syzbot


assert "uvn->u_obj.uo_refs == NUM" failed in uvm_vnode.c (2)

Status: upstream: reported syz repro on 2022/10/05 00:21
Reported-by: syzbot+8acb3d0ef5a5eb5456c8@syzkaller.appspotmail.com
First crash: 117d, last: 117d
similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
openbsd assert "uvn->u_obj.uo_refs == NUM" failed in uvm_vnode.c syz 8 163d 214d 3/3 fixed on 2022/08/31 23:31
Last patch testing requests:
Created Duration User Patch Repo Result
2023/01/13 02:32 8m retest repro openbsd error

Sample crash report:
panic: kernel diagnostic assertion "uvn->u_obj.uo_refs == 0" failed: file "/syzkaller/managers/setuid/kernel/sys/uvm/uvm_vnode.c", line 235
Stopped at      db_enter+0x18:  addq    $0x8,%rsp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
 277422  64346      0           0          0    1  syz-executor.0
*380328  64346      0           0  0x4000000    0K syz-executor.0
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:437
panic(ffffffff825a55e6) at panic+0x177 sys/kern/subr_prf.c:198
__assert(ffffffff8261b443,ffffffff8263e6a2,eb,ffffffff82637043) at __assert+0x25 sys/kern/subr_prf.c:157
uvn_attach(fffffd806a6b11c8,6) at uvn_attach+0x454 sys/uvm/uvm_vnode.c:235
uvm_mmapfile(fffffd806f090008,ffff8000213189f8,10000,2,6,11,445f8279a03234d4,fffffd806f090008,0,11) at uvm_mmapfile+0x194 sys/uvm/uvm_mmap.c:1029
sys_mmap(ffff8000ffff4fc0,ffff800021318aa0,ffff800021318b70) at sys_mmap+0xb4a sys/uvm/uvm_mmap.c:395
sys_pad_mmap(ffff8000ffff4fc0,ffff800021318b28,ffff800021318b70) at sys_pad_mmap+0x68 sys/uvm/uvm_mmap.c:470
syscall(ffff800021318bf0) at syscall+0x435 mi_syscall sys/sys/syscall_mi.h:101 [inline]
syscall(ffff800021318bf0) at syscall+0x435 sys/arch/amd64/amd64/trap.c:585
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x9190dffa090, count: 6
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: kernel diagnostic assertion "uvn->u_obj.uo_refs == 0" failed: file "/syzkaller/managers/setuid/kernel/sys/uvm/uvm_vnode.c", line 235
ddb{0}> trace
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:437
panic(ffffffff825a55e6) at panic+0x177 sys/kern/subr_prf.c:198
__assert(ffffffff8261b443,ffffffff8263e6a2,eb,ffffffff82637043) at __assert+0x25 sys/kern/subr_prf.c:157
uvn_attach(fffffd806a6b11c8,6) at uvn_attach+0x454 sys/uvm/uvm_vnode.c:235
uvm_mmapfile(fffffd806f090008,ffff8000213189f8,10000,2,6,11,445f8279a03234d4,fffffd806f090008,0,11) at uvm_mmapfile+0x194 sys/uvm/uvm_mmap.c:1029
sys_mmap(ffff8000ffff4fc0,ffff800021318aa0,ffff800021318b70) at sys_mmap+0xb4a sys/uvm/uvm_mmap.c:395
sys_pad_mmap(ffff8000ffff4fc0,ffff800021318b28,ffff800021318b70) at sys_pad_mmap+0x68 sys/uvm/uvm_mmap.c:470
syscall(ffff800021318bf0) at syscall+0x435 mi_syscall sys/sys/syscall_mi.h:101 [inline]
syscall(ffff800021318bf0) at syscall+0x435 sys/arch/amd64/amd64/trap.c:585
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x9190dffa090, count: -9
ddb{0}> show registers
rdi                                0
rsi                              0x1
rbp               0xffff800021318690
rbx               0xffffffff8296db8f    cpu_info_full_primary+0x2b8f
rdx                            0x3fd
rcx                                0
rax                             0x8c
r8                 0x101010101010101
r9                0x8080808080808080
r10               0x1ca017bc31a6ac42
r11               0x39324836b7e5cadb
r12               0xffffffff8296d990    cpu_info_full_primary+0x2990
r13                                0
r14                                0
r15                              0x1
rip               0xffffffff8228a448    db_enter+0x18
cs                               0x8
rflags                         0x246
rsp               0xffff800021318680
ss                              0x10
db_enter+0x18:  addq    $0x8,%rsp
ddb{0}> show proc
PROC (syz-executor.0) pid=380328 stat=onproc
    flags process=0 proc=4000000<THREAD>
    pri=32, usrpri=86, nice=20
    forw=0xffffffffffffffff, list=0xffff8000ffff4d20,0xffff8000ffff5cf0
    process=0xffff8000ffff8008 user=0xffff800021313000, vmspace=0xfffffd806f090008
    estcpu=36, cpticks=2, pctcpu=0.0
    user=0, sys=1, intr=0
ddb{0}> ps
   PID     TID   PPID    UID  S       FLAGS  WAIT          COMMAND
 64346  277422  69735      0  7           0                syz-executor.0
*64346  380328  69735      0  7   0x4000000                syz-executor.0
 64346  145777  69735      0  2   0x4000000                syz-executor.0
 69735  194909  72704      0  2       0x482                syz-executor.0
 72704  220828  36184      0  3        0x82  thrsleep      syz-execprog
 72704  151884  36184      0  2   0x4000482                syz-execprog
 72704  508581  36184      0  3   0x4000082  thrsleep      syz-execprog
 72704   43472  36184      0  3   0x4000082  wait          syz-execprog
 72704   61391  36184      0  3   0x4000082  kqread        syz-execprog
 72704  465187  36184      0  3   0x4000082  thrsleep      syz-execprog
 72704  366317  36184      0  3   0x4000082  thrsleep      syz-execprog
 72704    1164  36184      0  3   0x4000082  thrsleep      syz-execprog
 72704  394231  36184      0  3   0x4000082  thrsleep      syz-execprog
 36184  261147  82921      0  3    0x10008a  sigsusp       ksh
 82921   56518  23031      0  3        0x9a  kqread        sshd
 94567  156858      1      0  3    0x100083  ttyin         getty
 23031   54032      1      0  3        0x88  kqread        sshd
 63430   26484  77118     73  3   0x1100090  kqread        syslogd
 77118  373677      1      0  3    0x100082  netio         syslogd
 59131  508110      1      0  3    0x100080  kqread        resolvd
 77273  133465  79829     77  3    0x100092  kqread        dhcpleased
 27407  143588  79829     77  3    0x100092  kqread        dhcpleased
 79829   65990      1      0  3        0x80  kqread        dhcpleased
 39854   76154      0      0  3     0x14200  bored         smr
  8378  377605      0      0  3     0x14200  pgzero        zerothread
 82246  269044      0      0  3     0x14200  aiodoned      aiodoned
 37955  137228      0      0  3     0x14200  syncer        update
 93501  436937      0      0  3     0x14200  cleaner       cleaner
  5751  466781      0      0  3     0x14200  reaper        reaper
 78903  204130      0      0  3     0x14200  pgdaemon      pagedaemon
 85964  166911      0      0  3     0x14200  bored         viomb
  1023  263336      0      0  3  0x40014200  acpi0         acpi0
 98723  196445      0      0  3  0x40014200                idle1
 30470  329270      0      0  3     0x14200  bored         softnet
 43839  112708      0      0  3     0x14200  bored         softnet
 21365  305061      0      0  3     0x14200  bored         softnet
 13510  400119      0      0  3     0x14200  bored         softnet
 96389  289102      0      0  3     0x14200  bored         systqmp
 72206  341334      0      0  3     0x14200  bored         systq
 84552  398927      0      0  3  0x40014200  bored         softclock
 28369   65273      0      0  3  0x40014200                idle0
     1  326184      0      0  3        0x82  wait          init
     0       0     -1      0  3     0x10200  scheduler     swapper
ddb{0}> show all locks
Process 64346 (syz-executor.0) thread 0xffff8000ffff4d20 (277422)
exclusive rwlock uobjlk r = 0 (0xfffffd806a22cd38)
#0  witness_lock+0x44d
#1  rw_enter+0x3e1 sys/kern/kern_rwlock.c:310
#2  uvm_fault_lower+0x951 sys/uvm/uvm_fault.c:1324
#3  uvm_fault+0x238
#4  upageflttrap+0x82 sys/arch/amd64/amd64/trap.c:181
#5  usertrap+0x1aa sys/arch/amd64/amd64/trap.c:403
#6  recall_trap+0x8
Process 64346 (syz-executor.0) thread 0xffff8000ffff4fc0 (380328)
exclusive kernel_lock &kernel_lock r = 1 (0xffffffff82ba5240)
#0  witness_lock+0x44d
#1  syscall+0x41d mi_syscall sys/sys/syscall_mi.h:100 [inline]
#1  syscall+0x41d sys/arch/amd64/amd64/trap.c:585
#2  Xsyscall+0x128
ddb{0}> show malloc
           Type InUse  MemUse  HighUse   Limit  Requests Type Lim
         devbuf 10158   6391K    6420K  78643K     11248        0
            pcb    13      8K       8K  78643K        13        0
         rtable    80      2K       2K  78643K       133        0
         ifaddr    33      8K       8K  78643K        33        0
       counters    42     33K      33K  78643K        42        0
       ioctlops     0      0K       2K  78643K        26        0
          mount     1      1K       1K  78643K         1        0
            log     0      0K       0K  78643K         4        0
         vnodes  1166     73K      73K  78643K      1179        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     12548        0
      file desc     4      9K      13K  78643K       263        0
           proc    55     78K      91K  78643K       254        0
    NFS srvsock     1      0K       0K  78643K         1        0
     NFS daemon     1     16K      16K  78643K         1        0
       in_multi    22      1K       1K  78643K        22        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    25    122K     122K  78643K        25        0
           exec     0      0K       2K  78643K       440        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     8     62K      64K  78643K        10        0
       UVM amap   122     27K      27K  78643K      3453        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         6        0
           temp    23   4717K    4781K  78643K      3293        0
         kqueue    12     18K      18K  78643K        25        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       19    0       16     1     0     1     1     0     8    0
rtentry    112       34    0        1     1     0     1     1     0     8    0
unpcb      144       33    0       20     1     0     1     1     0     8    0
syncache   296        5    0        5     2     2     0     1     0     8    0
tcpcb      768        8    0        5     1     0     1     1     0     8    0
arp        120        4    0        0     1     0     1     1     0     8    0
inpcb      368       29    0       23     1     0     1     1     0     8    0
nd6         48        3    0        0     1     0     1     1     0     8    0
art_heap8  4096       1    0        0     1     0     1     1     0     8    0
art_heap4  256      144    0        0     9     0     9     9     0     8    0
art_table   32      145    0        0     2     0     2     2     0     8    0
art_node    16       33    0        3     1     0     1     1     0     8    0
dirhash    1024      17    0        0     3     0     3     3     0     8    0
dino2pl    256     1927    0      531    88     0    88    88     0     8    0
ffsino     272     1927    0      531    94     0    94    94     0     8    0
nchpl      144     2645    0     1025    61     0    61    61     0     8    0
uvmvnodes   80     1936    0        0    40     0    40    40     0     8    0
vnodes     216     1936    0        0   108     0   108   108     0     8    0
namei      1024    6546    0     6546     3     1     2     2     0     8    2
percpumem   16       33    0        0     1     0     1     1     0     8    0
kstatmem   264        8    0        0     1     0     1     1     0     8    0
scxspl     216     8218    0     8218    20    19     1     8     0     8    1
plimitpl   152       17    0        9     1     0     1     1     0     8    0
sigapl     424      564    0      532     5     0     5     5     0     8    1
futexpl     64     1190    0     1190     1     0     1     1     0     8    1
knotepl    120       56    0        0     2     0     2     2     0     8    0
kqueuepl   216       21    0       13     1     0     1     1     0     8    0
pipepl     320       99    0       92     2     1     1     1     0     8    0
fdescpl    496      547    0      532     4     1     3     3     0     8    1
filepl     152     2007    0     1941     4     1     3     4     0     8    0
lockfpl    104      491    0      488     1     0     1     1     0     8    0
lockfspl    48      247    0      244     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    104       64    0       54     1     0     1     1     0     8    0
zombiepl   144      532    0      532     2     1     1     1     0     8    1
processpl  1064     564    0      532     3     0     3     3     0     8    0
procpl     672     1070    0     1028     4     0     4     4     0     8    0
sockpl     488       81    0       59     3     0     3     3     0     8    0
mcl8k      8192       3    0        0     1     0     1     1     0     8    0
mcl4k      4096       3    0        0     1     0     1     1     0     8    0
mcl2k      2048      65    0        0     9     0     9     9     0     8    0
mtagpl      96        2    0        0     1     0     1     1     0     8    0
mbufpl     256      134    0        0     8     0     8     8     0     8    0
bufpl      288     4379    0      133   304     0   304   304     0     8    0
anonpl      24    94193    0    89977    49     4    45    45     0   186   19
amapchunkpl 152   51525    0    51054    20     1    19    19     0   158    0
amappl16   200      652    0      581     6     1     5     5     0     8    0
amappl15   192       79    0       71     1     0     1     1     0     8    0
amappl14   184        7    0        6     1     0     1     1     0     8    0
amappl13   176       39    0       37     2     1     1     1     0     8    0
amappl12   168      246    0      244     2     1     1     1     0     8    0
amappl11   160       42    0       29     1     0     1     1     0     8    0
amappl10   152       13    0       13     1     0     1     1     0     8    1
amappl9    144      907    0      905     2     1     1     1     0     8    0
amappl8    136      430    0      408     2     0     2     2     0     8    0
amappl7    128       85    0       74     1     0     1     1     0     8    0
amappl6    120      170    0      152     2     0     2     2     0     8    1
amappl5    112      328    0      320     1     0     1     1     0     8    0
amappl4    104      627    0      606     2     0     2     2     0     8    1
amappl3     96     1525    0     1492     2     0     2     2     0     8    1
amappl2     88      650    0      601     4     1     3     3     0     8    1
amappl1     80    16231    0    15696    23     2    21    21     0     8    8
amappl      88     3117    0     3038     4     1     3     3     0    92    1
dma4096    4096       1    0        1     1     1     0     1     0     8    0
dma1024    1024       1    0        0     1     0     1     1     0     8    0
dma256     256        6    0        6     1     1     0     1     0     8    0
dma128     128      253    0      253     1     1     0     1     0     8    0
dma64       64        6    0        6     1     1     0     1     0     8    0
dma32       32        7    0        7     1     1     0     1     0     8    0
dma16       16       18    0       17     1     0     1     1     0     8    0
aobjpl      72        2    0        0     1     0     1     1     0     8    0
uaddrrnd    24      547    0      532     1     0     1     1     0     8    0
uaddrbest   32        2    0        0     1     0     1     1     0     8    0
uaddr       24      547    0      532     1     0     1     1     0     8    0
vmmpekpl   168     9862    0     9844     2     0     2     2     0     8    1
vmmpepl    168    61237    0    59936   100     3    97    97     0   357   40
vmsppl     368      546    0      532     3     0     3     3     0     8    1
rwobjpl     56    17912    0    15135    42     0    42    42     0     8    2
pdppl      4096    1101    0     1064    71    28    43    53     0     8    6
pvpl        32   280224    0   271969   276     6   270   270     0   265  202
pmappl     248      546    0      532     3     1     2     2     0     8    1
extentpl    40       56    0       38     1     0     1     1     0     8    0
phpool     112      599    0       31    17     0    17    17     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:437
panic(ffffffff825a55e6) at panic+0x177 sys/kern/subr_prf.c:198
__assert(ffffffff8261b443,ffffffff8263e6a2,eb,ffffffff82637043) at __assert+0x25 sys/kern/subr_prf.c:157
uvn_attach(fffffd806a6b11c8,6) at uvn_attach+0x454 sys/uvm/uvm_vnode.c:235
uvm_mmapfile(fffffd806f090008,ffff8000213189f8,10000,2,6,11,445f8279a03234d4,fffffd806f090008,0,11) at uvm_mmapfile+0x194 sys/uvm/uvm_mmap.c:1029
sys_mmap(ffff8000ffff4fc0,ffff800021318aa0,ffff800021318b70) at sys_mmap+0xb4a sys/uvm/uvm_mmap.c:395
sys_pad_mmap(ffff8000ffff4fc0,ffff800021318b28,ffff800021318b70) at sys_pad_mmap+0x68 sys/uvm/uvm_mmap.c:470
syscall(ffff800021318bf0) at syscall+0x435 mi_syscall sys/sys/syscall_mi.h:101 [inline]
syscall(ffff800021318bf0) at syscall+0x435 sys/arch/amd64/amd64/trap.c:585
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x9190dffa090, count: -9
ddb{0}> machine ddbcpu 1
Stopped at      x86_ipi_db+0x1a:        addq    $0x8,%rsp
x86_ipi_db(ffff800020dd8ff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:393
x86_ipi_handler() at x86_ipi_handler+0xb7 sys/arch/amd64/amd64/ipi.c:106
Xresume_lapic_ipi() at Xresume_lapic_ipi+0x23
__mp_lock(ffffffff82ba5038) at __mp_lock+0x122 __mp_lock_spin sys/kern/kern_lock.c:116 [inline]
__mp_lock(ffffffff82ba5038) at __mp_lock+0x122 sys/kern/kern_lock.c:147
syscall(ffff80002130a350) at syscall+0x41d mi_syscall sys/sys/syscall_mi.h:100 [inline]
syscall(ffff80002130a350) at syscall+0x41d sys/arch/amd64/amd64/trap.c:585
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7ffffbc140, count: 9
ddb{1}> trace
x86_ipi_db(ffff800020dd8ff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:393
x86_ipi_handler() at x86_ipi_handler+0xb7 sys/arch/amd64/amd64/ipi.c:106
Xresume_lapic_ipi() at Xresume_lapic_ipi+0x23
__mp_lock(ffffffff82ba5038) at __mp_lock+0x122 __mp_lock_spin sys/kern/kern_lock.c:116 [inline]
__mp_lock(ffffffff82ba5038) at __mp_lock+0x122 sys/kern/kern_lock.c:147
syscall(ffff80002130a350) at syscall+0x41d mi_syscall sys/sys/syscall_mi.h:100 [inline]
syscall(ffff80002130a350) at syscall+0x41d sys/arch/amd64/amd64/trap.c:585
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7ffffbc140, count: -6

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Title
ci-openbsd-setuid 2022/10/05 01:33 openbsd 0b11e45035f5 267e3bb1 .config console log report syz [disk image] [bsd.gdb] [kernel image] assert "uvn->u_obj.uo_refs == NUM" failed in uvm_vnode.c
ci-openbsd-setuid 2022/10/05 00:21 openbsd 0b11e45035f5 267e3bb1 .config console log report [disk image] [bsd.gdb] [kernel image] assert "uvn->u_obj.uo_refs == NUM" failed in uvm_vnode.c
* Struck through repros no longer work on HEAD.