Messages in this thread Patch in this message | | | From | Ard Biesheuvel <> | Subject | [PATCH 5/7] x86/boot: Mark global variables as static | Date | Sun, 17 May 2020 14:57:52 +0200 |
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From: Arvind Sankar <nivedita@alum.mit.edu>
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@fireburn.co.uk> Tested-by: Mike Lothian <mike@fireburn.co.uk> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200511225849.1311869-1-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org> --- 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
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