4.19-stable review patch. If anyone has any objections, please let me know.
------------------ From: Alistair Strachan <[email protected]> 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 <[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: Greg Kroah-Hartman <[email protected]> --- 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 @@ -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 #
