From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-70.mta0.migadu.com [91.218.175.70]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 60366443AA7 for ; Mon, 7 Sep 2026 08:14:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.70 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788768885; cv=none; b=d+sIW6c7AMpxaLce+GXzCmjp+hhgt/EqraNkWmlYiSuGGj7uSe5xbA4ePdCH0LS9DgHK5jwOg9r6QKEMJ0q+JpEEm8jFpH6cwFAljA/D738RBUtV6JXf0STqDMUFtocVZ7DZ+lS9n4ohWTzvCdVfJxtmYES6L2vq3pGpdJAkYOI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788768885; c=relaxed/simple; bh=DbvxqJsFC8I1jdIyCJVYNExbjeNMqAcKd+QJ2gOnSsI=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=UoNqtePEkUW6o4BRvzUZ5f+EBvWL+f6R59ScU8zUoCtZFB8fBDStJ6qssmbri2a9qi/0pKBK7Uykw+ExmLTGieab3raFTkEjQEglpgmw7WpwZ0lzZmSQH5EQcH1TgvseGoPi+b7qscMr5dwjIxdFXffWcxPL+30Q9XNdTcj0fPw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=QsEv9tJx; arc=none smtp.client-ip=91.218.175.70 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="QsEv9tJx" X-Envelope-To: linux-security-module@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=DbvxqJsFC8I1jdIyCJVYNExbjeNMqAcKd+QJ2gOnSsI=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1788768881; v=1; x=1789373681; b=QsEv9tJx+htfHkVlXBVh0jqEMfIZhKIiV4pwh/o31FxltAeubh5Va9WuiRzlYNnLS4RGXW4x 3HwvGovI4EWm2dTeyV1ldFWXVea0E0hYEE3zKgj/wnYlr9LKJjErOiTjJr0WPsIeC7AFEexLstq DOoFXOu/yiKrsNroNAKn+bhU= X-Envelope-To: linux-security-module@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id a8a672054efb182f; Mon, 07 Sep 2026 08:14:40 +0000 X-Mizu-Trace-ID: a8a672054efb182f X-Migadu-Flow: FLOW_OUT From: Ye Liu To: Miaohe Lin , Andrew Morton Cc: Ye Liu , Michal Hocko , 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, ljs@kernel.org, sj@kernel.org, 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 v2 4/8] mm/memory-failure: convert process iterator to for_each_process_rculock Date: Mon, 7 Sep 2026 16:13:30 +0800 Message-Id: <20260907081334.1152889-5-ye.liu@linux.dev> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20260907081334.1152889-1-ye.liu@linux.dev> References: <20260907081334.1152889-1-ye.liu@linux.dev> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 --- 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