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 CD7E1244662 for ; Sat, 20 Sep 2025 12:11:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758370293; cv=none; b=BFqirHYQx9sMbpP5C1ER3ZJNne5EvX0UMMJUq/3XvPpc26FVGwTbLs6ti4fOUdB70HWkvq4/iny8/F8JRmKonwI7teYYD44bqt1vmZKOUYqRlDJpYD5hr2JW90y+WHO22csh/LxO2JF8Wt8d2e641vi3m0aiM57Ad1gh4UaZPGw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758370293; c=relaxed/simple; bh=/jpAur8LtSXcT2WcXmQY8ihBcX3e5jjp9nxJv/MHF9M=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=h5sw82JcONTmgJi7ppTZTkkpYINqOKzP/0BdAF2s2Fh8CBQyWOyHm4E5u0aLDFQXlAvGBlXU7tB0xejdERrF3VYi/82okqqU0QgKFEZkNUPHjLtQGEM+pdYl4nsFPsYb+Jwj4hxAORdHHpWT+s7C92ro+Na/16QO+/3xtLnAbVg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DkIcf5xT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="DkIcf5xT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 388F4C4CEF7; Sat, 20 Sep 2025 12:11:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758370293; bh=/jpAur8LtSXcT2WcXmQY8ihBcX3e5jjp9nxJv/MHF9M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DkIcf5xTRCra+vv5+L66ZUsk0wPapkLFndgMQXI1OIXyByrP6iXscM49IbtNHoyqC hUzZ1YRfUcORX9PCEgpTVsAI7cRsG1hOZvHGAq7RrGvlDqotyvomd+F0nmH3qM/4DG diV409SWzO2tFdsewcmrQGbE5hDaspg4QcGd1DiM8GaxKWyeCijOBeNKdetTHH5dgS T656ttjfGfWpiTYvSuPBhLmfQ7kmGkAU7Zwq7dDuzkVGEOCQLOVpSkafUb+WYudKmH wBucQ5jN2D00YwKETiSEDxYzBVpEYvgcj+bw9wWQKqX+LNwX5NaIad1axDIad4lSzp fDtRLqUrJHpmA== From: SeongJae Park To: Akinobu Mita Cc: SeongJae Park , damon@lists.linux.dev, stable@vger.ekrnel.org Subject: Re: [PATCH] mm/damon/sysfs: do not ignore callback's return value in damon_sysfs_damon_call() Date: Sat, 20 Sep 2025 05:11:31 -0700 Message-Id: <20250920121131.83174-1-sj@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250920105236.29952-1-akinobu.mita@gmail.com> 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 Sat, 20 Sep 2025 19:52:36 +0900 Akinobu Mita wrote: > The callback return value is ignored in damon_sysfs_damon_call(), which > means that it is not possible to detect invalid user input when writing > commands such as 'commit' to /sys/kernel/mm/damon/admin/kdamonds//state. > Fix it. Thank you for finding this issue, Akinobu! Before the introduction of damon_sysfs_damon_call() and its usages, DAMON sysfs interface was returning an error in case of such command failures. So this is fixing a user-visible unintended behavior change. Hence this may deserve Cc-ing stable@ in my opinion. > So, below may better to be added? Fixes: f64539dcdb87 ("mm/damon/sysfs: use damon_call() for update_schemes_stats") Cc: # v6.14.x > Signed-off-by: Akinobu Mita Reviewed-by: SeongJae Park > --- > mm/damon/sysfs.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c > index fe4e73d0ebbb..97e16f00f23e 100644 > --- a/mm/damon/sysfs.c > +++ b/mm/damon/sysfs.c > @@ -1627,12 +1627,15 @@ static int damon_sysfs_damon_call(int (*fn)(void *data), > struct damon_sysfs_kdamond *kdamond) > { > struct damon_call_control call_control = {}; > + int err; > > if (!kdamond->damon_ctx) > return -EINVAL; > call_control.fn = fn; > call_control.data = kdamond; > - return damon_call(kdamond->damon_ctx, &call_control); > + err = damon_call(kdamond->damon_ctx, &call_control); > + I think the above new line is not really needed, but it is definitely trivial. > + return err ? err : call_control.return_code; > } > > struct damon_sysfs_schemes_walk_data { > -- > 2.43.0 Thanks, SJ