From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-130.mta0.migadu.com [91.218.175.130]) (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 2843945D902 for ; Fri, 11 Sep 2026 07:59:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.130 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789113564; cv=none; b=JRTGdjqAjQ27b7plgVihtYQy1h4/nSsDwgk452B6pQhh2p+QLKW0K3f4CpAWFmv2oBzQrrjnkttrzT9ZyWSBoppaRwu9L1odSfMXdrLvsE6Wehcb7Bn8p0h0ndmo/06ypjUZa2Z06RwaY8wsTi2kXrl30n+ahRYcXkjJ86gOCoQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789113564; c=relaxed/simple; bh=0l6apGFhEMmIZSU/2v9JnhqbwzgAnZO6eQl/TQrNqjs=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=QCX99aSClRkT5DWxuPKGxWDVkiUp1/aejU27zI8KCoSOmSQsbeptUpdAs9Ythck/jAOf08YU+ifpYmUEjgG/PB22r9jc0ZypJNv3AK6imCCjmFAC006HB1rhcGzaZ3aDiiO1DfujPr3Zk+vS5lXGwwbhd7Uk+RryDjbcJNkKAnM= 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=KnEcOPqB; arc=none smtp.client-ip=91.218.175.130 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="KnEcOPqB" X-Envelope-To: linux-security-module@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=0l6apGFhEMmIZSU/2v9JnhqbwzgAnZO6eQl/TQrNqjs=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1789113560; v=1; x=1789718360; b=KnEcOPqB29IjWgp5jthU8JbZQa2v3D0SIW/x4p91ktzgWaHzFTJXCLupscoIm3krB/uo/qf4 CveAx/UMZEtGXjGCoz4L5CzclBGBbpVM2DWgluhxFSSKospT58neG0dvynVp+8ueLx2smALKNmk GCEaHPmLpyqorFWiG7XG9oog= X-Envelope-To: linux-security-module@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 45b1a7c312529d85; 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> 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 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