Re: kern/53261: kernel crash during test run

[Valery Ushakov <uwe%stderr.spb.ru@localhost>]

The following reply was made to PR kern/53261; it has been noted by GNATS.

From: Valery Ushakov <uwe%stderr.spb.ru@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: kern/53261: kernel crash during test run
Date: Wed, 23 May 2018 16:06:48 +0300

 On Wed, May 23, 2018 at 12:15:01 +0000, Martin Husemann wrote:
 
 >  An alternative is to make the syscall handling code in arm a lot more
 >  complex and check for specific misalignments, but then we would punish
 >  everyone for a stupid test interface that should just go away.
 
 The problem with arm code is that it uses MI indirect system call
 support from sys/kern/sys_syscall.c
 
 So if first copies the arguments into a buffer and then sys_syscall
 will advance uap to point to the next word in the buffer, which breaks
 alignment.
 
 Compare that to e.g. sparc, that handles SYS_syscall in MD code and
 copies real syscall arguments to the aligned buffer.
 
 -uwe