[CRIU] Re: [PATCH] restorer: close log file before detaching from crtools

[Cyrill Gorcunov]

On Mon, Feb 20, 2012 at 08:21:45PM +0400, Kinsbursky Stanislav wrote:
> 20.02.2012 19:31, Cyrill Gorcunov пишет:
> >On Mon, Feb 20, 2012 at 07:12:14PM +0400, Kinsbursky Stanislav wrote:
> >...
> >>>>+
> >>>>+core_restore_failed:
> >>>>+	asm volatile(
> >>>>+		"movq %0, %%rsp				\n"
> >>>>+		"jmp *%1				\n"
> >>>>+		:
> >>>>+		: "r"(ret), "r"(line)
> >>>>+		: );
> >>>>+	return ret;
> >>>We have a similar code in BUG_ON_HANDLER, but this code is better, so
> >>>I think you can improve BUG_ON_HANDLER and use it.
> >>Thanks for your valuable opinion. I'll keep that in mind.
> >>
> >Since both IP and SP are printed in dmesg I guess we might load
> >line number into SP and cause NULL dereference, something like
> >
> >core_restore_failed:
> >	asm volatile(
> >		"movq %0, %%rsp				\n"
> >		"xorl %%eax, %%eax			\n"
> >		"movl %%eax, (%%eax)			\n"
> >		:
> >		: "r"(line)
> >		: );
> 
> This is not as good, as my version is. My version also shows error code.
> Could you add it somehow?
> 
> >or, as Andrew mentioned, extend BUG_ON_HANDLER. Hm?
> >
> >	Cyrill
> 
> This BUG_ON_HANDLER relies on log fd is valid. It's not our case.
> 

I thought about extending it this way -- split it to two parts,
one to use without logfd (ie say BUG_RAISE macro which would simply
dereference NULL and setup sp to line number) and second part which
would be BUG_ON() with BUG_RAISE in body. This way we could use both
-- for regular bugs BUG_ON and for this case BUG_RAISE.

Stas, I somehow missed -- can't we use sys_exit here? With error
code combined by line and error number. Hm?

core_restore_panic:
	sys_exit(-((line << 16) | some-error));

	Cyrill