Hi,
We have caught bugs in kselftest suites on linux-next and on stable-RCs etc when using clang. There are two types of bugs (logs with clang-17 are attached.): As usually people use GCC, there are GCC-specific flags added to the Makefiles that clang doesn't recognize. For example: * clang: error: argument unused during compilation: '-pie' [-Werror,-Wunused-command-line-argument] * clang: error: unknown argument '-static-libasan'; did you mean '-static-libsan'? * clang: error: cannot specify -o when generating multiple output files
Clang has best static analysis tools. It is reporting static errors. For example: * test_execve.c:121:13: warning: variable 'have_outer_privilege' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] * test_execve.c:121:9: note: remove the 'if' if its condition is always true * test_memcontrol.c:727:6: warning: variable 'fd' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
We have found these issues through our new KernelCI system when enabling kselftest and clang there. The new system dashboard is a WIP, so It is not the web dashboard you are used-to with in KernelCI. We can show you ways of pulling the data if you are interest into.
Unless the above is some sort of false-positive or misconfiguration, it would be great to support clang for kselftests. What we can do from our side is that clang kselftests builds should be enabled on KernelCI to find and fix the errors. What is your stance about this?
Thanks, Usama
Thanks for the report. We've been tracking getting this working for a while: https://github.com/ClangBuiltLinux/linux/issues/1698. Other fires have continued to take priority.
On Thu, Apr 4, 2024 at 9:30 AM Muhammad Usama Anjum usama.anjum@collabora.com wrote:
Hi,
We have caught bugs in kselftest suites on linux-next and on stable-RCs etc when using clang. There are two types of bugs (logs with clang-17 are attached.): As usually people use GCC, there are GCC-specific flags added to the Makefiles that clang doesn't recognize. For example:
- clang: error: argument unused during compilation: '-pie'
[-Werror,-Wunused-command-line-argument]
- clang: error: unknown argument '-static-libasan'; did you mean
'-static-libsan'?
- clang: error: cannot specify -o when generating multiple output files
Clang has best static analysis tools. It is reporting static errors. For example:
- test_execve.c:121:13: warning: variable 'have_outer_privilege' is used
uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
- test_execve.c:121:9: note: remove the 'if' if its condition is always true
- test_memcontrol.c:727:6: warning: variable 'fd' is used uninitialized
whenever 'if' condition is true [-Wsometimes-uninitialized]
We have found these issues through our new KernelCI system when enabling kselftest and clang there. The new system dashboard is a WIP, so It is not the web dashboard you are used-to with in KernelCI. We can show you ways of pulling the data if you are interest into.
Unless the above is some sort of false-positive or misconfiguration, it would be great to support clang for kselftests. What we can do from our side is that clang kselftests builds should be enabled on KernelCI to find and fix the errors. What is your stance about this?
As with anything kernel related; help send patches for obvious fixes. Or provide steps to reproduce in https://github.com/ClangBuiltLinux/linux/issues/1698.
On 4/4/24 10:34, Nick Desaulniers wrote:
Thanks for the report. We've been tracking getting this working for a while: https://github.com/ClangBuiltLinux/linux/issues/1698. Other fires have continued to take priority.
On Thu, Apr 4, 2024 at 9:30 AM Muhammad Usama Anjum usama.anjum@collabora.com wrote:
Hi,
We have caught bugs in kselftest suites on linux-next and on stable-RCs etc when using clang. There are two types of bugs (logs with clang-17 are attached.): As usually people use GCC, there are GCC-specific flags added to the Makefiles that clang doesn't recognize. For example:
- clang: error: argument unused during compilation: '-pie'
[-Werror,-Wunused-command-line-argument]
- clang: error: unknown argument '-static-libasan'; did you mean
'-static-libsan'?
- clang: error: cannot specify -o when generating multiple output files
Clang has best static analysis tools. It is reporting static errors. For example:
- test_execve.c:121:13: warning: variable 'have_outer_privilege' is used
uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
- test_execve.c:121:9: note: remove the 'if' if its condition is always true
- test_memcontrol.c:727:6: warning: variable 'fd' is used uninitialized
whenever 'if' condition is true [-Wsometimes-uninitialized]
We have found these issues through our new KernelCI system when enabling kselftest and clang there. The new system dashboard is a WIP, so It is not the web dashboard you are used-to with in KernelCI. We can show you ways of pulling the data if you are interest into.
Unless the above is some sort of false-positive or misconfiguration, it would be great to support clang for kselftests. What we can do from our side is that clang kselftests builds should be enabled on KernelCI to find and fix the errors. What is your stance about this?
As with anything kernel related; help send patches for obvious fixes. Or provide steps to reproduce in https://github.com/ClangBuiltLinux/linux/issues/1698.
+1 on this. Please send patches to fixes as you find them. We have been taking fixes found by clang and -Wformat-security, -Werror checks.
thanks, -- Shuah
linux-kselftest-mirror@lists.linaro.org
-
Muhammad Usama Anjum -
Nick Desaulniers -
Shuah Khan