Re: [patch] measurements, numbers about CONFIG_OPTIMIZE

Re: [patch] measurements, numbers about CONFIG_OPTIMIZE_INLINING=y impact

Posted Jan 23, 2009 22:32 UTC (Fri) by oak (subscriber, #2786)
Parent article: Re: [patch] measurements, numbers about CONFIG_OPTIMIZE_INLINING=y impact

> We get oopses that have a nice symbolic back-trace, and it reports an
> error IN TOTALLY THE WRONG FUNCTION, because gcc "helpfully" inlined
> things to the point that only an expert can realize "oh, the bug was
> actually five hundred lines up, in that other function that was just
> called once, so gcc inlined it even though it is huge".

The problem isn't with GCC, but the backtrace.

Linus should get himself something that can read the kernel Dwarf3
debugging information provided by GCC and correct the quick backtrace
(which is AFAIK based just on framepointers).

Oops backtrace + kernel debug symbols + proper symbol resolver = developer
friendly backtrace.

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Re: [patch] measurements, numbers about CONFIG_OPTIMIZE_INLINING=y impact

Posted Jan 23, 2009 22:36 UTC (Fri) by dlang (✭ supporter ✭, #313) [Link]

the problem is that when the kernel acts up (when you need the report) you can't open files to access the data, all you can do is report what the kernel knows.

the debugging information for the kernel is HUGE, and nobody is interested in having that in ram all the time