tree c8a3610e216552dd488fb739beee072d115e3b82
parent a9bc15cb1cbd62b498b55958e92a90d0ea52a4b8
author Jinjiang Tu <tujinjiang@huawei.com> 1711624208 +0800
committer Andrew Morton <akpm@linux-foundation.org> 1714103789 -0700

mm/ksm: fix ksm exec support for prctl

Patch series "mm/ksm: fix ksm exec support for prctl", v4.

commit 3c6f33b7273a ("mm/ksm: support fork/exec for prctl") inherits
MMF_VM_MERGE_ANY flag when a task calls execve().  However, it doesn't
create the mm_slot, so ksmd will not try to scan this task.  The first
patch fixes the issue.

The second patch refactors to prepare for the third patch.  The third
patch extends the selftests of ksm to verfity the deduplication really
happens after fork/exec inherits ths KSM setting.


This patch (of 3):

commit 3c6f33b7273a ("mm/ksm: support fork/exec for prctl") inherits
MMF_VM_MERGE_ANY flag when a task calls execve().  Howerver, it doesn't
create the mm_slot, so ksmd will not try to scan this task.

To fix it, allocate and add the mm_slot to ksm_mm_head in __bprm_mm_init()
when the mm has MMF_VM_MERGE_ANY flag.

Link: https://lkml.kernel.org/r/20240328111010.1502191-1-tujinjiang@huawei.com
Link: https://lkml.kernel.org/r/20240328111010.1502191-2-tujinjiang@huawei.com
Fixes: 3c6f33b7273a ("mm/ksm: support fork/exec for prctl")
Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Stefan Roesch <shr@devkernel.io>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>