Messages in this thread | | | Subject | Re: [PATCH 1/2] mm/uffd: Fix pte marker when fork() without fork event | From | Miaohe Lin <> | Date | Sat, 17 Dec 2022 10:59:06 +0800 |
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On 2022/12/15 4:04, Peter Xu wrote: > When fork(), dst_vma is not guaranteed to have VM_UFFD_WP even if src may > have it and has pte marker installed. The warning is improper along with > the comment. The right thing is to inherit the pte marker when needed, or > keep the dst pte empty. > > A vague guess is this happened by an accident when there's the prior patch > to introduce src/dst vma into this helper during the uffd-wp feature got > developed and I probably messed up in the rebase, since if we replace > dst_vma with src_vma the warning & comment it all makes sense too. > > Hugetlb did exactly the right here (copy_hugetlb_page_range()). Fix the > general path. > > Reproducer: > > https://github.com/xupengfe/syzkaller_logs/blob/main/221208_115556_copy_page_range/repro.c > > Cc: <stable@vger.kernel.org> # 5.19+ > Fixes: c56d1b62cce8 ("mm/shmem: handle uffd-wp during fork()") > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216808 > Reported-by: Pengfei Xu <pengfei.xu@intel.com> > Signed-off-by: Peter Xu <peterx@redhat.com>
Looks good to me. Thanks. Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Thanks, Miaohe Lin
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