The patch titled
Subject: kernel/fork: convert vma assignment to a memcpy
has been added to the -mm mm-unstable branch. Its filename is
kernel-fork-convert-vma-assignment-to-a-memcpy.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kernel-fork-convert-vma-assignment-to-a-memcpy.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Subject: kernel/fork: convert vma assignment to a memcpy
Date: Wed, 25 Jan 2023 15:35:48 -0800
Patch series "introduce vm_flags modifier functions", v3.
This patchset was originally published as a part of per-VMA locking [1] and
was split after suggestion that it's viable on its own and to facilitate
the review process. It is now a preprequisite for the next version of per-VMA
lock patchset, which reuses vm_flags modifier functions to lock the VMA when
vm_flags are being updated.
VMA vm_flags modifications are usually done under exclusive mmap_lock
protection because this attrubute affects other decisions like VMA merging
or splitting and races should be prevented. Introduce vm_flags modifier
functions to enforce correct locking.
This patch (of 7):
Convert vma assignment in vm_area_dup() to a memcpy() to prevent compiler
errors when we add a const modifier to vma->vm_flags.
Link: https://lkml.kernel.org/r/20230125233554.153109-2-surenb@xxxxxxxxxx
Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/kernel/fork.c~kernel-fork-convert-vma-assignment-to-a-memcpy
+++ a/kernel/fork.c
@@ -472,7 +472,7 @@ struct vm_area_struct *vm_area_dup(struc
* orig->shared.rb may be modified concurrently, but the clone
* will be reinitialized.
*/
- *new = data_race(*orig);
+ memcpy(new, orig, sizeof(*new));
INIT_LIST_HEAD(&new->anon_vma_chain);
dup_anon_vma_name(orig, new);
}
_
Patches currently in -mm which might be from surenb@xxxxxxxxxx are
kernel-fork-convert-vma-assignment-to-a-memcpy.patch
mm-introduce-vma-vm_flags-wrapper-functions.patch
mm-replace-vm_locked_clear_mask-with-vm_locked_mask.patch
mm-replace-vma-vm_flags-direct-modifications-with-modifier-calls.patch
mm-replace-vma-vm_flags-indirect-modification-in-ksm_madvise.patch
mm-introduce-mod_vm_flags_nolock-and-use-it-in-untrack_pfn.patch
mm-export-dump_mm.patch
