Messages in this thread | | | Subject | Re: LZ4 decompressor broken on ARM due to missing strchrnul() string traverse in cpumask_parse" | From | Rasmus Villemoes <> | Date | Tue, 28 May 2019 13:33:12 +0200 |
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On 28/05/2019 13.04, Sebastian Andrzej Siewior wrote: > | CC arch/arm/boot/compressed/decompress.o > |In file included from include/linux/mm_types_task.h:14, > | from include/linux/mm_types.h:5, > | from include/linux/mmzone.h:21, > | from include/linux/gfp.h:6, > | from include/linux/umh.h:4, > | from include/linux/kmod.h:22, > | from include/linux/module.h:13, > | from arch/arm/boot/compressed/../../../../lib/lz4/lz4_decompress.c:39, > | from arch/arm/boot/compressed/../../../../lib/decompress_unlz4.c:13, > | from arch/arm/boot/compressed/decompress.c:55: > |include/linux/cpumask.h: In function ‘cpumask_parse’: > |include/linux/cpumask.h:636:21: error: implicit declaration of function ‘strchrnul’; did you mean ‘strchr’? [-Werror=implicit-function-declaration] > | unsigned int len = strchrnul(buf, '\n') - buf; > | ^~~~~~~~~ > | strchr > |include/linux/cpumask.h:636:42: error: invalid operands to binary - (have ‘int’ and ‘const char *’) > | unsigned int len = strchrnul(buf, '\n') - buf; > | ~~~~~~~~~~~~~~~~~~~~ ^ > |cc1: some warnings being treated as errors > > 3713a4e1fdb8da86f96a3e770b08e278d97529b4 is the first bad commit > commit 3713a4e1fdb8da86f96a3e770b08e278d97529b4 > Author: Yury Norov <ynorov@marvell.com> > Date: Tue May 14 15:44:46 2019 -0700 > > include/linux/cpumask.h: fix double string traverse in cpumask_parse > > cpumask_parse() finds first occurrence of either or strchr() and > strlen(). We can do it better with a single call of strchrnul(). > > [akpm@linux-foundation.org: remove unneeded cast] > Link: http://lkml.kernel.org/r/20190409204208.12190-1-ynorov@marvell.com > Signed-off-by: Yury Norov <ynorov@marvell.com> > Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org> > Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> > > :040000 040000 f20d8a9ec1755b3981520ecf015248f6a0d9f116 db67caf64f99a9be808cd73e413c106c5aee15b7 M include > > This commit is v5.2-rc1~62^2~49. > How do we deal with this one?
Urgh. The problem is really in arch/arm/boot/compressed/decompress.c which does
#define _LINUX_STRING_H_
preventing linux/string.h from providing strchrnul. It also #includes asm/string.h, which for arm has a declaration of strchr(), explaining why this didn't use to fail.
However, the solution is also in the same file, it already has a section
/* Not needed, but used in some headers pulled in by decompressors */ extern char * strstr(const char * s1, const char *s2); extern size_t strlen(const char *s); extern int memcmp(const void *cs, const void *ct, size_t count);
so just add another declaration to that list - I strongly assume we won't get a link failure since I find it hard to believe the decompressor would actually call cpumask_parse...
I'm wondering why this wasn't caught by 0day and/or while in -next?
Rasmus
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