linux-kernel - [ 2/9] xen/events: initialize local per-cpu mask for all possible events

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20130827010251.815986899@linuxfoundation.org>
Date:	Mon, 26 Aug 2013 18:04:53 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, David Vrabel <david.vrabel@...rix.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Subject: [ 2/9] xen/events: initialize local per-cpu mask for all possible events

3.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Vrabel <david.vrabel@...rix.com>

commit 84ca7a8e45dafb49cd5ca90a343ba033e2885c17 upstream.

The sizeof() argument in init_evtchn_cpu_bindings() is incorrect
resulting in only the first 64 (or 32 in 32-bit guests) ports having
their bindings being initialized to VCPU 0.

In most cases this does not cause a problem as request_irq() will set
the irq affinity which will set the correct local per-cpu mask.
However, if the request_irq() is called on a VCPU other than 0, there
is a window between the unmasking of the event and the affinity being
set were an event may be lost because it is not locally unmasked on
any VCPU. If request_irq() is called on VCPU 0 then local irqs are
disabled during the window and the race does not occur.

Fix this by initializing all NR_EVENT_CHANNEL bits in the local
per-cpu masks.

Signed-off-by: David Vrabel <david.vrabel@...rix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/xen/events.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -317,7 +317,7 @@ static void init_evtchn_cpu_bindings(voi

 	for_each_possible_cpu(i)
 		memset(per_cpu(cpu_evtchn_mask, i),
-		       (i == 0) ? ~0 : 0, sizeof(*per_cpu(cpu_evtchn_mask, i)));
+		       (i == 0) ? ~0 : 0, NR_EVENT_CHANNELS/8);
 }

 static inline void clear_evtchn(int port)

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/