From: Alistair Strachan <[email protected]>
[ Upstream commit cd01544a268ad8ee5b1dfe42c4393f1095f86879 ]
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 <[email protected]>
Reported-by: Carlos O'Donell <[email protected]>
Reported-by: "H. J. Lu" <[email protected]>
Signed-off-by: Alistair Strachan <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Tested-by: Laura Abbott <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Carlos O'Donell <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: [email protected]
Cc: Laura Abbott <[email protected]>
Cc: stable <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: X86 ML <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
---
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 839015f1b0de..ab7f730cf7f2 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -182,7 +182,8 @@ 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
#
--
2.20.1
