From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2C778C27C75 for ; Thu, 13 Jun 2024 08:37:29 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BE7336B009C; Thu, 13 Jun 2024 04:37:28 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B979C6B00A0; Thu, 13 Jun 2024 04:37:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A60186B00A1; Thu, 13 Jun 2024 04:37:28 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 880C06B009C for ; Thu, 13 Jun 2024 04:37:28 -0400 (EDT) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 36B6BA1811 for ; 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charset=us-ascii Content-Disposition: inline In-Reply-To: <20240613023044.45873-7-laoar.shao@gmail.com> X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 288CA20015 X-Stat-Signature: qd7rwiswzkunchjj68cheouu635z6nxe X-Rspam-User: X-HE-Tag: 1718267845-766551 X-HE-Meta: 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 oGaZ5kmd 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 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: List-Subscribe: List-Unsubscribe: On Thu, Jun 13, 2024 at 10:30:40AM +0800, Yafang Shao wrote: > Using __get_task_comm() to read the task comm ensures that the name is > always NUL-terminated, regardless of the source string. This approach also > facilitates future extensions to the task comm. > > Signed-off-by: Yafang Shao > Cc: Catalin Marinas > Cc: Andrew Morton > --- > mm/kmemleak.c | 8 +------- > 1 file changed, 1 insertion(+), 7 deletions(-) > > diff --git a/mm/kmemleak.c b/mm/kmemleak.c > index d5b6fba44fc9..ef29aaab88a0 100644 > --- a/mm/kmemleak.c > +++ b/mm/kmemleak.c > @@ -663,13 +663,7 @@ static struct kmemleak_object *__alloc_object(gfp_t gfp) > strncpy(object->comm, "softirq", sizeof(object->comm)); > } else { > object->pid = current->pid; > - /* > - * There is a small chance of a race with set_task_comm(), > - * however using get_task_comm() here may cause locking > - * dependency issues with current->alloc_lock. In the worst > - * case, the command line is not correct. > - */ > - strncpy(object->comm, current->comm, sizeof(object->comm)); > + __get_task_comm(object->comm, sizeof(object->comm), current); > } You deleted the comment stating why it does not use get_task_comm() without explaining why it would be safe now. I don't recall the details but most likely lockdep warned of some potential deadlocks with this function being called with the task_lock held. So, you either show why this is safe or just use strscpy() directly here (not sure we'd need strscpy_pad(); I think strscpy() would do, we just need the NUL-termination). -- Catalin