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Tue, 08 Sep 2026 09:41:08 -0700 (PDT) Date: Tue, 8 Sep 2026 19:45:15 +0300 From: Alexey Dobriyan To: Ye Liu Cc: Tony Luck , Reinette Chatre , x86@kernel.org, Christian Brauner , Andrew Morton , Jann Horn , "David Hildenbrand (arm)" , "Mike Rapoport (Microsoft)" , Lorenzo Stoakes , Oleg Nesterov , Ye Liu , Dave Martin , James Morse , Babu Moger , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 6/8] fs: convert process/thread iterators to for_each_*_rcu Message-ID: <662ade9d-d662-4f6f-869f-08c41da53170@p183> References: <20260904083001.553587-1-ye.liu@linux.dev> <20260904083001.553587-7-ye.liu@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260904083001.553587-7-ye.liu@linux.dev> On Fri, Sep 04, 2026 at 04:29:58PM +0800, Ye Liu wrote: > --- a/fs/proc/base.c > +++ b/fs/proc/base.c > @@ -1160,8 +1160,7 @@ static int __set_oom_adj(struct file *file, int oom_adj, bool legacy) > if (mm) { > struct task_struct *p; > > - rcu_read_lock(); > - for_each_process(p) { > + for_each_process_rcu(p) { > if (same_thread_group(task, p)) > continue; > > @@ -1177,7 +1176,6 @@ static int __set_oom_adj(struct file *file, int oom_adj, bool legacy) > } > task_unlock(p); > } > - rcu_read_unlock(); > mmdrop(mm); > } > err_unlock: What's going on here? Now it's RCU unlock after mmdrop(). These scoped guards kind of suck unless you allow infinite line length. A