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From: "hjl.tools at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug middle-end/106288] New: stack protector fails to check stack
 canary for noreturn function
Date: Wed, 13 Jul 2022 22:47:26 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D106288

            Bug ID: 106288
           Summary: stack protector fails to check stack canary for
                    noreturn function
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hjl.tools at gmail dot com
  Target Milestone: ---

[hjl@gnu-tgl-3 stack-protector]$ cat x.c
extern void foo (void) __attribute__ ((noreturn));

void
bar (void)
{
  foo ();
}
[hjl@gnu-tgl-3 stack-protector]$
/export/build/gnu/tools-build/gcc-gitlab-debug/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/tools-build/gcc-gitlab-debug/build-x86_64-linux/gcc/ -O2
-Wall -fstack-protector-all -S x.c
[hjl@gnu-tgl-3 stack-protector]$ cat x.s
        .file   "x.c"
        .text
        .p2align 4
        .globl  bar
        .type   bar, @function
bar:
.LFB0:
        .cfi_startproc
        subq    $24, %rsp
        .cfi_def_cfa_offset 32
        movq    %fs:40, %rax
        movq    %rax, 8(%rsp)
        xorl    %eax, %eax
        call    foo
        .cfi_endproc
.LFE0:
        .size   bar, .-bar
        .ident  "GCC: (GNU) 13.0.0 20220713 (experimental)"
        .section        .note.GNU-stack,"",@progbits
[hjl@gnu-tgl-3 stack-protector]$=20

There should be a stack canary check before calling foo since foo won't ret=
urn.=