On Tue, Jun 16 2020 at 09:05AM -0700, Paul E. McKenney wrote:
On Tue, Jun 16, 2020 at 11:49:24AM +0200, Marco Elver wrote:
We need to pass the arguments provided to --kmake-arg to all make invocations. In particular, the make invocations generating the configs need to see the final make arguments, e.g. if config variables depend on particular variables that are passed to make.
For example, when using '--kcsan --kmake-arg CC=clang-11', we would lose CONFIG_KCSAN=y due to 'make oldconfig' not seeing that we want to use a compiler that supports KCSAN.
Signed-off-by: Marco Elver elver@google.com
Queued and pushed, thank you!
Would the following patch make sense, at least until such time as some other compiler supports KCSAN?
Thanx, Paul
commit 88bcaa730b6d40ddf69b09ed6f0a14803d087d99 Author: Paul E. McKenney paulmck@kernel.org Date: Tue Jun 16 09:02:34 2020 -0700
torture: Make --kcsan default to using Clang 11Currently, Clang 11 is the only compiler that can support KCSAN. Therefore, as a convenience to the KCSAN user, this commit causes --kcsan to specify Clang 11 unless a "CC=" argument was already specified via the --kmake-arg argument.
As soon as more compilers support KCSAN (e.g. clang-12, etc...) we run the risk of actually inconveniencing ourselves more because then we really need to say '--kmake-arg CC=clang-1X' to not use the old compiler. Or revert this in time.
My command-line looks more like this right now:
kvm.sh ... --kmake-arg "CC="${HOME}/local/<gcc-or-clang>-11.kcsan/local/bin/<gcc-or-clang>" ...
I think the safer alternative would be to error if CONFIG_KCSAN=y is not in the config, and simply suggest "Did you forget to switch your compiler with '--kmake-arg CC=<cc-that-supports-kcsan>'?" (of course, a 'gcc' in $PATH that supports KCSAN would also be fine -- see below). Eventually, when the default compilers support KCSAN, this will resolve itself gracefully.
Also, I'm going to send a series later this week to re-enable GCC support. ;-)
Thanks, -- Marco