From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3E2977B for ; Tue, 16 Aug 2022 00:12:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A26ECC433D6; Tue, 16 Aug 2022 00:12:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660608738; bh=8Jobnfnb834DpLHUqKSpTUo6dVZq1+29pR0tWVF0JZs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ek0Mv6qxbGV2+YblJKEPMiTmBjvbTS5fWtxqwZUZRz3hHjh1tkcEH5LeIyNf/jqzD T5LD4Bl3zDupErWpSS2L3jYFYKdAsYheGvTy8xRS9O9tsAoGECmZzV0hRbctB7i2FG wqkKmJu8IKIr4BsXjJjLGZQ0dJwP6n8FtenJHdPN3QfsW/Ziw6w94HN32N896+Yji8 lNDnhtrhe45LIctU+eBameohmiUg2KWCw9miDCgpbicHi/vTFaLjpc1T75lOYUtbMb gaf9JoUnXSSo+XSPznkQRZYDoiARdTOzQqF2ViU3GSVyE20q+pC1BIbkBFU7LbimFq U5W2ByBpHjXOQ== From: SeongJae Park To: SeongJae Park Cc: "Pulavarty, Badari" , "damon@lists.linux.dev" , "linux-mm@kvack.org" Subject: RE: [PATCH] DAMON dbgfs_mk_context() error handling Date: Tue, 16 Aug 2022 00:12:15 +0000 Message-Id: <20220816001215.95156-1-sj@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220815234210.95016-1-sj@kernel.org> References: Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Mon, 15 Aug 2022 23:42:10 +0000 SeongJae Park wrote: > Hi Badari, > > > On Mon, 15 Aug 2022 21:51:04 +0000 "Pulavarty, Badari" wrote: > > > [-- Attachment #1: Type: text/plain, Size: 350 bytes --] > > > > Hi SI, > > > > > Nice finding, thank you! But, the return value of the debugfs call is intentionally ignored[2]. How about doing the duplicated name check in > > > dbgfs_mk_context() itself before the debugfs_create_dir() call? > > Please don't unwrap wrapped message. My monitor is not so wide :'( > > > > > > > [2] https://lore.kernel.org/linux-mm/20210205155902.31102-1-sjpark@amazon.com/ > > > > How about this? > > > > Thanks, > > Badari > > > > > > > > [-- Attachment #2: damon-mkcontext-fix.patch --] > > [-- Type: application/octet-stream, Size: 858 bytes --] > > Could you please don't send a patch as an attached file of the mail but put it > in the mail body so that we can easily read the patch and comment in line? > > > > > damon dbgfs_mk_context() should check to make sure there is no existing > > context with the same name. Otherwise, it will cause failure when we > > enabling the monitor. > > > > Test case: > > > > echo "off" > /sys/kernel/debug/damon/monitor_on > > echo "abc" > /sys/kernel/debug/damon/mk_context > > echo "abc" > /sys/kernel/debug/damon/mk_context > > echo > /sys/kernel/debug/damon/abc/target_ids > > echo "on" > /sys/kernel/debug/damon/monitor_on <<< fails > > > > Signed-off-by: Badari Pulavarty > > --- > > It would be good to put the changelog of this patch here: > https://docs.kernel.org/process/submitting-patches.html#the-canonical-patch-format > > > --- a/mm/damon/dbgfs.c 2022-08-15 14:27:38.308806431 -0700 > > +++ b/mm/damon/dbgfs.c 2022-08-15 14:33:31.661163048 -0700 > > @@ -817,6 +817,12 @@ > > if (!root) > > return -ENOENT; > > > > + new_dir = debugfs_lookup(name, root); > > + if (new_dir) { > > + dput(new_dir); > > + return -EEXIST; > > + } > > + > > The change looks ok to me at a glance, but the attached file seems not an > appropriate patch. Could you please repost this as a formal patch as suggested > for a better review? Also, please add 'Fixes:' tag and Cc stable@vger.kernel.org to the patch. Thanks, SJ > > Thanks, > SJ > > > new_dir = debugfs_create_dir(name, root); > > dbgfs_dirs[dbgfs_nr_ctxs] = new_dir;