Valgrind is critically dependent on getting siginfo with its synchronous
(caused by an instruction fault) signals; if it gets, say, a SIGSEGV
which doesn't have siginfo, it must terminate ASAP because it really
can't make any more progress without knowing what caused the SIGSEGV.

The trouble is that if some other completely unrelated program the user
is running at the time builds up a large queue of pending signals for
some reason (as KDE seems to on SuSE 9.2), it will cause Valgrind to
fail for that user, apparently inexplicably.

It seems to me that the kernel should always deliver siginfo with
synchronous fault signals (SIGSEGV, SIGBUS, SIGFPE, SIGTRAP, SIGILL).
They can't ever be blocked (because they're unconditionally fatal if you
do block them), and therefore never queued.  By definition, the task
which causes the signal is running at the time, and so can be
immediately delivered a siginfo without having to allocate one (except
temporarily).

Proposed patch against 2.6.11-rc4 attached.

    J