Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 38/51] x86/vdso: Pass --eh-frame-hdr to the linker | Date | Wed, 15 May 2019 12:56:13 +0200 |
| |
From: Alistair Strachan <astrachan@google.com>
commit cd01544a268ad8ee5b1dfe42c4393f1095f86879 upstream.
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.
See relevant bug reports for additional info:
https://bugzilla.kernel.org/show_bug.cgi?id=201741 https://bugzilla.redhat.com/show_bug.cgi?id=1659295
Fixes: 379d98ddf413 ("x86: vdso: Use $LD instead of $CC to link") Reported-by: Florian Weimer <fweimer@redhat.com> Reported-by: Carlos O'Donell <carlos@redhat.com> Reported-by: "H. J. Lu" <hjl.tools@gmail.com> Signed-off-by: Alistair Strachan <astrachan@google.com> Signed-off-by: Borislav Petkov <bp@suse.de> Tested-by: Laura Abbott <labbott@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Carlos O'Donell <carlos@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: kernel-team@android.com Cc: Laura Abbott <labbott@redhat.com> Cc: stable <stable@vger.kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: X86 ML <x86@kernel.org> Link: https://lkml.kernel.org/r/20181214223637.35954-1-astrachan@google.com Signed-off-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/x86/entry/vdso/Makefile | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -167,7 +167,8 @@ 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 #
| |