syzbot


malloc: free list modified: free (4)

Status: upstream: reported C repro on 2023/07/13 09:12
Reported-by: syzbot+58e7661fea8a101c4e3c@syzkaller.appspotmail.com
First crash: 346d, last: 27d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
openbsd malloc: free list modified: free (3) 1 687d 687d 0/3 auto-obsoleted due to no activity on 2022/11/04 09:24
openbsd malloc: free list modified: free (2) 1 787d 787d 0/3 auto-closed as invalid on 2022/07/27 14:00
openbsd malloc: free list modified: free 12 1486d 1708d 0/3 auto-closed as invalid on 2020/08/26 21:45
Last patch testing requests (5)
Created Duration User Patch Repo Result
2024/05/27 19:11 10m retest repro openbsd report log
2024/03/18 18:59 9m retest repro openbsd report log
2024/01/08 18:41 11m retest repro openbsd report log
2023/10/30 18:28 9m retest repro openbsd report log
2023/08/21 17:41 10m retest repro openbsd report log

Sample crash report:
panic: Data modified on freelist: word 4 of object 0xffff800000cc8c00 size 0x194 previous type free (0x6563 != 0xdeadbeef)

Stopped at      db_enter+0x1c:  addq    $0x8,%rsp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
*416028  48250      0           0          0    0  syz-executor2850578658
db_enter() at db_enter+0x1c sys/arch/amd64/amd64/db_interface.c:437
panic(ffffffff8277078e) at panic+0x165 sys/kern/subr_prf.c:198
malloc(194,2,a) at malloc+0xa85 sys/kern/kern_malloc.c:362
disk_attach(ffff8000006b5000,ffff8000006b5048) at disk_attach+0x8e sys/kern/subr_disk.c:1082
vndioctl(2902,c0384600,ffff8000216f4150,1,ffff8000ffff2db8) at vndioctl+0xeb6 sys/dev/vnd.c:539
VOP_IOCTL(fffffd806ede1eb8,c0384600,ffff8000216f4150,1,fffffd807f7d77b8,ffff8000ffff2db8) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:264
vn_ioctl(fffffd806f89af00,c0384600,ffff8000216f4150,ffff8000ffff2db8) at vn_ioctl+0xbb sys/kern/vfs_vnops.c:525
sys_ioctl(ffff8000ffff2db8,ffff8000216f4260,ffff8000216f42b0) at sys_ioctl+0x49e
syscall(ffff8000216f4330) at syscall+0x4a8 sys/arch/amd64/amd64/trap.c:623
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7d2a35df6d40, count: 5
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: Data modified on freelist: word 4 of object 0xffff800000cc8c00 size 0x194 previous type free (0x6563 != 0xdeadbeef)

ddb> trace
db_enter() at db_enter+0x1c sys/arch/amd64/amd64/db_interface.c:437
panic(ffffffff8277078e) at panic+0x165 sys/kern/subr_prf.c:198
malloc(194,2,a) at malloc+0xa85 sys/kern/kern_malloc.c:362
disk_attach(ffff8000006b5000,ffff8000006b5048) at disk_attach+0x8e sys/kern/subr_disk.c:1082
vndioctl(2902,c0384600,ffff8000216f4150,1,ffff8000ffff2db8) at vndioctl+0xeb6 sys/dev/vnd.c:539
VOP_IOCTL(fffffd806ede1eb8,c0384600,ffff8000216f4150,1,fffffd807f7d77b8,ffff8000ffff2db8) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:264
vn_ioctl(fffffd806f89af00,c0384600,ffff8000216f4150,ffff8000ffff2db8) at vn_ioctl+0xbb sys/kern/vfs_vnops.c:525
sys_ioctl(ffff8000ffff2db8,ffff8000216f4260,ffff8000216f42b0) at sys_ioctl+0x49e
syscall(ffff8000216f4330) at syscall+0x4a8 sys/arch/amd64/amd64/trap.c:623
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7d2a35df6d40, count: -10
ddb> show registers
rdi                                0
rsi                              0x1
rbp               0xffff8000216f3730
rbx               0xffff800000cc8c00
rdx                            0x3fd
rcx                                0
rax                             0x7c
r8                 0x101010101010101
r9                0x8080808080808080
r10               0xf3a5b7cd13330902
r11               0x241d597687c0be36
r12                                0
r13                             0x51
r14                                0
r15                              0x1
rip               0xffffffff8162a3fc    db_enter+0x1c
cs                               0x8
rflags                         0x246
rsp               0xffff8000216f3720
ss                              0x10
db_enter+0x1c:  addq    $0x8,%rsp
ddb> show proc
PROC (syz-executor2850578658) pid=416028 stat=onproc
    flags process=0 proc=0
    pri=51, usrpri=51, nice=20
    forw=0xffffffffffffffff, list=0xffff8000ffff3070,0xffff8000ffff2b10
    process=0xffff8000ffff0000 user=0xffff8000216ef000, vmspace=0xfffffd806c4ff740
    estcpu=2, cpticks=2, pctcpu=0.0
    user=0, sys=1, intr=0
ddb> ps
   PID     TID   PPID    UID  S       FLAGS  WAIT          COMMAND
 59715  353826   9277      0  3           0  biowait       syz-executor2850578658
 74739  305723  66721      0  3           0  biowait       syz-executor2850578658
*48250  416028  39420      0  7           0                syz-executor2850578658
 82911  266861  82839      0  3        0x80  nanoslp       syz-executor2850578658
 18738  468578  82839      0  3           0  biowait       syz-executor2850578658
 39420  445428  82839      0  3        0x80  nanoslp       syz-executor2850578658
 31976  485573  82839      0  3           0  getblk        syz-executor2850578658
 66472  450083  82839      0  3           0  getblk        syz-executor2850578658
 66721   96257  82839      0  3        0x80  nanoslp       syz-executor2850578658
 96910   67381  82839      0  3           0  getblk        syz-executor2850578658
  9277  124124  82839      0  3        0x80  nanoslp       syz-executor2850578658
 82839  306711  77128      0  3        0x82  nanoslp       syz-executor2850578658
 77128  109598  24205      0  3    0x10008a  sigsusp       ksh
 24205  142820  67500      0  3        0x9a  kqread        sshd
  1559   30100      1      0  3    0x100083  ttyin         getty
 67500  340612      1      0  3        0x88  kqread        sshd
 36769  240094  93725     73  3   0x1100090  kqread        syslogd
 93725   57840      1      0  3    0x100082  netio         syslogd
 97807  515231      1      0  3    0x100080  kqread        resolvd
  1482   36110   6684     77  3    0x100092  kqread        dhcpleased
 91784  295896   6684     77  3    0x100092  kqread        dhcpleased
  6684  303770      1      0  3        0x80  kqread        dhcpleased
 63590  147435      0      0  3     0x14200  bored         smr
  8828  357404      0      0  2     0x14200                zerothread
 12171  505880      0      0  3     0x14200  aiodoned      aiodoned
 60183  291702      0      0  3     0x14200  syncer        update
 97966  493393      0      0  3     0x14200  cleaner       cleaner
 17030  290903      0      0  3     0x14200  reaper        reaper
 71299  207533      0      0  3     0x14200  pgdaemon      pagedaemon
 13991   79174      0      0  3     0x14200  bored         viomb
 74055  232697      0      0  3  0x40014200  acpi0         acpi0
 95827  455559      0      0  3     0x14200  bored         softnet3
 88594  147395      0      0  3     0x14200  bored         softnet2
 85658  276053      0      0  3     0x14200  bored         softnet1
 97591  117395      0      0  3     0x14200  bored         softnet0
 18087  484541      0      0  3     0x14200  bored         systqmp
 52884  381598      0      0  3     0x14200  bored         systq
 47554  120322      0      0  3  0x40014200  bored         softclock
 94510   89207      0      0  3  0x40014200                idle0
     1  290386      0      0  3        0x82  wait          init
     0       0     -1      0  3     0x10200  scheduler     swapper
ddb> show all locks
No such command
ddb> show malloc
           Type InUse  MemUse  HighUse   Limit  Requests Type Lim
         devbuf 10133   6382K    6412K  78643K     11215        0
            pcb    13      8K       8K  78643K        13        0
         rtable    58      1K       2K  78643K       110        0
             pf    12      6K       6K  78643K        12        0
         ifaddr    11      5K       5K  78643K        11        0
        ifgroup    17      1K       1K  78643K        17        0
       counters    20     16K      16K  78643K        20        0
       ioctlops     0      0K       2K  78643K        21        0
          mount     1      1K       1K  78643K         1        0
            log     0      0K       0K  78643K         4        0
         vnodes  1174     73K      74K  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     12548        0
      file desc     1      0K       0K  78643K         1        0
           proc    55     58K      59K  78643K       246        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    25    122K     122K  78643K        25        0
           exec     0      0K       1K  78643K       243        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   128     69K      69K  78643K      2185        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     3      0K       0K  78643K         3        0
           temp     1   5844K    5908K  78643K      2761        0
         kqueue    11     16K      18K  78643K        24        0
      SYN cache     2     16K      16K  78643K         2        0
ddb> show all pools
Name      Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
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      144       33    0       20     1     0     1     1     0     8    0
syncache   296        5    0        5     2     1     1     1     0     8    1
tcpqe       32       61    0       61     1     1     0     1     0     8    0
tcpcb      808        8    0        5     1     0     1     1     0     8    0
arp         88        2    0        0     1     0     1     1     0     8    0
inpcb      336       26    0       20     1     0     1     1     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     1456    0       52    88     0    88    88     0     8    0
ffsino     240     1457    0       52    83     0    83    83     0     8    0
nchpl      144     1664    0       87    59     0    59    59     0     8    0
uvmvnodes   80     1467    0        0    30     0    30    30     0     8    0
vnodes     216     1467    0        0    82     0    82    82     0     8    0
namei      1024    4372    0     4370     3     1     2     2     0     8    1
kstatmem   264        6    0        0     1     0     1     1     0     8    0
scxspl     216     5708    0     5649    25    18     7     8     0     8    3
plimitpl   152       24    0       10     1     0     1     1     0     8    0
sigapl     424      329    0      288     5     0     5     5     0     8    0
knotepl    120     3377    0     3348     3     1     2     2     0     8    1
kqueuepl   184       20    0       13     1     0     1     1     0     8    0
pipepl     288       87    0       84     2     1     1     1     0     8    0
fdescpl    432      313    0      289     3     0     3     3     0     8    0
filepl     120     1160    0     1101     2     0     2     2     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       25    0        9     1     0     1     1     0     8    0
pgrppl      48       25    0        9     1     0     1     1     0     8    0
ucredpl    104       71    0       60     1     0     1     1     0     8    0
zombiepl   144      289    0      288     2     1     1     1     0     8    0
processpl  1008     329    0      288     7     1     6     6     0     8    0
procpl     696      329    0      288     5     1     4     4     0     8    0
sockpl     456       79    0       57     3     0     3     3     0     8    0
mcl8k      8192       9    0        9     2     1     1     1     0     8    1
mcl4k      4096       5    0        5     2     1     1     1     0     8    1
mcl2k      2048   10799    0    10761    34    24    10    30     0     8    4
mtagpl      96        4    0        4     1     1     0     1     0     8    0
mbufpl     256    17386    0    17344    17    11     6    17     0     8    0
bufpl      288     3155    0       92   219     0   219   219     0     8    0
anonpl      24   173333    0   171070    28    11    17    23     0   188    1
amapchunkpl 152    8142    0     7936     9     1     8     8     0   158    0
amappl16   200     5098    0     5068     8     5     3     5     0     8    0
amappl15   192       14    0       14     1     1     0     1     0     8    0
amappl14   184      127    0      118     1     0     1     1     0     8    0
amappl13   176       22    0       22     1     1     0     1     0     8    0
amappl12   168      801    0      781     1     0     1     1     0     8    0
amappl11   160       53    0       43     1     0     1     1     0     8    0
amappl10   152       27    0       27     2     1     1     1     0     8    1
amappl9    144      125    0      125     1     1     0     1     0     8    0
amappl8    136       44    0       42     1     0     1     1     0     8    0
amappl7    128       32    0       27     1     0     1     1     0     8    0
amappl6    120      151    0      140     1     0     1     1     0     8    0
amappl5    112       81    0       74     1     0     1     1     0     8    0
amappl4    104      455    0      418     2     0     2     2     0     8    1
amappl3     96     2223    0     2178     2     0     2     2     0     8    0
amappl2     88      464    0      422     2     1     1     2     0     8    0
amappl1     80     9018    0     8570    14     3    11    11     0     8    0
amappl      88     1907    0     1824     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      72        2    0        0     1     0     1     1     0     8    0
uaddrrnd    24      313    0      289     1     0     1     1     0     8    0
uaddrbest   32        2    0        0     1     0     1     1     0     8    0
uaddr       24      313    0      289     1     0     1     1     0     8    0
vmmpekpl   168     6912    0     6897     1     0     1     1     0     8    0
vmmpepl    168    33791    0    32589    58     3    55    55     0   357    0
vmsppl     368      312    0      289     3     0     3     3     0     8    0
rwobjpl     24    18520    0    16363    15     1    14    14     0     8    0
pdppl      4096     633    0      578    81    22    59    59     0     8    4
pvpl        32   267435    0   262493    59    15    44    51     0   265    1
pmappl     216      312    0      289     2     0     2     2     0     8    0
extentpl    40       56    0       38     1     0     1     1     0     8    0
phpool     112      550    0       63    14     0    14    14     0     8    0
ddb> machine ddbcpu 0
No such command
ddb> trace
db_enter() at db_enter+0x1c sys/arch/amd64/amd64/db_interface.c:437
panic(ffffffff8277078e) at panic+0x165 sys/kern/subr_prf.c:198
malloc(194,2,a) at malloc+0xa85 sys/kern/kern_malloc.c:362
disk_attach(ffff8000006b5000,ffff8000006b5048) at disk_attach+0x8e sys/kern/subr_disk.c:1082
vndioctl(2902,c0384600,ffff8000216f4150,1,ffff8000ffff2db8) at vndioctl+0xeb6 sys/dev/vnd.c:539
VOP_IOCTL(fffffd806ede1eb8,c0384600,ffff8000216f4150,1,fffffd807f7d77b8,ffff8000ffff2db8) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:264
vn_ioctl(fffffd806f89af00,c0384600,ffff8000216f4150,ffff8000ffff2db8) at vn_ioctl+0xbb sys/kern/vfs_vnops.c:525
sys_ioctl(ffff8000ffff2db8,ffff8000216f4260,ffff8000216f42b0) at sys_ioctl+0x49e
syscall(ffff8000216f4330) at syscall+0x4a8 sys/arch/amd64/amd64/trap.c:623
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7d2a35df6d40, count: -10
ddb> machine ddbcpu 1
No such command
ddb> trace
db_enter() at db_enter+0x1c sys/arch/amd64/amd64/db_interface.c:437
panic(ffffffff8277078e) at panic+0x165 sys/kern/subr_prf.c:198
malloc(194,2,a) at malloc+0xa85 sys/kern/kern_malloc.c:362
disk_attach(ffff8000006b5000,ffff8000006b5048) at disk_attach+0x8e sys/kern/subr_disk.c:1082
vndioctl(2902,c0384600,ffff8000216f4150,1,ffff8000ffff2db8) at vndioctl+0xeb6 sys/dev/vnd.c:539
VOP_IOCTL(fffffd806ede1eb8,c0384600,ffff8000216f4150,1,fffffd807f7d77b8,ffff8000ffff2db8) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:264
vn_ioctl(fffffd806f89af00,c0384600,ffff8000216f4150,ffff8000ffff2db8) at vn_ioctl+0xbb sys/kern/vfs_vnops.c:525
sys_ioctl(ffff8000ffff2db8,ffff8000216f4260,ffff8000216f42b0) at sys_ioctl+0x49e
syscall(ffff8000216f4330) at syscall+0x4a8 sys/arch/amd64/amd64/trap.c:623
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7d2a35df6d40, count: -10

Crashes (14):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/07/14 03:56 openbsd 996ed212dfaa d624500f .config console log report syz C [disk image] [bsd.gdb] [kernel image] ci-openbsd-main malloc: free list modified: free
2024/04/11 00:37 openbsd d11f3b71804f 33b9e058 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-multicore malloc: free list modified: free
2024/02/24 10:06 openbsd 127fa8d558c3 8d446f15 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main malloc: free list modified: free
2023/12/21 06:04 openbsd b71395ea3d48 4f9530a3 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main malloc: free list modified: free
2023/11/30 21:02 openbsd 7b53bb41f795 f819d6f7 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main malloc: free list modified: free
2023/11/13 08:31 openbsd 06d05a3069ab 6d6dbf8a .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main malloc: free list modified: free
2023/09/19 06:57 openbsd e88da610350a 0b6a67ac .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main malloc: free list modified: free
2023/07/18 01:43 openbsd 7196c146d32f 20f8b3c2 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main malloc: free list modified: free
2023/07/16 19:17 openbsd bd027751b05c 35d9ecc5 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main malloc: free list modified: free
2023/07/15 03:46 openbsd 5144f9456b75 35d9ecc5 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main malloc: free list modified: free
2023/07/14 22:27 openbsd 1557ddead48e 35d9ecc5 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main malloc: free list modified: free
2023/07/14 02:27 openbsd 996ed212dfaa d624500f .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main malloc: free list modified: free
2023/07/14 01:59 openbsd 996ed212dfaa d624500f .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main malloc: free list modified: free
2023/07/13 09:12 openbsd aa8d54b2e065 86081196 .config console log report [disk image] [bsd.gdb] [kernel image] ci-openbsd-main malloc: free list modified: free
* Struck through repros no longer work on HEAD.