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GNU C Library master sources branch master updated. glibc-2.26.9000-998-g368b6c8

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- Log -----------------------------------------------------------------;a=commitdiff;h=368b6c8da9f8ae453f5d70f8a62dbf3f1b6d5995

commit 368b6c8da9f8ae453f5d70f8a62dbf3f1b6d5995
Author: Sergei Trofimovich <>
Date:   Mon Dec 18 17:23:02 2017 +0000

    mips64: fix clobbering s0 in setjmp() [BZ #22624]
    When configured as --enable-stack-protector=all glibc
    inserts stack checking canary into every function
    including __sigsetjmp_aux(). Stack checking code
    ends up using s0 register to temporary hold address
    of global canary value.
    Unfortunately __sigsetjmp_aux assumes no caller' caller-save
    registers should be clobbered as it stores them as-is.
    The fix is to disable stack protection of __sigsetjmp_aux.
    Tested on the following test:
        #include <setjmp.h>
        #include <stdio.h>
        int main() {
            jmp_buf jb;
            volatile register long s0 asm ("$s0");
            s0 = 1234;
            if (setjmp(jb) == 0)
                longjmp(jb, 1);
            printf ("$s0 = %lu\n", s0);
    Without the fix:
        $ qemu-mipsn32 -L . ./mips-longjmp-bug
        $s0 = 1082346228
    With the fix:
        $ qemu-mipsn32 -L . ./mips-longjmp-bug
        $s0 = 1234
    	[BZ #22624]
    	* sysdeps/mips/mips64/setjmp_aux.c (__sigsetjmp_aux): Use

diff --git a/ChangeLog b/ChangeLog
index d290d60..4a71643 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2017-12-18  Sergei Trofimovich  <>
+	[BZ #22624]
+	* sysdeps/mips/mips64/setjmp_aux.c (__sigsetjmp_aux): Use
+	inhibit_stack_protector.
 2017-12-18  Dmitry V. Levin  <>
 	[BZ #22627]
diff --git a/sysdeps/mips/mips64/setjmp_aux.c b/sysdeps/mips/mips64/setjmp_aux.c
index b43c36a..43fffc7 100644
--- a/sysdeps/mips/mips64/setjmp_aux.c
+++ b/sysdeps/mips/mips64/setjmp_aux.c
@@ -24,7 +24,12 @@
    pointer.  We do things this way because it's difficult to reliably
    access them in C.  */
+/* Stack protection is disabled to avoid changing s0 (or any other
+   caller-save register) before storing it to environment.
+   See BZ #22624.  */
 __sigsetjmp_aux (jmp_buf env, int savemask, long long sp, long long fp,
 		 long long gp)


Summary of changes:
 ChangeLog                        |    6 ++++++
 sysdeps/mips/mips64/setjmp_aux.c |    5 +++++
 2 files changed, 11 insertions(+), 0 deletions(-)

GNU C Library master sources

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