Commit-ID: 6583327c4dd55acbbf2a6f25e775b28b3abf9a42 Gitweb: http://git.kernel.org/tip/6583327c4dd55acbbf2a6f25e775b28b3abf9a42 Author: Peter Oberparleiter <oberpar@xxxxxxxxxxxxxxxxxx> AuthorDate: Thu, 6 Feb 2014 15:58:20 +0100 Committer: H. Peter Anvin <hpa@xxxxxxxxx> CommitDate: Thu, 6 Feb 2014 07:15:20 -0800 x86, hweight: Fix BUG when booting with CONFIG_GCOV_PROFILE_ALL=y Commit d61931d89b, "x86: Add optimized popcnt variants" introduced compile flag -fcall-saved-rdi for lib/hweight.c. When combined with options -fprofile-arcs and -O2, this flag causes gcc to generate broken constructor code. As a result, a 64 bit x86 kernel compiled with CONFIG_GCOV_PROFILE_ALL=y prints message "gcov: could not create file" and runs into sproadic BUGs during boot. The gcc people indicate that these kinds of problems are endemic when using ad hoc calling conventions. It is therefore best to treat any file compiled with ad hoc calling conventions as an isolated environment and avoid things like profiling or coverage analysis, since those subsystems assume a "normal" calling conventions. This patch avoids the bug by excluding lib/hweight.o from coverage profiling. Reported-by: Meelis Roos <mroos@xxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Peter Oberparleiter <oberpar@xxxxxxxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/52F3A30C.7050205@xxxxxxxxxxxxxxxxxx Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> --- lib/Makefile | 1 + 1 file changed, 1 insertion(+) diff --git a/lib/Makefile b/lib/Makefile index a459c31..04944e9 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -43,6 +43,7 @@ obj-$(CONFIG_HAS_IOMEM) += iomap_copy.o devres.o obj-$(CONFIG_CHECK_SIGNATURE) += check_signature.o obj-$(CONFIG_DEBUG_LOCKING_API_SELFTESTS) += locking-selftest.o +GCOV_PROFILE_hweight.o := n CFLAGS_hweight.o = $(subst $(quote),,$(CONFIG_ARCH_HWEIGHT_CFLAGS)) obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html