        nfsio
 63469  520318      0      0  3     0x14280  nfsidl        nfsio
 25123   48798      0      0  3     0x14280  nfsidl        nfsio
 55651  197271      0      0  3     0x14280  nfsidl        nfsio
 15753  217182      0      0  3     0x14280  nfsidl        nfsio
 95318  334071      0      0  3     0x14280  nfsidl        nfsio
 98979  363536      0      0  3     0x14280  nfsidl        nfsio
 19148  342967      0      0  3     0x14280  nfsidl        nfsio
 93289  309450      0      0  3     0x14280  nfsidl        nfsio
  1284  468283      0      0  3     0x14280  nfsidl        nfsio
 68384  263073      0      0  3     0x14280  nfsidl        nfsio
 75035  463148      0      0  3     0x14280  nfsidl        nfsio
 43569   93024      0      0  3     0x14280  nfsidl        nfsio
 79703  135773      0      0  3     0x14280  nfsidl        nfsio
 86752  478933      0      0  3     0x14280  nfsidl        nfsio
 17901  371677  66438      0  3        0x82  wait          syz-executor
 82148   91095  66438      0  3        0x82  nanoslp       syz-executor
 22237  491919  66438      0  3        0x82  nanoslp       syz-executor
 54381   35980  66438      0  3        0x82  nanoslp       syz-executor
 24159  486974  66438      0  3        0x82  nanoslp       syz-executor
 51225   84913  66438      0  3        0x82  nanoslp       syz-executor
 26045  286662  66438      0  3        0x82  nanoslp       syz-executor
  9836  471851  66438      0  2         0x2                syz-executor
 66438  253740   1051      0  3        0x82  kqread        syz-executor
  1051  243907  81896      0  3    0x10008a  sigsusp       ksh
 81896  384394  85264      0  3        0x98  kqread        sshd-session
 85264  150825  71689      0  3        0x92  kqread        sshd-session
 29659  113418      1      0  3    0x100083  ttyopn        getty
 71689   99155      1      0  3        0x88  kqread        sshd
 79513  191390  92213     73  3   0x1100090  kqread        syslogd
 92213   77833      1      0  3    0x100082  sbwait        syslogd
 96678  269385      1      0  3    0x100080  kqread        resolvd
 63625  455063  36120     77  3    0x100092  kqread        dhcpleased
 98443  499462  36120     77  3    0x100092  kqread        dhcpleased
 36120  137274      1      0  3        0x80  kqread        dhcpleased
 80755  486825      0      0  3     0x14200  bored         smr
 35862   12227      0      0  2     0x14200                zerothread
 81087    1827      0      0  3     0x14200  aiodoned      aiodoned
 36236  326646      0      0  3     0x14200  syncer        update
 40889  192305      0      0  3     0x14200  cleaner       cleaner
 36299  149432      0      0  3     0x14200  reaper        reaper
 62920  481795      0      0  3     0x14200  pgdaemon      pagedaemon
 49424   72420      0      0  3     0x14200  bored         viomb
 24833  171058      0      0  3  0x40014200  acpi0         acpi0
 49326  144892      0      0  3     0x14200  bored         softnet0
 77135  201560      0      0  3     0x14200  bored         systqmp
 79132  259426      0      0  3     0x14200  bored         systq
 92757   97898      0      0  3  0x40014200  tmoslp        softclock
 89061  187722      0      0  3  0x40014200                idle0
     1  134968      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 11069  12176K   13201K 166960K     15051        0
            pcb    17     16K      18K 166960K       677        0
         rtable   161     10K      10K 166960K       714        0
             pf    29     12K      14K 166960K       139        0
         ifaddr    25      3K       8K 166960K       116        0
        ifgroup    46      2K       2K 166960K       176        0
         sysctl     4      1K       9K 166960K        14        0
       counters    32     17K      18K 166960K       170        0
       ioctlops     0      0K       4K 166960K       379        0
            iov     0      0K      16K 166960K       130        0
          mount     1      1K       1K 166960K         1        0
            log     0      0K       0K 166960K         4        0
         vnodes  1590    100K     100K 166960K      2949        0
      UFS quota     1     32K      32K 166960K         1        0
      UFS mount     5     36K      36K 166960K         5        0
            shm     2      1K       5K 166960K        15        0
         VM map     2      1K       1K 166960K         2        0
            sem    12      0K       1K 166960K        42        0
        dirhash    12      2K       2K 166960K        39        0
           ACPI  1692    195K     286K 166960K     12470        0
      file desc    18     65K     232K 166960K      1443        0
          sigio     0      0K       0K 166960K        22        0
           proc    62     59K     100K 166960K       687        0
        subproc    72      4K       4K 166960K        99        0
    NFS srvsock     1      0K       0K 166960K         1        0
     NFS daemon     1     16K      16K 166960K         1        0
    ip_moptions     0      0K       0K 166960K       115        0
       in_multi    46      3K       7K 166960K       181        0
    ether_multi     1      0K       0K 166960K         9        0
            mrt     0      0K       0K 166960K         3        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       594        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   227    134K     154K 166960K     14543        0
       UVM aobj    48     13K      13K 166960K        59        0
     pinsyscall    39     78K      94K 166960K      2600        0
        memdesc     1      4K       4K 166960K         1        0
    crypto data     1      1K       1K 166960K         1        0
    ip6_options     0      0K       1K 166960K        81        0
            NDP    10      0K       2K 166960K        75        0
           temp    81   8676K    8783K 166960K     52909        0
         kqueue    13     20K      32K 166960K       279        0
      SYN cache     2      8K      16K 166960K         3        0
ddb> show all pools
Name      Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
rtpcb      120      207    0      204     3     0     3     3     0     8    2
rtentry    136      189    0      142     4     0     4     4     0     8    0
unpcb      144     1161    0     1146     9     5     4     6     0     8    3
syncache   336       11    0       11     3     2     1     1     0     8    1
tcpqe       32        7    0        7     2     1     1     1     0     8    1
tcpcb      736      450    0      442    13     6     7     7     0     8    5
arp         96       33    0       25     1     0     1     1     0     8    0
ipq         40        3    0        3     1     0     1     1     0     8    1
ipqe        40       37    0       37     1     0     1     1     0     8    1
inpcb      328     1625    0     1613    20    13     7     9     0     8    5
ip6q        72        1    0        1     1     1     0     1     0     8    0
ip6af       40        2    0        2     1     1     0     1     0     8    0
nd6        112       38    0       27     1     0     1     1     0     8    0
pkpcb       40        6    0        6     1     0     1     1     0     8    1
kcovpl      48       11    0        3     1     0     1     1     0     8    0
mppekey    1024       4    0        4     2     1     1     1     0     8    1
ppxss      1072     122    0      122     2     1     1     1     0     8    1
pppxif     1384      11    0       11     3     2     1     1     0     8    1
art_heap8  4096       5    0        0     5     0     5     5     0     8    0
art_heap4  256      796    0      558    30     4    26    29     0     8    7
art_table   40      801    0      558     5     0     5     5     0     8    0
art_node    32      187    0      146     1     0     1     1     0     8    0
sysvmsgpl   40        5    0        3     2     1     1     1     0     8    0
semapl     112       38    0       28     1     0     1     1     0     8    0
shmpl      112       50    0       10     2     0     2     2     0     8    0
dirhash    1024      35    0       18     3     0     3     3     0     8    0
dino2pl    256     3950    0     2450    95     0    95    95     0     8    0
ffsino     256     3950    0     2450    95     0    95    95     0     8    0
nchpl      144     5909    0     4210    65     1    64    64     0     8    0
rtmask      32       16    0       16     1     0     1     1     0     8    1
vnodes     216     5126    0        0   285     0   285   285     0     8    0
namei      1024   20176    0    20175     3     2     1     2     0     8    0
vcpupl     3904       5    0        0     1     0     1     1     0     8    0
vmpool     808        6    0        1     1     0     1     1     0     8    0
kstatmem   264      106    0       86     2     0     2     2     0     8    0
scsiplug    72        6    0        6     2     1     1     1     0     8    1
scxspl     216    22733    0    22733    10     8     2     8     1     8    2
plimitpl   152      522    0      506     1     0     1     1     0     8    0
sigapl     424     1725    0     1662     9     1     8     8     0     8    0
knotepl    120    50896    0    50849    41    31    10    17     0     8    8
kqueuepl   184      502    0      492     4     0     4     4     0     8    3
pipepl     304      285    0      258     7     2     5     5     0     8    2
fdescpl    448     1691    0     1661     5     1     4     5     0     8    0
filepl     120    10786    0    10566    24    10    14    14     0     8    5
lockfpl    104      766    0      763     4     0     4     4     0     8    3
lockfspl    48      360    0      357     2     0     2     2     0     8    1
sessionpl  144       31    0       23     1     0     1     1     0     8    0
pgrppl      48       53    0       37     1     0     1     1     0     8    0
ucredpl    104     1473    0     1458     1     0     1     1     0     8    0
zombiepl   144     2225    0     2224     2     1     1     1     0     8    0
processpl  1152    1725    0     1662     5     0     5     5     0     8    0
procpl     664     3775    0     3701    10     1     9     9     0     8    1
sosppl     176        1    0        1     1     0     1     1     0     8    1
sockpl     552     3232    0     3202    38    27    11    19     0     8    8
mcl64k     65536    183    0      183     3     2     1     1     0     8    1
mcl16k     16384      7    0        7     3     2     1     1     0     8    1
mcl12k     12288      2    0        2     1     0     1     1     0     8    1
mcl9k      9216       1    0        1     1     0     1     1     0     8    1
mcl8k      8192      80    0       80     3     2     1     1     0     8    1
mcl4k      4096    4266    0     4212    16     8     8    14     0     8    0
mcl2k2     2112       2    0        2     2     1     1     1     0     8    1
mcl2k      2048    1618    0     1618     4     2     2     2     0     8    2
mtagpl      96       31    0       16     1     0     1     1     0     8    0
mbufpl     256    17915    0    17800    18     0    18    18     0     8    6
bufpl      280     8527    0     2306   445     0   445   445     0     8    0
anonpl      24   267272    0   264077    86    30    56    56     0   187   17
amapchunkpl 152   50454    0    49979    50    16    34    34     0   158   13
amappl16   200     5482    0     5447    37    22    15    20     0     8    8
amappl15   192        5    0        5     1     1     0     1     0     8    0
amappl14   184        6    0        6     1     1     0     1     0     8    0
amappl13   176      444    0      442     1     0     1     1     0     8    0
amappl12   168     2068    0     2030     2     0     2     2     0     8    0
amappl11   160        4    0        4     1     1     0     1     0     8    0
amappl10   152       45    0       35     1     0     1     1     0     8    0
amappl9    144      246    0      246     1     1     0     1     0     8    0
amappl8    136       33    0       31     1     0     1     1     0     8    0
amappl7    128       95    0       93     1     0     1     1     0     8    0
amappl6    120      307    0      296     1     0     1     1     0     8    0
amappl5    112       88    0       80     1     0     1     1     0     8    0
amappl4    104      429    0      405     1     0     1     1     0     8    0
amappl3     96     8531    0     8440     3     0     3     3     0     8    0
amappl2     88     1850    0     1779     2     0     2     2     0     8    0
amappl1     80    16278    0    15745    14     1    13    13     0     8    0
amappl      88    13530    0    13369     5     0     5     5     0    92    0
uvmvnodes   80      143    0        0     3     0     3     3     0     8    0
dma65536   65536      1    0        1     1     0     1     1     0     8    1
dma32768   32768      1    0        1     1     0     1     1     0     8    1
dma4096    4096       2    0        2     2     2     0     1     0     8    0
dma2048    2048       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     1     0     1     0     8    0
dma128     128      255    0      255     2     1     1     1     0     8    1
dma64       64        8    0        8     3     2     1     1     0     8    1
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       58    0       11     1     0     1     1     0     8    0
uaddrrnd    24     1691    0     1661     1     0     1     1     0     8    0
uaddrbest   32        2    0        0     1     0     1     1     0     8    0
uaddr       24     1691    0     1661     1     0     1     1     0     8    0
vmmpekpl   168    14976    0    14930     3     0     3     3     0     8    0
vmmpepl    168   113690    0   111861   107    12    95    95     0   357   13
vmsppl     368     1690    0     1661     4     1     3     4     0     8    0
rwobjpl     40    32047    0    31016    16     2    14    14     0     8    0
pdppl      4096    3400    0     3329   125    54    71    82     0     8    0
pvpl        32   741212    0   732431   178    51   127   127     0   265   24
pmappl     216     1696    0     1662     3     0     3     3     0     8    0
extentpl    40       45    0       27     1     0     1     1     0     8    0
phpool     112      438    0       90    11     0    11    11     0     8    0
ddb> machine ddbcpu 0
No such command
ddb> trace
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
panic(ffffffff83404581) at panic+0x1cf sys/kern/subr_prf.c:198
chgproccnt(212a200,ffffffff) at chgproccnt+0xcc
sys_setreuid(ffff800031903a30,ffff80003c930f50,ffff80003c930ea0) at sys_setreuid+0x563 sys/kern/kern_prot.c:688
syscall(ffff80003c930f50) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80003c930f50) at syscall+0x962 sys/arch/amd64/amd64/trap.c:775
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x3a64a5bc120, count: -6
ddb> machine ddbcpu 1
No such command
ddb> trace
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
panic(ffffffff83404581) at panic+0x1cf sys/kern/subr_prf.c:198
chgproccnt(212a200,ffffffff) at chgproccnt+0xcc
sys_setreuid(ffff800031903a30,ffff80003c930f50,ffff80003c930ea0) at sys_setreuid+0x563 sys/kern/kern_prot.c:688
syscall(ffff80003c930f50) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80003c930f50) at syscall+0x962 sys/arch/amd64/amd64/trap.c:775
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x3a64a5bc120, count: -6

Crashes (8):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/24 12:14 openbsd 652212f689da 40acda8a .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main panic: chgproccnt: procs < NUM
2025/11/27 22:07 openbsd 7de01a79e4ba e8331348 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore panic: chgproccnt: procs < NUM
2025/11/16 02:48 openbsd 42d4ce758e42 f7988ea4 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main panic: chgproccnt: procs < NUM
2025/08/26 13:20 openbsd d9624900b8bd bf27483f .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore panic: chgproccnt: procs < NUM
2025/06/18 01:39 openbsd 7cbb080c3e94 e77fae15 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore panic: chgproccnt: procs < NUM
2025/05/17 15:40 openbsd 007267a8c99a f41472b0 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore panic: chgproccnt: procs < NUM
2025/05/12 09:11 openbsd 1d7d4b26237d 77908e5f .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore panic: chgproccnt: procs < NUM
2025/02/22 06:57 openbsd 6a403588e274 d34966d1 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore panic: chgproccnt: procs < NUM
* Struck through repros no longer work on HEAD.