Re: [PATCH v2 21/40] mm/gup: error out early on !VMA_MAYREAD_BIT VMAs
From: sashiko-bot@kernel.org
Date: 2026-09-14 20:33:27
Also in:
bpf, dri-devel, kvm, kvmarm, linux-perf-users, linux-rdma, linux-s390, linux-scsi, selinux
When populating a VMA range via the aptly named populate_vma_page_range() an unreadable VMA will always eventually fail with -EFAULT. That a VMA is accessible is always checked, however VMA_MAYREAD_BIT is not. All user mappings always have VMA_MAYREAD_BIT set, so this check only impacts kernel mappings. It is implemented specifically to disallow population of uprobes XOL mappings which are exec-only. A nasty interaction with these mappings may occur if they are mlocked, so actively disallow this early. This allows a subsequent commit to remove the VM_IO check in __mm_populate() which otherwise requires non-MMIO mappings to be wrongly flagged simply as a workaround. Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Sashiko has reviewed this patch and found no issues. It looks great! -- Sashiko AI review · https://sashiko.dev/#/patchset/20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org?part=21