panic: kernel diagnostic assertion "ISSET(p->p_flag, P_SUSPSIG | P_SUSPSINGLE) == 0" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_sig.c", line 1602
Stopped at      db_enter+0x25:  addq    $0x8,%rsp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
*494757  64696      0  0x40009000  0x8080000    1  syz-executor
 504403  64696      0  0x40009000  0xc080000    0  syz-executor
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
panic(ffffffff834c2da4) at panic+0x1e5 sys/kern/subr_prf.c:198
__assert(ffffffff834fe739,ffffffff83462c9d,642,ffffffff83444f74) at __assert+0x29 sys/kern/subr_prf.c:-1
process_stop(ffff80003c45c4f8,8000000,1) at process_stop+0x3fe
cursig(ffff800032f8da28,ffff80003a3bbb68,0) at cursig+0x509 x86_atomic_setbits_u32 sys/arch/amd64/compile/SYZKALLER/obj/machine/atomic.h:-1 [inline]
cursig(ffff800032f8da28,ffff80003a3bbb68,0) at cursig+0x509 sys/kern/kern_sig.c:1445
userret(ffff800032f8da28) at userret+0x203 sys/kern/kern_sig.c:2207
syscall(ffff80003a3bbca0) at syscall+0x9ce mi_syscall_return sys/sys/syscall_mi.h:203 [inline]
syscall(ffff80003a3bbca0) at syscall+0x9ce sys/arch/amd64/amd64/trap.c:812
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x76f81cfa4ef0, 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.