Re: [PATCH 2/9] hugetlb/userfaultfd: Forbid huge pmd sharing when uffd enabled
From: Peter Xu <peterx@redhat.com>
Date: 2021-01-21 18:55:20
Also in:
linux-fsdevel, lkml
On Fri, Jan 15, 2021 at 11:04:44AM -0800, Axel Rasmussen wrote: [...]
quoted hunk ↗ jump to hunk
@@ -947,4 +948,15 @@ static inline __init void hugetlb_cma_check(void) } #endif +static inline bool want_pmd_share(struct vm_area_struct *vma) +{ +#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE + if (uffd_disable_huge_pmd_share(vma)) + return false; + return true; +#else + return false; +#endif +}
I got syzbot complains about this chunk when compile some other archs outside x86, probably because CONFIG_ARCH_WANT_HUGE_PMD_SHARE can be defined without CONFIG_USERFAULTFD. I don't know why it didn't complain here, so just a fyi that I've pushed some new version to the online repo so that they should have been fixed. For example, for this patch: https://github.com/xzpeter/linux/commit/0fd01db2c9ac3ab8600f3f7df23cf28fddcfee1b static inline bool want_pmd_share(struct vm_area_struct *vma) { #ifdef CONFIG_USERFAULTFD if (uffd_disable_huge_pmd_share(vma)) return false; #endif #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE return true; #else return false; #endif } Thanks, -- Peter Xu