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 CF070196C9B; Tue, 30 Jul 2024 09:49:42 +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=1722332982; cv=none; b=JaFW4n82vlbmqj8xCvB4/opWXnlz5GeTL3r+CU3bjiA/2yf/Ha3ldSe2tarohVqsVv3eACwnZDQn0j17F6Sah3KSuhiGz9L46oCzgc8M59C5fQ2kVcMQepP2kAvqwFTy8Vx4F6VcdQDjaq5vjFDkN/oTglaCjb5+jXyJuGhLQHQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722332982; c=relaxed/simple; bh=K+iZkNmIViomAg24z3v6dg2ldSKrDHEShkDzsj4OSPE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=q0INoybVzJdXKSQJEsiBHTwci1aAgZLeZ2BiJi1SZqeLaCXlCXs9Ude2pyENPFvzNGD23svTrj30pONNbXPAf8OqyHlupA7FfhMA3bvNnIk012hn6M/nhzBn4EjBFzR+E0h4xTJ5lJDJbvjn0hHnLv2p8XZqXvMK9HspBZRmMbk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bLshH0bW; 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="bLshH0bW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4623AC4AF0B; Tue, 30 Jul 2024 09:49:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722332982; bh=K+iZkNmIViomAg24z3v6dg2ldSKrDHEShkDzsj4OSPE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bLshH0bWGveXFScmbfagrf+5Rlbb6V9sI7oEJXqwXvDLnZ64gldWOq9MCDl5qZ0nD b3YCQno4d3bZ1xQKYB+GUWMVDyxYbzToI5nARvkR+EkUIWmVaPkcIkajDaUPEkA9QM ekBJ9xmTs3ARKeU7vkqfcKaGn3rR5UqqcgZbL1MB3qeTpbn+5IaIRKAssgJ9GByJc+ vT5yNfXH8/9uIGwNZLxw+ko9BY6+TvvvOBGQQDYReUQdsetQbRp34l0r7pxS+B1qF1 20UbWaCsOE0k3fClSdoiPblC9KDd41WYRMjNKLmohp4T3j/KG8UG7mi3Hu0fhjtR+6 yDQbbDzhCeN/Q== Date: Tue, 30 Jul 2024 11:49:37 +0200 From: Christian Brauner To: Olaf Hering Cc: Deepa Dinamani , Jeff Layton , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Viro , Jan Kara Subject: Re: [PATCH v1] mount: handle OOM on mnt_warn_timestamp_expiry Message-ID: <20240730-humpelt-deklamieren-eeefe1d623a9@brauner> References: <20240730085856.32385-1-olaf@aepfle.de> 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: <20240730085856.32385-1-olaf@aepfle.de> On Tue, Jul 30, 2024 at 10:58:13AM GMT, Olaf Hering wrote: > If no page could be allocated, an error pointer was used as format > string in pr_warn. > > Rearrange the code to return early in case of OOM. Also add a check > for the return value of d_path. The API of that function is not > documented. It currently returns only ERR_PTR values, but may return > also NULL in the future. Use PTR_ERR_OR_ZERO to cover both cases. > > Fixes: f8b92ba67c5d ("mount: Add mount warning for impending timestamp expiry") > > Signed-off-by: Olaf Hering > --- > fs/namespace.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/fs/namespace.c b/fs/namespace.c > index 328087a4df8a..539d4f203a20 100644 > --- a/fs/namespace.c > +++ b/fs/namespace.c > @@ -2922,7 +2922,14 @@ static void mnt_warn_timestamp_expiry(struct path *mountpoint, struct vfsmount * > (!(sb->s_iflags & SB_I_TS_EXPIRY_WARNED)) && > (ktime_get_real_seconds() + TIME_UPTIME_SEC_MAX > sb->s_time_max)) { > char *buf = (char *)__get_free_page(GFP_KERNEL); > - char *mntpath = buf ? d_path(mountpoint, buf, PAGE_SIZE) : ERR_PTR(-ENOMEM); > + char *mntpath; > + > + if (!buf) > + return; > + > + mntpath = d_path(mountpoint, buf, PAGE_SIZE); > + if (PTR_ERR_OR_ZERO(mntpath)) This needs to be IS_ERR_OR_NULL(). > + goto err; We should still warn when decoding the mountpoint fails. I'll just amend your patch to something like: diff --git a/fs/namespace.c b/fs/namespace.c index 328087a4df8a..0f2f140aaf05 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2921,16 +2921,21 @@ static void mnt_warn_timestamp_expiry(struct path *mountpoint, struct vfsmount * if (!__mnt_is_readonly(mnt) && (!(sb->s_iflags & SB_I_TS_EXPIRY_WARNED)) && (ktime_get_real_seconds() + TIME_UPTIME_SEC_MAX > sb->s_time_max)) { - char *buf = (char *)__get_free_page(GFP_KERNEL); - char *mntpath = buf ? d_path(mountpoint, buf, PAGE_SIZE) : ERR_PTR(-ENOMEM); + char *buf, *mntpath = NULL; + + buf = (char *)__get_free_page(GFP_KERNEL); + if (buf) + mntpath = d_path(mountpoint, buf, PAGE_SIZE); + if (IS_ERR_OR_NULL(mntpath)) + mntpath = "(unknown)"; pr_warn("%s filesystem being %s at %s supports timestamps until %ptTd (0x%llx)\n", sb->s_type->name, is_mounted(mnt) ? "remounted" : "mounted", mntpath, &sb->s_time_max, (unsigned long long)sb->s_time_max); - - free_page((unsigned long)buf); + if (buf) + free_page((unsigned long)buf); sb->s_iflags |= SB_I_TS_EXPIRY_WARNED; } }