syzbot


assert "curproc->p_kd == NULL" failed in kcov.c (2)

Status: fixed on 2020/09/01 02:15
Reported-by: syzbot+64122a5f01be1b1abb96@syzkaller.appspotmail.com
Fix commit: ece33e2f6ca2 Before clearing the kcov descriptor associated with a thread make sure no other thread is currently within a remote section. Otherwise, the remote subsystem could end up in a broken state where it doesn't reset the necessary bits upon leaving the remote section.
First crash: 767d, last: 767d
similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
openbsd assert "curproc->p_kd == NULL" failed in kcov.c 2 771d 773d 3/3 fixed on 2020/08/15 01:06

Sample crash report:
panic: kernel diagnostic assertion "curproc->p_kd == NULL" failed: file "/syzkaller/managers/multicore/kernel/sys/dev/kcov.c", line 519
Stopped at      db_enter+0x18:  addq    $0x8,%rsp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
 514551  26976     73    0x100010          0    0  syslogd
*360189  14771      0     0x14000      0x200    1  softnet
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic(ffffffff823c07fb) at panic+0x15e sys/kern/subr_prf.c:218
__assert(ffffffff8242e1df,ffffffff82429222,207,ffffffff823ce86e) at __assert+0x2b sys/kern/subr_prf.c:162
kcov_remote_enter(0,ffff800020ec4bd8) at kcov_remote_enter+0x155 sys/dev/kcov.c:519
taskq_thread(ffff80000002c000) at taskq_thread+0xd9 sys/kern/kern_task.c:447
end trace frame: 0x0, count: 10
https://www.openbsd.org/ddb.html describes the minimum info required in bug
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ddb{1}> 
ddb{1}> set $lines = 0
ddb{1}> set $maxwidth = 0
ddb{1}> show panic
kernel diagnostic assertion "curproc->p_kd == NULL" failed: file "/syzkaller/managers/multicore/kernel/sys/dev/kcov.c", line 519
ddb{1}> trace
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic(ffffffff823c07fb) at panic+0x15e sys/kern/subr_prf.c:218
__assert(ffffffff8242e1df,ffffffff82429222,207,ffffffff823ce86e) at __assert+0x2b sys/kern/subr_prf.c:162
kcov_remote_enter(0,ffff800020ec4bd8) at kcov_remote_enter+0x155 sys/dev/kcov.c:519
taskq_thread(ffff80000002c000) at taskq_thread+0xd9 sys/kern/kern_task.c:447
end trace frame: 0x0, count: -5
ddb{1}> show registers
rdi                                0
rsi                              0x1
rbp               0xffff800020db9cb0
rbx               0xffff800020db9cc0
rdx                             0x8b
rcx                              0x2
rax                              0x1
r8                0xffff800020db9c70
r9                0xffffffff814cffb6    kprintf+0x146
r10                              0x1
r11               0x559822f4eb52c7ca
r12                     0x3000000008
r13               0xffff800020db9d60
r14                            0x100
r15                              0x1
rip               0xffffffff8178dc98    db_enter+0x18
cs                               0x8
rflags                         0x246
rsp               0xffff800020db9ca0
ss                              0x10
db_enter+0x18:  addq    $0x8,%rsp
ddb{1}> show proc
PROC (softnet) pid=360189 stat=onproc
    flags process=14000<NOZOMBIE,SYSTEM> proc=200<SYSTEM>
    pri=32, usrpri=50, nice=20
    forw=0xffffffffffffffff, list=0xffff800020d98768,0xffff800020d98288
    process=0xffff800020d9b3b0 user=0xffff800020db4000, vmspace=0xffffffff828e8b68
    estcpu=0, cpticks=1, pctcpu=0.0
    user=0, sys=1, intr=0
ddb{1}> ps
   PID     TID   PPID    UID  S       FLAGS  WAIT          COMMAND
 20722  106720  96130      0  2         0x2                syz-executor.1
 77166  433287      0      0  3     0x14280  nfsidl        nfsio
 61957  232054      0      0  3     0x14280  nfsidl        nfsio
 38926  285097      0      0  3     0x14280  nfsidl        nfsio
 46142  373687      0      0  3     0x14280  nfsidl        nfsio
 84256  337494      0      0  3     0x14280  nfsidl        nfsio
 28180  226022      0      0  3     0x14280  nfsidl        nfsio
 43021  446620      0      0  3     0x14280  nfsidl        nfsio
 71266  356600      0      0  3     0x14280  nfsidl        nfsio
 88536  312922      0      0  3     0x14280  nfsidl        nfsio
 69147  468983      0      0  3     0x14280  nfsidl        nfsio
 45849  134833      0      0  3     0x14280  nfsidl        nfsio
 20110   25307      0      0  3     0x14280  nfsidl        nfsio
 15646  439697      0      0  3     0x14280  nfsidl        nfsio
 61141   86801      0      0  3     0x14280  nfsidl        nfsio
 20645  447391      0      0  3     0x14280  nfsidl        nfsio
 73967  508003      0      0  3     0x14280  nfsidl        nfsio
 25132  106867      0      0  3     0x14280  nfsidl        nfsio
 79613  502711      0      0  3     0x14280  nfsidl        nfsio
 44825  460124      0      0  3     0x14280  nfsidl        nfsio
 89436  208533      0      0  3     0x14280  nfsidl        nfsio
  4824  154991      0      0  3     0x14200  bored         sosplice
 20043  473591      1      0  3    0x100083  ttyin         getty
 96130  251360  61995      0  3        0x82  thrsleep      syz-fuzzer
 96130  177356  61995      0  3   0x4000082  nanosleep     syz-fuzzer
 96130  447200  61995      0  3   0x4000082  kqread        syz-fuzzer
 96130  237087  61995      0  3   0x4000082  thrsleep      syz-fuzzer
 96130  384298  61995      0  3   0x4000082  thrsleep      syz-fuzzer
 96130   23804  61995      0  3   0x4000082  thrsleep      syz-fuzzer
 96130   84471  61995      0  3   0x4000082  thrsleep      syz-fuzzer
 96130   53429  61995      0  3   0x4000082  thrsleep      syz-fuzzer
 61995    5676  47685      0  3    0x10008a  pause         ksh
 47685  280143  97833      0  3        0x92  select        sshd
 97833  335522      1      0  3        0x80  select        sshd
 75786  324328  83004     74  3    0x100092  bpf           pflogd
 83004  370348      1      0  3        0x80  netio         pflogd
 26976  514551  46013     73  7    0x100010                syslogd
 46013  420494      1      0  3    0x100082  netio         syslogd
 43105  410884      1     77  3    0x100090  poll          dhclient
  9052  147898      1      0  3        0x80  poll          dhclient
 29246  413235      0      0  3     0x14200  bored         smr
 43502  139933      0      0  2     0x14200                zerothread
  6472  438134      0      0  3     0x14200  aiodoned      aiodoned
 87342  127538      0      0  3     0x14200  syncer        update
 70549  258079      0      0  3     0x14200  cleaner       cleaner
 32058  454414      0      0  3     0x14200  reaper        reaper
 93204  504179      0      0  3     0x14200  pgdaemon      pagedaemon
 30845  197525      0      0  3     0x14200  bored         crynlk
 85256   10198      0      0  3     0x14200  bored         crypto
  2257  260560      0      0  3  0x40014200  acpi0         acpi0
  4863  439018      0      0  3  0x40014200                idle1
*14771  360189      0      0  7     0x14200                softnet
 39657  512404      0      0  3     0x14200  bored         systqmp
 10429  229370      0      0  3     0x14200  bored         systq
 73579  158546      0      0  3  0x40014200  bored         softclock
 60635  512540      0      0  3  0x40014200                idle0
     1   70692      0      0  3        0x82  wait          init
     0       0     -1      0  3     0x10200  scheduler     swapper
ddb{1}> show all locks
CPU 0:
exclusive mutex &map->mtx r = 0 (0xffffffff827cb378)
#0  witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline]
#0  witness_lock+0x4b0 sys/kern/subr_witness.c:1164
#1  mtx_enter_try+0x100
#2  mtx_enter+0x4b sys/kern/kern_lock.c:266
#3  vm_map_lock_ln+0x118 sys/uvm/uvm_map.c:5454
#4  uvm_map+0x325 sys/uvm/uvm_map.c:1236
#5  uvm_km_kmemalloc_pla+0x11d sys/uvm/uvm_km.c:335
#6  malloc+0x43e sys/kern/kern_malloc.c:230
#7  ufs_readdir+0x148 sys/ufs/ufs/ufs_vnops.c:1456
#8  VOP_READDIR+0xc6 sys/kern/vfs_vops.c:520
#9  sys_getdents+0x21d sys/kern/vfs_syscalls.c:3121
#10 syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline]
#10 syscall+0x4a1 sys/arch/amd64/amd64/trap.c:570
#11 Xsyscall+0x128
CPU 1:
exclusive mutex /syzkaller/managers/multicore/kernel/sys/dev/kcov.c:92 r = 0 (0xffffffff826ce048)
#0  witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline]
#0  witness_lock+0x4b0 sys/kern/subr_witness.c:1164
#1  mtx_enter_try+0x100
#2  mtx_enter+0x4b sys/kern/kern_lock.c:266
#3  kcov_remote_enter+0x62 kr_lookup sys/dev/kcov.c:676 [inline]
#3  kcov_remote_enter+0x62 sys/dev/kcov.c:513
#4  taskq_thread+0xd9 sys/kern/kern_task.c:447
#5  proc_trampoline+0x1c
Process 20722 (syz-executor.1) thread 0xffff800020e4c2b0 (106720)
Process 26976 (syslogd) thread 0xffff8000fffff3d0 (514551)
Process 14771 (softnet) thread 0xffff800020d984f0 (360189)
ddb{1}> show malloc
           Type InUse  MemUse  HighUse   Limit  Requests Type Lim
         devbuf  9538   6441K    7206K  78643K     17690        0
            pcb    13      8K       8K  78643K       418        0
         rtable    85      3K       7K  78643K      1616        0
         ifaddr    83     16K      16K  78643K       547        0
       counters    45     34K      34K  78643K       173        0
       ioctlops     0      0K       4K  78643K      2107        0
            iov     0      0K      24K  78643K       392        0
          mount     1      1K       1K  78643K         1        0
         vnodes  1227     77K      77K  78643K      3749        0
      UFS quota     1     32K      32K  78643K         1        0
      UFS mount     5     36K      36K  78643K         5        0
            shm     2      1K       9K  78643K       108        0
         VM map     2      1K       1K  78643K         2        0
            sem    12      1K       1K  78643K        90        0
        dirhash    12      2K       2K  78643K        12        0
           ACPI  1824    197K     290K  78643K     13058        0
      file desc     4      9K      25K  78643K      7275        0
          sigio     0      0K       0K  78643K       119        0
           proc    64     63K      95K  78643K      1189        0
        subproc    32      2K       2K  78643K       102        0
    NFS srvsock     1      0K       0K  78643K         1        0
     NFS daemon     1     16K      16K  78643K         1        0
    ip_moptions     0      0K       0K  78643K       453        0
       in_multi    26      1K       2K  78643K       380        0
    ether_multi     1      0K       0K  78643K        84        0
            mrt     0      0K       0K  78643K        86        0
    ISOFS mount     1     32K      32K  78643K         1        0
  MSDOSFS mount     1     16K      16K  78643K         1        0
           ttys    61    281K     281K  78643K        61        0
           exec     0      0K       2K  78643K       758        0
        pagedep     1      8K       8K  78643K         1        0
       inodedep     1     32K      32K  78643K         1        0
         newblk     1      0K       0K  78643K         1        0
        VM swap     7     26K      26K  78643K         7        0
       UVM amap   446   1264K    1272K  78643K     17941        0
       UVM aobj   131      8K       8K  78643K       131        0
        memdesc     1      4K       4K  78643K         1        0
    crypto data     1      1K       1K  78643K         1        0
    ip6_options     0      0K       0K  78643K       272        0
            NDP    15      0K       0K  78643K       121        0
           temp   145   3963K    4092K  78643K     44964        0
         kqueue     3      4K      22K  78643K       380        0
      SYN cache     2     16K      16K  78643K         2        0
ddb{1}> show all pools
Name      Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
arp         64       19    0       13     1     0     1     1     0     8    0
plcache    128       20    0        0     1     0     1     1     0     8    0
rtpcb       96      296    0      294     1     0     1     1     0     8    0
rtentry    112      196    0      165     2     0     2     2     0     8    0
unpcb      120     2103    0     2087     1     0     1     1     0     8    0
syncache   272       51    0       51     7     7     0     1     0     8    0
tcpqe       32       17    0       17     5     5     0     1     0     8    0
tcpcb      592     1425    0     1413    23    21     2     5     0     8    0
ipq         40        4    0        4     1     1     0     1     0     8    0
ipqe        40       12    0       12     1     1     0     1     0     8    0
inpcb      296     3610    0     3601     7     5     2     2     0     8    0
rttmr       72       25    0       25     3     3     0     1     0     8    0
nd6         48       55    0       51     1     0     1     1     0     8    0
pkpcb       40       36    0       36     5     5     0     1     0     8    0
kcovpl      48        6    0        4     1     0     1     1     0     8    0
ppxss      1136      14    0       14     2     1     1     1     0     8    1
pfstscr     40       26    0       26     2     2     0     1     0     8    0
pffrag     232       19    0       19     4     3     1     1     0   482    1
pffrnode    88       19    0       19     4     3     1     1     0     8    1
pffrent     40       51    0       51     6     5     1     1     0     8    1
pfosfp      40      847    0      423     5     0     5     5     0     8    0
pfosfpen   112     1436    0      714    21     0    21    21     0     8    0
pfrktable  1344     214    0      214     3     3     0     1     0     8    0
pftag       88        3    0        1     1     0     1     1     0     8    0
pfqueue    264       10    0        5     1     0     1     1     0     8    0
pfstitem    24       89    0       87     1     0     1     1     0     8    0
pfstkey    112      131    0      129     2     1     1     2     0     8    0
pfstate    328      110    0      108     7     6     1     5     0     8    0
pfrule     1360      82    0       76     2     1     1     2     0     8    0
art_heap8  4096       1    0        0     1     0     1     1     0     8    0
art_heap4  256      781    0      644    17     5    12    17     0     8    1
art_table   32      782    0      644     3     1     2     3     0     8    0
art_node    16      192    0      166     1     0     1     1     0     8    0
sysvmsgpl   40       40    0        0     1     0     1     1     0     8    0
semupl     112        6    0        6     1     1     0     1     0     8    0
semapl     112       81    0       71     1     0     1     1     0     8    0
shmpl      112      128    0        0     4     0     4     4     0     8    0
dirhash    1024      17    0        0     3     0     3     3     0     8    0
dino2pl    256    10881    0     9472    92     3    89    89     0     8    0
ffsino     272    10881    0     9472    95     0    95    95     0     8    0
nchpl      144    19787    0    18194    60     0    60    60     0     8    0
uvmvnodes   72     5926    0        0   108     0   108   108     0     8    0
vnodes     208     5926    0        0   312     0   312   312     0     8    0
namei      1024   50220    0    50220     2     1     1     1     0     8    1
percpumem   16       97    0       64     1     0     1     1     0     8    0
vcpupl     1984      78    0        0    10     0    10    10     0     8    0
vmpool     560       95    0       17     6     0     6     6     0     8    0
pfiaddrpl  120       59    0       59     2     2     0     1     0     8    0
scsiplug    72        7    0        7     1     1     0     1     0     8    0
scxspl     200    60470    0    60470    14    13     1     7     0     8    1
plimitpl   152      391    0      383     1     0     1     1     0     8    0
sigapl     424     7500    0     7449     6     0     6     6     0     8    0
futexpl     56    56490    0    56490     3     2     1     1     0     8    1
knotepl    112      650    0      630     2     1     1     2     0     8    0
kqueuepl   152     3243    0     3241     1     0     1     1     0     8    0
pipepl     304      535    0      524    13    11     2     2     0     8    0
fdescpl    496     7464    0     7449     3     0     3     3     0     8    0
filepl     152    27641    0    27538     8     3     5     6     0     8    0
lockfpl    104      899    0      898     1     0     1     1     0     8    0
lockfspl    48      323    0      322     1     0     1     1     0     8    0
sessionpl  120       23    0       12     1     0     1     1     0     8    0
pgrppl      48       59    0       48     1     0     1     1     0     8    0
ucredpl     96     4091    0     4082     1     0     1     1     0     8    0
zombiepl   144     7450    0     7449     2     1     1     1     0     8    0
processpl  1008    7500    0     7449     7     0     7     7     0     8    0
procpl     632    16647    0    16589     8     2     6     6     0     8    0
sosppl     144       97    0       97     7     6     1     1     0     8    1
sockpl     400     6051    0     6024    15    11     4     5     0     8    1
mcl64k     65536     21    0        0     3     0     3     3     0     8    0
mcl16k     16384      4    0        0     1     0     1     1     0     8    0
mcl12k     12288     17    0        0     2     0     2     2     0     8    0
mcl9k      9216      11    0        0     1     0     1     1     0     8    0
mcl8k      8192      25    0        0     4     1     3     3     0     8    0
mcl4k      4096      25    0        0     3     0     3     3     0     8    0
mcl2k2     2112       5    0        0     1     0     1     1     0     8    0
mcl2k      2048     314    0        0    16     0    16    16     0     8    0
mtagpl      96      477    0        0    12     0    12    12     0     8    0
mbufpl     256     1339    0        0    74     0    74    74     0     8    0
bufpl      280    15408    0     9150   448     0   448   448     0     8    0
anonpl      16   569346    0   561794    86    41    45    55     0   124   14
amapchunkpl 152   29989    0    29788    26    13    13    21     0   158    4
amappl16   192    25932    0    25605    63    40    23    35     0     8    6
amappl15   184      142    0      140     1     0     1     1     0     8    0
amappl14   176      923    0      913     1     0     1     1     0     8    0
amappl13   168      117    0      114     1     0     1     1     0     8    0
amappl12   160     5121    0     5114     1     0     1     1     0     8    0
amappl11   152       68    0       53     1     0     1     1     0     8    0
amappl10   144      331    0      325     1     0     1     1     0     8    0
amappl9    136      282    0      282     1     1     0     1     0     8    0
amappl8    128      410    0      293     4     0     4     4     0     8    0
amappl7    120      616    0      608     1     0     1     1     0     8    0
amappl6    112      166    0      141     1     0     1     1     0     8    0
amappl5    104     6875    0     6861     1     0     1     1     0     8    0
amappl4     96     1264    0     1225     1     0     1     1     0     8    0
amappl3     88     1124    0     1117     1     0     1     1     0     8    0
amappl2     80    57255    0    57171     4     1     3     3     0     8    0
amappl1     72   200456    0   200013    24    14    10    19     0     8    0
amappl      80    17106    0    16945     4     0     4     4     0    84    0
dma4096    4096       1    0        1     1     1     0     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      64      130    0        0     3     0     3     3     0     8    0
uaddrrnd    24     7559    0     7466     1     0     1     1     0     8    0
uaddrbest   32        2    0        0     1     0     1     1     0     8    0
uaddr       24     7559    0     7466     1     0     1     1     0     8    0
vmmpekpl   168    41176    0    41121     3     0     3     3     0     8    0
vmmpepl    168   913211    0   911455   142    48    94   100     0   357    7
vmsppl     368     7558    0     7466     9     0     9     9     0     8    0
pdppl      4096   15125    0    15010    16     0    16    16     0     8    1
pvpl        32  2441252    0  2430494   269   147   122   141     0   265   32
pmappl     232     7558    0     7466     6     0     6     6     0     8    0
extentpl    40       53    0       36     1     0     1     1     0     8    0
phpool     112      362    0       31    10     0    10    10     0     8    0
ddb{1}> machine ddbcpu 0
Stopped at      x86_ipi_db+0x1a:        addq    $0x8,%rsp
x86_ipi_db(ffffffff8274fff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:352
x86_ipi_handler() at x86_ipi_handler+0xb7 sys/arch/amd64/amd64/ipi.c:106
Xresume_lapic_ipi() at Xresume_lapic_ipi+0x23
__sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x6f sys/dev/kcov.c:118
__mp_acquire_count(ffffffff8287d640,1) at __mp_acquire_count+0x4c sys/kern/kern_lock.c:227
mi_switch() at mi_switch+0x390 sys/kern/sched_bsd.c:435
sleep_finish(ffff800020e62b80,1) at sleep_finish+0x111 sys/kern/kern_synch.c:418
sleep_finish_all(ffff800020e62b80,1) at sleep_finish_all+0x32 sleep_finish_timeout sys/kern/kern_synch.c:447 [inline]
sleep_finish_all(ffff800020e62b80,1) at sleep_finish_all+0x32 sys/kern/kern_synch.c:393
tsleep(fffffd806edd54a8,11,ffffffff823d28fa,0) at tsleep+0x1c2 sys/kern/kern_synch.c:155
vwaitforio(fffffd806edd5428,0,ffffffff823d28fa,ffffffffffffffff) at vwaitforio+0x98 sys/kern/vfs_subr.c:1878
ffs_fsync(ffff800020e62ce0) at ffs_fsync+0x39d sys/ufs/ffs/ffs_vnops.c:498
VOP_FSYNC(fffffd806edd5428,fffffd807f7bfae0,1,ffff8000fffff3d0) at VOP_FSYNC+0xbf sys/kern/vfs_vops.c:353
sys_fsync(ffff8000fffff3d0,ffff800020e62dd0,ffff800020e62e20) at sys_fsync+0x127 sys/kern/vfs_syscalls.c:2874
syscall(ffff800020e62ea0) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff800020e62ea0) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:570
end trace frame: 0xffff800020e62f20, count: 0
ddb{0}> trace
x86_ipi_db(ffffffff8274fff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:352
x86_ipi_handler() at x86_ipi_handler+0xb7 sys/arch/amd64/amd64/ipi.c:106
Xresume_lapic_ipi() at Xresume_lapic_ipi+0x23
__sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x6f sys/dev/kcov.c:118
__mp_acquire_count(ffffffff8287d640,1) at __mp_acquire_count+0x4c sys/kern/kern_lock.c:227
mi_switch() at mi_switch+0x390 sys/kern/sched_bsd.c:435
sleep_finish(ffff800020e62b80,1) at sleep_finish+0x111 sys/kern/kern_synch.c:418
sleep_finish_all(ffff800020e62b80,1) at sleep_finish_all+0x32 sleep_finish_timeout sys/kern/kern_synch.c:447 [inline]
sleep_finish_all(ffff800020e62b80,1) at sleep_finish_all+0x32 sys/kern/kern_synch.c:393
tsleep(fffffd806edd54a8,11,ffffffff823d28fa,0) at tsleep+0x1c2 sys/kern/kern_synch.c:155
vwaitforio(fffffd806edd5428,0,ffffffff823d28fa,ffffffffffffffff) at vwaitforio+0x98 sys/kern/vfs_subr.c:1878
ffs_fsync(ffff800020e62ce0) at ffs_fsync+0x39d sys/ufs/ffs/ffs_vnops.c:498
VOP_FSYNC(fffffd806edd5428,fffffd807f7bfae0,1,ffff8000fffff3d0) at VOP_FSYNC+0xbf sys/kern/vfs_vops.c:353
sys_fsync(ffff8000fffff3d0,ffff800020e62dd0,ffff800020e62e20) at sys_fsync+0x127 sys/kern/vfs_syscalls.c:2874
syscall(ffff800020e62ea0) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff800020e62ea0) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:570
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7ffffe3120, count: -15
ddb{0}> machine ddbcpu 1
Stopped at      db_enter+0x18:  addq    $0x8,%rsp
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic(ffffffff823c07fb) at panic+0x15e sys/kern/subr_prf.c:218
__assert(ffffffff8242e1df,ffffffff82429222,207,ffffffff823ce86e) at __assert+0x2b sys/kern/subr_prf.c:162
kcov_remote_enter(0,ffff800020ec4bd8) at kcov_remote_enter+0x155 sys/dev/kcov.c:519
taskq_thread(ffff80000002c000) at taskq_thread+0xd9 sys/kern/kern_task.c:447
end trace frame: 0x0, count: 10
ddb{1}> trace
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic(ffffffff823c07fb) at panic+0x15e sys/kern/subr_prf.c:218
__assert(ffffffff8242e1df,ffffffff82429222,207,ffffffff823ce86e) at __assert+0x2b sys/kern/subr_prf.c:162
kcov_remote_enter(0,ffff800020ec4bd8) at kcov_remote_enter+0x155 sys/dev/kcov.c:519
taskq_thread(ffff80000002c000) at taskq_thread+0xd9 sys/kern/kern_task.c:447
end trace frame: 0x0, count: -5

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-openbsd-multicore 2020/08/19 10:03 openbsd 7a3e72b5ba77 a7d4a4f9 .config log report
* Struck through repros no longer work on HEAD.