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From: Stefan Roesch <shr@devkernel.io>
To: kernel-team@fb.com
Cc: shr@devkernel.io, akpm@linux-foundation.org, david@redhat.com,
	hannes@cmpxchg.org, riel@surriel.com,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Carl Klemm <carl@uvos.xyz>
Subject: [PATCH v1 1/2] mm/ksm: support fork/exec for prctl
Date: Tue, 19 Sep 2023 13:51:57 -0700	[thread overview]
Message-ID: <20230919205158.1897353-2-shr@devkernel.io> (raw)
In-Reply-To: <20230919205158.1897353-1-shr@devkernel.io>

A process can enable KSM with the prctl system call. When the process is
forked the KSM flag is inherited by the child process. However if the
process is executing an exec system call directly after the fork, the
KSM setting is cleared. This patch addresses this problem.

Signed-off-by: Stefan Roesch <shr@devkernel.io>
Reported-by: Carl Klemm <carl@uvos.xyz>
---
 include/linux/sched/coredump.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/include/linux/sched/coredump.h b/include/linux/sched/coredump.h
index 0ee96ea7a0e9..205aa9917394 100644
--- a/include/linux/sched/coredump.h
+++ b/include/linux/sched/coredump.h
@@ -87,8 +87,11 @@ static inline int get_dumpable(struct mm_struct *mm)
 
 #define MMF_DISABLE_THP_MASK	(1 << MMF_DISABLE_THP)
 
+#define MMF_VM_MERGE_ANY	29
+#define MMF_VM_MERGE_ANY_MASK	(1 << MMF_VM_MERGE_ANY)
+
 #define MMF_INIT_MASK		(MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK |\
-				 MMF_DISABLE_THP_MASK | MMF_HAS_MDWE_MASK)
+				 MMF_DISABLE_THP_MASK | MMF_HAS_MDWE_MASK |\
+				 MMF_VM_MERGE_ANY_MASK)
 
-#define MMF_VM_MERGE_ANY	29
 #endif /* _LINUX_SCHED_COREDUMP_H */
-- 
2.39.3


  reply	other threads:[~2023-09-19 20:52 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-19 20:51 [PATCH v1 0/2] mm/ksm: add fork-exec support for prctl Stefan Roesch
2023-09-19 20:51 ` Stefan Roesch [this message]
2023-09-20 10:00   ` [PATCH v1 1/2] mm/ksm: support fork/exec " Carl Klemm
2023-09-20 13:11   ` David Hildenbrand
2023-09-20 16:29     ` Stefan Roesch
2023-09-19 20:51 ` [PATCH v1 2/2] mm/ksm: Test case for prctl fork/exec workflow Stefan Roesch
2023-09-20 13:16   ` David Hildenbrand
2023-09-20 18:57     ` Stefan Roesch

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