lkml.org 
[lkml]   [2018]   [Dec]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] x86: vdso: Pass --eh-frame-hdr to ld
From
Date
On 12/14/18 2:27 PM, Alistair Strachan wrote:
> Commit 379d98ddf413 ("x86: vdso: Use $LD instead of $CC to link")
> accidentally broke unwinding from userspace, because ld would strip the
> .eh_frame sections when linking.
>
> Originally, the compiler would implicitly add --eh-frame-hdr when
> invoking the linker, but when this Makefile was converted from invoking
> ld via the compiler, to invoking it directly (like vmlinux does),
> the flag was missed. (The EH_FRAME section is important for the VDSO
> shared libraries, but not for vmlinux.)
>
> Fix the problem by explicitly specifying --eh-frame-hdr, which restores
> parity with the old method.
>
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=201741
> Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1659295
> Reported-by: Laura Abbott <labbott@redhat.com>

You should probably use the bugzilla reporters instead
of me given I just did the boring part of sending an e-mail.
Instead you can use:

Tested-by: Laura Abbott <labbott@redhat.com>

> Fixes: 379d98ddf413 ("x86: vdso: Use $LD instead of $CC to link")
> Cc: stable@vger.kernel.org
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: X86 ML <x86@kernel.org>
> Cc: Florian Weimer <fweimer@redhat.com>,
> Cc: Carlos O'Donell <carlos@redhat.com>,
> Cc: "H. J. Lu" <hjl.tools@gmail.com>
> Cc: Joel Fernandes <joel@joelfernandes.org>
> Cc: kernel-team@android.com
> Signed-off-by: Alistair Strachan <astrachan@google.com>
> ---
> arch/x86/entry/vdso/Makefile | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
> index 141d415a8c80..c3d7ccd25381 100644
> --- a/arch/x86/entry/vdso/Makefile
> +++ b/arch/x86/entry/vdso/Makefile
> @@ -171,7 +171,8 @@ quiet_cmd_vdso = VDSO $@
> sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@'
>
> VDSO_LDFLAGS = -shared $(call ld-option, --hash-style=both) \
> - $(call ld-option, --build-id) -Bsymbolic
> + $(call ld-option, --build-id) $(call ld-option, --eh-frame-hdr) \
> + -Bsymbolic
> GCOV_PROFILE := n
>
> #
>

\
 
 \ /
  Last update: 2018-12-14 23:32    [W:0.075 / U:1.504 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site