Re: [uml-devel] 2.4.22-[67] problems

[Matt Z. <md...@de...>]

On Sun, Dec 28, 2003 at 02:12:40AM -0800, Matt Zimmerman wrote:

> So, the sequence of events in handle_trap is this:
> 
> 1. UPT_SYSCALL_NR(regs) == 78
> 
> 2. ptrace(PTRACE_POKEUSER,...)
> 
> 3. UPT_SYSCALL_NR(regs) == 78 (still OK)
> 
> 4. ptrace(PTRACE_SYSCALL,...)
> 
> 5. UPT_SYSCALL_NR(regs) == 78 (still OK)
> 
> 6. waitpid(pid,...)
> 
> 7. UPT_SYSCALL_NR(regs) == 0 (boom)
> 
> I have no idea why.

I added some code to dump the regs struct before and after waitpid, and it
turns out that in fact, the syscall element is the only one which is
different; the rest of the structure is untouched.  Corruption seems
unlikely, and the waitpid call certainly shouldn't be touching this...could
another thread be clobbering it somehow?

-- 
 - mdz