On Wednesday 10 December 2008 10:06, Carmelo AMOROSO wrote:
> Carmelo AMOROSO wrote:
> > Hi Khem,
> > I'm seeing similar problem on sh4-nptl as happened to you as you told me
> > yesterday.. Something recently merged is causing issues.
> > I'm doing investigation and keep you all informed.
> >
> > Further I'm just writing a detailed report on current status of merge,
> > that I can say is almost complete (once figured out what is not
> > actually working ;-) ).
> >
> > I'm currently 100% focused on uclibc.
> >
> > Cheers,
> > Carmelo
> Khem,
> I think to have found what is causing problems on nptl branch
> (anyway I don't know why yet).
>
> The cause is the change merged from trunk in the file
> libc/sysdeps/linux/common/bits/sigset.h (rev 24243)
>
> that includes all changes occurred in the same file on trunk
> in rev 24183 / 24220 / 24221 by vda.
>
> Please may you try on ARM reverting that file
> and see if it helps. On sh4-nptl it's working better now
> Below the boot log on my box... not more PANIC on INIT
> even if it's blocking on udev
>
> This seems confirming my idea on signal handling changes.
> I'll try to merge on my private branch all changes that are already
> in the nptl-branch but thos on signal handling.
The change is that sigset_t is not 1024 bits, but 64 bits
on almost all architectures. Only MIPS has 128.
This affects sigaction and sigprocmask, but they already
are translating libc struct sigaction / sigset_t to kernel's.
With this change sigset_t actually should match kernel one,
albeit struct sigaction is still different a bit.
Anyway, the symptom of breakage would be, for example,
in libc/sysdeps/linux/arm/sigaction.c:
int __libc_sigaction (int sig, const struct sigaction *act, struct sigaction
*oact)
{
int result;
struct kernel_sigaction kact, koact;
enum {
SIGSET_MIN_SIZE = sizeof(kact.sa_mask) < sizeof(act->sa_mask)
? sizeof(kact.sa_mask) : sizeof(act->sa_mask)
};
*** first thing to check is whether sizeof(kact.sa_mask) ==
sizeof(act->sa_mask).
I tried to make it work even if it does not, but it's always better if they
match.
add line
struct BUG { int bug[sizeof(kact.sa_mask) == sizeof(act->sa_mask) ? 1 : -1]; };
and if compile fails, sizeof's are not ==.
Let me know that.
if (act) {
kact.k_sa_handler = act->sa_handler;
memcpy (&kact.sa_mask, &act->sa_mask, SIGSET_MIN_SIZE);
kact.sa_flags = act->sa_flags;
# ifdef HAVE_SA_RESTORER
if (kact.sa_flags & SA_RESTORER) {
kact.sa_restorer = act->sa_restorer;
} else {
kact.sa_restorer = choose_restorer (kact.sa_flags);
kact.sa_flags |= SA_RESTORER;
}
# endif
}
*** next:
/* NB: kernel (as of 2.6.25) will return EINVAL
* if sizeof(kact.sa_mask) does not match kernel's sizeof(sigset_t) */
result = __syscall_rt_sigaction(sig,
act ? __ptrvalue (&kact) : NULL,
oact ? __ptrvalue (&koact) : NULL,
sizeof(kact.sa_mask));
Basically, if it throws EINVAL, always, then sizeof(kact.sa_mask) is botched.
(Kernel simply compares it with constant, it must be correct to work,
no "greater or equal" slack there).
I think adding if (errno == EINVAL) write(2, "EINVAL!\n", 8);
will tell you whether it happens.
sigprocmask is simpler:
int sigprocmask(int how, const sigset_t * set, sigset_t * oldset)
{
if (set &&
...
) {
__set_errno(EINVAL);
return -1;
}
return __rt_sigprocmask(how, set, oldset, _NSIG / 8);
Again, _NSIG / 8 must be correct here, or it will fail always.
Hope this helps
--
vda
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