kern/57275: ddb kill <proc> causes a panic

[jdc%coris.org@localhost.úk]

>Number:         57275
>Category:       kern
>Synopsis:       ddb kill <proc> causes a panic
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Mar 17 16:30:00 +0000 2023
>Originator:     Julian Coleman
>Release:        10.99.2 (Thu Mar  2 08:15:52 CET 2023)
>Organization:
>Environment:
NetBSD  10.99.2 NetBSD 10.99.2 (SUN4M_SCSI3.MP) #0: Thu Mar  2 08:15:52 CET 2023  jdc@morava:/mnt/obj/sparc/mnt/src/sys/arch/sparc/compile/SUN4M_SCSI3.MP sparc

>Description:
Trying to kill a running process from DDB panics the machine.

Command:
db{0}> kill 0t20810

Output:
Mutex error: mutex_vector_enter,511: assertion failed: !cpu_intr_p()

[ 9624.2695890] lock address : f21f5e00
[ 9624.2695890] current cpu  :                  0
[ 9624.2695890] current lwp  : 0x00000000f10a9040
[ 9624.2695890] owner field  : 000000000000000000 wait/spin:                0/0

[ 9624.2695890] panic: lock error: Mutex: mutex_vector_enter,511: assertion failed: !cpu_intr_p(): lock 0xf21f5e00 cpu 0 lwp 0xf10a9040
[ 9624.2695890] cpu0: Begin traceback...
[ 9624.2695890] 0x0(0xf058edd0, 0xf06091f8, 0xf0649140, 0x104, 0xf0649000, 0xf0648400) at netbsd:panic+0x20
[ 9624.2695890] panic(0xf058edd0, 0xf0586570, 0xf052b568, 0x1ff, 0xf05864d8, 0xf21f5e00) at netbsd:lockdebug_abort+0xb8
[ 9624.2695890] lockdebug_abort(0xf052b568, 0x1ff, 0xf21f5e00, 0xf061bcb0, 0xf05864d8, 0xf0002000) at netbsd:mutex_enter+0x380
[ 9624.2695890] mutex_enter(0xf21f5e00, 0xfffffff8, 0xf10a9040, 0x0, 0x1, 0x0) at netbsd:db_kill_proc+0x8c
[ 9624.2695890] db_kill_proc(0xf002fb18, 0x0, 0xffffffff, 0xf0609440, 0xf0624000, 0xf16ec8c0) at netbsd:db_command+0xa8
[ 9624.2695890] db_command(0xf0612d7c, 0xf0539b68, 0x0, 0xf063c400, 0xf0612c00, 0xf0511ea8) at netbsd:db_command_loop+0xac
[ 9624.2695890] db_command_loop(0xf002fb1c, 0x1, 0xf056c690, 0xf0612c00, 0xf063c400, 0xf0612d7c) at netbsd:db_trap+0xc8
[ 9624.2695890] db_trap(0x81, 0x0, 0x60, 0xf0002000, 0xf063d000, 0xf0631000) at netbsd:kdb_trap+0x14c
[ 9624.2695890] kdb_trap(0x81, 0xf0609820, 0xf060d400, 0xf060d400, 0xf06095f8, 0xf0631000) at netbsd:trap+0x1a0
[ 9624.2695890] trap(0x81, 0x1e400fc2, 0xf002fb14, 0xf0609820, 0x0, 0x11c197) at netbsd:memfault_sun4m+0x2cc
[ 9624.2695890] memfault_sun4m(0x0, 0x30, 0x30, 0xf0586400, 0xffede004, 0x74) at netbsd:zstty_stint+0x174
[ 9624.2695890] zstty_stint(0xf109a980, 0x0, 0x30, 0xf062c000, 0xf109aac0, 0xf4) at netbsd:zsc_intr_hard+0x50
[ 9624.2695890] zsc_intr_hard(0x0, 0xf109a994, 0xf109a9f8, 0xf109a9e4, 0xf109a980, 0x8) at netbsd:zshard+0x8
[ 9624.2695890] zshard(0xf109a940, 0xf000e924, 0xf00, 0x1e8000e6, 0x229, 0xf109a940) at netbsd:sparc_interrupt44c+0x150
[ 9624.2695890] sparc_interrupt44c(0x1, 0xf000ae70, 0xf0002000, 0x0, 0x212, 0xf10a9040) at netbsd:kpreempt_disabled+0x8
[ 9624.2695890] kpreempt_disabled(0xf0622a40, 0x0, 0x0, 0x0, 0xf0742000, 0xf0742000) at netbsd:idle_loop+0x36c
[ 9624.2695890] idle_loop(0xf0584700, 0xf05354a8, 0xf05354b8, 0xf0742000, 0x0, 0xf0002000) at netbsd:lwp_trampoline+0x8
[ 9624.2695890] cpu0: End traceback...
Stopped in pid 0.2 (system) at  netbsd:cpu_Debugger+0x4:        or              
%o7, %g0, %g1

>How-To-Repeat:
Enter DDB
Find a pid to kill with ps
Attempt to kill that process

>Fix:
Remove proc_lock from db_kill_proc() ?