From: Arvind Sankar <nivedita@xxxxxxxxxxxx>
Mike Lothian reports that after commit
964124a97b97 ("efi/x86: Remove extra headroom for setup block")
gcc 10.1.0 fails with
HOSTCC arch/x86/boot/tools/build
/usr/lib/gcc/x86_64-pc-linux-gnu/10.1.0/../../../../x86_64-pc-linux-gnu/bin/ld:
error: linker defined: multiple definition of '_end'
/usr/lib/gcc/x86_64-pc-linux-gnu/10.1.0/../../../../x86_64-pc-linux-gnu/bin/ld:
/tmp/ccEkW0jM.o: previous definition here
collect2: error: ld returned 1 exit status
make[1]: *** [scripts/Makefile.host:103: arch/x86/boot/tools/build] Error 1
make: *** [arch/x86/Makefile:303: bzImage] Error 2
The issue is with the _end variable that was added, to hold the end of
the compressed kernel from zoffsets.h (ZO__end). The name clashes with
the linker-defined _end symbol that indicates the end of the build
program itself.
Even when there is no compile-time error, this causes build to use
memory past the end of its .bss section.
To solve this, mark _end as static, and for symmetry, mark the rest of
the variables that keep track of symbols from the compressed kernel as
static as well.
Fixes: 964124a97b97 ("efi/x86: Remove extra headroom for setup block")
Reported-by: Mike Lothian <mike@xxxxxxxxxxxxxx>
Tested-by: Mike Lothian <mike@xxxxxxxxxxxxxx>
Signed-off-by: Arvind Sankar <nivedita@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20200511225849.1311869-1-nivedita@xxxxxxxxxxxx
Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
---
arch/x86/boot/tools/build.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/arch/x86/boot/tools/build.c b/arch/x86/boot/tools/build.c
index 8f8c8e386cea..c8b8c1a8d1fc 100644
--- a/arch/x86/boot/tools/build.c
+++ b/arch/x86/boot/tools/build.c
@@ -59,14 +59,14 @@ u8 buf[SETUP_SECT_MAX*512];
#define PECOFF_COMPAT_RESERVE 0x0
#endif
-unsigned long efi32_stub_entry;
-unsigned long efi64_stub_entry;
-unsigned long efi_pe_entry;
-unsigned long efi32_pe_entry;
-unsigned long kernel_info;
-unsigned long startup_64;
-unsigned long _ehead;
-unsigned long _end;
+static unsigned long efi32_stub_entry;
+static unsigned long efi64_stub_entry;
+static unsigned long efi_pe_entry;
+static unsigned long efi32_pe_entry;
+static unsigned long kernel_info;
+static unsigned long startup_64;
+static unsigned long _ehead;
+static unsigned long _end;
/*----------------------------------------------------------------------*/
--
2.17.1
