syzbot


uvm_fault: rtm_output

Status: fixed on 2021/09/07 20:47
Reported-by: syzbot+684597dbbb9b516e76ae@syzkaller.appspotmail.com
Fix commit: d2084f835172 Fix NULL pointer dereference introduced by previous commit.
First crash: 451d, last: 451d
duplicates (1):
Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
corrupted report (5) 3 451d 451d 0/3 closed as dup on 2021/09/07 12:09

Sample crash report:
login: uvm_fault(0xfffffd806f5e5738, 0x58, 0, 1) -> e
kernel: page fault trap, code=0
Stopped at      rtm_output+0x3d5:       movl    0x58(%r14),%edi
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
*266858  80516      0         0x2          0    0K syz-executor8183
 282110  92400      0        0x12          0    1  sshd
rtm_output(ffff800000b49300,ffff800021229888,ffff8000212297e8,8,0) at rtm_output+0x3d5 sys/net/rtsock.c:1035
route_output(fffffd806d1b5800,fffffd806eeb4b58,0,0) at route_output+0x6b8 sys/net/rtsock.c:864
route_usrreq(fffffd806eeb4b58,9,fffffd806d1b5800,0,0,ffff8000ffff62b0) at route_usrreq+0x391 sys/net/rtsock.c:283
sosend(fffffd806eeb4b58,0,ffff800021229a90,0,0,80) at sosend+0x671 sys/kern/uipc_socket.c:573
sendit(ffff8000ffff62b0,3,ffff800021229b70,0,ffff800021229c50) at sendit+0x589 sys/kern/uipc_syscalls.c:653
sys_sendto(ffff8000ffff62b0,ffff800021229c08,ffff800021229c50) at sys_sendto+0x80 sys/kern/uipc_syscalls.c:520
syscall(ffff800021229cd0) at syscall+0x5a9 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff800021229cd0) at syscall+0x5a9 sys/arch/amd64/amd64/trap.c:587
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7ffffde440, 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: uvm_fault(0xfffffd806f5e5738, 0x58, 0, 1) -> e
ddb{0}> trace
rtm_output(ffff800000b49300,ffff800021229888,ffff8000212297e8,8,0) at rtm_output+0x3d5 sys/net/rtsock.c:1035
route_output(fffffd806d1b5800,fffffd806eeb4b58,0,0) at route_output+0x6b8 sys/net/rtsock.c:864
route_usrreq(fffffd806eeb4b58,9,fffffd806d1b5800,0,0,ffff8000ffff62b0) at route_usrreq+0x391 sys/net/rtsock.c:283
sosend(fffffd806eeb4b58,0,ffff800021229a90,0,0,80) at sosend+0x671 sys/kern/uipc_socket.c:573
sendit(ffff8000ffff62b0,3,ffff800021229b70,0,ffff800021229c50) at sendit+0x589 sys/kern/uipc_syscalls.c:653
sys_sendto(ffff8000ffff62b0,ffff800021229c08,ffff800021229c50) at sys_sendto+0x80 sys/kern/uipc_syscalls.c:520
syscall(ffff800021229cd0) at syscall+0x5a9 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff800021229cd0) at syscall+0x5a9 sys/arch/amd64/amd64/trap.c:587
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7ffffde440, count: -8
ddb{0}> show registers
rdi                       0xffffffff
rsi                       0xffffffff
rbp               0xffff8000212297d0
rbx                              0x3
rdx                             0x8b
rcx                              0x8
rax                              0x1
r8                0xffffffff817b2c54    rtable_satoplen+0x1b4
r9                               0x1
r10               0xa867eb71460f6c27
r11               0xfc7cc1a016b3e991
r12                              0x8
r13                              0x8
r14                                0
r15               0xffff8000212297e8
rip               0xffffffff813fbf75    rtm_output+0x3d5
cs                               0x8
rflags                       0x10246    __ALIGN_SIZE+0xf246
rsp               0xffff800021229740
ss                              0x10
rtm_output+0x3d5:       movl    0x58(%r14),%edi
ddb{0}> show proc
PROC (syz-executor8183) pid=266858 stat=onproc
    flags process=2<EXEC> proc=0
    pri=52, usrpri=52, nice=20
    forw=0xffffffffffffffff, list=0xffff8000ffff6010,0xffffffff829deed8
    process=0xffff800021208440 user=0xffff800021224000, vmspace=0xfffffd806f5e5738
    estcpu=2, cpticks=1, pctcpu=0.0
    user=0, sys=1, intr=0
ddb{0}> ps
   PID     TID   PPID    UID  S       FLAGS  WAIT          COMMAND
*80516  266858  86867      0  7         0x2                syz-executor8183
 86867   43261  92400      0  3    0x10008a  sigsusp       ksh
 92400  282110  95331      0  7        0x12                sshd
 60321  240623      1      0  3    0x100083  ttyin         getty
 95331  179429      1      0  3        0x88  select        sshd
 22282  356684  12188     74  3    0x100092  bpf           pflogd
 12188  398161      1      0  3        0x80  netio         pflogd
 85437  391065  34559     73  3    0x100090  kqread        syslogd
 34559  287774      1      0  3    0x100082  netio         syslogd
 44024  454602      1      0  3    0x100080  kqread        resolvd
 98222   72476  23583     77  3    0x100092  kqread        dhcpleased
 45959  253558  23583     77  3    0x100092  kqread        dhcpleased
 23583   53548      1      0  3        0x80  kqread        dhcpleased
 60438    6853      0      0  3     0x14200  bored         smr
 55278  141486      0      0  3     0x14200  pgzero        zerothread
 55832  469260      0      0  3     0x14200  aiodoned      aiodoned
 94311   45255      0      0  3     0x14200  syncer        update
 77832  419825      0      0  3     0x14200  cleaner       cleaner
 77925   74530      0      0  3     0x14200  reaper        reaper
 59870  456312      0      0  3     0x14200  pgdaemon      pagedaemon
 35154  292900      0      0  3     0x14200  bored         crynlk
 42672  446726      0      0  3     0x14200  bored         crypto
 31848   23607      0      0  3     0x14200  bored         viomb
 79429  498236      0      0  3  0x40014200  acpi0         acpi0
 37271    3179      0      0  3  0x40014200                idle1
 55071  206439      0      0  3     0x14200  bored         softnet
 18364  161201      0      0  3     0x14200  bored         systqmp
  3105  334626      0      0  3     0x14200  bored         systq
 48195   95505      0      0  3  0x40014200  bored         softclock
 64195  161944      0      0  3  0x40014200                idle0
     1  285003      0      0  3        0x82  wait          init
     0       0     -1      0  3     0x10200  scheduler     swapper
ddb{0}> show all locks
Process 80516 (syz-executor8183) thread 0xffff8000ffff62b0 (266858)
exclusive kernel_lock &kernel_lock r = 0 (0xffffffff82a062b0)
#0  witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline]
#0  witness_lock+0x4b0 sys/kern/subr_witness.c:1182
#1  kpageflttrap+0x229 sys/arch/amd64/amd64/trap.c:274
#2  kerntrap+0xef sys/arch/amd64/amd64/trap.c:318
#3  alltraps_kern_meltdown+0x7b
#4  rtm_output+0x3d5 sys/net/rtsock.c:1035
#5  route_output+0x6b8 sys/net/rtsock.c:864
#6  route_usrreq+0x391 sys/net/rtsock.c:283
#7  sosend+0x671 sys/kern/uipc_socket.c:573
#8  sendit+0x589 sys/kern/uipc_syscalls.c:653
#9  sys_sendto+0x80 sys/kern/uipc_syscalls.c:520
#10 syscall+0x5a9 mi_syscall sys/sys/syscall_mi.h:102 [inline]
#10 syscall+0x5a9 sys/arch/amd64/amd64/trap.c:587
#11 Xsyscall+0x128
ddb{0}> show malloc
           Type InUse  MemUse  HighUse   Limit  Requests Type Lim
         devbuf 10111   6469K    6470K  78643K     11201        0
            pcb    13      8K       8K  78643K        13        0
         rtable    63      2K       2K  78643K       113        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         6        0
         vnodes  1183     74K      75K  78643K      1188        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       348        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    81      3K       6K  78643K      1719        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   4193K    4257K  78643K      1964        0
         kqueue     9     12K      12K  78643K         9        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       18    0       14     1     0     1     1     0     8    0
rtentry    112       23    0        1     1     0     1     1     0     8    0
unpcb      120       35    0       20     1     0     1     1     0     8    0
syncache   296        5    0        5     1     0     1     1     0     8    1
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        0     1     0     1     1     0     8    0
pfstkey    112        8    0        0     1     0     1     1     0     8    0
pfstate    320        8    0        0     1     0     1     1     0     8    0
pfrule     1360      21    0       16     2     1     1     2     0     8    0
art_heap8  4096       1    0        0     1     0     1     1     0     8    0
art_heap4  256       96    0        0     6     0     6     6     0     8    0
art_table   32       97    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     1413    0       23    87     0    87    87     0     8    0
ffsino     272     1413    0       23    93     0    93    93     0     8    0
nchpl      144     1588    0       40    58     0    58    58     0     8    0
uvmvnodes   72     1423    0        0    26     0    26    26     0     8    0
vnodes     224     1423    0        0    84     0    84    84     0     8    0
namei      1024    4146    0     4146     1     0     1     1     0     8    1
percpumem   16       32    0        0     1     0     1     1     0     8    0
scxspl     216     3556    0     3556     2     1     1     2     0     8    1
plimitpl   152       16    0        9     1     0     1     1     0     8    0
sigapl     424      255    0      224     4     0     4     4     0     8    0
knotepl    112       24    0        0     1     0     1     1     0     8    0
kqueuepl   216        5    0        0     1     0     1     1     0     8    0
pipepl     336       69    0       66     1     0     1     1     0     8    0
fdescpl    496      239    0      224     3     0     3     3     0     8    0
filepl     152     1085    0     1026     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       69    0       57     1     0     1     1     0     8    0
zombiepl   144      224    0      224     1     0     1     1     0     8    1
processpl  1072     255    0      224     3     0     3     3     0     8    0
procpl     672      255    0      224     3     0     3     3     0     8    0
sockpl     480       85    0       60     4     0     4     4     0     8    0
mcl8k      8192       5    0        0     1     0     1     1     0     8    0
mcl4k      4096       3    0        0     1     0     1     1     0     8    0
mcl2k      2048      75    0        0    10     0    10    10     0     8    0
mtagpl      96        1    0        0     1     0     1     1     0     8    0
mbufpl     256      127    0        0     8     0     8     8     0     8    0
bufpl      280     2014    0       93   138     0   138   138     0     8    0
anonpl      24    32701    0    30395    17     2    15    17     0   186    1
amapchunkpl 152    3023    0     2880     8     2     6     8     0   158    0
amappl16   200       96    0       92     1     0     1     1     0     8    0
amappl15   192        1    0        0     1     0     1     1     0     8    0
amappl13   176       18    0       17     1     0     1     1     0     8    0
amappl12   168       13    0       13     1     0     1     1     0     8    1
amappl11   160       52    0       38     1     0     1     1     0     8    0
amappl10   152       33    0       28     1     0     1     1     0     8    0
amappl9    144      222    0      219     1     0     1     1     0     8    0
amappl8    136      274    0      274     1     0     1     1     0     8    1
amappl7    128       51    0       44     1     0     1     1     0     8    0
amappl6    120       86    0       81     1     0     1     1     0     8    0
amappl5    112      169    0      152     1     0     1     1     0     8    0
amappl4    104      527    0      507     1     0     1     1     0     8    0
amappl3     96       48    0       45     1     0     1     1     0     8    0
amappl2     88      401    0      355     2     0     2     2     0     8    0
amappl1     80     7482    0     7103     9     0     9     9     0     8    0
amappl      88     1475    0     1411     2     0     2     2     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      239    0      224     1     0     1     1     0     8    0
uaddrbest   32        2    0        0     1     0     1     1     0     8    0
uaddr       24      239    0      224     1     0     1     1     0     8    0
vmmpekpl   168     6018    0     6003     1     0     1     1     0     8    0
vmmpepl    168    22477    0    21630    41     0    41    41     0   357    0
vmsppl     368      238    0      224     2     0     2     2     0     8    0
rwobjpl     56     6920    0     6365     9     0     9     9     0     8    1
pdppl      4096     486    0      448    50    12    38    44     0     8    0
pvpl        32   111609    0   107399    38     0    38    38     0   265    1
pmappl     224      238    0      224     2     0     2     2     0     8    0
extentpl    40       58    0       40     1     0     1     1     0     8    0
phpool     112      270    0       15     8     0     8     8     0     8    0
ddb{0}> machine ddbcpu 0
Invalid cpu 0
ddb{0}> trace
rtm_output(ffff800000b49300,ffff800021229888,ffff8000212297e8,8,0) at rtm_output+0x3d5 sys/net/rtsock.c:1035
route_output(fffffd806d1b5800,fffffd806eeb4b58,0,0) at route_output+0x6b8 sys/net/rtsock.c:864
route_usrreq(fffffd806eeb4b58,9,fffffd806d1b5800,0,0,ffff8000ffff62b0) at route_usrreq+0x391 sys/net/rtsock.c:283
sosend(fffffd806eeb4b58,0,ffff800021229a90,0,0,80) at sosend+0x671 sys/kern/uipc_socket.c:573
sendit(ffff8000ffff62b0,3,ffff800021229b70,0,ffff800021229c50) at sendit+0x589 sys/kern/uipc_syscalls.c:653
sys_sendto(ffff8000ffff62b0,ffff800021229c08,ffff800021229c50) at sys_sendto+0x80 sys/kern/uipc_syscalls.c:520
syscall(ffff800021229cd0) at syscall+0x5a9 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff800021229cd0) at syscall+0x5a9 sys/arch/amd64/amd64/trap.c:587
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7ffffde440, count: -8
ddb{0}> machine ddbcpu 1
Stopped at      x86_ipi_db+0x1a:        addq    $0x8,%rsp
x86_ipi_db(ffff800020d38ff0) 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(ffffffff82a060a8) at __mp_lock+0x122 __mp_lock_spin sys/kern/kern_lock.c:116 [inline]
__mp_lock(ffffffff82a060a8) at __mp_lock+0x122 sys/kern/kern_lock.c:147
syscall(ffff8000211be5e0) at syscall+0x42d mi_syscall sys/sys/syscall_mi.h:93 [inline]
syscall(ffff8000211be5e0) at syscall+0x42d sys/arch/amd64/amd64/trap.c:587
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7ffffb7580, count: 9
ddb{1}> trace
x86_ipi_db(ffff800020d38ff0) 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(ffffffff82a060a8) at __mp_lock+0x122 __mp_lock_spin sys/kern/kern_lock.c:116 [inline]
__mp_lock(ffffffff82a060a8) at __mp_lock+0x122 sys/kern/kern_lock.c:147
syscall(ffff8000211be5e0) at syscall+0x42d mi_syscall sys/sys/syscall_mi.h:93 [inline]
syscall(ffff8000211be5e0) at syscall+0x42d sys/arch/amd64/amd64/trap.c:587
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7ffffb7580, count: -6
ddb{1}> 

Crashes (14):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-openbsd-multicore 2021/09/07 13:09 openbsd 1a94ae9bed1a 6ca60148 .config log report syz C uvm_fault: rtm_output
ci-openbsd-main 2021/09/07 12:45 openbsd 1a94ae9bed1a 6ca60148 .config log report syz C uvm_fault: rtm_output
ci-openbsd-main 2021/09/07 12:29 openbsd 1a94ae9bed1a 6ca60148 .config log report uvm_fault: rtm_output
ci-openbsd-main 2021/09/07 12:28 openbsd 1a94ae9bed1a 6ca60148 .config log report uvm_fault: rtm_output
ci-openbsd-main 2021/09/07 12:26 openbsd 1a94ae9bed1a 6ca60148 .config log report uvm_fault: rtm_output
ci-openbsd-main 2021/09/07 12:26 openbsd 1a94ae9bed1a 6ca60148 .config log report uvm_fault: rtm_output
ci-openbsd-main 2021/09/07 12:26 openbsd 1a94ae9bed1a 6ca60148 .config log report uvm_fault: rtm_output
ci-openbsd-main 2021/09/07 12:23 openbsd 1a94ae9bed1a 6ca60148 .config log report uvm_fault: rtm_output
ci-openbsd-main 2021/09/07 12:22 openbsd 1a94ae9bed1a 6ca60148 .config log report uvm_fault: rtm_output
ci-openbsd-main 2021/09/07 12:22 openbsd 1a94ae9bed1a 6ca60148 .config log report uvm_fault: rtm_output
ci-openbsd-multicore 2021/09/07 12:05 openbsd 1a94ae9bed1a 6ca60148 .config log report uvm_fault: rtm_output
ci-openbsd-multicore 2021/09/07 12:03 openbsd 1a94ae9bed1a 6ca60148 .config log report uvm_fault: rtm_output
ci-openbsd-multicore 2021/09/07 12:02 openbsd 1a94ae9bed1a 6ca60148 .config log report uvm_fault: rtm_output
ci-openbsd-multicore 2021/09/07 12:01 openbsd 1a94ae9bed1a 6ca60148 .config log report uvm_fault: rtm_output
* Struck through repros no longer work on HEAD.