syzbot


uvm_fault: sys_shmat

Status: upstream: reported on 2025/06/28 10:38
Reported-by: syzbot+2b55c96a88f56a58a642@syzkaller.appspotmail.com
First crash: 19d, last: 19d

Sample crash report:
login: uvm_fault(0xffffffff839397f0, 0xffff800001508000, 0, 2) -> e
kernel: page fault trap, code=2
Stopped at      sys_shmat+0xe0: movl    $0xffffffffffffffff,0(%r14)
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
* 69536  91779      0           0  0x4000000    0  syz-executor
sys_shmat(ffff800039d199c0,ffff80002a8936b0,ffff80002a893600) at sys_shmat+0xe0 sys/kern/sysv_shm.c:235
syscall(ffff80002a8936b0) at syscall+0x97e mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80002a8936b0) at syscall+0x97e sys/arch/amd64/amd64/trap.c:579
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xc97dca3aca0, count: 12
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> 
ddb> set $lines = 0
ddb> set $maxwidth = 0
ddb> show panic
*cpu0: uvm_fault(0xffffffff839397f0, 0xffff800001508000, 0, 2) -> e
ddb> trace
sys_shmat(ffff800039d199c0,ffff80002a8936b0,ffff80002a893600) at sys_shmat+0xe0 sys/kern/sysv_shm.c:235
syscall(ffff80002a8936b0) at syscall+0x97e mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80002a8936b0) at syscall+0x97e sys/arch/amd64/amd64/trap.c:579
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xc97dca3aca0, count: -3
ddb> show registers
rdi                                0
rsi                       0x3e92675a
rbp               0xffff80002a8935d0
rbx               0xffff80002a8936b0
rdx                                0
rcx               0xffffffff8382aff0    cpu_info_full_primary+0x1ff0
rax               0xffff800039d199c0
r8                               0x2
r9                                 0
r10               0x94c7b39ccc5ab96a
r11               0x5ea1e78b1a31756d
r12               0xffff800039d199c0
r13               0xffff800001462000
r14               0xffff800001508000
r15                           0xa600    __ALIGN_SIZE+0x9600
rip               0xffffffff82d9e820    sys_shmat+0xe0
cs                               0x8
rflags                       0x10216    __ALIGN_SIZE+0xf216
rsp               0xffff80002a893540
ss                              0x10
sys_shmat+0xe0: movl    $0xffffffffffffffff,0(%r14)
ddb> show proc
PROC (syz-executor) tid=69536 pid=91779 tcnt=3 stat=onproc
    flags process=0 proc=4000000<THREAD>
    runpri=84, usrpri=84, slppri=32, nice=20
    wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0
    forw=0xffffffffffffffff, list=0xffff800039d19c50,0xffff80002a89b9f0
    process=0xffff8000ffff68e0 user=0xffff80002a88e000, vmspace=0xfffffd807e0e7170
    estcpu=34, cpticks=0, pctcpu=0.0, user=0, sys=0, intr=0
ddb> ps
   PID     TID   PPID    UID  S       FLAGS  WAIT          COMMAND
 91779  451113  22695      0  2           0                syz-executor
*91779   69536  22695      0  7   0x4000000                syz-executor
 91779  520253  22695      0  2   0x4000000                syz-executor
 84718   23898  67304      0  2           0                syz-executor
 84718   68819  67304      0  3   0x4000080  fsleep        syz-executor
 33408  431440  91182      0  2           0                syz-executor
 33408  106722  91182      0  3   0x4000080  wsevent_read  syz-executor
 33408  331193  91182      0  2   0x4000000                syz-executor
 12847    2977  81978      0  2   0x1000000                syz-executor
 12847  134489  81978      0  3   0x5000080  fsleep        syz-executor
 12847  295311  81978      0  3   0x5000080  fsleep        syz-executor
 12847  313948  81978      0  3   0x5000080  fsleep        syz-executor
 12847  308323  81978      0  2   0x5000000                syz-executor
 93912   34536  24622      0  3      0x3000  suspend       syz-executor
 93912  258412  24622      0  2   0x4081000                syz-executor
 90638  483699  59485      0  2           0                syz-executor
 90638  155269  59485      0  3   0x4000080  fsleep        syz-executor
 90638  178238  59485      0  3   0x4000080  fsleep        syz-executor
 90638   29149  59485      0  3   0x4000080  fsleep        syz-executor
 39257  230468      1      0  3    0x100083  ttyin         getty
 60315  287448  87681      0  2         0x2                syz-executor
 67304  194489  87681      0  3        0x82  nanoslp       syz-executor
 91182   25017  87681      0  3        0x82  nanoslp       syz-executor
 22695  211260  87681      0  3        0x82  nanoslp       syz-executor
 93738   91261  87681      0  3        0x82  wait          syz-executor
 51673  371243      0      0  3     0x14280  nfsidl        nfsio
 97611  125706      0      0  3     0x14280  nfsidl        nfsio
 16063   22670      0      0  3     0x14280  nfsidl        nfsio
 46334  233195      0      0  3     0x14280  nfsidl        nfsio
 42485  405774      0      0  3     0x14280  nfsidl        nfsio
 20349   37565      0      0  3     0x14280  nfsidl        nfsio
 43901  229252      0      0  3     0x14280  nfsidl        nfsio
 51101  478488      0      0  3     0x14280  nfsidl        nfsio
 63809  482161      0      0  3     0x14280  nfsidl        nfsio
 86300   48857      0      0  3     0x14280  nfsidl        nfsio
 89684  410443      0      0  3     0x14280  nfsidl        nfsio
 84050  226804      0      0  3     0x14280  nfsidl        nfsio
 62997  313367      0      0  3     0x14280  nfsidl        nfsio
 61986  393300      0      0  3     0x14280  nfsidl        nfsio
 71856  246318      0      0  3     0x14280  nfsidl        nfsio
 11261  432286      0      0  3     0x14280  nfsidl        nfsio
   360  146386      0      0  3     0x14280  nfsidl        nfsio
  5692  178520      0      0  3     0x14280  nfsidl        nfsio
 56079  115587      0      0  3     0x14280  nfsidl        nfsio
 76441  195811      0      0  3     0x14280  nfsidl        nfsio
 59485  500873  87681      0  3        0x82  nanoslp       syz-executor
 39709  133451      0      0  3     0x14200  bored         sosplice
 81978  161715  87681      0  3        0x82  nanoslp       syz-executor
 24622  324609  87681      0  3        0x82  nanoslp       syz-executor
 87681  239810  27994      0  3        0x82  kqread        syz-executor
 27994  256726  44754      0  3    0x10008a  sigsusp       ksh
 44754  520621  80347      0  3        0x98  kqread        sshd-session
 80347  473069  76043      0  3        0x92  kqread        sshd-session
 76043  394285      1      0  3        0x88  kqread        sshd
 82001   46338  89659     73  3   0x1100090  kqread        syslogd
 89659  125105      1      0  3    0x100082  sbwait        syslogd
 15729  443449      1      0  3    0x100080  kqread        resolvd
 84822  126966  98652     77  3    0x100092  kqread        dhcpleased
 16801  158448  98652     77  3    0x100092  kqread        dhcpleased
 98652   21632      1      0  3        0x80  kqread        dhcpleased
 49828  219288      0      0  3     0x14200  bored         smr
  1828  184741      0      0  2     0x14200                zerothread
 66043   19970      0      0  3     0x14200  aiodoned      aiodoned
 47889  336080      0      0  3     0x14200  syncer        update
  9924  484227      0      0  3     0x14200  cleaner       cleaner
 33715   85656      0      0  3     0x14200  reaper        reaper
 79529  293649      0      0  3     0x14200  pgdaemon      pagedaemon
 77120  287542      0      0  3     0x14200  bored         viomb
 81737  459772      0      0  3  0x40014200  acpi0         acpi0
 42462   71439      0      0  3     0x14200  bored         softnet3
 75764   76952      0      0  3     0x14200  bored         softnet2
  4531  503846      0      0  3     0x14200  bored         softnet1
 30594  137908      0      0  3     0x14200  bored         softnet0
 31353  260626      0      0  3     0x14200  bored         systqmp
 81542  319502      0      0  3     0x14200  bored         systq
 79213  173565      0      0  2  0x40014200                softclock
 53709  376939      0      0  3  0x40014200                idle0
     1  251674      0      0  3        0x82  wait          init
     0       0     -1      0  3  0x10010200  scheduler     swapper
ddb> show all locks
No such command
ddb> show malloc
           Type InUse  MemUse  HighUse   Limit  Requests Type Lim
         devbuf 10193  11069K   11524K 166960K     13933        0
            pcb    17     13K      13K 166960K       207        0
         rtable   203     10K      10K 166960K       815        0
             pf    36     14K      16K 166960K       173        0
         ifaddr    38      6K       7K 166960K       141        0
        ifgroup    54      2K       2K 166960K       226        0
         sysctl     4      1K       9K 166960K        22        0
       counters    33     17K      18K 166960K       114        0
       ioctlops     0      0K       4K 166960K       318        0
            iov     0      0K      24K 166960K        78        0
          mount     1      1K       1K 166960K         1        0
            log     0      0K       0K 166960K         4        0
         vnodes  1404     88K      89K 166960K      2871        0
      UFS quota     1     32K      32K 166960K         1        0
      UFS mount     5     36K      36K 166960K         5        0
            shm     3      5K       9K 166960K        34        0
         VM map     2      1K       1K 166960K         2        0
            sem    12      0K       0K 166960K        66        0
        dirhash    15      2K       2K 166960K        42        0
           ACPI  1692    195K     286K 166960K     12470        0
      file desc    17     61K     232K 166960K      1686        0
          sigio     0      0K       0K 166960K        21        0
           proc    60     59K     100K 166960K       922        0
        subproc    72      4K       4K 166960K       167        0
    NFS srvsock     1      0K       0K 166960K         1        0
     NFS daemon     1     16K      16K 166960K         1        0
    ip_moptions     0      0K       0K 166960K       148        0
       in_multi    83      6K       7K 166960K       257        0
    ether_multi     1      0K       0K 166960K        15        0
            mrt     3      0K       0K 166960K        11        0
    ISOFS mount     1     32K      32K 166960K         1        0
  MSDOSFS mount     1     16K      16K 166960K         1        0
           ttys    85    387K     387K 166960K        85        0
           exec     0      0K       1K 166960K       878        0
   fusefs mount     1     32K      32K 166960K         1        0
     pfkey data     0      0K       0K 166960K         2        0
            tdb     3      0K       0K 166960K         3        0
        VM swap     8     62K      64K 166960K        10        0
       UVM amap   234    143K     162K 166960K     16678        0
       UVM aobj   131      4K       4K 166960K       138        0
     pinsyscall    38     76K      94K 166960K      2993        0
        memdesc     1      4K       4K 166960K         1        0
    crypto data     1      1K       1K 166960K         1        0
    ip6_options     0      0K       0K 166960K        71        0
            NDP    12      0K       2K 166960K        98        0
           temp    72   8686K    8810K 166960K     47418        0
         kqueue    13     20K      30K 166960K       273        0
      SYN cache     2     16K      16K 166960K         2        0
ddb> show all pools
Name      Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
rtpcb      120      149    0      146     1     0     1     1     0     8    0
rtentry    136      261    0      177     4     0     4     4     0     8    0
unpcb      144     1126    0     1109     9     3     6     6     0     8    5
syncache   336        8    0        8     4     3     1     1     0     8    1
tcpqe       32        6    0        6     3     2     1     1     0     8    1
tcpcb      736      573    0      568    13     9     4     7     0     8    3
pool(tcpcb): free list modified: page 0xffff8000014b3000; item ordinal 0; addr 0xffff8000014b4d18 (p 0xfffffd806c052000); offset 0x8=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): page inconsistency: page 0xffff8000014b3000; item ordinal 1; addr 0xffff800030e45ba7
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 0; addr 0xffff8000014ba1a0 (p 0xfffffd806c052000); offset 0x0=0xe1811ee3ffffffff
pool(tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 0; addr 0xffff8000014ba1a0 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 1; addr 0xffff8000014b9ec0 (p 0xfffffd806c052000); offset 0x0=0xe1811ee3ffffffff
pool(tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 1; addr 0xffff8000014b9ec0 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 2; addr 0xffff8000014b9be0 (p 0xfffffd806c052000); offset 0x0=0xe1811ee3ffffffff
pool(tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 2; addr 0xffff8000014b9be0 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 3; addr 0xffff8000014b9900 (p 0xfffffd806c052000); offset 0x0=0xe1811ee3ffffffff
pool(tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 3; addr 0xffff8000014b9900 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 4; addr 0xffff8000014b9620 (p 0xfffffd806c052000); offset 0x0=0xe1811ee3ffffffff
pool(tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 4; addr 0xffff8000014b9620 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 5; addr 0xffff8000014b9060 (p 0xfffffd806c052000); offset 0x0=0xe1811ee3ffffffff
pool(tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 5; addr 0xffff8000014b9060 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 6; addr 0xffff8000014b9340 (p 0xfffffd806c052000); offset 0x0=0xe1811ee3ffffffff
pool(tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 6; addr 0xffff8000014b9340 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 7; addr 0xffff8000014ba760 (p 0xfffffd806c052000); offset 0x0=0xe1811ee3ffffffff
pool(tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 7; addr 0xffff8000014ba760 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 8; addr 0xffff8000014bad20 (p 0xfffffd806c052000); offset 0x0=0xe1811ee3ffffffff
pool(tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 8; addr 0xffff8000014bad20 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 9; addr 0xffff8000014baa40 (p 0xfffffd806c052000); offset 0x0=0xe1811ee3ffffffff
pool(tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 9; addr 0xffff8000014baa40 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 10; addr 0xffff8000014ba480 (p 0xfffffd806c052000); offset 0x0=0xe1811ee3ffffffff
pool(tcpcb): free list modified: page 0xffff8000014b9000; item ordinal 10; addr 0xffff8000014ba480 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 0; addr 0xffff8000014aa330 (p 0xfffffd806c052000); offset 0x0=0xc6bb1079ffffffff
pool(tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 0; addr 0xffff8000014aa330 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 1; addr 0xffff8000014aa050 (p 0xfffffd806c052000); offset 0x0=0xc6bb1079ffffffff
pool(tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 1; addr 0xffff8000014aa050 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 2; addr 0xffff8000014aa610 (p 0xfffffd806c052000); offset 0x0=0xc6bb1079ffffffff
pool(tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 2; addr 0xffff8000014aa610 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 3; addr 0xffff8000014aa8f0 (p 0xfffffd806c052000); offset 0x0=0xc6bb1079ffffffff
pool(tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 3; addr 0xffff8000014aa8f0 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 4; addr 0xffff8000014ab470 (p 0xfffffd806c052000); offset 0x0=0xc6bb1079ffffffff
pool(tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 4; addr 0xffff8000014ab470 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 5; addr 0xffff8000014abd10 (p 0xfffffd806c052000); offset 0x0=0xc6bb1079ffffffff
pool(tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 5; addr 0xffff8000014abd10 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 6; addr 0xffff8000014aba30 (p 0xfffffd806c052000); offset 0x0=0xc6bb1079ffffffff
pool(tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 6; addr 0xffff8000014aba30 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 7; addr 0xffff8000014ab190 (p 0xfffffd806c052000); offset 0x0=0xc6bb1079ffffffff
pool(tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 7; addr 0xffff8000014ab190 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 8; addr 0xffff8000014ab750 (p 0xfffffd806c052000); offset 0x0=0xc6bb1079ffffffff
pool(tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 8; addr 0xffff8000014ab750 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 9; addr 0xffff8000014aabd0 (p 0xfffffd806c052000); offset 0x0=0xc6bb1079ffffffff
pool(tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 9; addr 0xffff8000014aabd0 (p 0xfffffd806c052000); offset 0x0=0xffffffff
tcpcb: pool(0xffffffff838bd118:tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 10; addr 0xffff8000014aaeb0 (p 0xfffffd806c052000); offset 0x0=0xc6bb1079ffffffff
pool(tcpcb): free list modified: page 0xffff8000014aa000; item ordinal 10; addr 0xffff8000014aaeb0 (p 0xfffffd806c052000); offset 0x0=0xffffffff
arp         88       44    0       27     1     0     1     1     0     8    0
ipq         40        5    0        5     1     0     1     1     0     8    1
ipqe        40        6    0        6     1     0     1     1     0     8    1
inpcb      328     1497    0     1486    16     9     7     7     0     8    5
ip6q        72        6    0        4     1     0     1     1     0     8    0
ip6af       40       13    0        8     1     0     1     1     0     8    0
nd6        104       64    0       42     1     0     1     1     0     8    0
pkpcb       40        5    0        5     1     1     0     1     0     8    0
kcovpl      48       18    0       10     1     0     1     1     0     8    0
mppekey    1024       2    0        2     2     1     1     1     0     8    1
ppxss      1072      52    0       52     4     3     1     1     0     8    1
pppxif     1384       9    0        9     4     3     1     1     0     8    1
pfstscr     40        2    0        2     1     1     0     1     0     8    0
pfrktable  1344       2    0        2     2     1     1     1     0     8    1
pfrktable: pool(0xffffffff838bf780:pfrktable): page inconsistency: page 0xffff8000ffffffff; at page head addr 0xffff800001507f90 (p 0xffff800001504000)
uvm_fault(0xffffffff839397f0, 0xffff8001000000d7, 0, 1) -> e
kernel: page fault trap, code=0
Faulted in DDB; continuing...
ddb> machine ddbcpu 0
No such command
ddb> trace
sys_shmat(ffff800039d199c0,ffff80002a8936b0,ffff80002a893600) at sys_shmat+0xe0 sys/kern/sysv_shm.c:235
syscall(ffff80002a8936b0) at syscall+0x97e mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80002a8936b0) at syscall+0x97e sys/arch/amd64/amd64/trap.c:579
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xc97dca3aca0, count: -3
ddb> machine ddbcpu 1
No such command
ddb> trace
sys_shmat(ffff800039d199c0,ffff80002a8936b0,ffff80002a893600) at sys_shmat+0xe0 sys/kern/sysv_shm.c:235
syscall(ffff80002a8936b0) at syscall+0x97e mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80002a8936b0) at syscall+0x97e sys/arch/amd64/amd64/trap.c:579
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xc97dca3aca0, count: -3

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/28 10:38 openbsd d7bdfee22977 fc9d8ee5 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main uvm_fault: sys_shmat
* Struck through repros no longer work on HEAD.