Re: [RFC PATCH 2/3] x86/mm: make sure LAM is up-to-date during context switching

[Yosry Ahmed <yosryahmed@google.com>]

On Mon, Mar 11, 2024 at 09:09:34AM +0300, Dan Carpenter wrote:
> Hi Yosry,
> 
> [This is a private test report for your RFC patch.]
> kernel test robot noticed the following build warnings:
> 
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/Yosry-Ahmed/x86-mm-fix-LAM-cr3-mask-inconsistency-during-context-switch/20240307-214052
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
> patch link:    https://lore.kernel.org/r/20240307133916.3782068-3-yosryahmed%40google.com
> patch subject: [RFC PATCH 2/3] x86/mm: make sure LAM is up-to-date during context switching
> config: x86_64-randconfig-161-20240310 (https://download.01.org/0day-ci/archive/20240310/202403101713.eM4pyFpc-lkp@intel.com/config)
> compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> | Closes: https://lore.kernel.org/r/202403101713.eM4pyFpc-lkp@intel.com/
> 
> smatch warnings:
> arch/x86/mm/tlb.c:655 switch_mm_irqs_off() error: uninitialized symbol 'new_asid'.

Thanks for reporting this. I think it may be a false positive, but this
code chunk will be dropped in the next version anyway.