syzbot


panic: Data modified on freelist: word 4 of object ADDR size 0x84 previous type free (ADDR != ADDR)

Status: closed as invalid on 2019/10/13 14:21
Reported-by: syzbot+5f43a916780eff0b386f@syzkaller.appspotmail.com
First crash: 1628d, last: 1628d

Sample crash report:
panic: Data modified on freelist: word 4 of object 0xffff800000b22600 size 0x84 previous type free (0x20ab0290 != 0xdead4110)

Stopped at      db_enter+0x18:  addq    $0x8,%rsp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
*519064  85788      0      0x2004  0x4000000    0  syz-executor.1
 501404  51032      0     0x14000      0x200    1  smr
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic() at panic+0x15c sys/kern/subr_prf.c:207
malloc(84,3f,1) at malloc+0xa23 sys/kern/kern_malloc.c:331
sys_execve(ffff800020a5e280,ffff800021b59638,ffff800021b59680) at sys_execve+0xdf sys/kern/kern_exec.c:286
syscall(ffff800021b59700) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:92 [inline]
syscall(ffff800021b59700) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:555
Xsyscall(6,0,fffffffffffffed5,0,3,f5373e0a010) at Xsyscall+0x128
end of kernel
end trace frame: 0xf558e8ea530, count: 9
https://www.openbsd.org/ddb.html describes the minimum info required in bug
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ddb{0}> 
ddb{0}> set $lines = 0
ddb{0}> set $maxwidth = 0
ddb{0}> show panic
Data modified on freelist: word 4 of object 0xffff800000b22600 size 0x84 previous type free (0x20ab0290 != 0xdead4110)

ddb{0}> trace
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic() at panic+0x15c sys/kern/subr_prf.c:207
malloc(84,3f,1) at malloc+0xa23 sys/kern/kern_malloc.c:331
sys_execve(ffff800020a5e280,ffff800021b59638,ffff800021b59680) at sys_execve+0xdf sys/kern/kern_exec.c:286
syscall(ffff800021b59700) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:92 [inline]
syscall(ffff800021b59700) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:555
Xsyscall(6,0,fffffffffffffed5,0,3,f5373e0a010) at Xsyscall+0x128
end of kernel
end trace frame: 0xf558e8ea530, count: -6
ddb{0}> show registers
rdi               0xffffffff812a6277    db_enter+0x17
rsi                           0x7606    __ALIGN_SIZE+0x6606
rbp               0xffff800021b58ff0
rbx               0xffff800021b590a0
rdx                           0x7607    __ALIGN_SIZE+0x6607
rcx               0xffff800021b66000
rax               0xffff800021b66000
r8                0xffffffff814600ef    kprintf+0x16f
r9                               0x1
r10                             0x25
r11               0x360d54e7dc8721ef
r12                     0x3000000008
r13               0xffff800021b59000
r14                            0x100
r15                              0x1
rip               0xffffffff812a6278    db_enter+0x18
cs                               0x8
rflags                         0x246
rsp               0xffff800021b58fe0
ss                              0x10
db_enter+0x18:  addq    $0x8,%rsp
ddb{0}> show proc
PROC (syz-executor.1) pid=519064 stat=onproc
    flags process=2004<INEXEC,SINGLEUNWIND> proc=4000000<THREAD>
    pri=32, usrpri=79, nice=20
    forw=0xffffffffffffffff, list=0xffff800020ab0780,0xffff800020ab02a0
    process=0xffff800020adc000 user=0xffff800021b54000, vmspace=0xfffffd807f00b170
    estcpu=36, cpticks=2, pctcpu=0.0
    user=0, sys=2, intr=0
ddb{0}> ps
   PID     TID   PPID    UID  S       FLAGS  WAIT          COMMAND
 85788  506175  73300      0  4     0x82004                syz-executor.1
*85788  519064  73300      0  7   0x4002004                syz-executor.1
 85788   15995  73300      0  4   0x4082004                syz-executor.1
 85788  476944  73300      0  4   0x4082004                syz-executor.1
 85788   45846  73300      0  4   0x4082004                syz-executor.1
 86584  512100      0      0  3     0x14200  acct          acct
 52660  369152  90794      0  2         0x2                syz-executor.0
 96293  364456      0      0  3     0x14200  bored         sosplice
 73300   94858  90794      0  3        0x82  nanosleep     syz-executor.1
 90794  470574   1831      0  3        0x82  thrsleep      syz-fuzzer
 90794   98957   1831      0  3   0x4000082  nanosleep     syz-fuzzer
 90794   33994   1831      0  3   0x4000082  thrsleep      syz-fuzzer
 90794    8117   1831      0  3   0x4000082  thrsleep      syz-fuzzer
 90794  140221   1831      0  3   0x4000082  thrsleep      syz-fuzzer
 90794  252963   1831      0  3   0x4000082  thrsleep      syz-fuzzer
 90794  131234   1831      0  3   0x4000082  kqread        syz-fuzzer
 90794  155526   1831      0  3   0x4000082  thrsleep      syz-fuzzer
 90794   25022   1831      0  3   0x4000082  thrsleep      syz-fuzzer
 90794  152668   1831      0  3   0x4000082  thrsleep      syz-fuzzer
  1831  119680  79490      0  3    0x10008a  pause         ksh
 79490  144501  89544      0  3        0x92  select        sshd
 85911      62      1      0  3    0x100083  ttyin         getty
 89544  257138      1      0  3        0x80  select        sshd
 23897   40951  98144     74  3    0x100092  bpf           pflogd
 98144  178015      1      0  3        0x80  netio         pflogd
 29168  417905  87266     73  3    0x100090  kqread        syslogd
 87266   43003      1      0  3    0x100082  netio         syslogd
 22766  207130      1     77  3    0x100090  poll          dhclient
 67565  176166      1      0  3        0x80  poll          dhclient
 23942  460632      0      0  2     0x14200                zerothread
 91297  327585      0      0  3     0x14200  aiodoned      aiodoned
 30311  132438      0      0  3     0x14200  syncer        update
 13806  117631      0      0  3     0x14200  cleaner       cleaner
 54192   16379      0      0  3     0x14200  reaper        reaper
 82488  387076      0      0  3     0x14200  pgdaemon      pagedaemon
 78753  248129      0      0  3     0x14200  bored         crynlk
 32497  322523      0      0  3     0x14200  bored         crypto
 25485  262728      0      0  3  0x40014200  acpi0         acpi0
 46510  291943      0      0  3  0x40014200                idle1
 81724  401903      0      0  3     0x14200  bored         softnet
  5339   85060      0      0  3     0x14200  bored         systqmp
 97004  145912      0      0  3     0x14200  bored         systq
 63026  314289      0      0  3  0x40014200  bored         softclock
  9658  399345      0      0  3  0x40014200                idle0
 51032  501404      0      0  7     0x14200                smr
     1  168787      0      0  3        0x82  wait          init
     0       0     -1      0  3     0x10200  scheduler     swapper
ddb{0}> show all locks
CPU 0:
exclusive mutex /syzkaller/managers/multicore/kernel/sys/kern/kern_malloc.c:104 r = 0 (0xffffffff8251ebe0)
#0  witness_lock+0x52e sys/kern/subr_witness.c:1163
#1  mtx_enter_try+0x102
#2  mtx_enter+0x4b sys/kern/kern_lock.c:266
#3  malloc+0x23b sys/kern/kern_malloc.c:209
#4  sys_execve+0xdf sys/kern/kern_exec.c:286
#5  syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:92 [inline]
#5  syscall+0x4a4 sys/arch/amd64/amd64/trap.c:555
#6  Xsyscall+0x128
Process 85788 (syz-executor.1) thread 0xffff800020a5e280 (519064)
exclusive kernel_lock &kernel_lock r = 0 (0xffffffff8263bf20)
#0  witness_lock+0x52e sys/kern/subr_witness.c:1163
#1  __mp_acquire_count+0x51 sys/kern/kern_lock.c:227
#2  mi_switch+0x392 sys/kern/sched_bsd.c:441
#3  sleep_finish+0x113 sys/kern/kern_synch.c:373
#4  tsleep+0x198 sleep_finish_timeout sys/kern/kern_synch.c:397 [inline]
#4  tsleep+0x198 sleep_finish_all sys/kern/kern_synch.c:183 [inline]
#4  tsleep+0x198 sys/kern/kern_synch.c:152
#5  single_thread_set+0x391 single_thread_wait sys/kern/kern_sig.c:2058 [inline]
#5  single_thread_set+0x391 sys/kern/kern_sig.c:2049
#6  sys_execve+0x55 sys/kern/kern_exec.c:269
#7  syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:92 [inline]
#7  syscall+0x4a4 sys/arch/amd64/amd64/trap.c:555
#8  Xsyscall+0x128
exclusive mutex /syzkaller/managers/multicore/kernel/sys/kern/kern_malloc.c:104 r = 0 (0xffffffff8251ebe0)
#0  witness_lock+0x52e sys/kern/subr_witness.c:1163
#1  mtx_enter_try+0x102
#2  mtx_enter+0x4b sys/kern/kern_lock.c:266
#3  malloc+0x23b sys/kern/kern_malloc.c:209
#4  sys_execve+0xdf sys/kern/kern_exec.c:286
#5  syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:92 [inline]
#5  syscall+0x4a4 sys/arch/amd64/amd64/trap.c:555
#6  Xsyscall+0x128
Process 51032 (smr) thread 0xffff800020a118b0 (501404)
shared rwlock smr r = 0 (0xffffffff824e99d0)
#0  witness_lock+0x52e sys/kern/subr_witness.c:1163
#1  smr_thread+0x242 sys/kern/kern_smr.c:119
#2  proc_trampoline+0x1c
ddb{0}> show malloc
           Type InUse  MemUse  HighUse   Limit  Requests Type Lim Kern Lim
         devbuf  9555   6560K    7587K  78643K     13406        0        0
            pcb    13      8K       8K  78643K       170        0        0
         rtable    81      8K       8K  78643K       517        0        0
         ifaddr    65     14K      14K  78643K       189        0        0
       counters    39     33K      33K  78643K        39        0        0
       ioctlops     0      0K       4K  78643K      1487        0        0
            iov     0      0K      16K  78643K       121        0        0
          mount     1      1K       1K  78643K         1        0        0
         vnodes  1231     77K      78K  78643K      1978        0        0
      UFS quota     1     32K      32K  78643K         1        0        0
      UFS mount     5     36K      36K  78643K         5        0        0
            shm     2      1K       5K  78643K         4        0        0
         VM map     2      1K       1K  78643K         4        0        0
            sem    12      0K       1K  78643K       196        0        0
        dirhash    12      2K       2K  78643K        12        0        0
           ACPI  1808    196K     290K  78643K     12765        0        0
      file desc     5     13K      25K  78643K       553        0        0
          sigio     0      0K       0K  78643K         8        0        0
           proc    60     63K      83K  78643K       538        0        0
        subproc    32      2K       2K  78643K        51        0        0
    NFS srvsock     1      0K       0K  78643K         1        0        0
     NFS daemon     1     16K      16K  78643K         1        0        0
    ip_moptions     0      0K       0K  78643K       137        0        0
       in_multi    13      0K       2K  78643K        89        0        0
    ether_multi     1      0K       0K  78643K         9        0        0
            mrt     0      0K       0K  78643K         5        0        0
    ISOFS mount     1     32K      32K  78643K         1        0        0
  MSDOSFS mount     1     16K      16K  78643K         1        0        0
           ttys    54    238K     238K  78643K        54        0        0
           exec     0      0K       1K  78643K       312        0        0
     pfkey data     0      0K       0K  78643K         1        0        0
        pagedep     1      8K       8K  78643K         1        0        0
       inodedep     1     32K      32K  78643K         1        0        0
         newblk     1      0K       0K  78643K         1        0        0
        VM swap     7     26K      26K  78643K         7        0        0
       UVM amap   119     22K      38K  78643K      2934        0        0
       UVM aobj    34      2K       2K  78643K        36        0        0
        memdesc     1      4K       4K  78643K         1        0        0
    crypto data     1      1K       1K  78643K         1        0        0
    ip6_options     0      0K       0K  78643K       124        0        0
            NDP    15      0K       0K  78643K        52        0        0
           temp   193   3560K    3625K  78643K     20587        0        0
         kqueue     0      0K       0K  78643K         4        0        0
      SYN cache     2     16K      16K  78643K         2        0        0
ddb{0}> show all pools
Name      Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
arp         64        8    0        6     1     0     1     1     0     8    0
plcache    128       20    0        0     1     0     1     1     0     8    0
rtpcb       80       49    0       47     1     0     1     1     0     8    0
rtentry    112       71    0       45     2     0     2     2     0     8    0
unpcb      120      359    0      339     1     0     1     1     0     8    0
syncache   264       12    0       12     3     2     1     1     0     8    1
tcpqe       32       60    0       60     1     1     0     1     0     8    0
tcpcb      544      363    0      358     3     1     2     2     0     8    1
inpcb      280      864    0      857     5     3     2     2     0     8    1
rttmr       72        2    0        2     2     1     1     1     0     8    1
nd6         48        6    0        6     1     1     0     1     0     8    0
pkpcb       40        6    0        6     2     2     0     1     0     8    0
ppxss      1128      19    0       19     4     3     1     1     0     8    1
pffrag     232       11    0       11     3     3     0     1     0   482    0
pffrnode    88       11    0       11     3     3     0     1     0     8    0
pffrent     40      323    0      323     3     3     0     1     0     8    0
pfosfp      40      846    0      423     5     0     5     5     0     8    0
pfosfpen   112     1428    0      714    21     0    21    21     0     8    0
pfstitem    24       67    0       18     1     0     1     1     0     8    0
pfstkey    112       67    0       18     2     0     2     2     0     8    0
pfstate    328       67    0       18     5     0     5     5     0     8    0
pfrule     1360      21    0       16     2     1     1     2     0     8    0
art_heap8  4096       4    0        2     4     2     2     3     0     8    0
art_heap4  256      292    0      164    14     5     9    14     0     8    0
art_table   32      296    0      166     2     0     2     2     0     8    0
art_node    16       68    0       44     1     0     1     1     0     8    0
sysvmsgpl   40       21    0       15     1     0     1     1     0     8    0
semapl     112      194    0      184     1     0     1     1     0     8    0
shmpl      112       34    0        2     1     0     1     1     0     8    0
dirhash    1024      17    0        0     3     0     3     3     0     8    0
dino1pl    128     2343    0      934    46     0    46    46     0     8    0
ffsino     272     2343    0      934    96     1    95    95     0     8    0
nchpl      144     3438    0     1825    61     0    61    61     0     8    0
uvmvnodes   72     3017    0        0    55     0    55    55     0     8    0
vnodes     208     3017    0        0   159     0   159   159     0     8    0
namei      1024   10584    0    10584     1     0     1     1     0     8    1
percpumem   16       30    0        0     1     0     1     1     0     8    0
vmpool     552        2    0        2     2     1     1     1     0     8    1
scsiplug    64        2    0        2     1     1     0     1     0     8    0
scxspl     192     9780    0     9780     9     8     1     7     0     8    1
plimitpl   152       53    0       45     1     0     1     1     0     8    0
sigapl     432      750    0      735     3     1     2     3     0     8    0
futexpl     56    12697    0    12697     1     0     1     1     0     8    1
knotepl    112      138    0      119     1     0     1     1     0     8    0
kqueuepl   104      188    0      186     1     0     1     1     0     8    0
pipepl     112      534    0      515     4     3     1     2     0     8    0
fdescpl    488      751    0      735     3     0     3     3     0     8    0
filepl     152     6001    0     5888     9     3     6     6     0     8    1
lockfpl    104      180    0      178     1     0     1     1     0     8    0
lockfspl    48       62    0       60     1     0     1     1     0     8    0
sessionpl  112       19    0        8     1     0     1     1     0     8    0
pgrppl      48       21    0       10     1     0     1     1     0     8    0
ucredpl     96      715    0      706     1     0     1     1     0     8    0
zombiepl   144      735    0      735     1     0     1     1     0     8    1
processpl  896      768    0      735     4     0     4     4     0     8    0
procpl     632     2092    0     2046     5     0     5     5     0     8    1
srpgc       64        4    0        4     1     1     0     1     0     8    0
sosppl     128        4    0        4     2     2     0     1     0     8    0
sockpl     384     1300    0     1271     8     4     4     5     0     8    1
mcl64k     65536      8    0        0     1     0     1     1     0     8    0
mcl16k     16384     10    0        0     2     0     2     2     0     8    0
mcl12k     12288      4    0        0     1     0     1     1     0     8    0
mcl9k      9216       6    0        0     1     0     1     1     0     8    0
mcl8k      8192       4    0        0     1     0     1     1     0     8    0
mcl4k      4096      11    0        0     2     0     2     2     0     8    0
mcl2k2     2112       2    0        0     1     0     1     1     0     8    0
mcl2k      2048     161    0        0    20     0    20    20     0     8    0
mtagpl      80       27    0        0     1     0     1     1     0     8    0
mbufpl     256      293    0        0    16     0    16    16     0     8    0
bufpl      256     9657    0     2609   441     0   441   441     0     8    0
anonpl      16   100636    0    81995    90     6    84    89     0   124    7
amapchunkpl 152    4510    0     4348    11     0    11    11     0   158    3
amappl16   192     4327    0     3324    75    21    54    63     0     8    3
amappl15   184        9    0        8     2     1     1     1     0     8    0
amappl14   176       36    0       34     1     0     1     1     0     8    0
amappl13   168       73    0       72     1     0     1     1     0     8    0
amappl12   160       11    0        9     1     0     1     1     0     8    0
amappl11   152      313    0      296     1     0     1     1     0     8    0
amappl10   144      196    0      189     1     0     1     1     0     8    0
amappl9    136      631    0      625     1     0     1     1     0     8    0
amappl8    128      196    0      164     2     0     2     2     0     8    0
amappl7    120      224    0      219     1     0     1     1     0     8    0
amappl6    112      328    0      315     1     0     1     1     0     8    0
amappl5    104      147    0      133     1     0     1     1     0     8    0
amappl4     96     1045    0     1011     2     1     1     2     0     8    0
amappl3     88      131    0      126     1     0     1     1     0     8    0
amappl2     80     5099    0     5028     3     1     2     3     0     8    0
amappl1     72    26360    0    25911    26    16    10    20     0     8    0
amappl      80     2369    0     2318     2     0     2     2     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       17    0       17     1     1     0     1     0     8    0
aobjpl      64       35    0        2     1     0     1     1     0     8    0
uaddrrnd    24      753    0      735     1     0     1     1     0     8    0
uaddrbest   32        2    0        0     1     0     1     1     0     8    0
uaddr       24      753    0      735     1     0     1     1     0     8    0
vmmpekpl   168    10423    0    10390     2     0     2     2     0     8    0
vmmpepl    168   100297    0    98124   145    39   106   133     0   357    7
vmsppl     368      750    0      735     2     0     2     2     0     8    0
pdppl      4096    1513    0     1474     6     0     6     6     0     8    0
pvpl        32   285520    0   263656   212    10   202   208     0   265   24
pmappl     232      752    0      737     3     2     1     2     0     8    0
extentpl    40       41    0       26     1     0     1     1     0     8    0
phpool     112      616    0       12    18     0    18    18     0     8    0

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/10/12 20:32 openbsd b8f72638b638 426631dd .config console log report ci-openbsd-multicore
* Struck through repros no longer work on HEAD.