panic: kernel diagnostic assertion "cpipe->pipe_buffer.cnt == 0" failed: file "/syzkaller/managers/main/kernel/sys/kern/sys_pipe.c", line 223 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *321386 46521 0 0 0x4000000 0 syz-executor.1 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic() at panic+0x15c sys/kern/subr_prf.c:212 __assert(ffffffff81f8ad79,ffffffff81f99791,df,ffffffff81f2c9d6) at __assert+0x2e sys/kern/subr_prf.c:159 pipespace(fffffd8036450628,10000) at pipespace+0x16f sys/kern/sys_pipe.c:219 pipe_write(fffffd8035f36c40,ffff800017a087a8,0) at pipe_write+0x952 sys/kern/sys_pipe.c:472 dofilewritev(ffff8000ffff38c8,4,ffff800017a087a8,0,ffff800017a088b0) at dofilewritev+0x1ac sys/kern/sys_generic.c:364 sys_write(ffff8000ffff38c8,ffff800017a08848,ffff800017a088b0) at sys_write+0x83 sys/kern/sys_generic.c:284 syscall(ffff800017a08910) at syscall+0x508 Xsyscall(6,0,c,0,3,449435551b0) at Xsyscall+0x128 end of kernel end trace frame: 0x44c25765b90, 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> ddb> set $lines = 0 ddb> set $maxwidth = 0 ddb> show panic kernel diagnostic assertion "cpipe->pipe_buffer.cnt == 0" failed: file "/syzkaller/managers/main/kernel/sys/kern/sys_pipe.c", line 223 ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic() at panic+0x15c sys/kern/subr_prf.c:212 __assert(ffffffff81f8ad79,ffffffff81f99791,df,ffffffff81f2c9d6) at __assert+0x2e sys/kern/subr_prf.c:159 pipespace(fffffd8036450628,10000) at pipespace+0x16f sys/kern/sys_pipe.c:219 pipe_write(fffffd8035f36c40,ffff800017a087a8,0) at pipe_write+0x952 sys/kern/sys_pipe.c:472 dofilewritev(ffff8000ffff38c8,4,ffff800017a087a8,0,ffff800017a088b0) at dofilewritev+0x1ac sys/kern/sys_generic.c:364 sys_write(ffff8000ffff38c8,ffff800017a08848,ffff800017a088b0) at sys_write+0x83 sys/kern/sys_generic.c:284 syscall(ffff800017a08910) at syscall+0x508 Xsyscall(6,0,c,0,3,449435551b0) at Xsyscall+0x128 end of kernel end trace frame: 0x44c25765b90, count: -9 ddb> show registers rdi 0xffffffff81c87f67 db_enter+0x17 rsi 0x3d1a __ALIGN_SIZE+0x2d1a rbp 0xffff800017a08520 rbx 0xffff800017a085d0 rdx 0x3d1b __ALIGN_SIZE+0x2d1b rcx 0xffff800016ded000 rax 0xffff800016ded000 r8 0xffff800017a084e0 r9 0x1 r10 0xffff800000997f80 r11 0xfd18cd0874d08145 r12 0x3000000008 r13 0xffff800017a08530 r14 0x100 r15 0x1 rip 0xffffffff81c87f68 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800017a08510 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor.1) pid=321386 stat=onproc flags process=0 proc=4000000 pri=16, usrpri=81, nice=20 forw=0xffffffffffffffff, list=0xffff8000ffff3b40,0xffff8000ffff3170 process=0xffff8000ffff6d90 user=0xffff800017a03000, vmspace=0xfffffd803f013110 estcpu=31, cpticks=1, pctcpu=0.0 user=0, sys=1, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 9056 109734 16454 0 2 0 syz-executor.0 9056 308703 16454 0 3 0x4000080 kqread syz-executor.0 46521 265240 48238 0 2 0 syz-executor.1 46521 373024 48238 0 2 0x4000000 syz-executor.1 46521 37230 48238 0 2 0x4000000 syz-executor.1 *46521 321386 48238 0 7 0x4000000 syz-executor.1 47579 185211 0 0 3 0x14200 bored sosplice 48238 461056 60544 0 3 0x82 nanosleep syz-executor.1 16454 351175 60544 0 3 0x82 nanosleep syz-executor.0 60544 105611 11508 0 3 0x82 kqread syz-fuzzer 60544 39875 11508 0 3 0x4000082 thrsleep syz-fuzzer 60544 383306 11508 0 3 0x4000082 thrsleep syz-fuzzer 60544 398179 11508 0 3 0x4000082 thrsleep syz-fuzzer 60544 121080 11508 0 3 0x4000082 thrsleep syz-fuzzer 60544 487764 11508 0 3 0x4000082 thrsleep syz-fuzzer 60544 516199 11508 0 3 0x4000082 thrsleep syz-fuzzer 11508 149330 5108 0 3 0x10008a pause ksh 5108 193597 10050 0 3 0x92 select sshd 39007 338760 1 0 3 0x100083 ttyin getty 10050 62743 1 0 3 0x80 select sshd 37976 307909 90044 73 3 0x100090 kqread syslogd 90044 216665 1 0 3 0x100082 netio syslogd 68225 487720 1 77 3 0x100090 poll dhclient 60682 330584 1 0 3 0x80 poll dhclient 70048 450380 0 0 2 0x14200 zerothread 93370 217747 0 0 3 0x14200 aiodoned aiodoned 58933 267609 0 0 3 0x14200 syncer update 68561 501575 0 0 3 0x14200 cleaner cleaner 78771 237447 0 0 3 0x14200 reaper reaper 86685 331720 0 0 3 0x14200 pgdaemon pagedaemon 40101 143548 0 0 3 0x14200 bored crynlk 5266 447670 0 0 3 0x14200 bored crypto 94135 326089 0 0 3 0x40014200 acpi0 acpi0 36074 497697 0 0 3 0x14200 bored softnet 38080 351590 0 0 3 0x14200 bored systqmp 29807 300129 0 0 3 0x14200 bored systq 28372 382823 0 0 3 0x40014200 bored softclock 49920 129996 0 0 3 0x40014200 idle0 16796 41435 0 0 3 0x14200 bored smr 1 470138 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 Kern Lim devbuf 9495 6338K 6974K 78643K 13452 0 0 pcb 23 9K 11K 78643K 478 0 0 rtable 111 4K 4K 78643K 428 0 0 ifaddr 56 13K 14K 78643K 158 0 0 counters 19 16K 16K 78643K 19 0 0 ioctlops 0 0K 2K 78643K 75 0 0 iov 0 0K 32K 78643K 126 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1215 76K 77K 78643K 2443 0 0 UFS quota 1 32K 32K 78643K 1 0 0 UFS mount 5 36K 36K 78643K 5 0 0 shm 2 1K 5K 78643K 6 0 0 VM map 2 0K 0K 78643K 2 0 0 sem 12 0K 0K 78643K 223 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1793 195K 288K 78643K 12645 0 0 file desc 6 17K 25K 78643K 1599 0 0 sigio 0 0K 0K 78643K 35 0 0 proc 41 30K 54K 78643K 414 0 0 subproc 32 2K 2K 78643K 34 0 0 NFS srvsock 1 0K 0K 78643K 1 0 0 NFS daemon 1 16K 16K 78643K 1 0 0 ip_moptions 0 0K 0K 78643K 134 0 0 in_multi 33 2K 2K 78643K 125 0 0 ether_multi 1 0K 0K 78643K 27 0 0 ISOFS mount 1 32K 32K 78643K 1 0 0 MSDOSFS mount 1 16K 16K 78643K 1 0 0 ttys 60 265K 265K 78643K 60 0 0 exec 0 0K 1K 78643K 258 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 93 21K 38K 78643K 4431 0 0 UVM aobj 20 2K 2K 78643K 20 0 0 memdesc 1 4K 4K 78643K 1 0 0 crypto data 1 1K 1K 78643K 1 0 0 ip6_options 0 0K 0K 78643K 88 0 0 NDP 11 0K 0K 78643K 47 0 0 temp 123 2713K 2781K 78643K 7353 0 0 SYN cache 2 16K 16K 78643K 2 0 0 ddb> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle arp 64 6 0 0 1 0 1 1 0 8 0 inpcbpl 280 452 0 445 1 0 1 1 0 8 0 rtentry 112 45 0 1 2 0 2 2 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpqe 32 32 0 32 4 4 0 1 0 8 0 tcpcb 544 205 0 201 1 0 1 1 0 8 0 nd6 48 6 0 0 1 0 1 1 0 8 0 ppxss 1128 27 0 26 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 188 0 0 12 0 12 12 0 8 0 art_table 32 189 0 0 2 0 2 2 0 8 0 art_node 16 44 0 4 1 0 1 1 0 8 0 semapl 112 221 0 211 1 0 1 1 0 8 0 shmpl 112 18 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 4155 0 2728 48 1 47 47 0 8 0 ffsino 240 4155 0 2728 85 0 85 85 0 8 0 nchpl 144 6227 0 4584 61 0 61 61 0 8 0 uvmvnodes 72 4788 0 0 88 0 88 88 0 8 0 vnodes 200 4788 0 0 252 0 252 252 0 8 0 namei 1024 16543 0 16543 4 3 1 1 0 8 1 scxspl 192 16876 0 16876 11 10 1 6 0 8 1 plimitpl 152 78 0 71 1 0 1 1 0 8 0 sigapl 432 1770 0 1756 2 0 2 2 0 8 0 futexpl 56 13241 0 13241 6 5 1 1 0 8 1 knotepl 112 241 0 222 1 0 1 1 0 8 0 kqueuepl 104 224 0 220 1 0 1 1 0 8 0 pipepl 112 514 0 493 3 2 1 2 0 8 0 fdescpl 424 1771 0 1756 2 0 2 2 0 8 0 filepl 120 7218 0 7116 5 1 4 5 0 8 0 lockfpl 104 221 0 220 5 4 1 1 0 8 0 lockfspl 48 68 0 67 5 4 1 1 0 8 0 sessionpl 112 17 0 7 1 0 1 1 0 8 0 pgrppl 48 41 0 31 1 0 1 1 0 8 0 ucredpl 96 2014 0 2007 1 0 1 1 0 8 0 zombiepl 144 1756 0 1756 6 5 1 1 0 8 1 processpl 864 1786 0 1756 4 0 4 4 0 8 0 procpl 632 3665 0 3625 4 0 4 4 0 8 0 sosppl 128 48 0 48 2 2 0 1 0 8 0 sockpl 384 872 0 855 7 4 3 4 0 8 1 mcl64k 65536 98 0 98 5 4 1 1 0 8 1 mcl9k 9216 30 0 30 4 3 1 1 0 8 1 mcl8k 8192 21 0 21 2 2 0 1 0 8 0 mcl4k 4096 113 0 113 4 3 1 1 0 8 1 mcl2k2 2112 21 0 21 2 2 0 1 0 8 0 mcl2k 2048 16135 0 16102 16 10 6 8 0 8 1 mtagpl 80 4 0 4 2 2 0 1 0 8 0 mbufpl 256 45329 0 45287 12 7 5 8 0 8 0 bufpl 256 8072 0 3506 286 0 286 286 0 8 0 anonpl 16 222590 0 218692 88 67 21 46 0 62 0 amapchunkpl 152 7285 0 7201 16 12 4 11 0 158 0 amappl16 192 11690 0 11518 71 61 10 31 0 8 0 amappl15 184 750 0 748 1 0 1 1 0 8 0 amappl14 176 798 0 790 1 0 1 1 0 8 0 amappl13 168 7 0 7 1 1 0 1 0 8 0 amappl12 160 9 0 5 1 0 1 1 0 8 0 amappl11 152 874 0 860 1 0 1 1 0 8 0 amappl10 144 60 0 58 2 1 1 1 0 8 0 amappl9 136 241 0 238 1 0 1 1 0 8 0 amappl8 128 126 0 111 1 0 1 1 0 8 0 amappl7 120 29 0 25 1 0 1 1 0 8 0 amappl6 112 868 0 860 1 0 1 1 0 8 0 amappl5 104 776 0 766 1 0 1 1 0 8 0 amappl4 96 1253 0 1227 2 1 1 2 0 8 0 amappl3 88 1665 0 1651 1 0 1 1 0 8 0 amappl2 80 13364 0 13289 4 2 2 3 0 8 0 amappl1 72 37855 0 37428 26 17 9 19 0 8 0 amappl 80 3926 0 3891 1 0 1 1 0 84 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 19 0 0 1 0 1 1 0 8 0 uaddrrnd 24 1771 0 1756 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 1771 0 1756 1 0 1 1 0 8 0 vmmpekpl 168 14510 0 14487 2 0 2 2 0 8 0 vmmpepl 168 210581 0 209254 143 84 59 77 0 357 1 vmsppl 272 1770 0 1756 2 1 1 2 0 8 0 pdppl 4096 3548 0 3512 6 1 5 6 0 8 0 pvpl 32 561263 0 554310 194 115 79 120 0 265 20 pmappl 200 1770 0 1756 1 0 1 1 0 8 0 extentpl 40 41 0 26 1 0 1 1 0 8 0 phpool 112 441 0 33 12 0 12 12 0 8 0