From: Borislav Petkov <bp@alien8.de>
To: Alan Stern <stern@rowland.harvard.edu>,
Geert Uytterhoeven <geert@linux-m68k.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>,
Ayush Sawal <ayush.sawal@chelsio.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Rohit Maheshwari <rohitm@chelsio.com>,
Steven Rostedt <rostedt@goodmis.org>,
Vinay Kumar Yadav <vinay.yadav@chelsio.com>,
alsa-devel@alsa-project.org,
bcm-kernel-feedback-list@broadcom.com,
intel-gfx@lists.freedesktop.org,
intel-gvt-dev@lists.freedesktop.org, linux-alpha@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org,
linux-crypto@vger.kernel.org, linux-edac@vger.kernel.org,
linux-fbdev@vger.kernel.org, linux-hyperv@vger.kernel.org,
linux-iio@vger.kernel.org, linux-leds@vger.kernel.org,
linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org,
linux-pm@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-remoteproc@vger.kernel.org,
linux-renesas-soc@vger.kernel.org, linux-s390@vger.kernel.org,
linux-scsi@vger.kernel.org, linux-sh@vger.kernel.org,
linux-staging@lists.linux.dev, linux-tegra@vger.kernel.org,
linux-um@lists.infradead.org, linux-usb@vger.kernel.org,
linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org,
openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org,
sparclinux@vger.kernel.org, x86@kernel.org,
xen-devel@lists.xenproject.org
Subject: Re: [PATCH v0 00/42] notifiers: Return an error when callback is already registered
Date: Mon, 8 Nov 2021 15:35:50 +0100 [thread overview]
Message-ID: <YYk1xi3eJdMJdjHC@zn.tnic> (raw)
In-Reply-To: <YYkzJ3+faVga2Tl3@zn.tnic>
On Mon, Nov 08, 2021 at 03:24:39PM +0100, Borislav Petkov wrote:
> I guess I can add another indirection to notifier_chain_register() and
> avoid touching all the call sites.
IOW, something like this below.
This way I won't have to touch all the callsites and the registration
routines would still return a proper value instead of returning 0
unconditionally.
---
diff --git a/kernel/notifier.c b/kernel/notifier.c
index b8251dc0bc0f..04f08b2ef17f 100644
--- a/kernel/notifier.c
+++ b/kernel/notifier.c
@@ -19,14 +19,12 @@ BLOCKING_NOTIFIER_HEAD(reboot_notifier_list);
* are layered on top of these, with appropriate locking added.
*/
-static int notifier_chain_register(struct notifier_block **nl,
- struct notifier_block *n)
+static int __notifier_chain_register(struct notifier_block **nl,
+ struct notifier_block *n)
{
while ((*nl) != NULL) {
- if (unlikely((*nl) == n)) {
- WARN(1, "double register detected");
- return 0;
- }
+ if (unlikely((*nl) == n))
+ return -EEXIST;
if (n->priority > (*nl)->priority)
break;
nl = &((*nl)->next);
@@ -36,6 +34,18 @@ static int notifier_chain_register(struct notifier_block **nl,
return 0;
}
+static int notifier_chain_register(struct notifier_block **nl,
+ struct notifier_block *n)
+{
+ int ret = __notifier_chain_register(nl, n);
+
+ if (ret == -EEXIST)
+ WARN(1, "double register of notifier callback %ps detected",
+ n->notifier_call);
+
+ return ret;
+}
+
static int notifier_chain_unregister(struct notifier_block **nl,
struct notifier_block *n)
{
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2021-11-08 14:36 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20211108101157.15189-1-bp@alien8.de>
2021-11-08 10:11 ` [PATCH v0 35/42] sh: Check notifier registration return value Borislav Petkov
2021-11-08 13:31 ` Geert Uytterhoeven
2021-11-08 13:49 ` Borislav Petkov
2021-11-08 14:03 ` Geert Uytterhoeven
2021-11-08 14:48 ` Sergey Shtylyov
2021-11-08 10:11 ` [PATCH v0 42/42] notifier: Return an error when callback is already registered Borislav Petkov
2021-11-08 14:07 ` Geert Uytterhoeven
2021-11-08 14:21 ` Borislav Petkov
2021-11-08 15:25 ` Geert Uytterhoeven
2021-11-08 15:58 ` Borislav Petkov
2021-11-08 16:12 ` Geert Uytterhoeven
2021-11-08 16:21 ` Borislav Petkov
2021-11-08 20:59 ` Alan Stern
2021-11-08 21:18 ` Borislav Petkov
2021-11-08 10:19 ` [PATCH v0 00/42] notifiers: " Borislav Petkov
2021-11-08 14:17 ` Alan Stern
2021-11-08 14:24 ` Borislav Petkov
2021-11-08 14:35 ` Borislav Petkov [this message]
2021-11-08 16:23 ` Steven Rostedt
2021-11-08 16:29 ` Borislav Petkov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YYk1xi3eJdMJdjHC@zn.tnic \
--to=bp@alien8.de \
--cc=alsa-devel@alsa-project.org \
--cc=arnd@arndb.de \
--cc=ayush.sawal@chelsio.com \
--cc=bcm-kernel-feedback-list@broadcom.com \
--cc=geert@linux-m68k.org \
--cc=gregkh@linuxfoundation.org \
--cc=intel-gfx@lists.freedesktop.org \
--cc=intel-gvt-dev@lists.freedesktop.org \
--cc=linux-alpha@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-clk@vger.kernel.org \
--cc=linux-crypto@vger.kernel.org \
--cc=linux-edac@vger.kernel.org \
--cc=linux-fbdev@vger.kernel.org \
--cc=linux-hyperv@vger.kernel.org \
--cc=linux-iio@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-leds@vger.kernel.org \
--cc=linux-mips@vger.kernel.org \
--cc=linux-parisc@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=linux-remoteproc@vger.kernel.org \
--cc=linux-renesas-soc@vger.kernel.org \
--cc=linux-s390@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
--cc=linux-sh@vger.kernel.org \
--cc=linux-staging@lists.linux.dev \
--cc=linux-tegra@vger.kernel.org \
--cc=linux-um@lists.infradead.org \
--cc=linux-usb@vger.kernel.org \
--cc=linux-xtensa@linux-xtensa.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=netdev@vger.kernel.org \
--cc=openipmi-developer@lists.sourceforge.net \
--cc=rcu@vger.kernel.org \
--cc=rohitm@chelsio.com \
--cc=rostedt@goodmis.org \
--cc=sparclinux@vger.kernel.org \
--cc=stern@rowland.harvard.edu \
--cc=vinay.yadav@chelsio.com \
--cc=x86@kernel.org \
--cc=xen-devel@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).