From: David Hildenbrand <david@redhat.com>
To: Kalesh Singh <kaleshsingh@google.com>
Cc: akpm@linux-foundation.org, minchan@kernel.org,
lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com,
rppt@kernel.org, pfalcato@suse.de, kernel-team@android.com,
android-mm@google.com, Alexander Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
Kees Cook <kees@kernel.org>, Vlastimil Babka <vbabka@suse.cz>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>,
Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
Valentin Schneider <vschneid@redhat.com>,
Jann Horn <jannh@google.com>, Shuah Khan <shuah@kernel.org>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org,
linux-kselftest@vger.kernel.org
Subject: Re: [PATCH v2 6/7] mm: add assertion for VMA count limit
Date: Wed, 17 Sep 2025 20:34:10 +0200 [thread overview]
Message-ID: <322fd5d2-d7f4-40d8-8a06-6e7c5e9ef180@redhat.com> (raw)
In-Reply-To: <CAC_TJvctkyGEKv8mVE83D2DzCd-HiXh9co_DuZfwuF86FJoiJw@mail.gmail.com>
>> Can't that fire when changing the max count from user space at just the
>> wrong time?
>
> You are right: technically it's possible if it was raised between the
> time of checking and when the new VMA is added.
>
>>
>> I assume we'll have to tolerated that and might just want to drop this
>> patch from the series.
>>
>
> It is compiled out in !CONFIG_VM_DEBUG builds, would we still want to drop it?
Due to the racy nature I think any kinds of assertions would be wrong.
Without any such races possible I would agree that the checks would be
nice to have.
--
Cheers
David / dhildenb
next prev parent reply other threads:[~2025-09-17 18:34 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-15 16:36 [PATCH v2 0/7] vma count: fixes, test and improvements Kalesh Singh
2025-09-15 16:36 ` [PATCH v2 1/7] mm: fix off-by-one error in VMA count limit checks Kalesh Singh
2025-09-15 22:36 ` Andrew Morton
2025-09-16 14:20 ` Jonathan Corbet
2025-09-17 1:16 ` Andrew Morton
2025-09-16 9:45 ` Pedro Falcato
2025-09-17 7:44 ` SeongJae Park
2025-09-17 10:52 ` David Hildenbrand
2025-09-18 11:31 ` Pedro Falcato
2025-09-18 13:53 ` Lorenzo Stoakes
2025-09-15 16:36 ` [PATCH v2 2/7] mm/selftests: add max_vma_count tests Kalesh Singh
2025-09-17 10:58 ` David Hildenbrand
2025-09-17 16:49 ` Kalesh Singh
2025-09-18 14:42 ` Lorenzo Stoakes
2025-09-18 16:21 ` Kalesh Singh
2025-09-15 16:36 ` [PATCH v2 3/7] mm: introduce vma_count_remaining() Kalesh Singh
2025-09-17 13:38 ` David Hildenbrand
2025-09-17 17:10 ` Kalesh Singh
2025-09-18 13:20 ` Lorenzo Stoakes
2025-09-18 13:26 ` Lorenzo Stoakes
2025-09-18 14:31 ` Lorenzo Stoakes
2025-09-18 15:52 ` Kalesh Singh
2025-09-15 16:36 ` [PATCH v2 4/7] mm: rename mm_struct::map_count to vma_count Kalesh Singh
2025-09-17 13:41 ` David Hildenbrand
2025-09-18 11:46 ` Pedro Falcato
2025-09-18 14:48 ` Lorenzo Stoakes
2025-09-15 16:36 ` [PATCH v2 5/7] mm: harden vma_count against direct modification Kalesh Singh
2025-09-18 14:52 ` Lorenzo Stoakes
2025-09-18 15:43 ` Kalesh Singh
2025-09-15 16:36 ` [PATCH v2 6/7] mm: add assertion for VMA count limit Kalesh Singh
2025-09-17 13:44 ` David Hildenbrand
2025-09-17 17:22 ` Kalesh Singh
2025-09-17 18:34 ` David Hildenbrand [this message]
2025-09-17 20:31 ` Kalesh Singh
2025-09-18 11:48 ` Pedro Falcato
2025-09-18 13:30 ` Lorenzo Stoakes
2025-09-15 16:36 ` [PATCH v2 7/7] mm/tracing: introduce max_vma_count_exceeded trace event Kalesh Singh
2025-09-15 23:41 ` Steven Rostedt
2025-09-16 1:19 ` Kalesh Singh
2025-09-16 15:52 ` Steven Rostedt
2025-09-16 17:36 ` Kalesh Singh
2025-09-16 17:48 ` Steven Rostedt
2025-09-16 17:57 ` Kalesh Singh
2025-09-16 18:02 ` Steven Rostedt
2025-09-16 18:23 ` Kalesh Singh
2025-09-16 18:51 ` Steven Rostedt
2025-09-16 20:08 ` Kalesh Singh
2025-09-18 11:38 ` Pedro Falcato
2025-09-18 14:48 ` Steven Rostedt
2025-09-18 13:42 ` Lorenzo Stoakes
2025-09-18 13:51 ` Lorenzo Stoakes
2025-09-18 15:55 ` Kalesh Singh
2025-09-15 22:34 ` [PATCH v2 0/7] vma count: fixes, test and improvements Andrew Morton
2025-09-15 23:10 ` Kalesh Singh
2025-09-16 0:05 ` Andrew Morton
2025-09-16 1:23 ` Kalesh Singh
2025-09-16 10:12 ` Lorenzo Stoakes
2025-09-16 17:47 ` Kalesh Singh
2025-09-17 2:16 ` Andrew Morton
2025-09-17 5:36 ` Lorenzo Stoakes
2025-09-17 23:32 ` Andrew Morton
2025-09-18 10:29 ` Lorenzo Stoakes
2025-09-18 12:07 ` David Hildenbrand
2025-09-18 12:49 ` Lorenzo Stoakes
2025-09-18 20:59 ` Andrew Morton
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