| 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
| ||
|
Message-Id: <20230903214150.2877023-2-dmitry.baryshkov@linaro.org>
Date: Mon, 4 Sep 2023 00:41:39 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>,
Andrzej Hajda <andrzej.hajda@...el.com>,
Neil Armstrong <neil.armstrong@...aro.org>,
Robert Foss <rfoss@...nel.org>,
Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
Jonas Karlman <jonas@...boo.se>,
Jernej Skrabec <jernej.skrabec@...il.com>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>,
Thomas Zimmermann <tzimmermann@...e.de>,
"Bryan O'Donoghue" <bryan.odonoghue@...aro.org>,
Guenter Roeck <linux@...ck-us.net>,
Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
Janne Grunau <j@...nau.net>, Simon Ser <contact@...rsion.fr>,
Andy Gross <agross@...nel.org>,
Bjorn Andersson <andersson@...nel.org>,
Konrad Dybcio <konrad.dybcio@...aro.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: dri-devel@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
freedreno@...ts.freedesktop.org, Won Chung <wonchung@...gle.com>
Subject: [RFC PATCH v1 01/12] Revert "drm/sysfs: Link DRM connectors to corresponding Type-C connectors"
The kdev->fwnode pointer is never set in drm_sysfs_connector_add(), so
dev_fwnode() checks never succeed, making the respective commit NOP.
And if drm_sysfs_connector_add() is modified to set kdev->fwnode, it
breaks drivers already using components (as it was pointed at [1]),
resulting in a deadlock. Lockdep trace is provided below.
Granted these two issues, it seems impractical to fix this commit in any
sane way. Revert it instead.
[1] https://lore.kernel.org/dri-devel/Y24bcYJKGy%2Fgd5fV@phenom.ffwll.local/
============================================
WARNING: possible recursive locking detected
6.5.0-rc6-next-20230816-10542-g090e2ca9feae-dirty #713 Tainted: G W
--------------------------------------------
kworker/u16:0/11 is trying to acquire lock:
ffffce0f54bea490 (component_mutex){+.+.}-{3:3}, at: __component_add+0x64/0x170
but task is already holding lock:
ffffce0f54bea490 (component_mutex){+.+.}-{3:3}, at: __component_add+0x64/0x170
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(component_mutex);
lock(component_mutex);
*** DEADLOCK ***
May be due to missing lock nesting notation
6 locks held by kworker/u16:0/11:
#0: ffff5b7680008d38 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x14c/0x51c
#1: ffff8000800abde0 (deferred_probe_work){+.+.}-{0:0}, at: process_one_work+0x14c/0x51c
#2: ffff5b76837a2908 (&dev->mutex){....}-{3:3}, at: __device_attach+0x38/0x188
#3: ffffce0f54bea490 (component_mutex){+.+.}-{3:3}, at: __component_add+0x64/0x170
#4: ffffce0f54bdeb40 (drm_connector_list_iter){.+.+}-{0:0}, at: drm_modeset_register_all+0x80/0x9c
#5: ffff5b76866ad0d0 (&connector->mutex){+.+.}-{3:3}, at: drm_connector_register.part.0+0x28/0x104
stack backtrace:
CPU: 6 PID: 11 Comm: kworker/u16:0 Tainted: G W 6.5.0-rc6-next-20230816-10542-g090e2ca9feae-dirty #713
Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT)
Workqueue: events_unbound deferred_probe_work_func
Call trace:
dump_backtrace+0x98/0xf0
show_stack+0x18/0x24
dump_stack_lvl+0x60/0xac
dump_stack+0x18/0x24
print_deadlock_bug+0x254/0x340
__lock_acquire+0x105c/0x1ebc
lock_acquire+0x1ec/0x314
__lock_acquire+0x105c/0x1ebc
lock_acquire+0x1ec/0x314
__mutex_lock+0xa0/0x77c
mutex_lock_nested+0x24/0x30
__component_add+0x64/0x170
component_add+0x14/0x20
drm_sysfs_connector_add+0x144/0x1a0
drm_connector_register.part.0+0x5c/0x104
drm_connector_register_all+0x84/0x160
drm_modeset_register_all+0x80/0x9c
drm_dev_register+0x120/0x238
msm_drm_bind+0x550/0x6e0
try_to_bring_up_aggregate_device+0x164/0x1d0
__component_add+0xa8/0x170
component_add+0x14/0x20
dsi_dev_attach+0x20/0x2c
dsi_host_attach+0x9c/0x144
devm_mipi_dsi_attach+0x34/0xb4
lt9611uxc_attach_dsi.isra.0+0x84/0xfc
lt9611uxc_probe+0x5ac/0x66c
i2c_device_probe+0x148/0x290
really_probe+0x148/0x2ac
__driver_probe_device+0x78/0x12c
driver_probe_device+0x3c/0x160
__device_attach_driver+0xb8/0x138
bus_for_each_drv+0x80/0xdc
__device_attach+0x9c/0x188
device_initial_probe+0x14/0x20
bus_probe_device+0xac/0xb0
deferred_probe_work_func+0x8c/0xc8
process_one_work+0x1ec/0x51c
worker_thread+0x1ec/0x3e4
kthread+0x120/0x124
ret_from_fork+0x10/0x20
Fixes: c5c51b242062 ("drm/sysfs: Link DRM connectors to corresponding Type-C connectors")
Cc: Won Chung <wonchung@...gle.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
---
drivers/gpu/drm/drm_sysfs.c | 40 -------------------------------------
1 file changed, 40 deletions(-)
diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
index b169b3e44a92..06662cc8d3f4 100644
--- a/drivers/gpu/drm/drm_sysfs.c
+++ b/drivers/gpu/drm/drm_sysfs.c
@@ -11,14 +11,12 @@
*/
#include <linux/acpi.h>
-#include <linux/component.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/gfp.h>
#include <linux/i2c.h>
#include <linux/kdev_t.h>
-#include <linux/property.h>
#include <linux/slab.h>
#include <drm/drm_accel.h>
@@ -98,34 +96,6 @@ static char *drm_devnode(const struct device *dev, umode_t *mode)
return kasprintf(GFP_KERNEL, "dri/%s", dev_name(dev));
}
-static int typec_connector_bind(struct device *dev,
- struct device *typec_connector, void *data)
-{
- int ret;
-
- ret = sysfs_create_link(&dev->kobj, &typec_connector->kobj, "typec_connector");
- if (ret)
- return ret;
-
- ret = sysfs_create_link(&typec_connector->kobj, &dev->kobj, "drm_connector");
- if (ret)
- sysfs_remove_link(&dev->kobj, "typec_connector");
-
- return ret;
-}
-
-static void typec_connector_unbind(struct device *dev,
- struct device *typec_connector, void *data)
-{
- sysfs_remove_link(&typec_connector->kobj, "drm_connector");
- sysfs_remove_link(&dev->kobj, "typec_connector");
-}
-
-static const struct component_ops typec_connector_ops = {
- .bind = typec_connector_bind,
- .unbind = typec_connector_unbind,
-};
-
static CLASS_ATTR_STRING(version, S_IRUGO, "drm 1.1.0 20060810");
/**
@@ -394,16 +364,9 @@ int drm_sysfs_connector_add(struct drm_connector *connector)
connector->kdev = kdev;
- if (dev_fwnode(kdev)) {
- r = component_add(kdev, &typec_connector_ops);
- if (r)
- drm_err(dev, "failed to add component to create link to typec connector\n");
- }
-
if (connector->ddc)
return sysfs_create_link(&connector->kdev->kobj,
&connector->ddc->dev.kobj, "ddc");
-
return 0;
err_free:
@@ -419,9 +382,6 @@ void drm_sysfs_connector_remove(struct drm_connector *connector)
if (connector->ddc)
sysfs_remove_link(&connector->kdev->kobj, "ddc");
- if (dev_fwnode(connector->kdev))
- component_del(connector->kdev, &typec_connector_ops);
-
DRM_DEBUG("removing \"%s\" from sysfs\n",
connector->name);
--
2.39.2
Powered by blists - more mailing lists