Linux-ARM-Kernel Archive on lore.kernel.org
 help / color / Atom feed
From: Julien Grall <julien@xen.org>
To: xen-devel@lists.xenproject.org
Cc: jgross@suse.com, sstabellini@kernel.org,
	Julien Grall <jgrall@amazon.com>,
	linux-kernel@vger.kernel.org, Ian Jackson <iwj@xenproject.org>,
	dwmw@amazon.co.uk, boris.ostrovsky@oracle.com,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm/xen: Don't probe xenbus as part of an early initcall
Date: Wed, 10 Feb 2021 17:06:54 +0000
Message-ID: <20210210170654.5377-1-julien@xen.org> (raw)

From: Julien Grall <jgrall@amazon.com>

After Commit 3499ba8198cad ("xen: Fix event channel callback via
INTX/GSI"), xenbus_probe() will be called too early on Arm. This will
recent to a guest hang during boot.

If there hang wasn't there, we would have ended up to call
xenbus_probe() twice (the second time is in xenbus_probe_initcall()).

We don't need to initialize xenbus_probe() early for Arm guest.
Therefore, the call in xen_guest_init() is now removed.

After this change, there is no more external caller for xenbus_probe().
So the function is turned to a static one. Interestingly there were two
prototypes for it.

Fixes: 3499ba8198cad ("xen: Fix event channel callback via INTX/GSI")
Reported-by: Ian Jackson <iwj@xenproject.org>
Signed-off-by: Julien Grall <jgrall@amazon.com>

CC: dwmw@amazon.co.uk

---

The offending commit unfortunately got backport to stable trees. So
this will need to be backported as well.
---
 arch/arm/xen/enlighten.c          | 2 --
 drivers/xen/xenbus/xenbus.h       | 1 -
 drivers/xen/xenbus/xenbus_probe.c | 2 +-
 include/xen/xenbus.h              | 2 --
 4 files changed, 1 insertion(+), 6 deletions(-)

diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 5a957a9a0984..8ad576ecd0f1 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -370,8 +370,6 @@ static int __init xen_guest_init(void)
 		return -ENOMEM;
 	}
 	gnttab_init();
-	if (!xen_initial_domain())
-		xenbus_probe();
 
 	/*
 	 * Making sure board specific code will not set up ops for
diff --git a/drivers/xen/xenbus/xenbus.h b/drivers/xen/xenbus/xenbus.h
index dc1537335414..2a93b7c9c159 100644
--- a/drivers/xen/xenbus/xenbus.h
+++ b/drivers/xen/xenbus/xenbus.h
@@ -115,7 +115,6 @@ int xenbus_probe_node(struct xen_bus_type *bus,
 		      const char *type,
 		      const char *nodename);
 int xenbus_probe_devices(struct xen_bus_type *bus);
-void xenbus_probe(void);
 
 void xenbus_dev_changed(const char *node, struct xen_bus_type *bus);
 
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index 18ffd0551b54..8a75092bb148 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -683,7 +683,7 @@ void unregister_xenstore_notifier(struct notifier_block *nb)
 }
 EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
 
-void xenbus_probe(void)
+static void xenbus_probe(void)
 {
 	xenstored_ready = 1;
 
diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h
index 2c43b0ef1e4d..bf3cfc7c35d0 100644
--- a/include/xen/xenbus.h
+++ b/include/xen/xenbus.h
@@ -192,8 +192,6 @@ void xs_suspend_cancel(void);
 
 struct work_struct;
 
-void xenbus_probe(void);
-
 #define XENBUS_IS_ERR_READ(str) ({			\
 	if (!IS_ERR(str) && strlen(str) == 0) {		\
 		kfree(str);				\
-- 
2.17.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

             reply index

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-10 17:06 Julien Grall [this message]
2021-02-10 17:49 ` Woodhouse, David
2021-02-10 21:36   ` Stefano Stabellini
2021-02-11  6:55 ` Jürgen Groß

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=20210210170654.5377-1-julien@xen.org \
    --to=julien@xen.org \
    --cc=boris.ostrovsky@oracle.com \
    --cc=dwmw@amazon.co.uk \
    --cc=iwj@xenproject.org \
    --cc=jgrall@amazon.com \
    --cc=jgross@suse.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=sstabellini@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

Linux-ARM-Kernel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-arm-kernel/0 linux-arm-kernel/git/0.git
	git clone --mirror https://lore.kernel.org/linux-arm-kernel/1 linux-arm-kernel/git/1.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-arm-kernel linux-arm-kernel/ https://lore.kernel.org/linux-arm-kernel \
		linux-arm-kernel@lists.infradead.org
	public-inbox-index linux-arm-kernel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.infradead.lists.linux-arm-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git