------- Comment #5 from tglx at linutronix dot de 2009-11-19 19:27 -------
(In reply to comment #4)
> Is this really a bug since you have:
> struct entry {
> ...
> } __attribute__((__aligned__((1 << (4)))));
>
> ...
>
> void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
> void *timerf, char *comm,
> unsigned int timer_flag)
> {
> spinlock_t *lock;
> struct entry *entry, input;
>
>
> Since input is required to be 16byte aligned by the __aligned__ attribute on
> the struct.
Yes, Andrew pointed that out in the LKML thread as well. This still does not
explain why the mcount magic
push %ebp
mov %esp, %ebp
happens _after_ the alignment and the stack layout assumption of mcount:
return address
saved ebp
is done via a copy of the return address instead of just keeping the
push %ebp
mov %esp, %ebp
sequence right at the beginning of the function.
GCC 4.4.x silently changed this and we now need to figure out how to _NOT_ trip
over that.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109
