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Commit d7a6c68a authored by Shi Weihua's avatar Shi Weihua Committed by Tony Luck
Browse files

[IA64] signal(ia64): add a signal stack overflow check 



The similar check has been added to x86_32(i386) in commit
id 83bd0102.
So we add this check to ia64 and improve it a liitle bit in that
we need to check for stack overflow only when the signal is on stack.

Signed-off-by: default avatarShi Weihua <shiwh@cn.fujitsu.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent bd3be240

arch/ia64/kernel/signal.c

+27 −9
Original line number Diff line number Diff line
@@ -342,15 +342,33 @@ setup_frame (int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set, 


	new_sp = scr->pt.r12;

	tramp_addr = (unsigned long) __kernel_sigtramp;

	if ((ka->sa.sa_flags & SA_ONSTACK) && sas_ss_flags(new_sp) == 0) {

	if (ka->sa.sa_flags & SA_ONSTACK) {

		int onstack = sas_ss_flags(new_sp);



		if (onstack == 0) {

			new_sp = current->sas_ss_sp + current->sas_ss_size;

			/*

		 * We need to check for the register stack being on the signal stack

		 * separately, because it's switched separately (memory stack is switched

		 * in the kernel, register stack is switched in the signal trampoline).

			 * We need to check for the register stack being on the

			 * signal stack separately, because it's switched

			 * separately (memory stack is switched in the kernel,

			 * register stack is switched in the signal trampoline).

			 */

			if (!rbs_on_sig_stack(scr->pt.ar_bspstore))

			new_rbs = (current->sas_ss_sp + sizeof(long) - 1) & ~(sizeof(long) - 1);

				new_rbs = ALIGN(current->sas_ss_sp,

						sizeof(long));

		} else if (onstack == SS_ONSTACK) {

			unsigned long check_sp;



			/*

			 * If we are on the alternate signal stack and would

			 * overflow it, don't. Return an always-bogus address

			 * instead so we will die with SIGSEGV.

			 */

			check_sp = (new_sp - sizeof(*frame)) & -STACK_ALIGN;

			if (!likely(on_sig_stack(check_sp)))

				return force_sigsegv_info(sig, (void __user *)

							  check_sp);

		}

	}

	frame = (void __user *) ((new_sp - sizeof(*frame)) & -STACK_ALIGN);