Commit 0f8f3089 authored Mar 26, 2009 by Hiroshi Shimamoto Committed by Ingo Molnar Apr 01, 2009

x86: signal: check sas_ss_size instead of sas_ss_flags()



Impact: fix redundant and incorrect check

Oleg Nesterov noticed wrt commit:

  14fc9fbc: x86: signal: check signal stack overflow properly

>> No need to check SA_ONSTACK if we're already using alternate signal stack.
>
> Yes, but this also mean that we don't need sas_ss_flags() under
> "if (!onsigstack)",

Checking on_sig_stack() in sas_ss_flags() at get_sigframe() is redundant
and not correct on 64 bit. To check sas_ss_size is enough.

Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Cc: roland@redhat.com
LKML-Reference: <49CBB54C.5080201@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 93394a76

arch/x86/kernel/signal.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -221,7 +221,7 @@ get_sigframe(struct k_sigaction ka, struct pt_regs regs, size_t frame_size,
		if (!onsigstack) {
		/* This is the X/Open sanctioned signal stack switching. */
		if (ka->sa.sa_flags & SA_ONSTACK) {
		if (sas_ss_flags(sp) == 0)
		if (current->sas_ss_size)
		sp = current->sas_ss_sp + current->sas_ss_size;
		} else {
		#ifdef CONFIG_X86_32

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