Subject: Re: bad kdump output with 64bit syscalls under 32bit emul
To: None <>
From: Christos Zoulas <>
List: tech-kern
Date: 10/31/2007 01:40:29
In article <>,
Nicolas Joly  <> wrote:
>While tracing some 32bit linux process on my -current NetBSD/amd64
>workstation, i noticed that kdump(1) show an incorrect number of
>arguments for some syscalls.
>  4190      1 exit     CALL  close(3,3)
>  4190      1 exit     RET   close 0
>After looking at it, i discovered that kdump(1) argument count is bad
>when dealing with 64bit syscalls under 32bit emulation.
>6       NOARGS  { int sys_close(int fd); }
>The problem is that ktrace argsize depends on syscall args struct
>size, which depends on syscallarg macro definition. this size which
>should be, under compat linux32, a multiple of register32_t. But with
>a 64bit syscall, it will be a multiple of register_t; leading to an
>argsize two times larger than expected.
>It looks like that 64bit syscalls should not be used directly under
>32bit emulation in order have correct kdump output.
>Unless there is a better way to fix it, that i'm currently
>missing. I'll plan to fix this by replacing all native syscalls with
>the netbsd32 equivalents, likewise for linux32 vs. linux calls.

I don't see a better way. How does sparc32 emulation on sparc64 works?