Commit-ID: cd01544a268ad8ee5b1dfe42c4393f1095f86879 Gitweb: https://git.kernel.org/tip/cd01544a268ad8ee5b1dfe42c4393f1095f86879 Author: Alistair Strachan <astrachan@xxxxxxxxxx> AuthorDate: Fri, 14 Dec 2018 14:36:37 -0800 Committer: Borislav Petkov <bp@xxxxxxx> CommitDate: Sat, 15 Dec 2018 11:37:51 +0100 x86/vdso: Pass --eh-frame-hdr to the linker 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@xxxxxxxxxx> Reported-by: Carlos O'Donell <carlos@xxxxxxxxxx> Reported-by: "H. J. Lu" <hjl.tools@xxxxxxxxx> Signed-off-by: Alistair Strachan <astrachan@xxxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Tested-by: Laura Abbott <labbott@xxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Carlos O'Donell <carlos@xxxxxxxxxx> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Joel Fernandes <joel@xxxxxxxxxxxxxxxxx> Cc: kernel-team@xxxxxxxxxxx Cc: Laura Abbott <labbott@xxxxxxxxxx> Cc: stable <stable@xxxxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: X86 ML <x86@xxxxxxxxxx> Link: https://lkml.kernel.org/r/20181214223637.35954-1-astrachan@xxxxxxxxxx --- 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 0624bf2266fd..5bfe2243a08f 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 #
