panic: kernel diagnostic assertion "atomic_load_int(&fdp->fd_nuserevents) == 0" failed: file "/syzkaller/managers/setuid/kernel/sys/kern/kern_descrip.c", line 1218 Stopped at db_enter+0x25: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 215848 69188 32767 0x10 0x4000000 0 syz-executor db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438 panic(ffffffff833759fd) at panic+0x1e5 sys/kern/subr_prf.c:198 __assert(ffffffff833b0386,ffffffff83381f46,4c2,ffffffff8333c353) at __assert+0x29 sys/kern/subr_prf.c:-1 fdfree(ffff8000398294e8) at fdfree+0x349 exit1(ffff8000398294e8,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215 sys_exit(ffff8000398294e8,ffff80002a3c9cd0,ffff80002a3c9c20) at sys_exit+0x1a sys/kern/kern_exit.c:-1 syscall(ffff80002a3c9cd0) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80002a3c9cd0) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:748 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x76f7c31498c0, 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{1}> ddb{1}> set $lines = 0 ddb{1}> set $maxwidth = 0 ddb{1}> show panic *cpu1: kernel diagnostic assertion "atomic_load_int(&fdp->fd_nuserevents) == 0" failed: file "/syzkaller/managers/setuid/kernel/sys/kern/kern_descrip.c", line 1218 ddb{1}> trace db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438 panic(ffffffff833759fd) at panic+0x1e5 sys/kern/subr_prf.c:198 __assert(ffffffff833b0386,ffffffff83381f46,4c2,ffffffff8333c353) at __assert+0x29 sys/kern/subr_prf.c:-1 fdfree(ffff8000398294e8) at fdfree+0x349 exit1(ffff8000398294e8,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215 sys_exit(ffff8000398294e8,ffff80002a3c9cd0,ffff80002a3c9c20) at sys_exit+0x1a sys/kern/kern_exit.c:-1 syscall(ffff80002a3c9cd0) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80002a3c9cd0) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:748 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x76f7c31498c0, count: -8 ddb{1}> show registers rdi 0 rsi 0x1 rbp 0xffff80002a3c9a10 rbx 0xffff8000299eeddf rdx 0 rcx 0xffff8000398294e8 rax 0xffff8000299edff0 r8 0x101010101010101 r9 0x8080808080808080 r10 0xfcd3cd754cd4f74f r11 0x3688087b928a7bfd r12 0xffff8000299eebe0 r13 0 r14 0 r15 0x1 rip 0xffffffff82f50db5 db_enter+0x25 cs 0x8 rflags 0x246 rsp 0xffff80002a3c9a00 ss 0x10 db_enter+0x25: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor) tid=6943 pid=50620 tcnt=0 stat=onproc flags process=1018 proc=2000 runpri=32, usrpri=86, slppri=32, nice=20 wchan=0x0, wmesg=, ps_single=0xffff8000398294e8 scnt=-1 ecnt=1 forw=0xffffffffffffffff, list=0xffff800039828558,0xffff800039829a28 process=0xffff80003c47bab0 user=0xffff80002a3c4000, vmspace=0xfffffd800c2fb5e0 estcpu=36, cpticks=16, pctcpu=0.0, user=0, sys=1, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 19895 124329 95456 0 2 0x2 syz-executor 69188 389864 467 32767 2 0x10 syz-executor 69188 215848 467 32767 7 0x4000010 syz-executor 13737 505680 86914 0 3 0x82 sbwait sshd-session 24783 423165 0 0 3 0x14200 bored sosplice 34829 154449 92859 32767 3 0x90 nanoslp syz-executor 68275 244638 57823 32767 3 0x90 nanoslp syz-executor 76747 351146 78854 32767 3 0x90 piperd syz-executor 29799 151888 60864 32767 3 0x90 piperd syz-executor 467 20546 60534 32767 3 0x90 nanoslp syz-executor 15839 233725 87687 32767 3 0x90 piperd syz-executor 57823 98633 95456 0 3 0x82 wait syz-executor 87687 403743 95456 0 3 0x82 wait syz-executor 60534 411571 95456 0 3 0x82 wait syz-executor 78854 281570 95456 0 3 0x82 wait syz-executor 60864 513729 95456 0 3 0x82 wait syz-executor 92859 181844 95456 0 3 0x82 wait syz-executor 95456 45687 49368 0 3 0x82 nanoslp syz-executor 49368 356888 52924 0 3 0x10008a sigsusp ksh 52924 308276 53038 0 3 0x98 kqread sshd-session 53038 101506 86914 0 3 0x92 kqread sshd-session 41943 424941 1 0 3 0x100083 ttyin getty 86914 420004 1 0 3 0x88 kqread sshd 69286 478515 47288 73 3 0x1100090 kqread syslogd 47288 2432 1 0 3 0x100082 sbwait syslogd 22169 430877 1 0 3 0x100080 kqread resolvd 60833 360116 92191 77 3 0x100092 kqread dhcpleased 51736 243145 92191 77 3 0x100092 kqread dhcpleased 92191 182385 1 0 3 0x80 kqread dhcpleased 53552 255610 0 0 3 0x14200 bored smr 77068 290075 0 0 2 0x14200 zerothread 74425 45983 0 0 3 0x14200 aiodoned aiodoned 36243 345577 0 0 3 0x14200 syncer update 48015 66734 0 0 3 0x14200 cleaner cleaner 87213 438110 0 0 3 0x14200 reaper reaper 93127 235552 0 0 3 0x14200 pgdaemon pagedaemon 64437 372354 0 0 3 0x14200 bored viomb 27773 28090 0 0 3 0x40014200 acpi0 acpi0 61026 392055 0 0 3 0x40014200 idle1 20369 72804 0 0 3 0x14200 bored softnet7 20069 44633 0 0 3 0x14200 bored softnet6 47526 399427 0 0 3 0x14200 bored softnet5 11604 235594 0 0 3 0x14200 bored softnet4 84340 453554 0 0 3 0x14200 bored softnet3 27311 178330 0 0 3 0x14200 bored softnet2 31230 486543 0 0 3 0x14200 bored softnet1 80087 196715 0 0 3 0x14200 bored softnet0 24120 429076 0 0 3 0x14200 bored systqmp 31876 498870 0 0 3 0x14200 bored systq 93288 464347 0 0 3 0x14200 tmoslp softclockmp 81429 148279 0 0 3 0x40014200 tmoslp softclock 37179 231898 0 0 3 0x40014200 idle0 1 367195 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10187 10952K 10968K 166960K 11271 0 pcb 17 12K 12K 166960K 17 0 rtable 175 5K 6K 166960K 273 0 pf 27 16K 16K 166960K 31 0 ifaddr 34 6K 7K 166960K 44 0 ifgroup 42 1K 2K 166960K 50 0 sysctl 3 1K 9K 166960K 10 0 counters 64 36K 36K 166960K 68 0 ioctlops 0 0K 2K 166960K 35 0 iov 0 0K 16K 166960K 132 0 mount 1 1K 1K 166960K 1 0 log 0 0K 0K 166960K 4 0 vnodes 1335 84K 84K 166960K 1583 0 UFS quota 1 32K 32K 166960K 1 0 UFS mount 5 36K 36K 166960K 5 0 shm 2 1K 9K 166960K 8 0 VM map 2 1K 1K 166960K 2 0 sem 12 0K 0K 166960K 16 0 dirhash 12 2K 2K 166960K 18 0 ACPI 1692 195K 286K 166960K 12470 0 file desc 17 61K 125K 166960K 478 0 sigio 0 0K 0K 166960K 2 0 proc 58 99K 131K 166960K 504 0 subproc 57 3K 4K 166960K 291 0 NFS srvsock 1 0K 0K 166960K 1 0 NFS daemon 1 16K 16K 166960K 1 0 ip_moptions 0 0K 0K 166960K 74 0 in_multi 77 5K 7K 166960K 120 0 ether_multi 1 0K 0K 166960K 5 0 ISOFS mount 1 32K 32K 166960K 1 0 MSDOSFS mount 1 16K 16K 166960K 1 0 ttys 61 281K 281K 166960K 61 0 exec 0 0K 1K 166960K 386 0 fusefs mount 1 32K 32K 166960K 1 0 tdb 3 0K 0K 166960K 3 0 VM swap 8 62K 64K 166960K 10 0 UVM amap 221 175K 197K 166960K 5462 0 UVM aobj 17 2K 3K 166960K 19 0 pinsyscall 41 82K 113K 166960K 1495 0 memdesc 1 4K 4K 166960K 1 0 crypto data 1 1K 1K 166960K 1 0 ip6_options 0 0K 0K 166960K 21 0 NDP 9 0K 2K 166960K 27 0 temp 45 8646K 8709K 166960K 5646 0 kqueue 16 22K 25K 166960K 72 0 SYN cache 2 16K 16K 166960K 2 0 ddb{1}> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle plcache 128 26 0 0 1 0 1 1 0 8 0 rtpcb 120 123 0 120 3 2 1 3 0 8 0 rtentry 176 102 0 23 5 0 5 5 0 8 0 unpcb 144 206 0 189 2 1 1 2 0 8 0 syncache 336 6 0 6 1 0 1 1 0 8 1 tcpqe 32 1 0 1 1 0 1 1 0 8 1 tcpcb 736 150 0 144 4 0 4 4 0 8 3 arp 128 10 0 2 1 0 1 1 0 8 0 ipq 40 1 0 0 1 0 1 1 0 8 0 ipqe 40 1 0 0 1 0 1 1 0 8 0 inpcb 328 432 0 423 7 3 4 5 0 8 3 ip6q 72 1 0 1 1 1 0 1 0 8 0 ip6af 40 3 0 3 1 1 0 1 0 8 0 nd6 144 23 0 8 1 0 1 1 0 8 0 kcovpl 48 32 0 26 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 460 0 99 29 2 27 29 0 8 3 art_table 40 461 0 99 5 0 5 5 0 8 0 art_node 32 102 0 31 1 0 1 1 0 8 0 sysvmsgpl 40 7 0 7 1 0 1 1 0 8 1 semupl 112 1 0 1 1 1 0 1 0 8 0 semapl 112 13 0 3 1 0 1 1 0 8 0 shmpl 112 16 0 2 1 0 1 1 0 8 0 dirhash 1024 21 0 4 3 0 3 3 0 8 0 dino2pl 256 1919 0 387 96 0 96 96 0 8 0 ffsino 296 1919 0 387 118 0 118 118 0 8 0 nchpl 144 2437 0 738 64 0 64 64 0 8 0 uvmvnodes 80 2219 0 0 46 0 46 46 0 8 0 vnodes 216 2219 0 0 124 0 124 124 0 8 0 namei 1024 7547 0 7547 2 1 1 2 0 8 1 percpumem 16 49 0 2 1 0 1 1 0 8 0 kstatmem 264 24 0 4 2 0 2 2 0 8 0 scxspl 216 8842 0 8842 9 8 1 8 1 8 1 plimitpl 152 183 0 161 2 0 2 2 0 8 1 sigapl 424 709 0 655 8 0 8 8 0 8 0 knotepl 120 311 0 0 10 0 10 10 0 8 0 kqueuepl 224 91 0 81 1 0 1 1 0 8 0 pipepl 344 325 0 298 9 2 7 9 0 8 4 fdescpl 528 686 0 655 4 1 3 4 0 8 0 filepl 160 3519 0 3328 14 2 12 14 0 8 2 lockfpl 104 158 0 156 1 0 1 1 0 8 0 lockfspl 48 27 0 25 1 0 1 1 0 8 0 sessionpl 144 48 0 33 1 0 1 1 0 8 0 pgrppl 48 92 0 70 1 0 1 1 0 8 0 ucredpl 104 388 0 371 1 0 1 1 0 8 0 zombiepl 144 657 0 655 1 0 1 1 0 8 0 processpl 1248 709 0 655 7 1 6 6 0 8 0 procpl 664 1126 0 1071 8 1 7 7 0 8 1 sosppl 168 1 0 1 1 0 1 1 0 8 1 sockpl 752 764 0 735 13 5 8 13 0 8 4 mcl64k 65536 4 0 0 1 0 1 1 0 8 0 mcl8k 8192 3 0 0 1 0 1 1 0 8 0 mcl4k 4096 117 0 0 15 0 15 15 0 8 0 mcl2k 2048 42 0 0 6 0 6 6 0 8 0 mtagpl 96 2 0 0 1 0 1 1 0 8 0 mbufpl 256 292 0 0 19 0 19 19 0 8 0 bufpl 280 3328 0 116 230 0 230 230 0 8 0 anonpl 32 7611 0 0 62 0 62 62 0 246 0 amapchunkpl 152 19154 0 18717 30 6 24 29 0 158 2 amappl16 200 2599 0 2577 14 3 11 11 0 8 8 amappl15 192 11 0 11 1 1 0 1 0 8 0 amappl14 184 123 0 112 1 0 1 1 0 8 0 amappl13 176 4 0 4 2 1 1 1 0 8 1 amappl12 168 1293 0 1262 2 0 2 2 0 8 0 amappl11 160 80 0 70 1 0 1 1 0 8 0 amappl10 152 10 0 10 1 1 0 1 0 8 0 amappl9 144 250 0 250 1 1 0 1 0 8 0 amappl8 136 19 0 16 1 0 1 1 0 8 0 amappl7 128 129 0 118 1 0 1 1 0 8 0 amappl6 120 175 0 170 1 0 1 1 0 8 0 amappl5 112 115 0 109 1 0 1 1 0 8 0 amappl4 104 276 0 258 1 0 1 1 0 8 0 amappl3 96 3003 0 2902 4 0 4 4 0 8 0 amappl2 88 624 0 562 2 0 2 2 0 8 0 amappl1 80 9712 0 9080 15 0 15 15 0 8 0 amappl 88 4756 0 4606 5 0 5 5 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 18 0 2 1 0 1 1 0 8 0 uaddrrnd 24 686 0 655 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 686 0 655 1 0 1 1 0 8 0 vmmpekpl 168 8204 0 8152 3 0 3 3 0 8 0 vmmpepl 168 50548 0 48620 105 4 101 101 0 357 3 vmsppl 488 685 0 655 7 2 5 6 0 8 0 rwobjpl 80 18520 0 15392 69 1 68 68 0 8 0 pdppl 4096 1380 0 1310 118 36 82 98 0 8 12 pvpl 32 14938 0 0 122 1 121 121 0 265 0 pmappl 256 685 0 655 4 1 3 3 0 8 0 extentpl 40 45 0 27 1 0 1 1 0 8 0 phpool 112 303 0 42 8 0 8 8 0 8 0 ddb{1}> machine ddbcpu 0 Stopped at x86_ipi_db+0x27: addq $0x8,%rsp x86_ipi_db(ffffffff8383bff0) at x86_ipi_db+0x27 sys/arch/amd64/amd64/db_interface.c:394 x86_ipi_handler() at x86_ipi_handler+0xd9 sys/arch/amd64/amd64/ipi.c:106 Xresume_lapic_ipi() at Xresume_lapic_ipi+0x27 __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x33 kd_curproc sys/dev/kcov.c:585 [inline] __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x33 sys/dev/kcov.c:153 __mp_lock(ffffffff838c27a0) at __mp_lock+0x1a3 __mp_lock_spin sys/kern/kern_lock.c:134 [inline] __mp_lock(ffffffff838c27a0) at __mp_lock+0x1a3 sys/kern/kern_lock.c:165 softintr_dispatch(0) at softintr_dispatch+0x125 sys/kern/kern_softintr.c:83 dosoftint(0) at dosoftint+0x54 sys/arch/amd64/amd64/intr.c:847 Xsoftclock() at Xsoftclock+0x27 __mp_lock(ffffffff838c27a0) at __mp_lock+0x199 __mp_lock_spin sys/kern/kern_lock.c:134 [inline] __mp_lock(ffffffff838c27a0) at __mp_lock+0x199 sys/kern/kern_lock.c:165 sysctl_file(ffff80002a3d56b8,4,200000000100,ffff80002a3d56e8,ffff800039828fb8) at sysctl_file+0x27ef sys/kern/kern_sysctl.c:1784 kern_sysctl(ffff80002a3d56b4,5,200000000100,ffff80002a3d56e8,0,37,e8c5fa6deb5ce64b) at kern_sysctl+0x139 sys/kern/kern_sysctl.c:733 sys_sysctl(ffff800039828fb8,ffff80002a3d5820,ffff80002a3d5770) at sys_sysctl+0x3e5 sys/kern/kern_sysctl.c:-1 syscall(ffff80002a3d5820) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80002a3d5820) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:748 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xfb157419070, count: 1 ddb{0}> trace x86_ipi_db(ffffffff8383bff0) at x86_ipi_db+0x27 sys/arch/amd64/amd64/db_interface.c:394 x86_ipi_handler() at x86_ipi_handler+0xd9 sys/arch/amd64/amd64/ipi.c:106 Xresume_lapic_ipi() at Xresume_lapic_ipi+0x27 __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x33 kd_curproc sys/dev/kcov.c:585 [inline] __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x33 sys/dev/kcov.c:153 __mp_lock(ffffffff838c27a0) at __mp_lock+0x1a3 __mp_lock_spin sys/kern/kern_lock.c:134 [inline] __mp_lock(ffffffff838c27a0) at __mp_lock+0x1a3 sys/kern/kern_lock.c:165 softintr_dispatch(0) at softintr_dispatch+0x125 sys/kern/kern_softintr.c:83 dosoftint(0) at dosoftint+0x54 sys/arch/amd64/amd64/intr.c:847 Xsoftclock() at Xsoftclock+0x27 __mp_lock(ffffffff838c27a0) at __mp_lock+0x199 __mp_lock_spin sys/kern/kern_lock.c:134 [inline] __mp_lock(ffffffff838c27a0) at __mp_lock+0x199 sys/kern/kern_lock.c:165 sysctl_file(ffff80002a3d56b8,4,200000000100,ffff80002a3d56e8,ffff800039828fb8) at sysctl_file+0x27ef sys/kern/kern_sysctl.c:1784 kern_sysctl(ffff80002a3d56b4,5,200000000100,ffff80002a3d56e8,0,37,e8c5fa6deb5ce64b) at kern_sysctl+0x139 sys/kern/kern_sysctl.c:733 sys_sysctl(ffff800039828fb8,ffff80002a3d5820,ffff80002a3d5770) at sys_sysctl+0x3e5 sys/kern/kern_sysctl.c:-1 syscall(ffff80002a3d5820) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80002a3d5820) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:748 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xfb157419070, count: -14 ddb{0}> machine ddbcpu 1 Stopped at db_enter+0x25: addq $0x8,%rsp db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438 panic(ffffffff833759fd) at panic+0x1e5 sys/kern/subr_prf.c:198 __assert(ffffffff833b0386,ffffffff83381f46,4c2,ffffffff8333c353) at __assert+0x29 sys/kern/subr_prf.c:-1 fdfree(ffff8000398294e8) at fdfree+0x349 exit1(ffff8000398294e8,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215 sys_exit(ffff8000398294e8,ffff80002a3c9cd0,ffff80002a3c9c20) at sys_exit+0x1a sys/kern/kern_exit.c:-1 syscall(ffff80002a3c9cd0) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80002a3c9cd0) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:748 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x76f7c31498c0, count: 7 ddb{1}> trace db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438 panic(ffffffff833759fd) at panic+0x1e5 sys/kern/subr_prf.c:198 __assert(ffffffff833b0386,ffffffff83381f46,4c2,ffffffff8333c353) at __assert+0x29 sys/kern/subr_prf.c:-1 fdfree(ffff8000398294e8) at fdfree+0x349 exit1(ffff8000398294e8,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215 sys_exit(ffff8000398294e8,ffff80002a3c9cd0,ffff80002a3c9c20) at sys_exit+0x1a sys/kern/kern_exit.c:-1 syscall(ffff80002a3c9cd0) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80002a3c9cd0) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:748 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x76f7c31498c0, count: -8