gcov: Disable gcov build with GCC 10

GCOV built with GCC 10 doesn't initialize n_function variable.  This
produces different kernel panics as was seen by Colin in Ubuntu and me
in FC 32.

As a workaround, let's disable GCOV build for broken GCC 10 version.

Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1891288
Link: https://lore.kernel.org/lkml/20200827133932.3338519-1-leon@kernel.org
Link: https://lore.kernel.org/lkml/CAHk-=whbijeSdSvx-Xcr0DPMj0BiwhJ+uiNnDSVZcr_h_kg7UA@mail.gmail.com/
Cc: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/gcov/Kconfig b/kernel/gcov/Kconfig
index 3110c77..bb4b680 100644 (file)
--- a/kernel/gcov/Kconfig
+++ b/kernel/gcov/Kconfig
@@ -4,6 +4,7 @@ menu "GCOV-based kernel profiling"
 config GCOV_KERNEL
        bool "Enable gcov-based kernel profiling"
        depends on DEBUG_FS
+       depends on !CC_IS_GCC || GCC_VERSION < 100000
        select CONSTRUCTORS if !UML
        default n
        help