assert "ps->ps_uvncount == 0" failed in kern

assert "ps->ps_uvncount == 0" failed in kern_unveil.c

Status: fixed on 2019/10/02 09:51
Reported-by: syzbot+db66362e1ffdc72e5aeb@syzkaller.appspotmail.com
Fix commit: a239dbafd306 Only increment the ps_uvncount counter when a path is successfully added to the corresponding red-black tree; meaning the path was not already present in the tree. This prevents an assertion to trigger in unveil_destroy() later on when the process exits.
First crash: 2152d, last: 1884d

▶ ▼ Duplicate bugs (1)

duplicates (1):
Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
panic: kernel diagnostic assertion "ps->ps_uvncount == 0" failed: file "/syzkaller/managers/setuid/kernel/sys/kern/kern_				2	2163d	2168d	0/3	closed as dup on 2018/12/31 16:38

▶ ▼ Similar bugs (1)

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
openbsd	assert "ps->ps_uvncount == 0" failed in kern_unveil.c (2)				1	1727d	1727d	0/3	auto-closed as invalid on 2020/05/29 05:13

▶ ▼ Last patch testing requests (1)


Created	Duration	User	Patch	Repo	Result
2019/09/28 09:37	16m	anton@basename.se		https://github.com/mptre/openbsd-src unveil	OK

Sample crash report:

login: panic: kernel diagnostic assertion "ps->ps_uvncount == 0" failed: file "/syzkaller/managers/setuid/kernel/sys/kern/kern_unveil.c", line 196
Stopped at      db_enter+0x18:  addq    $0x8,%rsp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
 335166  26209      0     0x14000      0x200    1  reaper
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399
panic() at panic+0x16c sys/kern/subr_prf.c:208
__assert(ffffffff814df464,ffff800020c7fb00,ffff800000957000,50) at __assert+0x24 sys/kern/subr_prf.c:155
unveil_destroy(7fa4af3dbb8f70cc) at unveil_destroy+0x178 sys/kern/kern_unveil.c:196
exit1(0,ffff800020be4970,7f7ffffc2038) at exit1+0x337 sys/kern/kern_exit.c:216
sys_exit(ffffffff818ead43,ffff800020c7fbc0,0) at sys_exit+0x13 sys/kern/kern_exit.c:94
syscall(1af602ef04197bd5) at syscall+0x5a0 mi_syscall sys/sys/syscall_mi.h:99 [inline]
syscall(1af602ef04197bd5) at syscall+0x5a0 sys/arch/amd64/amd64/trap.c:583
Xsyscall(6,1,0,1,0,7f7ffffc2074) at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7ffffc2040, 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}> show panic
kernel diagnostic assertion "ps->ps_uvncount == 0" failed: file "/syzkaller/managers/setuid/kernel/sys/kern/kern_unveil.c", line 196
ddb{0}> trace
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399
panic() at panic+0x16c sys/kern/subr_prf.c:208
__assert(ffffffff814df464,ffff800020c7fb00,ffff800000957000,50) at __assert+0x24 sys/kern/subr_prf.c:155
unveil_destroy(7fa4af3dbb8f70cc) at unveil_destroy+0x178 sys/kern/kern_unveil.c:196
exit1(0,ffff800020be4970,7f7ffffc2038) at exit1+0x337 sys/kern/kern_exit.c:216
sys_exit(ffffffff818ead43,ffff800020c7fbc0,0) at sys_exit+0x13 sys/kern/kern_exit.c:94
syscall(1af602ef04197bd5) at syscall+0x5a0 mi_syscall sys/sys/syscall_mi.h:99 [inline]
syscall(1af602ef04197bd5) at syscall+0x5a0 sys/arch/amd64/amd64/trap.c:583
Xsyscall(6,1,0,1,0,7f7ffffc2074) at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7ffffc2040, count: -8
ddb{0}> show registers
rdi                                0
rsi                              0x1
rbp               0xffff800020c7fa60
rbx               0xffff800020c7fb00
rdx               0xffffffff81ec8b28    cmd0646_9_tim_udma+0x14f93
rcx                            0x201
rax                              0x1
r8                0xffffffff814dfdf4    kprintf+0x174
r9                               0x1
r10               0x8b25aedd989a7a0a
r11               0xc9d6af427db244e6
r12                     0x3000000008
r13               0xffff800020c7fa70
r14                            0x100
r15                              0x1
rip               0xffffffff8184b4f8    db_enter+0x18
cs                               0x8
rflags                         0x246
rsp               0xffff800020c7fa50
ss                              0x10
db_enter+0x18:  addq    $0x8,%rsp
ddb{0}> show proc
PROC (syz-executor0) pid=423488 stat=onproc
    flags process=1008<EXITING,SINGLEEXIT> proc=2000<WEXIT>
    pri=50, usrpri=86, nice=20
    forw=0xffffffffffffffff, list=0xffff800020be5780,0xffffffff82314aa0
    process=0xffff800020b94010 user=0xffff800020c7a000, vmspace=0xfffffd807f00c000
    estcpu=36, cpticks=7, pctcpu=0.0
    user=0, sys=1, intr=0
ddb{0}> ps
   PID     TID   PPID    UID  S       FLAGS  WAIT          COMMAND
 30447  294212  85686      0  2      0x3000                syz-executor1
 96531   85810  90489      0  3        0x82  nanosleep     syz-executor0
 85686  260484  90489      0  3        0x82  nanosleep     syz-executor1
 90489   22302  90013      0  3        0x82  thrsleep      syz-execprog
 90489   18495  90013      0  3   0x4000082  thrsleep      syz-execprog
 90489  475988  90013      0  3   0x4000082  thrsleep      syz-execprog
 90489  246031  90013      0  3   0x4000082  thrsleep      syz-execprog
 90489  285510  90013      0  3   0x4000082  thrsleep      syz-execprog
 90489  178595  90013      0  3   0x4000082  thrsleep      syz-execprog
 90489  438346  90013      0  3   0x4000082  thrsleep      syz-execprog
 90489  187323  90013      0  3   0x4000082  thrsleep      syz-execprog
 90489  401180  90013      0  3   0x4000082  kqread        syz-execprog
 90489   30139  90013      0  3   0x4000082  thrsleep      syz-execprog
 90013  186868   8263      0  3    0x10008a  pause         ksh
  8263  437841    766      0  3        0x92  select        sshd
 72437  295214      1      0  3    0x100083  ttyin         getty
   766  342216      1      0  3        0x80  select        sshd
 83032  492286  28311     73  3    0x100090  kqread        syslogd
 28311  385851      1      0  3    0x100082  netio         syslogd
 14231   58688      1     77  3    0x100090  poll          dhclient
  9577  167964      1      0  3        0x80  poll          dhclient
 63474  170100      0      0  3     0x14200  pgzero        zerothread
 58085  497138      0      0  3     0x14200  aiodoned      aiodoned
 55487   55098      0      0  3     0x14200  syncer        update
 34955  397780      0      0  3     0x14200  cleaner       cleaner
 26209  335166      0      0  7     0x14200                reaper
 71447  221455      0      0  3     0x14200  pgdaemon      pagedaemon
 41578  153715      0      0  3     0x14200  bored         crynlk
  3234  101814      0      0  3     0x14200  bored         crypto
 37491  185009      0      0  3  0x40014200  acpi0         acpi0
 16977  413812      0      0  3  0x40014200                idle1
 87030    5107      0      0  3     0x14200  bored         softnet
 74701  191049      0      0  3     0x14200  bored         systqmp
 83385  166970      0      0  3     0x14200  bored         systq
 97011  179211      0      0  3  0x40014200  bored         softclock
 70962  222966      0      0  3  0x40014200                idle0
     1  230101      0      0  3        0x82  wait          init
     0       0     -1      0  3     0x10200  scheduler     swapper
ddb{0}> show all locks
ddb{0}> show malloc
           Type InUse  MemUse  HighUse   Limit  Requests Type Lim Kern Lim
         devbuf  9452   6320K    6320K  78643K     10539        0        0
            pcb    23      9K       9K  78643K        55        0        0
         rtable    97      3K       3K  78643K       167        0        0
         ifaddr    34      9K       9K  78643K        34        0        0
       counters    39     33K      33K  78643K        39        0        0
       ioctlops     0      0K       2K  78643K        15        0        0
          mount     1      1K       1K  78643K         1        0        0
         vnodes    12      1K      73K  78643K      1171        0        0
      UFS quota     1     32K      32K  78643K         1        0        0
      UFS mount     5     36K      36K  78643K         5        0        0
            shm     2      1K       1K  78643K         2        0        0
         VM map     2      1K       1K  78643K         2        0        0
            sem     2      0K       0K  78643K         2        0        0
        dirhash     9      1K       2K  78643K        12        0        0
           ACPI  1792    194K     288K  78643K     12592        0        0
      file desc     5     13K      25K  78643K      6061        0        0
           proc    48     62K      86K  78643K     30460        0        0
    NFS srvsock     1      0K       0K  78643K         1        0        0
     NFS daemon     1     16K      16K  78643K         1        0        0
       in_multi    33      2K       2K  78643K        33        0        0
    ether_multi     1      0K       0K  78643K         1        0        0
    ISOFS mount     1     32K      32K  78643K         1        0        0
  MSDOSFS mount     1     16K      16K  78643K         1        0        0
           ttys    18     79K      79K  78643K        18        0        0
           exec     0      0K       1K  78643K       165        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    75     20K      20K  78643K     12943        0        0
       UVM aobj     2      2K       2K  78643K         2        0        0
        memdesc     1      4K       4K  78643K         1        0        0
    crypto data     1      1K       1K  78643K         1        0        0
            NDP     5      0K       0K  78643K         9        0        0
           temp    46   2350K    2414K  78643K     14771        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        4    0        0     1     0     1     1     0     8    0
inpcbpl    280       26    0       20     1     0     1     1     0     8    0
plimitpl   152       15    0        8     1     0     1     1     0     8    0
plcache    128       20    0        0     1     0     1     1     0     8    0
rtentry    112       41    0        1     2     0     2     2     0     8    0
syncache   264        5    0        5     2     2     0     1     0     8    0
tcpcb      544        8    0        5     1     0     1     1     0     8    0
nd6         48        4    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      185    0        0    12     0    12    12     0     8    0
art_table   32      186    0        0     2     0     2     2     0     8    0
art_node    16       40    0        6     1     0     1     1     0     8    0
dirhash    1024      17    0        2     3     0     3     3     0     8    1
dino1pl    128     7461    0     1361   197     0   197   197     0     8    0
ffsino     272     7461    0     1361   407     0   407   407     0     8    0
nchpl      144    19745    0    18362    59     0    59    59     0     8    1
uvmvnodes   72     6104    0        0   111     0   111   111     0     8    0
vnodes     200     6104    0        0   322     0   322   322     0     8    0
namei      1024   51900    0    51900     2     1     1     1     0     8    1
percpumem   16       30    0        0     1     0     1     1     0     8    0
scxspl     192    40011    0    40011    35    34     1     6     0     8    1
sigapl     432     6232    0     6218     2     0     2     2     0     8    0
futexpl     56    14527    0    14527     1     0     1     1     0     8    1
knotepl    112       63    0       38     2     0     2     2     0     8    0
kqueuepl   104        2    0        0     1     0     1     1     0     8    0
pipepl     112      138    0      119     3     2     1     1     0     8    0
fdescpl    488     6233    0     6219     3     1     2     3     0     8    0
filepl     152     6966    0     6905     3     0     3     3     0     8    0
lockfpl    104        6    0        6     1     1     0     1     0     8    0
lockfspl    32        3    0        3     1     1     0     1     0     8    0
sessionpl  112       19    0        9     1     0     1     1     0     8    0
pgrppl      48       19    0        9     1     0     1     1     0     8    0
ucredpl     96       47    0       40     1     0     1     1     0     8    0
zombiepl   144     6220    0     6218     3     2     1     1     0     8    0
processpl  840     6247    0     6218     4     0     4     4     0     8    0
procpl     600    12358    0    12319     4     0     4     4     0     8    0
sockpl     384       68    0       52     2     0     2     2     0     8    0
mcl4k      4096       2    0        0     1     0     1     1     0     8    0
mcl2k      2048      61    0        0     8     0     8     8     0     8    0
mtagpl      80        1    0        0     1     0     1     1     0     8    0
mbufpl     256      125    0        0     8     0     8     8     0     8    0
bufpl      256    10903    0     4648   436     0   436   436     0     8    0
anonpl      16   317318    0   314805    19     8    11    12     0   125    0
amapchunkpl 152   18998    0    18907     4     0     4     4     0   158    0
amappl16   192    25386    0    25283     6     0     6     6     0     8    0
amappl15   184     3024    0     3021     1     0     1     1     0     8    0
amappl14   176        3    0        1     2     1     1     1     0     8    0
amappl13   168       23    0       19     1     0     1     1     0     8    0
amappl12   160       28    0       24     2     1     1     1     0     8    0
amappl11   152      183    0      174     1     0     1     1     0     8    0
amappl10   144     6098    0     6095     3     2     1     1     0     8    0
amappl9    136      209    0      207     1     0     1     1     0     8    0
amappl8    128      143    0      127     1     0     1     1     0     8    0
amappl7    120       35    0       30     1     0     1     1     0     8    0
amappl6    112       46    0       41     1     0     1     1     0     8    0
amappl5    104     3136    0     3123     1     0     1     1     0     8    0
amappl4     96      304    0      280     2     1     1     2     0     8    0
amappl3     88      130    0      125     1     0     1     1     0     8    0
amappl2     80    61043    0    60980     2     0     2     2     0     8    0
amappl1     72    93784    0    93354    23    13    10    19     0     8    0
amappl      72    12583    0    12547     1     0     1     1     0    75    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
dma64       64      259    0      259     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        1    0        0     1     0     1     1     0     8    0
uaddrrnd    24     6233    0     6218     1     0     1     1     0     8    0
uaddrbest   32        2    0        0     1     0     1     1     0     8    0
uaddr       24     6233    0     6218     1     0     1     1     0     8    0
vmmpekpl   168    30101    0    30078     2     0     2     2     0     8    0
vmmpepl    168   469218    0   468168    92    45    47    71     0   357    1
vmsppl     360     6232    0     6218     2     0     2     2     0     8    0
pdppl      4096   12473    0    12436     6     1     5     6     0     8    0
pvpl        32   922571    0   917525   102    61    41    92     0   265    0
pmappl     224     6232    0     6218     1     0     1     1     0     8    0
extentpl    40       39    0       25     1     0     1     1     0     8    0
phpool     112      887    0        4    26     0    26    26     0     8    0

Crashes (226):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	Manager
2019/02/03 07:26	openbsd	010f0b318512	c198d5dd	.config	console log	report	syz	ci-openbsd-setuid
2019/09/25 07:26	openbsd	aadd6faada39	e38a6630	.config	console log	report		ci-openbsd-setuid
2019/09/25 05:36	openbsd	aadd6faada39	e38a6630	.config	console log	report		ci-openbsd-setuid
2019/09/23 15:31	openbsd	8566a01b6d70	1e9788a0	.config	console log	report		ci-openbsd-setuid
2019/09/09 21:31	openbsd	62d8f86c43d3	a60cb4cd	.config	console log	report		ci-openbsd-multicore
2019/09/03 12:54	openbsd	0abf16dec3ff	48448e71	.config	console log	report		ci-openbsd-multicore
2019/08/16 20:13	openbsd	3f6f9f7d8362	8fd428a1	.config	console log	report		ci-openbsd-main
2019/08/16 15:50	openbsd	bb94865e4f07	8fd428a1	.config	console log	report		ci-openbsd-multicore
2019/08/06 22:57	openbsd	e3935f160f4a	da562c0b	.config	console log	report		ci-openbsd-main
2019/08/05 00:18	openbsd	864b814f529e	6affd8e8	.config	console log	report		ci-openbsd-multicore
2019/07/26 20:13	openbsd	840a6881aa40	8fe30d3e	.config	console log	report		ci-openbsd-setuid
2019/07/24 18:14	openbsd	c069312dbbcc	32329ceb	.config	console log	report		ci-openbsd-multicore
2019/07/19 09:48	openbsd	966bc0c5a553	8304907d	.config	console log	report		ci-openbsd-multicore
2019/07/03 08:04	openbsd	3b11bbaaee57	55565fa0	.config	console log	report		ci-openbsd-main
2019/06/30 03:31	openbsd	49974d0d6380	7509bf36	.config	console log	report		ci-openbsd-multicore
2019/06/28 23:58	openbsd	ab325ad227c9	7509bf36	.config	console log	report		ci-openbsd-setuid
2019/06/27 19:21	openbsd	1d0e7814962b	7509bf36	.config	console log	report		ci-openbsd-setuid
2019/06/18 00:19	openbsd	ebca5146cc05	442206d7	.config	console log	report		ci-openbsd-main
2019/06/16 04:07	openbsd	6205d5a71267	442206d7	.config	console log	report		ci-openbsd-main
2019/05/30 15:56	openbsd	bd4b76f8bf7d	d9aaf3c2	.config	console log	report		ci-openbsd-main
2019/05/30 14:19	openbsd	bd4b76f8bf7d	d9aaf3c2	.config	console log	report		ci-openbsd-main
2019/05/30 03:19	openbsd	7e4900cc8c0d	d9aaf3c2	.config	console log	report		ci-openbsd-setuid
2019/05/30 01:31	openbsd	7e4900cc8c0d	d9aaf3c2	.config	console log	report		ci-openbsd-setuid
2019/05/24 01:37	openbsd	df989dde9731	0dadcd9d	.config	console log	report		ci-openbsd-main
2019/05/23 04:34	openbsd	f537473e237b	84b9d384	.config	console log	report		ci-openbsd-main
2019/05/23 00:33	openbsd	f537473e237b	84b9d384	.config	console log	report		ci-openbsd-main
2019/05/22 17:22	openbsd	e7d7f4196e8f	84b9d384	.config	console log	report		ci-openbsd-main
2019/05/17 18:05	openbsd	ea578e49926d	2755003a	.config	console log	report		ci-openbsd-multicore
2019/05/10 07:34	openbsd	8d0369da87f8	214bf476	.config	console log	report		ci-openbsd-multicore
2019/05/10 06:29	openbsd	8d0369da87f8	214bf476	.config	console log	report		ci-openbsd-setuid
2019/05/10 05:05	openbsd	8d0369da87f8	214bf476	.config	console log	report		ci-openbsd-main
2019/05/10 04:03	openbsd	8d0369da87f8	214bf476	.config	console log	report		ci-openbsd-setuid
2019/05/10 03:35	openbsd	8d0369da87f8	214bf476	.config	console log	report		ci-openbsd-setuid
2019/05/10 02:33	openbsd	8d0369da87f8	214bf476	.config	console log	report		ci-openbsd-multicore
2019/05/10 01:26	openbsd	8d0369da87f8	214bf476	.config	console log	report		ci-openbsd-main
2019/05/10 00:00	openbsd	8d0369da87f8	214bf476	.config	console log	report		ci-openbsd-multicore
2019/05/09 22:45	openbsd	8d0369da87f8	214bf476	.config	console log	report		ci-openbsd-multicore
2019/05/09 21:43	openbsd	8d0369da87f8	214bf476	.config	console log	report		ci-openbsd-multicore
2019/05/09 20:36	openbsd	8d0369da87f8	214bf476	.config	console log	report		ci-openbsd-setuid
2019/05/09 19:34	openbsd	8d0369da87f8	214bf476	.config	console log	report		ci-openbsd-multicore
2019/05/09 19:11	openbsd	8d0369da87f8	214bf476	.config	console log	report		ci-openbsd-multicore
2019/05/09 18:01	openbsd	8d0369da87f8	214bf476	.config	console log	report		ci-openbsd-multicore
2019/05/09 16:40	openbsd	8d0369da87f8	214bf476	.config	console log	report		ci-openbsd-multicore
2019/05/09 15:39	openbsd	8d0369da87f8	214bf476	.config	console log	report		ci-openbsd-setuid
2019/05/09 14:35	openbsd	2f8707c8a257	1ab4c999	.config	console log	report		ci-openbsd-setuid
2019/05/09 13:39	openbsd	2f8707c8a257	1ab4c999	.config	console log	report		ci-openbsd-setuid
2019/05/09 12:29	openbsd	2f8707c8a257	1ab4c999	.config	console log	report		ci-openbsd-main
2019/05/09 11:09	openbsd	2f8707c8a257	1ab4c999	.config	console log	report		ci-openbsd-setuid
2019/05/09 10:12	openbsd	2f8707c8a257	1ab4c999	.config	console log	report		ci-openbsd-main
2018/12/31 16:02	openbsd	1838c31d434f	70b2a9e8	.config	console log	report		ci-openbsd-setuid

* ~~Struck through~~ repros no longer work on HEAD.