syzbot


panic: chgproccnt: procs < NUM

Status: upstream: reported on 2025/02/22 06:58
Reported-by: syzbot+265d5006dac2f45c9e9d@syzkaller.appspotmail.com
First crash: 274d, last: 7d23h

Sample crash report:
panic: chgproccnt: procs < 0
Stopped at      db_enter+0x25:  addq    $0x8,%rsp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
*519805  92485      0        0x10  0x4000000    0  syz-executor
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
panic(ffffffff833ee998) at panic+0x1cf sys/kern/subr_prf.c:198
chgproccnt(ee00,ffffffff) at chgproccnt+0xcc
sys_setreuid(ffff80002a7ccd18,ffff80002f4ff280,ffff80002f4ff1d0) at sys_setreuid+0x563 sys/kern/kern_prot.c:688
syscall(ffff80002f4ff280) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80002f4ff280) at syscall+0x962 sys/arch/amd64/amd64/trap.c:765
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xd7a442e2170, 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(ffffffff833ee998) at panic+0x1cf sys/kern/subr_prf.c:198
chgproccnt(ee00,ffffffff) at chgproccnt+0xcc
sys_setreuid(ffff80002a7ccd18,ffff80002f4ff280,ffff80002f4ff1d0) at sys_setreuid+0x563 sys/kern/kern_prot.c:688
syscall(ffff80002f4ff280) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80002f4ff280) at syscall+0x962 sys/arch/amd64/amd64/trap.c:765
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xd7a442e2170, count: -6
ddb> show registers
rdi                                0
rsi                              0x1
rbp               0xffff80002f4ff060
rbx                           0xee00    __ALIGN_SIZE+0xde00
rdx               0xffff800001465a40
rcx                                0
rax               0xffff80002a7ccd18
r8                 0x101010101010101
r9                0x8080808080808080
r10               0x1821fc8906c415c9
r11               0x253b96c0b14dcde6
r12                                0
r13               0xfffffd8007bfd208
r14                                0
r15                              0x1
rip               0xffffffff8287ba05    db_enter+0x25
cs                               0x8
rflags                         0x246
rsp               0xffff80002f4ff050
ss                              0x10
db_enter+0x25:  addq    $0x8,%rsp
ddb> show proc
PROC (syz-executor) tid=519805 pid=92485 tcnt=3 stat=onproc
    flags process=10<SUGID> proc=4000000<THREAD>
    runpri=50, usrpri=50, slppri=32, nice=20
    wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0
    forw=0xffffffffffffffff, list=0xffff80002a7e5cb0,0xffff80002a7ccfc0
    process=0xffff8000ffff8498 user=0xffff80002f4fa000, vmspace=0xfffffd806cb3f2f0
    estcpu=2, cpticks=0, pctcpu=0.0, user=0, sys=0, intr=0
ddb> ps
   PID     TID   PPID    UID  S       FLAGS  WAIT          COMMAND
 75046  182569  82324      0  2           0                syz-executor
 75046  522390  82324      0  3   0x4000080  fsleep        syz-executor
 75046  217541  82324      0  3   0x4000080  fsleep        syz-executor
 49605  281875   7815      0  2           0                syz-executor
 49605  183782   7815      0  3   0x4000080  fsleep        syz-executor
 49605  351860   7815      0  3   0x4000080  fsleep        syz-executor
 32129   37172  84257      0  2     0x82000                syz-executor
 32129   57732  84257      0  3   0x4002000  suspend       syz-executor
 92485  116548   8314      0  2        0x10                syz-executor
*92485  519805   8314      0  7   0x4000010                syz-executor
 92485  430067   8314      0  2   0x4000010                syz-executor
 58956  161995  17583      0  2           0                syz-executor
 58956  411530  17583      0  3   0x4000080  fsleep        syz-executor
 19143  308548  71517      0  3      0x3000  suspend       syz-executor
 19143  498612  71517      0  2   0x4081000                syz-executor
 86760  245471   3016      0  2         0x2                sh
  3016  287840  43720      0  2  0x10000002                syz-executor
 17583  373879  43720      0  3        0x82  nanoslp       syz-executor
  8314  304915  43720      0  3        0x82  nanoslp       syz-executor
 71517  227206  43720      0  3        0x82  nanoslp       syz-executor
  7815  423782  43720      0  3        0x82  nanoslp       syz-executor
 60128  399862  43720      0  2         0x2                syz-executor
 82324  306512  43720      0  3        0x82  nanoslp       syz-executor
 84257  135670  43720      0  3        0x82  nanoslp       syz-executor
 43720  490034  14767      0  3        0x82  kqread        syz-executor
 14767  186795  32498      0  3    0x10008a  sigsusp       ksh
 32498   83790  98261      0  3        0x98  kqread        sshd-session
 98261   55038  12532      0  3        0x92  kqread        sshd-session
 23348  401406      1      0  3    0x100083  ttyin         getty
 12532   61383      1      0  3        0x88  kqread        sshd
 59811  211449  38258     73  3   0x1100090  kqread        syslogd
 38258  509086      1      0  3    0x100082  sbwait        syslogd
 65910   48602      1      0  3    0x100080  kqread        resolvd
 99157  220042  61596     77  3    0x100092  kqread        dhcpleased
 96986   70433  61596     77  3    0x100092  kqread        dhcpleased
 61596  158392      1      0  3        0x80  kqread        dhcpleased
 41299  131336      0      0  3     0x14200  bored         smr
 97502  342703      0      0  2     0x14200                zerothread
 29641  334218      0      0  3     0x14200  aiodoned      aiodoned
 58582  391167      0      0  3     0x14200  syncer        update
 45483   53493      0      0  3     0x14200  cleaner       cleaner
 63702  119083      0      0  3     0x14200  reaper        reaper
 73275   69720      0      0  3     0x14200  pgdaemon      pagedaemon
 55845  298464      0      0  3     0x14200  bored         viomb
 23320   21410      0      0  3  0x40014200  acpi0         acpi0
 76131  510369      0      0  3     0x14200  bored         softnet0
 68978  325470      0      0  3     0x14200  bored         systqmp
 14337  343044      0      0  3     0x14200  bored         systq
 10881  440964      0      0  3  0x40014200  tmoslp        softclock
 66805   97398      0      0  3  0x40014200                idle0
     1   99684      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 10176  11131K   11558K 166960K     11344        0
            pcb    17     14K      16K 166960K       104        0
         rtable   203      6K       6K 166960K       372        0
             pf    30     12K      13K 166960K        42        0
         ifaddr    37      6K       7K 166960K        55        0
        ifgroup    48      2K       2K 166960K        70        0
         sysctl     1      1K       9K 166960K         5        0
       counters    32     17K      18K 166960K        40        0
       ioctlops     0      0K       2K 166960K        38        0
            iov     0      0K      12K 166960K         2        0
          mount     1      1K       1K 166960K         1        0
            log     0      0K       0K 166960K         4        0
         vnodes  1344     85K      85K 166960K      1572        0
      UFS quota     1     32K      32K 166960K         1        0
      UFS mount     5     36K      36K 166960K         5        0
            shm     2      1K       5K 166960K         4        0
         VM map     2      1K       1K 166960K         2        0
            sem     4      0K       0K 166960K         5        0
        dirhash    12      2K       2K 166960K        12        0
           ACPI  1692    195K     286K 166960K     12470        0
      file desc    17     61K      89K 166960K       200        0
          sigio     0      0K       0K 166960K         1        0
           proc    63     67K      91K 166960K       498        0
        subproc    72      4K       4K 166960K        81        0
    NFS srvsock     1      0K       0K 166960K         1        0
     NFS daemon     1     16K      16K 166960K         1        0
    ip_moptions     0      0K       0K 166960K         5        0
       in_multi    78      5K       6K 166960K       105        0
    ether_multi     1      0K       0K 166960K         1        0
    ISOFS mount     1     32K      32K 166960K         1        0
  MSDOSFS mount     1     16K      16K 166960K         1        0
           ttys    49    228K     228K 166960K        49        0
           exec     0      0K       1K 166960K       432        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   221    142K     151K 166960K      3491        0
       UVM aobj     6      2K       2K 166960K         6        0
     pinsyscall    38     76K      92K 166960K      1282        0
        memdesc     1      4K       4K 166960K         1        0
    crypto data     1      1K       1K 166960K         1        0
    ip6_options     1      0K       1K 166960K        10        0
            NDP    11      0K       1K 166960K        32        0
           temp    74   8660K    8728K 166960K      4248        0
         kqueue    13     20K      28K 166960K        34        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       40    0       37     1     0     1     1     0     8    0
rtentry    136      118    0       26     4     0     4     4     0     8    0
unpcb      144       47    0       32     1     0     1     1     0     8    0
syncache   336        3    0        3     1     1     0     1     0     8    0
tcpcb      736       32    0       26     1     0     1     1     0     8    0
arp         96       19    0        4     1     0     1     1     0     8    0
inpcb      328      167    0      158     7     6     1     7     0     8    0
nd6        112       25    0        6     1     0     1     1     0     8    0
kcovpl      48        9    0        1     1     0     1     1     0     8    0
ppxss      1072       4    0        3     2     1     1     1     0     8    0
pppxif     1384       3    0        3     2     1     1     1     0     8    1
art_heap8  4096       1    0        0     1     0     1     1     0     8    0
art_heap4  256      469    0      100    29     0    29    29     0     8    4
art_table   40      470    0      100     5     0     5     5     0     8    0
art_node    32      118    0       34     1     0     1     1     0     8    0
semapl     112        3    0        1     1     0     1     1     0     8    0
shmpl      112        3    0        0     1     0     1     1     0     8    0
dirhash    1024      17    0        0     3     0     3     3     0     8    0
dino2pl    256     1810    0      304    95     0    95    95     0     8    0
ffsino     256     1810    0      304    95     0    95    95     0     8    0
nchpl      144     2075    0      382    63     0    63    63     0     8    0
vnodes     216     1928    0        0   108     0   108   108     0     8    0
namei      1024    6348    0     6348     3     2     1     2     0     8    1
kstatmem   264       32    0       10     2     0     2     2     0     8    0
scsiplug    72        1    0        1     1     1     0     1     0     8    0
scxspl     216     6365    0     6365     9     1     8     8     1     8    8
plimitpl   152       65    0       49     1     0     1     1     0     8    0
sigapl     424      484    0      442     6     1     5     6     0     8    0
knotepl    120     4957    0     4910     9     0     9     9     0     8    5
kqueuepl   184       34    0       24     1     0     1     1     0     8    0
pipepl     304      120    0       93     3     0     3     3     0     8    0
fdescpl    448      471    0      442     5     1     4     5     0     8    0
filepl     120     2257    0     2044    15     8     7    15     0     8    0
lockfpl    104       38    0       36     1     0     1     1     0     8    0
lockfspl    48       13    0       11     1     0     1     1     0     8    0
sessionpl  144       22    0       14     1     0     1     1     0     8    0
pgrppl      48       32    0       16     1     0     1     1     0     8    0
ucredpl    104      604    0      591     1     0     1     1     0     8    0
zombiepl   144      466    0      465     2     1     1     1     0     8    0
processpl  1152     484    0      442     4     0     4     4     0     8    0
procpl     664      595    0      544     6     0     6     6     0     8    1
sosppl     176        1    0        1     1     0     1     1     0     8    1
sockpl     552      256    0      229     8     5     3     8     0     8    0
mcl64k     65536      3    0        3     1     1     0     1     0     8    0
mcl8k      8192       5    0        5     1     1     0     1     0     8    0
mcl4k      4096    2526    0     2470    14     6     8    14     0     8    0
mcl2k      2048     301    0      299     4     3     1     4     0     8    0
mtagpl      96        9    0        4     1     0     1     1     0     8    0
mbufpl     256     4784    0     4634    18     0    18    18     0     8    1
bufpl      280     2331    0      118   159     0   159   159     0     8    0
anonpl      24    85380    0    82371    21     2    19    21     0   187    0
amapchunkpl 152    9635    0     9182    20     1    19    19     0   158    0
amappl16   200     1176    0     1156     4     2     2     4     0     8    0
amappl15   192        7    0        7     1     1     0     1     0     8    0
amappl14   184        6    0        6     1     1     0     1     0     8    0
amappl13   176      435    0      433     1     0     1     1     0     8    0
amappl12   168      803    0      766     2     0     2     2     0     8    0
amappl11   160       10    0       10     1     1     0     1     0     8    0
amappl10   152       43    0       32     1     0     1     1     0     8    0
amappl9    144      254    0      253     1     0     1     1     0     8    0
amappl8    136       19    0       18     1     0     1     1     0     8    0
amappl7    128       86    0       85     1     0     1     1     0     8    0
amappl6    120      266    0      253     1     0     1     1     0     8    0
amappl5    112       72    0       65     1     0     1     1     0     8    0
amappl4    104      377    0      354     1     0     1     1     0     8    0
amappl3     96     1552    0     1466     3     0     3     3     0     8    0
amappl2     88      565    0      500     2     0     2     2     0     8    0
amappl1     80     8938    0     8412    12     0    12    12     0     8    0
amappl      88     2790    0     2636     4     0     4     4     0    92    0
uvmvnodes   80       97    0        0     2     0     2     2     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        5    0        0     1     0     1     1     0     8    0
uaddrrnd    24      471    0      442     1     0     1     1     0     8    0
uaddrbest   32        2    0        0     1     0     1     1     0     8    0
uaddr       24      471    0      442     1     0     1     1     0     8    0
vmmpekpl   168     5493    0     5453     2     0     2     2     0     8    0
vmmpepl    168    37041    0    35330    80     2    78    79     0   357    0
vmsppl     368      470    0      442     4     1     3     4     0     8    0
rwobjpl     40    12915    0    11997    10     0    10    10     0     8    0
pdppl      4096     949    0      884    97    30    67    79     0     8    2
pvpl        32   217558    0   208885    82     3    79    79     0   265    7
pmappl     216      470    0      442     2     0     2     2     0     8    0
extentpl    40       45    0       27     1     0     1     1     0     8    0
phpool     112      375    0       48    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(ffffffff833ee998) at panic+0x1cf sys/kern/subr_prf.c:198
chgproccnt(ee00,ffffffff) at chgproccnt+0xcc
sys_setreuid(ffff80002a7ccd18,ffff80002f4ff280,ffff80002f4ff1d0) at sys_setreuid+0x563 sys/kern/kern_prot.c:688
syscall(ffff80002f4ff280) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80002f4ff280) at syscall+0x962 sys/arch/amd64/amd64/trap.c:765
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xd7a442e2170, 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(ffffffff833ee998) at panic+0x1cf sys/kern/subr_prf.c:198
chgproccnt(ee00,ffffffff) at chgproccnt+0xcc
sys_setreuid(ffff80002a7ccd18,ffff80002f4ff280,ffff80002f4ff1d0) at sys_setreuid+0x563 sys/kern/kern_prot.c:688
syscall(ffff80002f4ff280) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80002f4ff280) at syscall+0x962 sys/arch/amd64/amd64/trap.c:765
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xd7a442e2170, count: -6

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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.