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Fri, 11 Sep 2026 07:59:19 +0000 X-Mizu-Trace-ID: 45b1a7c312529d85 X-Migadu-Flow: FLOW_OUT From: Ye Liu To: Miaohe Lin , Andrew Morton Cc: Ye Liu , Michal Hocko , Lorenzo Stoakes , SJ Park , Gregory Price , peterz@infradead.org, paulmck@kernel.org, mingo@redhat.com, rostedt@goodmis.org, jpoimboe@kernel.org, mic@digikod.net, oleg@redhat.com, tglx@kernel.org, david@kernel.org, nao.horiguchi@gmail.com, rafael@kernel.org, gnoack3000@gmail.com, rientjes@google.com, shakeel.butt@linux.dev, xu.xin16@zte.com.cn, chengming.zhou@linux.dev, will@kernel.org, boqun@kernel.org, frederic@kernel.org, neeraj.upadhyay@kernel.org, joelagnelf@nvidia.com, josh@joshtriplett.org, urezki@gmail.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, tony.luck@intel.com, reinette.chatre@intel.com, x86@kernel.org, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, pavel@kernel.org, lance.yang@linux.dev, mhiramat@kernel.org, pmladek@suse.com, longman@redhat.com, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, qiang.zhang@linux.dev, dietmar.eggemann@arm.com, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, kprateek.nayak@amd.com, mark.rutland@arm.com, Dave.Martin@arm.com, james.morse@arm.com, babu.moger@amd.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, rcu@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v3 04/15] mm/memory-failure: convert process iterator to for_each_process_rculock Date: Fri, 11 Sep 2026 15:57:49 +0800 Message-Id: <20260911075800.491472-5-ye.liu@linux.dev> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20260911075800.491472-1-ye.liu@linux.dev> References: <20260911075800.491472-1-ye.liu@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 5D5C140002 X-Stat-Signature: j6r7cfpkyd7y99dzxgqjfsy6q4oai3uo X-Rspam-User: X-HE-Tag: 1789113561-388478 X-HE-Meta: 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 GRjOtKmH 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Ye Liu Replace the manual rcu_read_lock()/rcu_read_unlock() pairs combined with for_each_process() loop in mm/memory-failure.c with for_each_process_rculock(), which scopes the RCU read lock to the loop body via scoped_guard(rcu). In collect_procs_file(), the page_pgoff() call now falls outside the RCU read-side critical section. This is safe because page_pgoff() only reads folio->index and does not traverse any RCU-protected structures. Signed-off-by: Ye Liu Acked-by: Michal Hocko Acked-by: Miaohe Lin Reviewed-by: Lorenzo Stoakes (ARM) Reviewed-by: SJ Park Reviewed-by: Gregory Price (Meta) --- Changes in v2: - Rename *_rcu to *_rculock - Clarify page_pgoff() safety outside RCU lock (SJ Park) mm/memory-failure.c | 16 ++++------------ 1 file changed, 4 insertions(+), 12 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index a8b03e2920ba..7d93deb1f7b3 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -555,8 +555,7 @@ static void collect_procs_anon(const struct folio *folio, return; pgoff = page_pgoff(folio, page); - rcu_read_lock(); - for_each_process(tsk) { + for_each_process_rculock(tsk) { struct vm_area_struct *vma; struct anon_vma_chain *vmac; struct task_struct *t = task_early_kill(tsk, force_early); @@ -572,7 +571,6 @@ static void collect_procs_anon(const struct folio *folio, add_to_kill_anon_file(t, page, vma, to_kill, addr); } } - rcu_read_unlock(); anon_vma_unlock_read(av); } @@ -589,9 +587,8 @@ static void collect_procs_file(const struct folio *folio, pgoff_t pgoff; i_mmap_lock_read(mapping); - rcu_read_lock(); pgoff = page_pgoff(folio, page); - for_each_process(tsk) { + for_each_process_rculock(tsk) { struct task_struct *t = task_early_kill(tsk, force_early); unsigned long addr; @@ -611,7 +608,6 @@ static void collect_procs_file(const struct folio *folio, add_to_kill_anon_file(t, page, vma, to_kill, addr); } } - rcu_read_unlock(); i_mmap_unlock_read(mapping); } @@ -635,8 +631,7 @@ static void collect_procs_fsdax(const struct page *page, struct task_struct *tsk; i_mmap_lock_read(mapping); - rcu_read_lock(); - for_each_process(tsk) { + for_each_process_rculock(tsk) { struct task_struct *t = tsk; /* @@ -653,7 +648,6 @@ static void collect_procs_fsdax(const struct page *page, add_to_kill_fsdax(t, page, vma, to_kill, pgoff); } } - rcu_read_unlock(); i_mmap_unlock_read(mapping); } #endif /* CONFIG_FS_DAX */ @@ -2288,8 +2282,7 @@ static void collect_procs_pfn(struct pfn_address_space *pfn_space, struct address_space *mapping = pfn_space->mapping; i_mmap_lock_read(mapping); - rcu_read_lock(); - for_each_process(tsk) { + for_each_process_rculock(tsk) { struct task_struct *t = tsk; t = task_early_kill(tsk, true); @@ -2303,7 +2296,6 @@ static void collect_procs_pfn(struct pfn_address_space *pfn_space, add_to_kill_pgoff(t, vma, to_kill, pgoff); } } - rcu_read_unlock(); i_mmap_unlock_read(mapping); } -- 2.25.1