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| author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2017-12-04 21:48:18 +0100 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2017-12-06 10:22:55 +0100 |
| commit | a703c55004e1c5076d57e43771b3e11117796ea0 (patch) | |
| tree | 2be0916f74fc5e69786a4347e19f0d793cbf4309 /drivers/gpu/drm/drm_mode_config.c | |
| parent | ae64f9bd1d3621b5e60d7363bc20afb46aede215 (diff) | |
drm: safely free connectors from connector_iter
In
commit 613051dac40da1751ab269572766d3348d45a197
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Wed Dec 14 00:08:06 2016 +0100
drm: locking&new iterators for connector_list
we've went to extreme lengths to make sure connector iterations works
in any context, without introducing any additional locking context.
This worked, except for a small fumble in the implementation:
When we actually race with a concurrent connector unplug event, and
our temporary connector reference turns out to be the final one, then
everything breaks: We call the connector release function from
whatever context we happen to be in, which can be an irq/atomic
context. And connector freeing grabs all kinds of locks and stuff.
Fix this by creating a specially safe put function for connetor_iter,
which (in this rare case) punts the cleanup to a worker.
Reported-by: Ben Widawsky <ben@bwidawsk.net>
Cc: Ben Widawsky <ben@bwidawsk.net>
Fixes: 613051dac40d ("drm: locking&new iterators for connector_list")
Cc: Dave Airlie <airlied@gmail.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: <stable@vger.kernel.org> # v4.11+
Reviewed-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171204204818.24745-1-daniel.vetter@ffwll.ch
Diffstat (limited to 'drivers/gpu/drm/drm_mode_config.c')
| -rw-r--r-- | drivers/gpu/drm/drm_mode_config.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c index cda8bfab6d3b..cc78b3d9e5e4 100644 --- a/drivers/gpu/drm/drm_mode_config.c +++ b/drivers/gpu/drm/drm_mode_config.c @@ -431,6 +431,8 @@ void drm_mode_config_cleanup(struct drm_device *dev) drm_connector_put(connector); } drm_connector_list_iter_end(&conn_iter); + /* connector_iter drops references in a work item. */ + flush_scheduled_work(); if (WARN_ON(!list_empty(&dev->mode_config.connector_list))) { drm_connector_list_iter_begin(dev, &conn_iter); drm_for_each_connector_iter(connector, &conn_iter) |