• Jan Beulich's avatar
    [PATCH] i386/x86-64: Work around gcc bug with noreturn functions in unwinder · adf14236
    Jan Beulich authored
    Current gcc generates calls not jumps to noreturn functions. When that happens the
    return address can point to the next function, which confuses the unwinder.
    This patch works around it by marking asynchronous exception
    frames in contrast normal call frames in the unwind information.  Then teach
    the unwinder to decode this.
    For normal call frames the unwinder now subtracts one from the address which avoids
    this problem.  The standard libgcc unwinder uses the same trick.
    It doesn't include adjustment of the printed address (i.e. for the original
    example, it'd still be kernel_math_error+0 that gets displayed, but the
    unwinder wouldn't get confused anymore.
    This only works with binutils 2.6.17+ and some versions of H.J.Lu's 2.6.16
    unfortunately because earlier binutils don't support .cfi_signal_frame
    [AK: added automatic detection of the new binutils and wrote description]
    Signed-off-by: default avatarJan Beulich <jbeulich@novell.com>
    Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Kbuild.include 8.23 KB