panic: kernel diagnostic assertion "sb->sb_cc == 0" failed: file "/syzkaller/managers/main/kernel/sys/kern/uipc_socket2.c", line 934 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821c8ff1) at panic+0x15c sys/kern/subr_prf.c:207 __assert(ffffffff822204b8,ffffffff821fe148,3a6,ffffffff82209b73) at __assert+0x2b sys/kern/subr_prf.c:154 sbflush(ffff80001e43fb18,ffff80001e43fba0) at sbflush+0x17d sys/kern/uipc_socket2.c:935 sbrelease(ffff80001e43fb18,ffff80001e43fba0) at sbrelease+0x2e sys/kern/uipc_socket2.c:525 sorflush(fffffd805299d658) at sorflush+0x14b sys/kern/uipc_socket.c:1131 sofree(fffffd805299d658,42) at sofree+0x147 sys/kern/uipc_socket.c:257 soclose(fffffd805299d658,0) at soclose+0x268 sys/kern/uipc_socket.c:338 soo_close(fffffd805d8848f0,ffff80001d35e398) at soo_close+0x40 fdrop(fffffd805d8848f0,ffff80001d35e398) at fdrop+0xc2 sys/kern/kern_descrip.c:1264 closef(fffffd805d8848f0,ffff80001d35e398) at closef+0x117 sys/kern/kern_descrip.c:1248 fdfree(ffff80001d35e398) at fdfree+0x100 sys/kern/kern_descrip.c:1180 exit1(ffff80001d35e398,0,0,1) at exit1+0x334 sys/kern/kern_exit.c:196 sys_exit(ffff80001d35e398,ffff80001e43ff70,ffff80001e43ffc0) at sys_exit+0x16 sys/kern/kern_exit.c:94 end trace frame: 0xffff80001e440030, count: 0 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 "sb->sb_cc == 0" failed: file "/syzkaller/managers/main/kernel/sys/kern/uipc_socket2.c", line 934 ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821c8ff1) at panic+0x15c sys/kern/subr_prf.c:207 __assert(ffffffff822204b8,ffffffff821fe148,3a6,ffffffff82209b73) at __assert+0x2b sys/kern/subr_prf.c:154 sbflush(ffff80001e43fb18,ffff80001e43fba0) at sbflush+0x17d sys/kern/uipc_socket2.c:935 sbrelease(ffff80001e43fb18,ffff80001e43fba0) at sbrelease+0x2e sys/kern/uipc_socket2.c:525 sorflush(fffffd805299d658) at sorflush+0x14b sys/kern/uipc_socket.c:1131 sofree(fffffd805299d658,42) at sofree+0x147 sys/kern/uipc_socket.c:257 soclose(fffffd805299d658,0) at soclose+0x268 sys/kern/uipc_socket.c:338 soo_close(fffffd805d8848f0,ffff80001d35e398) at soo_close+0x40 fdrop(fffffd805d8848f0,ffff80001d35e398) at fdrop+0xc2 sys/kern/kern_descrip.c:1264 closef(fffffd805d8848f0,ffff80001d35e398) at closef+0x117 sys/kern/kern_descrip.c:1248 fdfree(ffff80001d35e398) at fdfree+0x100 sys/kern/kern_descrip.c:1180 exit1(ffff80001d35e398,0,0,1) at exit1+0x334 sys/kern/kern_exit.c:196 sys_exit(ffff80001d35e398,ffff80001e43ff70,ffff80001e43ffc0) at sys_exit+0x16 sys/kern/kern_exit.c:94 syscall(ffff80001e440040) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffffaf80, count: -16 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001e43f9a0 rbx 0xffff80001e43fa50 rdx 0x2 rcx 0 rax 0 r8 0xffff80001e43f960 r9 0x1 r10 0 r11 0x5bfbf2f16214953c r12 0x3000000008 r13 0xffff80001e43f9b0 r14 0x100 r15 0x1 rip 0xffffffff81cd8128 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001e43f990 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor.0) pid=336385 stat=onproc flags process=1018 proc=2000 pri=32, usrpri=72, nice=20 forw=0xffffffffffffffff, list=0xffff80001d35e128,0xffffffff82567650 process=0xffff8000ffffbc10 user=0xffff80001e43b000, vmspace=0xfffffd8067600cc8 estcpu=22, cpticks=4, pctcpu=0.6 user=0, sys=1, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 16057 517824 42051 0 2 0x482 syz-executor.0 59979 43540 0 0 3 0x14200 acct acct 10946 151421 0 0 3 0x14200 bored sosplice 60333 351233 42051 0 3 0x82 piperd syz-executor.1 42051 386260 65520 0 3 0x82 thrsleep syz-fuzzer 42051 387100 65520 0 3 0x4000082 thrsleep syz-fuzzer 42051 67215 65520 0 3 0x4000082 thrsleep syz-fuzzer 42051 266409 65520 0 3 0x4000082 thrsleep syz-fuzzer 42051 319493 65520 0 3 0x4000082 kqread syz-fuzzer 42051 78901 65520 0 3 0x4000082 thrsleep syz-fuzzer 42051 366811 65520 0 3 0x4000082 thrsleep syz-fuzzer 42051 413783 65520 0 3 0x4000082 thrsleep syz-fuzzer 65520 502839 72041 0 3 0x10008a pause ksh 72041 249799 35875 0 3 0x92 select sshd 72681 214153 1 0 3 0x100083 ttyin getty 35875 385180 1 0 3 0x80 select sshd 2745 522500 15967 73 3 0x100090 kqread syslogd 15967 27219 1 0 3 0x100082 netio syslogd 49514 305576 1 77 3 0x100090 poll dhclient 10600 332374 1 0 3 0x80 poll dhclient 3829 295987 0 0 3 0x14200 pgzero zerothread 82068 265109 0 0 3 0x14200 aiodoned aiodoned 33259 21959 0 0 3 0x14200 syncer update 34567 442414 0 0 3 0x14200 cleaner cleaner 26210 192500 0 0 3 0x14200 reaper reaper 13703 237398 0 0 3 0x14200 pgdaemon pagedaemon 37210 354743 0 0 3 0x14200 bored crynlk 80593 349637 0 0 3 0x14200 bored crypto 73253 318999 0 0 3 0x40014200 acpi0 acpi0 56199 293669 0 0 3 0x14200 bored softnet 55602 112343 0 0 3 0x14200 bored systqmp 73212 504564 0 0 3 0x14200 bored systq 53468 350090 0 0 3 0x40014200 bored softclock 1018 273510 0 0 3 0x40014200 idle0 10261 52884 0 0 3 0x14200 bored smr 1 226598 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 9497 6357K 6844K 78643K 11199 0 pcb 13 10K 12K 78643K 64 0 rtable 99 2K 3K 78643K 308 0 ifaddr 65 12K 13K 78643K 116 0 counters 21 16K 16K 78643K 25 0 ioctlops 0 0K 2K 78643K 44 0 iov 0 0K 24K 78643K 78 0 mount 1 1K 1K 78643K 1 0 vnodes 1218 77K 77K 78643K 1393 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 5 0 VM map 2 0K 0K 78643K 2 0 sem 12 0K 0K 78643K 72 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1794 195K 288K 78643K 12646 0 file desc 5 13K 25K 78643K 321 0 sigio 0 0K 0K 78643K 4 0 proc 49 38K 55K 78643K 423 0 subproc 32 2K 2K 78643K 51 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 24 0 in_multi 45 2K 3K 78643K 89 0 ether_multi 1 0K 0K 78643K 8 0 mrt 0 0K 0K 78643K 2 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 55 254K 254K 78643K 55 0 exec 0 0K 1K 78643K 247 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 114 54K 54K 78643K 1626 0 UVM aobj 17 2K 2K 78643K 19 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 1K 78643K 40 0 NDP 11 0K 0K 78643K 23 0 temp 119 3024K 3088K 78643K 20143 0 kqueue 3 4K 12K 78643K 36 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 arp 64 9 0 3 1 0 1 1 0 8 0 rtpcb 80 39 0 37 1 0 1 1 0 8 0 rtentry 112 70 0 29 2 0 2 2 0 8 0 unpcb 120 159 0 149 1 0 1 1 0 8 0 syncache 264 8 0 8 2 2 0 1 0 8 0 tcpqe 32 91 0 91 1 1 0 1 0 8 0 tcpcb 544 532 0 524 20 17 3 15 0 8 1 ipq 40 6 0 6 2 1 1 1 0 8 1 ipqe 40 102 0 102 2 1 1 1 0 8 1 inpcb 280 912 0 901 9 7 2 9 0 8 0 rttmr 72 1 0 1 1 1 0 1 0 8 0 nd6 48 11 0 7 1 0 1 1 0 8 0 pkpcb 40 2 0 2 1 1 0 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 286 0 114 13 1 12 13 0 8 1 art_table 32 287 0 114 2 0 2 2 0 8 0 art_node 16 67 0 29 1 0 1 1 0 8 0 sysvmsgpl 40 20 0 8 1 0 1 1 0 8 0 semupl 112 3 0 3 1 1 0 1 0 8 0 semapl 112 70 0 60 1 0 1 1 0 8 0 shmpl 112 17 0 2 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 1865 0 468 46 0 46 46 0 8 0 ffsino 240 1865 0 468 83 0 83 83 0 8 0 nchpl 144 2620 0 1022 60 0 60 60 0 8 0 uvmvnodes 72 2007 0 0 37 0 37 37 0 8 0 vnodes 208 2007 0 0 106 0 106 106 0 8 0 namei 1024 7530 0 7530 1 0 1 1 0 8 1 vcpupl 1984 3 0 0 1 0 1 1 0 8 0 vmpool 528 7 0 4 1 0 1 1 0 8 0 scsiplug 64 1 0 1 1 1 0 1 0 8 0 scxspl 192 7657 0 7657 1 0 1 1 0 8 1 plimitpl 152 34 0 27 1 0 1 1 0 8 0 sigapl 432 489 0 476 2 0 2 2 0 8 0 futexpl 56 9088 0 9088 1 0 1 1 0 8 1 knotepl 112 119 0 100 1 0 1 1 0 8 0 kqueuepl 144 582 0 580 5 4 1 5 0 8 0 pipelkpl 16 173 0 163 1 0 1 1 0 8 0 pipepl 120 346 0 327 3 1 2 2 0 8 1 fdescpl 432 490 0 476 2 0 2 2 0 8 0 filepl 120 4304 0 4204 11 6 5 11 0 8 1 lockfpl 104 98 0 95 1 0 1 1 0 8 0 lockfspl 48 35 0 33 1 0 1 1 0 8 0 sessionpl 112 18 0 8 1 0 1 1 0 8 0 pgrppl 48 18 0 8 1 0 1 1 0 8 0 ucredpl 96 333 0 324 1 0 1 1 0 8 0 zombiepl 144 477 0 476 1 0 1 1 0 8 0 processpl 896 506 0 476 4 0 4 4 0 8 0 procpl 624 884 0 847 4 0 4 4 0 8 0 sosppl 128 12 0 12 2 1 1 1 0 8 1 sockpl 400 1118 0 1094 18 14 4 14 0 8 1 mcl64k 65536 302 0 302 33 2 31 33 0 8 31 mcl16k 16384 4 0 4 1 1 0 1 0 8 0 mcl12k 12288 12 0 12 2 1 1 1 0 8 1 mcl9k 9216 5 0 5 2 1 1 1 0 8 1 mcl8k 8192 36 0 36 1 0 1 1 0 8 1 mcl4k 4096 44 0 44 2 1 1 1 0 8 1 mcl2k2 2112 3 0 3 2 1 1 1 0 8 1 mcl2k 2048 65428 0 65393 13 7 6 11 0 8 1 mtagpl 80 19 0 19 2 1 1 1 0 8 1 mbufpl 256 107222 0 107151 26 10 16 23 0 8 8 bufpl 280 4895 0 165 338 0 338 338 0 8 0 anonpl 16 66639 0 50760 80 4 76 76 0 107 8 amapchunkpl 152 2195 0 2046 10 3 7 9 0 158 1 amappl16 192 2626 0 1712 59 3 56 58 0 8 8 amappl15 184 1 0 0 1 0 1 1 0 8 0 amappl14 176 6 0 1 2 1 1 1 0 8 0 amappl13 168 37 0 35 1 0 1 1 0 8 0 amappl12 160 106 0 106 2 1 1 1 0 8 1 amappl11 152 73 0 61 1 0 1 1 0 8 0 amappl10 144 188 0 180 1 0 1 1 0 8 0 amappl9 136 376 0 373 1 0 1 1 0 8 0 amappl8 128 287 0 269 1 0 1 1 0 8 0 amappl7 120 282 0 269 1 0 1 1 0 8 0 amappl6 112 26 0 22 1 0 1 1 0 8 0 amappl5 104 527 0 515 1 0 1 1 0 8 0 amappl4 96 460 0 427 2 1 1 2 0 8 0 amappl3 88 118 0 111 1 0 1 1 0 8 0 amappl2 80 3078 0 3015 3 1 2 3 0 8 0 amappl1 72 18346 0 17924 26 17 9 20 0 8 0 amappl 80 1131 0 1081 2 0 2 2 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 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 18 0 2 1 0 1 1 0 8 0 uaddrrnd 24 497 0 480 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 497 0 480 1 0 1 1 0 8 0 vmmpekpl 168 7479 0 7451 2 0 2 2 0 8 0 vmmpepl 168 65847 0 63849 138 17 121 121 0 357 33 vmsppl 272 496 0 480 2 0 2 2 0 8 0 pdppl 4096 1000 0 963 6 1 5 6 0 8 0 pvpl 32 202266 0 183417 181 4 177 177 0 265 17 pmappl 200 496 0 480 1 0 1 1 0 8 0 extentpl 40 46 0 29 1 0 1 1 0 8 0 phpool 112 229 0 56 6 0 6 6 0 8 0