linux/arch/x86/entry/vdso
Alistair Strachan cd01544a26 x86/vdso: Pass --eh-frame-hdr to the linker
Commit

  379d98ddf4 ("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: 379d98ddf4 ("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
2018-12-15 11:37:51 +01:00
..
vdso32 x86: Add build salt to the vDSO 2018-07-18 01:18:05 +09:00
.gitignore
checkundef.sh
Makefile x86/vdso: Pass --eh-frame-hdr to the linker 2018-12-15 11:37:51 +01:00
vclock_gettime.c x86/vdso: Rearrange do_hres() to improve code generation 2018-10-05 21:03:23 +02:00
vdso2c.c x86: Use ARRAY_SIZE 2017-10-19 16:15:47 +02:00
vdso2c.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vdso32-setup.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vdso-layout.lds.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vdso-note.S x86: Add build salt to the vDSO 2018-07-18 01:18:05 +09:00
vdso.lds.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vdsox32.lds.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vgetcpu.c x86/fsgsbase/64: Clean up various details 2018-10-08 10:45:04 +02:00
vma.c x86: convert vdso to use vm_fault_t 2018-10-26 16:25:19 -07:00