syzbot


witness: shared lock of (rwlock) mpaddr while exclusively locked

Status: upstream: reported on 2026/01/03 14:57
Reported-by: syzbot+610755708e0266e487b2@syzkaller.appspotmail.com
First crash: 53d, last: 53d

Sample crash report:
witness: shared lock of (rwlock) mpaddr while exclusively locked
anic: excl->share
Stopped at      db_enter+0x25:  addq    $0x8,%rsp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
 288305  73040      0         0x2          0    0  syz-executor
*349296  96838      0     0x14000      0x200    1  softnet0
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
panic(ffffffff833b5a1c) at panic+0x1e5 sys/kern/subr_prf.c:198
witness_checkorder(ffff800000c31078,1,0) at witness_checkorder+0x122c sys/kern/subr_witness.c:854
rw_do_enter_read(ffff800000c31060,0) at rw_do_enter_read+0x99 sys/kern/kern_rwlock.c:355
in6_hasmulti(fffffd8064e01af0,ffff800000c31000) at in6_hasmulti+0x41 in6_lookupmulti sys/netinet6/in6.c:-1 [inline]
in6_hasmulti(fffffd8064e01af0,ffff800000c31000) at in6_hasmulti+0x41 sys/netinet6/in6.c:1150
ip6_output(fffffd8064e01a00,ffffffff83987338,0,0,ffff80002a210480,0) at ip6_output+0x13bd sys/netinet6/ip6_output.c:507
mld6_sendpkt(ffff80000154e700,84,ffff80002a210518) at mld6_sendpkt+0x385 sys/netinet6/mld6.c:499
mld6_stop_listening(ffff80000154e700,ffff800000c31000) at mld6_stop_listening+0x125 sys/netinet6/mld6.c:168
in6_delmulti(ffff80000154e700) at in6_delmulti+0xb1 sys/netinet6/in6.c:1118
in6_purgeaddr(ffff800001614c00) at in6_purgeaddr+0x1d5 in6_leavegroup sys/netinet6/in6.c:1181 [inline]
in6_purgeaddr(ffff800001614c00) at in6_purgeaddr+0x1d5 sys/netinet6/in6.c:916
nd6_expire(0) at nd6_expire+0x111 sys/netinet6/nd6.c:-1
taskq_thread(ffff80000002c000) at taskq_thread+0x157 sys/kern/kern_task.c:446
end trace frame: 0x0, count: 3
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{1}> 
ddb{1}> set $lines = 0
ddb{1}> set $maxwidth = 0
ddb{1}> show panic
*cpu1: excl->share
ddb{1}> trace
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
panic(ffffffff833b5a1c) at panic+0x1e5 sys/kern/subr_prf.c:198
witness_checkorder(ffff800000c31078,1,0) at witness_checkorder+0x122c sys/kern/subr_witness.c:854
rw_do_enter_read(ffff800000c31060,0) at rw_do_enter_read+0x99 sys/kern/kern_rwlock.c:355
in6_hasmulti(fffffd8064e01af0,ffff800000c31000) at in6_hasmulti+0x41 in6_lookupmulti sys/netinet6/in6.c:-1 [inline]
in6_hasmulti(fffffd8064e01af0,ffff800000c31000) at in6_hasmulti+0x41 sys/netinet6/in6.c:1150
ip6_output(fffffd8064e01a00,ffffffff83987338,0,0,ffff80002a210480,0) at ip6_output+0x13bd sys/netinet6/ip6_output.c:507
mld6_sendpkt(ffff80000154e700,84,ffff80002a210518) at mld6_sendpkt+0x385 sys/netinet6/mld6.c:499
mld6_stop_listening(ffff80000154e700,ffff800000c31000) at mld6_stop_listening+0x125 sys/netinet6/mld6.c:168
in6_delmulti(ffff80000154e700) at in6_delmulti+0xb1 sys/netinet6/in6.c:1118
in6_purgeaddr(ffff800001614c00) at in6_purgeaddr+0x1d5 in6_leavegroup sys/netinet6/in6.c:1181 [inline]
in6_purgeaddr(ffff800001614c00) at in6_purgeaddr+0x1d5 sys/netinet6/in6.c:916
nd6_expire(0) at nd6_expire+0x111 sys/netinet6/nd6.c:-1
taskq_thread(ffff80000002c000) at taskq_thread+0x157 sys/kern/kern_task.c:446
end trace frame: 0x0, count: -12
ddb{1}> show registers
rdi                                0
rsi                              0x1
rbp               0xffff80002a2100d0
rbx               0xffff8000299dee07
rdx                                0
rcx               0xffff8000ffffe298
rax               0xffff8000299ddff0
r8                 0x101010101010101
r9                0x8080808080808080
r10               0x3164f5fb8233b428
r11               0x62e399ec95bd36bd
r12               0xffff8000299dec08
r13                                0
r14                                0
r15                              0x1
rip               0xffffffff817c1d35    db_enter+0x25
cs                               0x8
rflags                         0x246
rsp               0xffff80002a2100c0
ss                              0x10
db_enter+0x25:  addq    $0x8,%rsp
ddb{1}> show proc
PROC (softnet0) tid=349296 pid=96838 tcnt=1 stat=onproc
    flags process=14000<NOZOMBIE,SYSTEM> proc=200<SYSTEM>
    runpri=32, usrpri=50, slppri=32, nice=20
    wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0
    forw=0xffffffffffffffff, list=0xffff8000ffffe530,0xffff8000ffffe010
    process=0xffff8000ffff8000 user=0xffff80002a20b000, vmspace=0xffffffff838bee00
    estcpu=0, cpticks=14, pctcpu=0.1, user=0, sys=0, intr=0
ddb{1}> ps
   PID     TID   PPID    UID  S       FLAGS  WAIT          COMMAND
 97502  370282  52484      0  2           0                syz-executor
 97502  330749  52484      0  2   0x4000000                syz-executor
 98966  132725  88774      0  2           0                syz-executor
 98966  347775  88774      0  3   0x4000080  fsleep        syz-executor
 11064   66418  13356      0  2           0                syz-executor
 11064  148167  13356      0  3   0x4000080  fsleep        syz-executor
 98203  312873  46190      0  2           0                syz-executor
 98203  134274  46190      0  3   0x4000080  fsleep        syz-executor
 98203  426634  46190      0  2   0x4000000                syz-executor
 28829  199161   9023      0  2           0                syz-executor
 28829  105221   9023      0  3   0x4000080  fsleep        syz-executor
 33888  162273  17076      0  2           0                syz-executor
 33888  396099  17076      0  2   0x4000000                syz-executor
 69539  353873  58503      0  3      0x3000  suspend       syz-executor
 69539  356269  58503      0  2   0x4081000                syz-executor
 69539  317991  58503      0  3   0x4081000  inode         syz-executor
 69539  379110  58503      0  3   0x4081000  inode         syz-executor
 52484  255404  92881      0  2       0xc82                syz-executor
  2045   14661      0      0  3     0x14200  acct          acct
 90255  230138      0      0  3     0x14280  nfsidl        nfsio
 49549  119018      0      0  3     0x14280  nfsidl        nfsio
 40092  254536      0      0  3     0x14280  nfsidl        nfsio
 55083  428941      0      0  3     0x14280  nfsidl        nfsio
 75604  127508      0      0  3     0x14280  nfsidl        nfsio
 88232   43767      0      0  3     0x14280  nfsidl        nfsio
 19713  123936      0      0  3     0x14280  nfsidl        nfsio
 20335   94694      0      0  3     0x14280  nfsidl        nfsio
  9627  240984      0      0  3     0x14280  nfsidl        nfsio
 34727  476340      0      0  3     0x14280  nfsidl        nfsio
 45833  160482      0      0  3     0x14280  nfsidl        nfsio
 66537  140883      0      0  3     0x14280  nfsidl        nfsio
 90730    5723      0      0  3     0x14280  nfsidl        nfsio
  1778  241688      0      0  3     0x14280  nfsidl        nfsio
 58604  104856      0      0  3     0x14280  nfsidl        nfsio
 58365  158385      0      0  3     0x14280  nfsidl        nfsio
 70727  159903      0      0  3     0x14280  nfsidl        nfsio
 75252   83450      0      0  3     0x14280  nfsidl        nfsio
 39268  215502      0      0  3     0x14280  nfsidl        nfsio
 39922  175264      0      0  3     0x14280  nfsidl        nfsio
 13356  101328  92881      0  2       0xc82                syz-executor
  9023   11106  92881      0  2       0xc82                syz-executor
 88774  184617  92881      0  2       0xc82                syz-executor
 17076  328689  92881      0  2       0xc82                syz-executor
 73040  288305  92881      0  7         0x2                syz-executor
 46190  501937  92881      0  2       0xc82                syz-executor
 58503    4195  92881      0  2         0x2                syz-executor
 92881  218250  46883      0  2         0x2                syz-executor
 46883  171983   6161      0  3    0x10008a  sigsusp       ksh
  6161  240842  93387      0  3        0x98  kqread        sshd-session
 93387  428035  75112      0  3        0x92  kqread        sshd-session
 24028   90134      1      0  3    0x100083  ttyopn        getty
 75112  126355      1      0  3        0x88  kqread        sshd
 70609  127837  99424     74  3   0x1100092  bpf           pflogd
 99424  307506      1      0  3        0x80  sbwait        pflogd
  9925  246459  22192     73  3   0x1100090  kqread        syslogd
 22192  431049      1      0  3    0x100082  sbwait        syslogd
 37469  153095      1      0  3    0x100080  kqread        resolvd
  6961  158867  90982     77  3    0x100092  kqread        dhcpleased
 97554  309750  90982     77  3    0x100092  kqread        dhcpleased
 90982  111683      1      0  3        0x80  kqread        dhcpleased
 11989  456837      0      0  3     0x14200  bored         smr
 45121  422307      0      0  2     0x14200                zerothread
 26572   96118      0      0  3     0x14200  aiodoned      aiodoned
 90128    1801      0      0  2     0x14e00                update
 11425   40690      0      0  3     0x14200  cleaner       cleaner
 30935  466208      0      0  3     0x14200  reaper        reaper
 42638   49824      0      0  3     0x14200  pgdaemon      pagedaemon
 78495   55358      0      0  3     0x14200  bored         viomb
 45508  294912      0      0  3  0x40014200  acpi0         acpi0
 87212   82260      0      0  3  0x40014200                idle1
 66370  342418      0      0  3     0x14200  bored         softnet1
*96838  349296      0      0  7     0x14200                softnet0
 94911  178857      0      0  3     0x14200  smrbar        systqmp
  7469  330958      0      0  3     0x14200  bored         systq
 37308  247007      0      0  3     0x14200  tmoslp        softclockmp
 86495   13074      0      0  3  0x40014200  tmoslp        softclock
 19450  160408      0      0  3  0x40014200                idle0
     1  241704      0      0  3     0x80082  wait          init
     0       0     -1      0  3  0x10010200  scheduler     swapper
ddb{1}> show all locks
Process 98203 (syz-executor) thread 0xffff80003c4defc8 (312873)
exclusive rwlock vmmaplk r = 0 (0xfffffd80649e34f8)
#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_write+0x419 sys/kern/kern_rwlock.c:320
#2  vm_map_lock_ln+0x12e sys/uvm/uvm_map.c:5165
#3  uvm_map_protect+0xe0 sys/uvm/uvm_map.c:3069
#4  sys_mprotect+0x351 sys/uvm/uvm_mmap.c:590
#5  syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
#5  syscall+0xbd4 sys/arch/amd64/amd64/trap.c:775
#6  Xsyscall+0x128
Process 69539 (syz-executor) thread 0xffff80003c4de038 (356269)
exclusive rrwlock inode r = 0 (0xfffffd806ef0eb70)
#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_write+0x419 sys/kern/kern_rwlock.c:320
#2  rrw_enter+0xc6 sys/kern/kern_rwlock.c:621
#3  VOP_LOCK+0xbd sys/kern/vfs_vops.c:527
#4  vn_lock+0xa4 sys/kern/vfs_vnops.c:570
#5  vn_write+0x18f sys/kern/vfs_vnops.c:405
#6  dofilewritev+0x242 sys/kern/sys_generic.c:380
#7  sys_write+0xa2 sys/kern/sys_generic.c:300
#8  syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
#8  syscall+0xbd4 sys/arch/amd64/amd64/trap.c:775
#9  Xsyscall+0x128
Process 69539 (syz-executor) thread 0xffff80003c4de2d0 (317991)
exclusive rrwlock inode r = 0 (0xfffffd806bdf78f8)
#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_write+0x419 sys/kern/kern_rwlock.c:320
#2  rrw_enter+0xc6 sys/kern/kern_rwlock.c:621
#3  VOP_LOCK+0xbd sys/kern/vfs_vops.c:527
#4  vn_lock+0xa4 sys/kern/vfs_vnops.c:570
#5  vfs_lookup+0x11c sys/kern/vfs_lookup.c:-1
#6  namei+0x7ca sys/kern/vfs_lookup.c:250
#7  domknodat+0xb4 sys/kern/vfs_syscalls.c:1592
#8  syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline]
#8  syscall+0xb17 sys/arch/amd64/amd64/trap.c:775
#9  Xsyscall+0x128
Process 73040 (syz-executor) thread 0xffff8000ffffc538 (288305)
exclusive rwlock amaplk r = 0 (0xfffffd806c432d00)
#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_write+0x419 sys/kern/kern_rwlock.c:320
#2  uvm_fault_check+0x8a9 sys/uvm/uvm_fault.c:834
#3  uvm_fault+0x106 sys/uvm/uvm_fault.c:627
#4  kpageflttrap+0x2f4 sys/arch/amd64/amd64/trap.c:283
#5  kerntrap+0x19c sys/arch/amd64/amd64/trap.c:520
#6  alltraps_kern_meltdown+0x7b
#7  copyout+0x64
#8  ufs_readdir+0x427 sys/ufs/ufs/ufs_vnops.c:-1
#9  VOP_READDIR+0x125 sys/kern/vfs_vops.c:453
#10 sys_getdents+0x2df sys/kern/vfs_syscalls.c:3183
#11 syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline]
#11 syscall+0xb17 sys/arch/amd64/amd64/trap.c:775
#12 Xsyscall+0x128
shared rwlock vmmaplk r = 0 (0xfffffd800b063100)
#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  kpageflttrap+0x2f4 sys/arch/amd64/amd64/trap.c:283
#6  kerntrap+0x19c sys/arch/amd64/amd64/trap.c:520
#7  alltraps_kern_meltdown+0x7b
#8  copyout+0x64
#9  ufs_readdir+0x427 sys/ufs/ufs/ufs_vnops.c:-1
#10 VOP_READDIR+0x125 sys/kern/vfs_vops.c:453
#11 sys_getdents+0x2df sys/kern/vfs_syscalls.c:3183
#12 syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline]
#12 syscall+0xb17 sys/arch/amd64/amd64/trap.c:775
#13 Xsyscall+0x128
exclusive kernel_lock &kernel_lock r = 0 (0xffffffff83970b08)
#0  witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline]
#0  witness_lock+0x5f1 sys/kern/subr_witness.c:1160
#1  __mp_acquire_count+0x58 sys/kern/kern_lock.c:-1
#2  malloc+0xe3 sys/kern/kern_malloc.c:175
#3  ufs_readdir+0x13f sys/ufs/ufs/ufs_vnops.c:1364
#4  VOP_READDIR+0x125 sys/kern/vfs_vops.c:453
#5  sys_getdents+0x2df sys/kern/vfs_syscalls.c:3183
#6  syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline]
#6  syscall+0xb17 sys/arch/amd64/amd64/trap.c:775
#7  Xsyscall+0x128
exclusive rrwlock inode r = 0 (0xfffffd80606d6460)
#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_write+0x419 sys/kern/kern_rwlock.c:320
#2  rrw_enter+0xc6 sys/kern/kern_rwlock.c:621
#3  VOP_LOCK+0xbd sys/kern/vfs_vops.c:527
#4  vn_lock+0xa4 sys/kern/vfs_vnops.c:570
#5  sys_getdents+0x254 sys/kern/vfs_syscalls.c:3168
#6  syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline]
#6  syscall+0xb17 sys/arch/amd64/amd64/trap.c:775
#7  Xsyscall+0x128
Process 96838 (softnet0) thread 0xffff8000ffffe298 (349296)
exclusive rwlock maddr r = 0 (0xffff800000c31078)
#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_write+0x419 sys/kern/kern_rwlock.c:320
#2  in6_delmulti+0x9d sys/netinet6/in6.c:1116
#3  in6_purgeaddr+0x1d5 in6_leavegroup sys/netinet6/in6.c:1181 [inline]
#3  in6_purgeaddr+0x1d5 sys/netinet6/in6.c:916
#4  nd6_expire+0x111 sys/netinet6/nd6.c:-1
#5  taskq_thread+0x157 sys/kern/kern_task.c:446
#6  proc_trampoline+0x10
exclusive rwlock netlock r = 0 (0xffffffff83832e50)
#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_write+0x419 sys/kern/kern_rwlock.c:320
#2  nd6_expire+0x2e sys/netinet6/nd6.c:467
#3  taskq_thread+0x157 sys/kern/kern_task.c:446
#4  proc_trampoline+0x10
shared rwlock softnet0 r = 0 (0xffff80000002c078)
#0  witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline]
#0  witness_lock+0x5f1 sys/kern/subr_witness.c:1160
#1  taskq_thread+0x12a sys/kern/kern_task.c:442
#2  proc_trampoline+0x10
Process 94911 (systqmp) thread 0xffff8000ffffe530 (178857)
shared rwlock systqmp r = 0 (0xffffffff837bcb68)
#0  witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline]
#0  witness_lock+0x5f1 sys/kern/subr_witness.c:1160
#1  taskq_thread+0x12a sys/kern/kern_task.c:442
#2  proc_trampoline+0x10
ddb{1}> show malloc
           Type InUse  MemUse  HighUse   Limit  Requests Type Lim
         devbuf 11079  12101K   12416K 166960K     13189        0
            pcb    18     12K      12K 166960K       123        0
         rtable   233     10K      10K 166960K       462        0
             pf    39     18K      19K 166960K        99        0
         ifaddr    43      7K       7K 166960K        80        0
        ifgroup    61      2K       2K 166960K       107        0
         sysctl     3      1K       9K 166960K        12        0
       counters    76     37K      38K 166960K       148        0
       ioctlops     0      0K       4K 166960K      1586        0
            iov     0      0K      26K 166960K        77        0
          mount     1      1K       1K 166960K         1        0
            log     0      0K       0K 166960K         4        0
         vnodes  1404     88K      89K 166960K      1983        0
      UFS quota     1     32K      32K 166960K         1        0
      UFS mount     5     36K      36K 166960K         5        0
            shm     2      1K       9K 166960K         8        0
         VM map     2      1K       1K 166960K         2        0
            sem    12      0K       0K 166960K        31        0
        dirhash    12      2K       3K 166960K        33        0
           ACPI  1692    195K     286K 166960K     12470        0
      file desc    17     61K      93K 166960K       697        0
          sigio     0      0K       0K 166960K        13        0
           proc    72    115K     180K 166960K       621        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        69        0
       in_multi    90      6K       7K 166960K       137        0
    ether_multi     1      0K       0K 166960K         2        0
            mrt     2      0K       0K 166960K         6        0
    ISOFS mount     1     32K      32K 166960K         1        0
  MSDOSFS mount     1     16K      16K 166960K         1        0
           ttys   103    466K     466K 166960K       103        0
           exec     0      0K       1K 166960K       468        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   233    159K     173K 166960K      8186        0
       UVM aobj    10      2K       2K 166960K        10        0
     pinsyscall    42     84K     104K 166960K      1852        0
        memdesc     1      4K       4K 166960K         1        0
    crypto data     1      1K       1K 166960K         1        0
    ip6_options     0      0K       0K 166960K        42        0
            NDP    14      0K       1K 166960K        54        0
           temp    54   8674K    8746K 166960K     35810        0
         kqueue    14     22K      28K 166960K       149        0
      SYN cache     2     16K      16K 166960K         2        0
ddb{1}> show all pools
Name      Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
plcache    128       26    0        0     1     0     1     1     0     8    0
rtpcb      120      104    0      101     2     1     1     2     0     8    0
rtentry    176      136    0       43     6     0     6     6     0     8    0
unpcb      144      285    0      267     2     1     1     2     0     8    0
syncache   336        4    0        4     2     2     0     1     0     8    0
tcpcb      736      185    0      181     2     1     1     2     0     8    0
arp        136       20    0        6     1     0     1     1     0     8    0
inpcb      328      767    0      759    14     7     7     7     0     8    6
nd6        152       29    0        6     1     0     1     1     0     8    0
pkpcb       40       40    0       40     3     2     1     1     0     8    1
kcovpl      48        9    0        1     1     0     1     1     0     8    0
mppekey    1024       1    0        1     1     1     0     1     0     8    0
ppxss      1192      36    0       34     2     1     1     1     0     8    0
pfstscr     40        1    0        1     1     1     0     1     0     8    0
pffrag     232        5    0        1     1     0     1     1     0   482    0
pffrnode    88        5    0        1     1     0     1     1     0     8    0
pffrent     40        8    0        4     1     0     1     1     0     8    0
pfosfp      40     1428    0     1005     5     0     5     5     0     8    0
pfosfpen   112     1428    0      714    21     0    21    21     0     8    0
pfstitem    24       54    0        4     1     0     1     1     0     8    0
pfstkey    128       55    0        5     2     0     2     2     0     8    0
pfstate    448       55    0        5     6     0     6     6     0     8    0
pfrule     1344      25    0       20     2     1     1     2     0     8    0
rttmr      136        2    0        1     2     1     1     1     0     8    0
art_heap8  4096       3    0        0     3     0     3     3     0     8    0
art_heap4  256      671    0      208    31     2    29    29     0     8    0
art_table   40      674    0      208     5     0     5     5     0     8    0
art_node    32      135    0       51     1     0     1     1     0     8    0
sysvmsgpl   40        5    0        2     1     0     1     1     0     8    0
semupl     112        4    0        4     1     1     0     1     0     8    0
semapl     112       28    0       18     1     0     1     1     0     8    0
shmpl      112        7    0        0     1     0     1     1     0     8    0
dirhash    1024      31    0       14     3     0     3     3     0     8    0
dino2pl    256     2687    0     1178    96     0    96    96     0     8    0
ffsino     296     2687    0     1178   118     0   118   118     0     8    0
nchpl      144     3626    0     1929    64     0    64    64     0     8    0
rtmask      32       11    0       11     2     2     0     1     0     8    0
vnodes     216     3151    0        0   176     0   176   176     0     8    0
namei      1024   11979    0    11977     3     2     1     2     0     8    0
percpumem   16       89    0       36     1     0     1     1     0     8    0
kstatmem   264       74    0       42     4     1     3     3     0     8    0
scsiplug    72        2    0        2     2     1     1     1     0     8    1
scxspl     216    16647    0    16646    10     9     1     8     1     8    0
plimitpl   152      248    0      230     1     0     1     1     0     8    0
sigapl     424     1026    0      958     8     0     8     8     0     8    0
knotepl    120      625    0        0    19     0    19    19     0     8    0
kqueuepl   224      244    0      234     2     1     1     2     0     8    0
pipepl     344      159    0      132     3     0     3     3     0     8    0
fdescpl    528      988    0      957     3     0     3     3     0     8    0
filepl     160     5625    0     5410    23    10    13    19     0     8    3
lockfpl    104      221    0      219     1     0     1     1     0     8    0
lockfspl    48       93    0       91     1     0     1     1     0     8    0
sessionpl  144       24    0       15     1     0     1     1     0     8    0
pgrppl      48       40    0       23     1     0     1     1     0     8    0
ucredpl    104      812    0      798     1     0     1     1     0     8    0
zombiepl   144      993    0      992     1     0     1     1     0     8    0
processpl  1232    1026    0      958     6     0     6     6     0     8    0
procpl     664     1991    0     1913     8     0     8     8     0     8    0
sosppl     176        5    0        5     3     2     1     1     0     8    1
sockpl     752     1209    0     1180    21    10    11    11     0     8    7
mcl64k     65536      3    0        0     1     0     1     1     0     8    0
mcl16k     16384      2    0        0     1     0     1     1     0     8    0
mcl12k     12288      1    0        0     1     0     1     1     0     8    0
mcl8k      8192       4    0        0     1     0     1     1     0     8    0
mcl4k      4096     126    0        0    16     0    16    16     0     8    0
mcl2k2     2112       1    0        0     1     0     1     1     0     8    0
mcl2k      2048      40    0        0     5     0     5     5     0     8    0
mtagpl      96       16    0        0     1     0     1     1     0     8    0
mbufpl     256      251    0        0    16     0    16    16     0     8    0
bufpl      280     6176    0      131   432     0   432   432     0     8    0
anonpl      32    11584    0        0    94     0    94    94     0   246    0
amapchunkpl 152   26741    0    26275    41    15    26    30     0   158    5
amappl16   200     3640    0     3573    35    23    12    28     0     8    5
amappl15   192        8    0        8     1     1     0     1     0     8    0
amappl14   184        5    0        5     1     1     0     1     0     8    0
amappl13   176      436    0      434     1     0     1     1     0     8    0
amappl12   168     1359    0     1317     3     0     3     3     0     8    0
amappl11   160       32    0       31     1     0     1     1     0     8    0
amappl10   152       49    0       34     1     0     1     1     0     8    0
amappl9    144      244    0      244     1     1     0     1     0     8    0
amappl8    136       26    0       24     1     0     1     1     0     8    0
amappl7    128       87    0       85     1     0     1     1     0     8    0
amappl6    120      308    0      295     1     0     1     1     0     8    0
amappl5    112       81    0       71     1     0     1     1     0     8    0
amappl4    104      419    0      390     1     0     1     1     0     8    0
amappl3     96     4494    0     4405     4     1     3     3     0     8    0
amappl2     88     1104    0     1027     2     0     2     2     0     8    0
amappl1     80    11726    0    11121    17     2    15    15     0     8    0
amappl      88     7342    0     7185     5     0     5     5     0    92    0
uvmvnodes   80      126    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        7    0        7     2     2     0     1     0     8    0
dma128     128      253    0      253     1     1     0     1     0     8    0
dma64       64        7    0        7     2     2     0     1     0     8    0
dma32       32        7    0        7     1     1     0     1     0     8    0
dma16       16       19    0       18     1     0     1     1     0     8    0
aobjpl      72        9    0        0     1     0     1     1     0     8    0
uaddrrnd    24      988    0      957     1     0     1     1     0     8    0
uaddrbest   32        2    0        0     1     0     1     1     0     8    0
uaddr       24      988    0      957     1     0     1     1     0     8    0
vmmpekpl   168     9661    0     9619     3     0     3     3     0     8    0
vmmpepl    168    69471    0    67513   109    13    96   108     0   357    1
vmsppl     488      987    0      957     6     1     5     5     0     8    0
rwobjpl     80    21308    0    20210    33     4    29    32     0     8    0
pdppl      4096    1983    0     1914   105    34    71    85     0     8    2
pvpl        32    18807    0        0   152     0   152   152     0   265    0
pmappl     256      987    0      957     3     0     3     3     0     8    0
extentpl    40       45    0       27     1     0     1     1     0     8    0
phpool     112      299    0       45     8     0     8     8     0     8    0
ddb{1}> machine ddbcpu 0
Stopped at      x86_ipi_db+0x27:        addq    $0x8,%rsp
x86_ipi_db(ffffffff83878ff0) 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
__sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x33 kd_curproc sys/dev/kcov.c:585 [inline]
__sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x33 sys/dev/kcov.c:153
witness_checkorder(ffffffff83970b08,9,0) at witness_checkorder+0xa7 sys/kern/subr_witness.c:830
__mp_lock(ffffffff83970900) at __mp_lock+0xe1 read_rflags sys/arch/amd64/compile/SYZKALLER/obj/machine/cpufunc.h:212 [inline]
__mp_lock(ffffffff83970900) at __mp_lock+0xe1 intr_disable sys/arch/amd64/compile/SYZKALLER/obj/machine/cpufunc.h:233 [inline]
__mp_lock(ffffffff83970900) at __mp_lock+0xe1 sys/kern/kern_lock.c:168
__mp_acquire_count(ffffffff83970900,1) at __mp_acquire_count+0x58 sys/kern/kern_lock.c:-1
tsleep_nsec(fffffd806f5b7e58,11,ffffffff83461be4,ffffffffffffffff) at tsleep_nsec+0x23d sys/kern/kern_synch.c:-1
biowait(fffffd806f5b7e58) at biowait+0xc6 sys/kern/vfs_bio.c:1242
bwrite(fffffd806f5b7e58) at bwrite+0x2e7 sys/kern/vfs_bio.c:754
ffs_update(fffffd80606d63c0,1) at ffs_update+0x2fe sys/ufs/ffs/ffs_inode.c:111
ffs_truncate(fffffd80606d63c0,0,4,fffffd80097fd340) at ffs_truncate+0xc9b sys/ufs/ffs/ffs_inode.c:-1
ufs_rmdir(ffff80002a344980) at ufs_rmdir+0x2f1 sys/ufs/ufs/ufs_vnops.c:1265
VOP_RMDIR(fffffd806d03eb38,fffffd8064be3530,ffff80002a344a58) at VOP_RMDIR+0x192 sys/kern/vfs_vops.c:413
end trace frame: 0xffff80002a344af0, count: 0
ddb{0}> trace
x86_ipi_db(ffffffff83878ff0) 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
__sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x33 kd_curproc sys/dev/kcov.c:585 [inline]
__sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x33 sys/dev/kcov.c:153
witness_checkorder(ffffffff83970b08,9,0) at witness_checkorder+0xa7 sys/kern/subr_witness.c:830
__mp_lock(ffffffff83970900) at __mp_lock+0xe1 read_rflags sys/arch/amd64/compile/SYZKALLER/obj/machine/cpufunc.h:212 [inline]
__mp_lock(ffffffff83970900) at __mp_lock+0xe1 intr_disable sys/arch/amd64/compile/SYZKALLER/obj/machine/cpufunc.h:233 [inline]
__mp_lock(ffffffff83970900) at __mp_lock+0xe1 sys/kern/kern_lock.c:168
__mp_acquire_count(ffffffff83970900,1) at __mp_acquire_count+0x58 sys/kern/kern_lock.c:-1
tsleep_nsec(fffffd806f5b7e58,11,ffffffff83461be4,ffffffffffffffff) at tsleep_nsec+0x23d sys/kern/kern_synch.c:-1
biowait(fffffd806f5b7e58) at biowait+0xc6 sys/kern/vfs_bio.c:1242
bwrite(fffffd806f5b7e58) at bwrite+0x2e7 sys/kern/vfs_bio.c:754
ffs_update(fffffd80606d63c0,1) at ffs_update+0x2fe sys/ufs/ffs/ffs_inode.c:111
ffs_truncate(fffffd80606d63c0,0,4,fffffd80097fd340) at ffs_truncate+0xc9b sys/ufs/ffs/ffs_inode.c:-1
ufs_rmdir(ffff80002a344980) at ufs_rmdir+0x2f1 sys/ufs/ufs/ufs_vnops.c:1265
VOP_RMDIR(fffffd806d03eb38,fffffd8064be3530,ffff80002a344a58) at VOP_RMDIR+0x192 sys/kern/vfs_vops.c:413
dounlinkat(ffff8000ffffc538,ffffff9c,7ab05b95cbf0,8) at dounlinkat+0x2e0 sys/kern/vfs_syscalls.c:1901
syscall(ffff80002a344bd0) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80002a344bd0) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:775
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7ab05b95cbe0, count: -17
ddb{0}> machine ddbcpu 1
Stopped at      db_enter+0x25:  addq    $0x8,%rsp
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
panic(ffffffff833b5a1c) at panic+0x1e5 sys/kern/subr_prf.c:198
witness_checkorder(ffff800000c31078,1,0) at witness_checkorder+0x122c sys/kern/subr_witness.c:854
rw_do_enter_read(ffff800000c31060,0) at rw_do_enter_read+0x99 sys/kern/kern_rwlock.c:355
in6_hasmulti(fffffd8064e01af0,ffff800000c31000) at in6_hasmulti+0x41 in6_lookupmulti sys/netinet6/in6.c:-1 [inline]
in6_hasmulti(fffffd8064e01af0,ffff800000c31000) at in6_hasmulti+0x41 sys/netinet6/in6.c:1150
ip6_output(fffffd8064e01a00,ffffffff83987338,0,0,ffff80002a210480,0) at ip6_output+0x13bd sys/netinet6/ip6_output.c:507
mld6_sendpkt(ffff80000154e700,84,ffff80002a210518) at mld6_sendpkt+0x385 sys/netinet6/mld6.c:499
mld6_stop_listening(ffff80000154e700,ffff800000c31000) at mld6_stop_listening+0x125 sys/netinet6/mld6.c:168
in6_delmulti(ffff80000154e700) at in6_delmulti+0xb1 sys/netinet6/in6.c:1118
in6_purgeaddr(ffff800001614c00) at in6_purgeaddr+0x1d5 in6_leavegroup sys/netinet6/in6.c:1181 [inline]
in6_purgeaddr(ffff800001614c00) at in6_purgeaddr+0x1d5 sys/netinet6/in6.c:916
nd6_expire(0) at nd6_expire+0x111 sys/netinet6/nd6.c:-1
taskq_thread(ffff80000002c000) at taskq_thread+0x157 sys/kern/kern_task.c:446
end trace frame: 0x0, count: 3
ddb{1}> trace
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
panic(ffffffff833b5a1c) at panic+0x1e5 sys/kern/subr_prf.c:198
witness_checkorder(ffff800000c31078,1,0) at witness_checkorder+0x122c sys/kern/subr_witness.c:854
rw_do_enter_read(ffff800000c31060,0) at rw_do_enter_read+0x99 sys/kern/kern_rwlock.c:355
in6_hasmulti(fffffd8064e01af0,ffff800000c31000) at in6_hasmulti+0x41 in6_lookupmulti sys/netinet6/in6.c:-1 [inline]
in6_hasmulti(fffffd8064e01af0,ffff800000c31000) at in6_hasmulti+0x41 sys/netinet6/in6.c:1150
ip6_output(fffffd8064e01a00,ffffffff83987338,0,0,ffff80002a210480,0) at ip6_output+0x13bd sys/netinet6/ip6_output.c:507
mld6_sendpkt(ffff80000154e700,84,ffff80002a210518) at mld6_sendpkt+0x385 sys/netinet6/mld6.c:499
mld6_stop_listening(ffff80000154e700,ffff800000c31000) at mld6_stop_listening+0x125 sys/netinet6/mld6.c:168
in6_delmulti(ffff80000154e700) at in6_delmulti+0xb1 sys/netinet6/in6.c:1118
in6_purgeaddr(ffff800001614c00) at in6_purgeaddr+0x1d5 in6_leavegroup sys/netinet6/in6.c:1181 [inline]
in6_purgeaddr(ffff800001614c00) at in6_purgeaddr+0x1d5 sys/netinet6/in6.c:916
nd6_expire(0) at nd6_expire+0x111 sys/netinet6/nd6.c:-1
taskq_thread(ffff80000002c000) at taskq_thread+0x157 sys/kern/kern_task.c:446
end trace frame: 0x0, count: -12

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/03 14:56 openbsd 80bc9799356e e3fbc05e .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore witness: shared lock of (rwlock) mpaddr while exclusively locked
* Struck through repros no longer work on HEAD.