linux-kernel - [PATCH] drm/i915: Hold struct_mutex during hotplug processing

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-next>] [day] [month] [year] [list]

Message-Id: <1311613829-4990-1-git-send-email-keithp@keithp.com>
Date:	Mon, 25 Jul 2011 10:10:29 -0700
From:	Keith Packard <keithp@...thp.com>
To:	Dave Airlie <airlied@...hat.com>
Cc:	linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
	intel-gfx@...ts.freedesktop.org, Keith Packard <keithp@...thp.com>
Subject: [PATCH] drm/i915: Hold struct_mutex during hotplug processing

Hotplug detection is a mode setting operation and must hold the
struct_mutex or risk colliding with other mode setting operations.

In particular, the display port hotplug function attempts to re-train
the link if the monitor is supposed to be running when plugged back
in. If that happens while mode setting is underway, the link will get
scrambled, leaving it in an inconsistent state.

Signed-off-by: Keith Packard <keithp@...thp.com>
---
 drivers/gpu/drm/i915/i915_irq.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 3b03f85..5fe8f28 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -306,12 +306,15 @@ static void i915_hotplug_work_func(struct work_struct *work)
 	struct drm_mode_config *mode_config = &dev->mode_config;
 	struct intel_encoder *encoder;
 
+	mutex_lock(&dev_priv->dev->struct_mutex);
 	DRM_DEBUG_KMS("running encoder hotplug functions\n");
 
 	list_for_each_entry(encoder, &mode_config->encoder_list, base.head)
 		if (encoder->hot_plug)
 			encoder->hot_plug(encoder);
 
+	mutex_unlock(&dev_priv->dev->struct_mutex);
+
 	/* Just fire off a uevent and let userspace tell us what to do */
 	drm_helper_hpd_irq_event(dev);
 }
-- 
1.7.5.4

--
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/