Commit c36d891d authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'core_urgent_for_v5.16_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull signal handlign fix from Borislav Petkov:

 - Prevent lock contention on the new sigaltstack lock on the
   common-case path, when no changes have been made to the alternative
   signal stack.

* tag 'core_urgent_for_v5.16_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  signal: Skip the altstack update when not needed
parents a4cc5ea4 6c3118c3

kernel/signal.c

+9 −0
Original line number Diff line number Diff line
@@ -4185,6 +4185,15 @@ do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp, 
				ss_mode != 0))

			return -EINVAL;



		/*

		 * Return before taking any locks if no actual

		 * sigaltstack changes were requested.

		 */

		if (t->sas_ss_sp == (unsigned long)ss_sp &&

		    t->sas_ss_size == ss_size &&

		    t->sas_ss_flags == ss_flags)

			return 0;



		sigaltstack_lock();

		if (ss_mode == SS_DISABLE) {

			ss_size = 0;