syzbot


panic: vndioctl: null vp

Status: fixed on 2021/12/21 15:21
Reported-by: syzbot+c87cdc2905b441c20d39@syzkaller.appspotmail.com
Fix commit: 4d2db379fd33 Ensure that the disk has been initialized after acquiring the lock and not before as we might end up sleeping while acquiring the lock, introducing a potential race.
First crash: 351d, last: 350d
Patch testing requests:
Created Duration User Patch Repo Result
2021/12/19 07:16 0m anton@basename.se https://github.com/mptre/openbsd-src vnd error

Sample crash report:
login: panic: vndioctl: null vp
Stopped at      db_enter+0x18:  addq    $0x8,%rsp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
 393320  80133      0           0  0x4000000    1  syz-executor1231
*140312  70460      0           0  0x4000000    0K syz-executor1231
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:440
panic(ffffffff824a2454) at panic+0x177 sys/kern/subr_prf.c:202
vndsetcred(2902,80384601,ffff80002123c3a0,1) at vndsetcred
VOP_IOCTL(fffffd806e4f4ae8,80384601,ffff80002123c3a0,1,fffffd807f7d7660,ffff800021193268) at VOP_IOCTL+0x96 sys/kern/vfs_vops.c:264
vn_ioctl(fffffd806e587568,80384601,ffff80002123c3a0,ffff800021193268) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531
sys_ioctl(ffff800021193268,ffff80002123c4b8,ffff80002123c510) at sys_ioctl+0x4a2
syscall(ffff80002123c580) at syscall+0x489 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff80002123c580) at syscall+0x489 sys/arch/amd64/amd64/trap.c:585
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x171d74be4e0, count: 7
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{0}> 
ddb{0}> set $lines = 0
ddb{0}> set $maxwidth = 0
ddb{0}> show panic
*cpu0: vndioctl: null vp
ddb{0}> trace
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:440
panic(ffffffff824a2454) at panic+0x177 sys/kern/subr_prf.c:202
vndsetcred(2902,80384601,ffff80002123c3a0,1) at vndsetcred
VOP_IOCTL(fffffd806e4f4ae8,80384601,ffff80002123c3a0,1,fffffd807f7d7660,ffff800021193268) at VOP_IOCTL+0x96 sys/kern/vfs_vops.c:264
vn_ioctl(fffffd806e587568,80384601,ffff80002123c3a0,ffff800021193268) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531
sys_ioctl(ffff800021193268,ffff80002123c4b8,ffff80002123c510) at sys_ioctl+0x4a2
syscall(ffff80002123c580) at syscall+0x489 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff80002123c580) at syscall+0x489 sys/arch/amd64/amd64/trap.c:585
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x171d74be4e0, count: -8
ddb{0}> show registers
rdi                                0
rsi                              0x1
rbp               0xffff80002123bae0
rbx               0xffffffff827e3bff    cpu_info_full_primary+0x2bff
rdx                             0x8b
rcx                              0x2
rax                             0x19
r8                0xffffffff817eb474    kprintf+0x144
r9                               0x1
r10               0x8ed20437e8388a88
r11               0xc0887af3ae9824e6
r12               0xffffffff827e3a00    cpu_info_full_primary+0x2a00
r13                                0
r14                                0
r15                              0x1
rip               0xffffffff81552b08    db_enter+0x18
cs                               0x8
rflags                         0x246
rsp               0xffff80002123bad0
ss                              0x10
db_enter+0x18:  addq    $0x8,%rsp
ddb{0}> show proc
PROC (syz-executor1231) pid=140312 stat=onproc
    flags process=0 proc=4000000<THREAD>
    pri=32, usrpri=58, nice=20
    forw=0xffffffffffffffff, list=0xffff8000211927e8,0xffff800021193518
    process=0xffff8000211f1900 user=0xffff800021237000, vmspace=0xfffffd8008582000
    estcpu=36, cpticks=0, pctcpu=0.0
    user=0, sys=0, intr=0
ddb{0}> ps
   PID     TID   PPID    UID  S       FLAGS  WAIT          COMMAND
 80133  211500  53238      0  3        0x80  nanoslp       syz-executor1231
 80133  393320  53238      0  7   0x4000000                syz-executor1231
 80133  184629  53238      0  3   0x4000080  fsleep        syz-executor1231
 70460  308449  31436      0  3        0x80  nanoslp       syz-executor1231
*70460  140312  31436      0  7   0x4000000                syz-executor1231
 70460   40575  31436      0  3   0x4000080  fsleep        syz-executor1231
 53238  318563  57233      0  3        0x80  nanoslp       syz-executor1231
 31436  102970  57233      0  3        0x80  nanoslp       syz-executor1231
 57233  281650  71399      0  3        0x82  nanoslp       syz-executor1231
 71399  282405  54364      0  3    0x10008a  sigsusp       ksh
 54364  172014  51591      0  3        0x9a  kqread        sshd
 69143   98391      1      0  3    0x100083  ttyin         getty
 51591  209388      1      0  3        0x88  kqread        sshd
 91055  118854  37160     74  3    0x100092  bpf           pflogd
 37160  195490      1      0  3        0x80  netio         pflogd
 59269  489417  78538     73  3    0x100090  kqread        syslogd
 78538   50481      1      0  3    0x100082  netio         syslogd
 93138  356985      1      0  3    0x100080  kqread        resolvd
 74073  150888  46366     77  3    0x100092  kqread        dhcpleased
 52979  301027  46366     77  3    0x100092  kqread        dhcpleased
 46366    9037      1      0  3        0x80  kqread        dhcpleased
 41215  466177      0      0  3     0x14200  bored         smr
  2980  391234      0      0  3     0x14200  pgzero        zerothread
 23823  273219      0      0  3     0x14200  aiodoned      aiodoned
 79095  103314      0      0  3     0x14200  syncer        update
 28809  260796      0      0  3     0x14200  cleaner       cleaner
 92625  216351      0      0  3     0x14200  reaper        reaper
 51428  347553      0      0  3     0x14200  pgdaemon      pagedaemon
 47197  261302      0      0  3     0x14200  bored         viomb
 20766   49142      0      0  3  0x40014200  acpi0         acpi0
  2523  303346      0      0  3  0x40014200                idle1
 11284  148528      0      0  3     0x14200  bored         softnet
 72783   13181      0      0  3     0x14200  bored         systqmp
 95706  238264      0      0  3     0x14200  bored         systq
 38795  301691      0      0  3  0x40014200  bored         softclock
 79495   18343      0      0  3  0x40014200                idle0
     1  135028      0      0  3        0x82  wait          init
     0       0     -1      0  3     0x10200  scheduler     swapper
ddb{0}> show all locks
Process 80133 (syz-executor1231) thread 0xffff800021193508 (393320)
exclusive rwlock futex r = 0 (0xffffffff827e4980)
#0  witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline]
#0  witness_lock+0x4b0 sys/kern/subr_witness.c:1182
#1  sys_futex+0x5c sys/kern/sys_futex.c:108
#2  syscall+0x489 mi_syscall sys/sys/syscall_mi.h:102 [inline]
#2  syscall+0x489 sys/arch/amd64/amd64/trap.c:585
#3  Xsyscall+0x128
Process 70460 (syz-executor1231) thread 0xffff800021193268 (140312)
exclusive rwlock dklk r = 0 (0xffff8000006ac068)
#0  witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline]
#0  witness_lock+0x4b0 sys/kern/subr_witness.c:1182
#1  rw_enter+0x3e2 sys/kern/kern_rwlock.c:310
#2  vndioctl+0x4f1 sys/dev/vnd.c:538
#3  VOP_IOCTL+0x96 sys/kern/vfs_vops.c:264
#4  vn_ioctl+0xba sys/kern/vfs_vnops.c:531
#5  sys_ioctl+0x4a2
#6  syscall+0x489 mi_syscall sys/sys/syscall_mi.h:102 [inline]
#6  syscall+0x489 sys/arch/amd64/amd64/trap.c:585
#7  Xsyscall+0x128
exclusive kernel_lock &kernel_lock r = 0 (0xffffffff828ba480)
#0  witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline]
#0  witness_lock+0x4b0 sys/kern/subr_witness.c:1182
#1  __mp_acquire_count+0x4c sys/kern/kern_lock.c:227
#2  mi_switch+0x3d3 sys/kern/sched_bsd.c:416
#3  sleep_finish+0x1b2 sys/kern/kern_synch.c:433
#4  rw_enter+0x35b sys/kern/kern_rwlock.c:286
#5  vndioctl+0x4f1 sys/dev/vnd.c:538
#6  VOP_IOCTL+0x96 sys/kern/vfs_vops.c:264
#7  vn_ioctl+0xba sys/kern/vfs_vnops.c:531
#8  sys_ioctl+0x4a2
#9  syscall+0x489 mi_syscall sys/sys/syscall_mi.h:102 [inline]
#9  syscall+0x489 sys/arch/amd64/amd64/trap.c:585
#10 Xsyscall+0x128
ddb{0}> show malloc
           Type InUse  MemUse  HighUse   Limit  Requests Type Lim
         devbuf 10109   6415K    6416K  78643K     11429        0
            pcb    13      8K       8K  78643K        13        0
         rtable    62      2K       2K  78643K       118        0
         ifaddr    29      8K       8K  78643K        30        0
       counters    40     33K      33K  78643K        40        0
       ioctlops     0      0K       4K  78643K      1479        0
          mount     1      1K       1K  78643K         1        0
            log     0      0K       0K  78643K         4        0
         vnodes  1183     74K      75K  78643K      1189        0
      UFS quota     1     32K      32K  78643K         1        0
      UFS mount     5     36K      36K  78643K         5        0
            shm     2      1K       1K  78643K         2        0
         VM map     2      1K       1K  78643K         2        0
            sem     2      0K       0K  78643K         2        0
        dirhash    12      2K       2K  78643K        12        0
           ACPI  1697    195K     286K  78643K     12598        0
      file desc     1      0K       0K  78643K         1        0
           proc    67     87K      87K  78643K       278        0
    NFS srvsock     1      0K       0K  78643K         1        0
     NFS daemon     1     16K      16K  78643K         1        0
       in_multi    11      0K       0K  78643K        11        0
    ether_multi     1      0K       0K  78643K         1        0
    ISOFS mount     1     32K      32K  78643K         1        0
  MSDOSFS mount     1     16K      16K  78643K         1        0
           ttys    19     95K      95K  78643K        19        0
           exec     0      0K       2K  78643K       368        0
            tdb     3      0K       0K  78643K         3        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   114      4K       6K  78643K      7447        0
       UVM aobj     3      2K       2K  78643K         3        0
        memdesc     1      4K       4K  78643K         1        0
    crypto data     1      1K       1K  78643K         1        0
            NDP     4      0K       0K  78643K         4        0
           temp    23   4181K    4245K  78643K      3377        0
         kqueue    11     16K      16K  78643K        20        0
      SYN cache     2     16K      16K  78643K         2        0
ddb{0}> show all pools
Name      Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
plcache    128       22    0        0     1     0     1     1     0     8    0
rtpcb      120       20    0       17     1     0     1     1     0     8    0
rtentry    112       23    0        1     1     0     1     1     0     8    0
unpcb      128       35    0       20     1     0     1     1     0     8    0
syncache   296        5    0        5     2     2     0     1     0     8    0
tcpcb      736        8    0        5     1     0     1     1     0     8    0
arp        120        2    0        0     1     0     1     1     0     8    0
inpcb      304       32    0       26     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        8    0        2     1     0     1     1     0     8    0
pfstkey    112        8    0        2     1     0     1     1     0     8    0
pfstate    320        8    0        2     1     0     1     1     0     8    0
pfrule     1360      21    0       15     2     0     2     2     0     8    0
art_heap8  4096       1    0        0     1     0     1     1     0     8    0
art_heap4  256       97    0        0     7     0     7     7     0     8    0
art_table   32       98    0        0     1     0     1     1     0     8    0
art_node    16       22    0        2     1     0     1     1     0     8    0
dirhash    1024      17    0        0     3     0     3     3     0     8    0
dino2pl    256     2301    0      905    88     0    88    88     0     8    0
ffsino     272     2301    0      905    94     0    94    94     0     8    0
nchpl      144     3361    0     1806    58     0    58    58     0     8    0
uvmvnodes   72     2312    0        0    43     0    43    43     0     8    0
vnodes     224     2312    0        0   136     0   136   136     0     8    0
namei      1024    8414    0     8414     2     1     1     1     0     8    1
percpumem   16       32    0        0     1     0     1     1     0     8    0
scxspl     216     9065    0     9065    11    10     1     8     0     8    1
plimitpl   152       16    0        9     1     0     1     1     0     8    0
sigapl     424      708    0      675     4     0     4     4     0     8    0
futexpl     64     1634    0     1631     1     0     1     1     0     8    0
knotepl    112       36    0        0     2     0     2     2     0     8    0
kqueuepl   216       16    0        9     1     0     1     1     0     8    0
pipepl     336       72    0       69     2     1     1     1     0     8    0
fdescpl    496      694    0      675     3     0     3     3     0     8    0
filepl     152     2427    0     2365     3     0     3     3     0     8    0
lockfpl    104        6    0        4     1     0     1     1     0     8    0
lockfspl    48        4    0        2     1     0     1     1     0     8    0
sessionpl  144       18    0        9     1     0     1     1     0     8    0
pgrppl      48       18    0        9     1     0     1     1     0     8    0
ucredpl     96      299    0      287     1     0     1     1     0     8    0
zombiepl   144      675    0      675     2     1     1     1     0     8    1
processpl  1064     708    0      675     3     0     3     3     0     8    0
procpl     672     2000    0     1963     4     0     4     4     0     8    0
sockpl     480       87    0       63     5     1     4     4     0     8    0
mcl8k      8192       4    0        0     1     0     1     1     0     8    0
mcl4k      4096       2    0        0     1     0     1     1     0     8    0
mcl2k      2048      75    0        0    10     0    10    10     0     8    0
mtagpl      96        2    0        0     1     0     1     1     0     8    0
mbufpl     256      140    0        0     8     0     8     8     0     8    0
bufpl      280     3131    0       92   218     0   218   218     0     8    0
anonpl      24   116335    0   113486    21     3    18    18     0   186    0
amapchunkpl 152   15686    0    15474    10     1     9     9     0   158    0
amappl16   200      473    0      469     2     1     1     1     0     8    0
amappl15   192       70    0       67     1     0     1     1     0     8    0
amappl13   176       18    0       17     2     1     1     1     0     8    0
amappl12   168        3    0        3     1     1     0     1     0     8    0
amappl11   160       59    0       42     1     0     1     1     0     8    0
amappl10   152       10    0        7     1     0     1     1     0     8    0
amappl9    144      230    0      228     1     0     1     1     0     8    0
amappl8    136      295    0      290     1     0     1     1     0     8    0
amappl7    128       33    0       32     1     0     1     1     0     8    0
amappl6    120       35    0       31     1     0     1     1     0     8    0
amappl5    112      213    0      195     1     0     1     1     0     8    0
amappl4    104      987    0      964     1     0     1     1     0     8    0
amappl3     96      602    0      585     1     0     1     1     0     8    0
amappl2     88      308    0      276     1     0     1     1     0     8    0
amappl1     80    14216    0    13798    11     2     9     9     0     8    0
amappl      88     7189    0     7094     3     0     3     3     0    92    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      64        2    0        0     1     0     1     1     0     8    0
uaddrrnd    24      694    0      675     1     0     1     1     0     8    0
uaddrbest   32        2    0        0     1     0     1     1     0     8    0
uaddr       24      694    0      675     1     0     1     1     0     8    0
vmmpekpl   168     9834    0     9820     1     0     1     1     0     8    0
vmmpepl    168    53073    0    52042    50     4    46    46     0   357    1
vmsppl     368      693    0      675     2     0     2     2     0     8    0
rwobjpl     56    15214    0    14618    11     2     9     9     0     8    0
pdppl      4096    1396    0     1350    72    26    46    46     0     8    0
pvpl        32   245590    0   240701    47     6    41    41     0   265    1
pmappl     224      693    0      675     2     0     2     2     0     8    0
extentpl    40       58    0       40     1     0     1     1     0     8    0
phpool     112      297    0       30     8     0     8     8     0     8    0
ddb{0}> machine ddbcpu 0
Invalid cpu 0
ddb{0}> trace
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:440
panic(ffffffff824a2454) at panic+0x177 sys/kern/subr_prf.c:202
vndsetcred(2902,80384601,ffff80002123c3a0,1) at vndsetcred
VOP_IOCTL(fffffd806e4f4ae8,80384601,ffff80002123c3a0,1,fffffd807f7d7660,ffff800021193268) at VOP_IOCTL+0x96 sys/kern/vfs_vops.c:264
vn_ioctl(fffffd806e587568,80384601,ffff80002123c3a0,ffff800021193268) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531
sys_ioctl(ffff800021193268,ffff80002123c4b8,ffff80002123c510) at sys_ioctl+0x4a2
syscall(ffff80002123c580) at syscall+0x489 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff80002123c580) at syscall+0x489 sys/arch/amd64/amd64/trap.c:585
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x171d74be4e0, count: -8
ddb{0}> 

Crashes (3):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-openbsd-multicore 2021/12/15 14:05 openbsd 03319b45cc1f f752fb53 .config log report syz C panic: vndioctl: null vp
ci-openbsd-multicore 2021/12/16 20:34 openbsd 0eeaa5490dc5 8dd6a5e3 .config log report panic: vndioctl: null vp
ci-openbsd-multicore 2021/12/15 13:47 openbsd 03319b45cc1f f752fb53 .config log report panic: vndioctl: null vp
* Struck through repros no longer work on HEAD.