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Fri, 21 Aug 2020 11:20:44 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.40.192.73]) by smtp.corp.redhat.com (Postfix) with SMTP id 0DA705F705; Fri, 21 Aug 2020 11:20:42 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Fri, 21 Aug 2020 13:20:44 +0200 (CEST) Date: Fri, 21 Aug 2020 13:20:41 +0200 From: Oleg Nesterov To: Davidlohr Bueso Cc: akpm@linux-foundation.org, catalin.marinas@arm.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Davidlohr Bueso Subject: Re: [PATCH] mm/kmemleak: rely on rcu for task stack scanning Message-ID: <20200821112041.GH4546@redhat.com> References: <20200820203902.11308-1-dave@stgolabs.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200820203902.11308-1-dave@stgolabs.net> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Rspamd-Queue-Id: DD217180F9836 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam01 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 08/20, Davidlohr Bueso wrote: > > @@ -1471,15 +1471,15 @@ static void kmemleak_scan(void) > if (kmemleak_stack_scan) { > struct task_struct *p, *g; > > - read_lock(&tasklist_lock); > - do_each_thread(g, p) { > + rcu_read_lock(); > + for_each_process_thread(g, p) { > void *stack = try_get_task_stack(p); > if (stack) { > scan_block(stack, stack + THREAD_SIZE, NULL); > put_task_stack(p); > } > - } while_each_thread(g, p); > - read_unlock(&tasklist_lock); > + } > + rcu_read_unlock(); Acked-by: Oleg Nesterov