| Message ID | 20171213085720.6059-1-m.szyprowski@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Quoting Marek Szyprowski (2017-12-13 08:57:20) > drm_mode_config_cleanup() might be called from a workqueue context (for > example in error path handling of deferred probe), so it must not call > flush_scheduled_work(), because it would deadlock in such case. Replace > that call with explicit counting of the scheduled connector free works > and waiting until it reaches zero. > > Fixes: a703c55004e1 ("drm: safely free connectors from connector_iter") > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> > --- > This fixes the issue discussed in the following thread: > https://www.spinics.net/lists/arm-kernel/msg622332.html > --- > drivers/gpu/drm/drm_connector.c | 6 +++++- > drivers/gpu/drm/drm_mode_config.c | 6 +++++- > include/drm/drm_mode_config.h | 13 +++++++++++++ > 3 files changed, 23 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c > index 0b7e0974e6da..7620ac1ad1b1 100644 > --- a/drivers/gpu/drm/drm_connector.c > +++ b/drivers/gpu/drm/drm_connector.c > @@ -161,6 +161,8 @@ static void drm_connector_free_work_fn(struct work_struct *work) > > drm_mode_object_unregister(dev, &connector->base); > connector->funcs->destroy(connector); > + atomic_dec(&dev->mode_config.connector_free_works); > + wake_up_all(&dev->mode_config.connector_free_queue); > } > > /** > @@ -552,8 +554,10 @@ EXPORT_SYMBOL(drm_connector_list_iter_begin); > static void > drm_connector_put_safe(struct drm_connector *conn) > { > - if (refcount_dec_and_test(&conn->base.refcount.refcount)) > + if (refcount_dec_and_test(&conn->base.refcount.refcount)) { > + atomic_inc(&conn->dev->mode_config.connector_free_works); > schedule_work(&conn->free_work); > + } > } > > /** > diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c > index 6ffe952142e6..cca443faebd8 100644 > --- a/drivers/gpu/drm/drm_mode_config.c > +++ b/drivers/gpu/drm/drm_mode_config.c > @@ -381,6 +381,7 @@ void drm_mode_config_init(struct drm_device *dev) > idr_init(&dev->mode_config.tile_idr); > ida_init(&dev->mode_config.connector_ida); > spin_lock_init(&dev->mode_config.connector_list_lock); > + init_waitqueue_head(&dev->mode_config.connector_free_queue); > > drm_mode_create_standard_properties(dev); > > @@ -431,8 +432,11 @@ 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(); > + wait_event(dev->mode_config.connector_free_queue, > + !atomic_read(&dev->mode_config.connector_free_works)); > + > 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) > diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h > index a0afeb591dcb..83a7db997e83 100644 > --- a/include/drm/drm_mode_config.h > +++ b/include/drm/drm_mode_config.h > @@ -413,6 +413,19 @@ struct drm_mode_config { > * &struct drm_connector_list_iter to walk this list. > */ > struct list_head connector_list; > + /** > + * @pending_connector_free_works: > + * > + * Number of scheduled connector->free_work instances, see > + * drm_connector_put_safe(). > + */ > + atomic_t connector_free_works; > + /** > + * @pending_connector_free_queue: > + * > + * Wait queue for waiting until connector->free_work is finished. > + */ > + wait_queue_head_t connector_free_queue; Just move from a system_wq to a local wq? -Chris
On Wed, Dec 13, 2017 at 09:57:20AM +0100, Marek Szyprowski wrote: > drm_mode_config_cleanup() might be called from a workqueue context (for > example in error path handling of deferred probe), so it must not call > flush_scheduled_work(), because it would deadlock in such case. Replace > that call with explicit counting of the scheduled connector free works > and waiting until it reaches zero. > > Fixes: a703c55004e1 ("drm: safely free connectors from connector_iter") > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> I don't like hand-rolling wait stuff if it's avoidable (although cross-release will catch all the fun nowadays). I'm working on a patch to rework the cleanup logic so we can flush stuff directly. Bit more work, but imo cleaner logic. -Daniel > --- > This fixes the issue discussed in the following thread: > https://www.spinics.net/lists/arm-kernel/msg622332.html > --- > drivers/gpu/drm/drm_connector.c | 6 +++++- > drivers/gpu/drm/drm_mode_config.c | 6 +++++- > include/drm/drm_mode_config.h | 13 +++++++++++++ > 3 files changed, 23 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c > index 0b7e0974e6da..7620ac1ad1b1 100644 > --- a/drivers/gpu/drm/drm_connector.c > +++ b/drivers/gpu/drm/drm_connector.c > @@ -161,6 +161,8 @@ static void drm_connector_free_work_fn(struct work_struct *work) > > drm_mode_object_unregister(dev, &connector->base); > connector->funcs->destroy(connector); > + atomic_dec(&dev->mode_config.connector_free_works); > + wake_up_all(&dev->mode_config.connector_free_queue); > } > > /** > @@ -552,8 +554,10 @@ EXPORT_SYMBOL(drm_connector_list_iter_begin); > static void > drm_connector_put_safe(struct drm_connector *conn) > { > - if (refcount_dec_and_test(&conn->base.refcount.refcount)) > + if (refcount_dec_and_test(&conn->base.refcount.refcount)) { > + atomic_inc(&conn->dev->mode_config.connector_free_works); > schedule_work(&conn->free_work); > + } > } > > /** > diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c > index 6ffe952142e6..cca443faebd8 100644 > --- a/drivers/gpu/drm/drm_mode_config.c > +++ b/drivers/gpu/drm/drm_mode_config.c > @@ -381,6 +381,7 @@ void drm_mode_config_init(struct drm_device *dev) > idr_init(&dev->mode_config.tile_idr); > ida_init(&dev->mode_config.connector_ida); > spin_lock_init(&dev->mode_config.connector_list_lock); > + init_waitqueue_head(&dev->mode_config.connector_free_queue); > > drm_mode_create_standard_properties(dev); > > @@ -431,8 +432,11 @@ 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(); > + wait_event(dev->mode_config.connector_free_queue, > + !atomic_read(&dev->mode_config.connector_free_works)); > + > 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) > diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h > index a0afeb591dcb..83a7db997e83 100644 > --- a/include/drm/drm_mode_config.h > +++ b/include/drm/drm_mode_config.h > @@ -413,6 +413,19 @@ struct drm_mode_config { > * &struct drm_connector_list_iter to walk this list. > */ > struct list_head connector_list; > + /** > + * @pending_connector_free_works: > + * > + * Number of scheduled connector->free_work instances, see > + * drm_connector_put_safe(). > + */ > + atomic_t connector_free_works; > + /** > + * @pending_connector_free_queue: > + * > + * Wait queue for waiting until connector->free_work is finished. > + */ > + wait_queue_head_t connector_free_queue; > /** > * @num_encoder: > * > -- > 2.15.0 > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel
Hi Marek, I love your patch! Perhaps something to improve: [auto build test WARNING on v4.15-rc3] [cannot apply to drm/drm-next drm-exynos/exynos-drm/for-next drm-intel/for-linux-next next-20171215] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] url: https://github.com/0day-ci/linux/commits/Marek-Szyprowski/drm-Fix-possible-deadlock-in-drm_mode_config_cleanup/20171216-102239 reproduce: make htmldocs All warnings (new ones prefixed by >>): include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' include/net/cfg80211.h:3278: warning: Excess enum value 'WIPHY_FLAG_SUPPORTS_SCHED_SCAN' description in 'wiphy_flags' kernel/sched/core.c:5113: warning: No description found for parameter 't' kernel/sched/core.c:5113: warning: Excess function parameter 'interval' description in 'sched_rr_get_interval' drivers/gpio/gpiolib.c:601: warning: No description found for parameter '16' drivers/gpio/gpiolib.c:601: warning: Excess struct member 'events' description in 'lineevent_state' include/linux/iio/iio.h:610: warning: No description found for parameter 'iio_dev' include/linux/iio/iio.h:610: warning: Excess function parameter 'indio_dev' description in 'iio_device_register' include/linux/iio/trigger.h:79: warning: No description found for parameter 'owner' fs/inode.c:1680: warning: No description found for parameter 'rcu' include/linux/jbd2.h:443: warning: No description found for parameter 'i_transaction' include/linux/jbd2.h:443: warning: No description found for parameter 'i_next_transaction' include/linux/jbd2.h:443: warning: No description found for parameter 'i_list' include/linux/jbd2.h:443: warning: No description found for parameter 'i_vfs_inode' include/linux/jbd2.h:443: warning: No description found for parameter 'i_flags' include/linux/jbd2.h:497: warning: No description found for parameter 'h_rsv_handle' include/linux/jbd2.h:497: warning: No description found for parameter 'h_reserved' include/linux/jbd2.h:497: warning: No description found for parameter 'h_type' include/linux/jbd2.h:497: warning: No description found for parameter 'h_line_no' include/linux/jbd2.h:497: warning: No description found for parameter 'h_start_jiffies' include/linux/jbd2.h:497: warning: No description found for parameter 'h_requested_credits' include/linux/jbd2.h:497: warning: No description found for parameter 'saved_alloc_context' include/linux/jbd2.h:1050: warning: No description found for parameter 'j_chkpt_bhs' include/linux/jbd2.h:1050: warning: No description found for parameter 'j_devname' include/linux/jbd2.h:1050: warning: No description found for parameter 'j_average_commit_time' include/linux/jbd2.h:1050: warning: No description found for parameter 'j_min_batch_time' include/linux/jbd2.h:1050: warning: No description found for parameter 'j_max_batch_time' include/linux/jbd2.h:1050: warning: No description found for parameter 'j_commit_callback' include/linux/jbd2.h:1050: warning: No description found for parameter 'j_failed_commit' include/linux/jbd2.h:1050: warning: No description found for parameter 'j_chksum_driver' include/linux/jbd2.h:1050: warning: No description found for parameter 'j_csum_seed' fs/jbd2/transaction.c:511: warning: No description found for parameter 'type' fs/jbd2/transaction.c:511: warning: No description found for parameter 'line_no' fs/jbd2/transaction.c:641: warning: No description found for parameter 'gfp_mask' include/drm/drm_drv.h:594: warning: No description found for parameter 'gem_prime_pin' include/drm/drm_drv.h:594: warning: No description found for parameter 'gem_prime_unpin' include/drm/drm_drv.h:594: warning: No description found for parameter 'gem_prime_res_obj' include/drm/drm_drv.h:594: warning: No description found for parameter 'gem_prime_get_sg_table' include/drm/drm_drv.h:594: warning: No description found for parameter 'gem_prime_import_sg_table' include/drm/drm_drv.h:594: warning: No description found for parameter 'gem_prime_vmap' include/drm/drm_drv.h:594: warning: No description found for parameter 'gem_prime_vunmap' include/drm/drm_drv.h:594: warning: No description found for parameter 'gem_prime_mmap' include/drm/drm_mode_config.h:778: warning: No description found for parameter 'connector_free_works' include/drm/drm_mode_config.h:778: warning: No description found for parameter 'connector_free_queue' include/drm/drm_mode_config.h:778: warning: No description found for parameter 'modifiers_property' >> include/drm/drm_mode_config.h:778: warning: Excess struct member 'pending_connector_free_works' description in 'drm_mode_config' >> include/drm/drm_mode_config.h:778: warning: Excess struct member 'pending_connector_free_queue' description in 'drm_mode_config' include/drm/drm_mode_config.h:778: warning: Excess struct member 'modifiers' description in 'drm_mode_config' include/drm/drm_plane.h:552: warning: No description found for parameter 'modifiers' include/drm/drm_plane.h:552: warning: No description found for parameter 'modifier_count' drivers/gpu/drm/drm_edid.c:4837: warning: No description found for parameter 'is_hdmi2_sink' drivers/gpu/drm/drm_syncobj.c:306: warning: No description found for parameter 'file_private' drivers/gpu/drm/drm_syncobj.c:306: warning: No description found for parameter 'syncobj' drivers/gpu/drm/drm_syncobj.c:306: warning: No description found for parameter 'handle' drivers/gpu/drm/drm_syncobj.c:307: warning: No description found for parameter 'file_private' drivers/gpu/drm/drm_syncobj.c:307: warning: No description found for parameter 'syncobj' drivers/gpu/drm/drm_syncobj.c:307: warning: No description found for parameter 'handle' drivers/gpu/drm/i915/i915_gem.c:548: warning: No description found for parameter 'rps_client' drivers/gpu/drm/i915/i915_gem.c:548: warning: Excess function parameter 'rps' description in 'i915_gem_object_wait' Error: Cannot open file drivers/gpu/drm/i915/intel_guc_loader.c WARNING: kernel-doc 'scripts/kernel-doc -rst -enable-lineno -function GuC-specific firmware loader drivers/gpu/drm/i915/intel_guc_loader.c' failed with return code 1 Error: Cannot open file drivers/gpu/drm/i915/intel_guc_loader.c Error: Cannot open file drivers/gpu/drm/i915/intel_guc_loader.c WARNING: kernel-doc 'scripts/kernel-doc -rst -enable-lineno -internal drivers/gpu/drm/i915/intel_guc_loader.c' failed with return code 2 drivers/gpu/host1x/bus.c:50: warning: No description found for parameter 'driver' drivers/gpu/drm/tve200/tve200_drv.c:1: warning: no structured comments found net/core/dev.c:1678: warning: Excess function parameter 'dev' description in 'call_netdevice_notifiers_info' net/core/dev.c:6361: warning: No description found for parameter 'extack' net/core/dev.c:6384: warning: No description found for parameter 'extack' include/linux/rcupdate.h:571: ERROR: Unexpected indentation. include/linux/rcupdate.h:575: ERROR: Unexpected indentation. include/linux/rcupdate.h:579: WARNING: Block quote ends without a blank line; unexpected unindent. include/linux/rcupdate.h:581: WARNING: Block quote ends without a blank line; unexpected unindent. include/linux/rcupdate.h:581: WARNING: Inline literal start-string without end-string. kernel/time/timer.c:1253: ERROR: Unexpected indentation. kernel/time/timer.c:1255: ERROR: Unexpected indentation. kernel/time/timer.c:1256: WARNING: Block quote ends without a blank line; unexpected unindent. include/linux/wait.h:110: WARNING: Block quote ends without a blank line; unexpected unindent. include/linux/wait.h:113: ERROR: Unexpected indentation. include/linux/wait.h:115: WARNING: Block quote ends without a blank line; unexpected unindent. kernel/time/hrtimer.c:989: WARNING: Block quote ends without a blank line; unexpected unindent. kernel/signal.c:325: WARNING: Inline literal start-string without end-string. include/linux/iio/iio.h:219: ERROR: Unexpected indentation. include/linux/iio/iio.h:220: WARNING: Block quote ends without a blank line; unexpected unindent. include/linux/iio/iio.h:226: WARNING: Definition list ends without a blank line; unexpected unindent. drivers/ata/libata-core.c:5913: ERROR: Unknown target name: "hw". drivers/message/fusion/mptbase.c:5051: WARNING: Definition list ends without a blank line; unexpected unindent. drivers/tty/serial/serial_core.c:1899: WARNING: Definition list ends without a blank line; unexpected unindent. include/linux/regulator/driver.h:271: ERROR: Unknown target name: "regulator_regmap_x_voltage". include/linux/spi/spi.h:373: ERROR: Unexpected indentation. drivers/w1/w1_io.c:197: WARNING: Definition list ends without a blank line; unexpected unindent. net/core/dev.c:4483: ERROR: Unknown target name: "page_is". Documentation/trace/ftrace-uses.rst:53: WARNING: Definition list ends without a blank line; unexpected unindent. Documentation/trace/ftrace-uses.rst:89: WARNING: Inline emphasis start-string without end-string. Documentation/trace/ftrace-uses.rst:89: WARNING: Inline emphasis start-string without end-string. Documentation/errseq.rst:: WARNING: document isn't included in any toctree Documentation/networking/msg_zerocopy.rst:: WARNING: document isn't included in any toctree Documentation/trace/ftrace-uses.rst:: WARNING: document isn't included in any toctree Documentation/virtual/kvm/vcpu-requests.rst:: WARNING: document isn't included in any toctree Documentation/dev-tools/kselftest.rst:15: WARNING: Could not lex literal_block as "c". Highlighting skipped. 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in <test> isn't supported and may not work as expected Fontconfig warning: "/home/kbuild/.config/fontconfig/fonts.conf", line 164: Having multiple values in <test> isn't supported and may not work as expected Fontconfig warning: "/home/kbuild/.config/fontconfig/fonts.conf", line 193: Having multiple values in <test> isn't supported and may not work as expected Fontconfig warning: "~/.fonts.conf", line 43: Having multiple values in <test> isn't supported and may not work as expected Fontconfig warning: "~/.fonts.conf", line 56: Having multiple values in <test> isn't supported and may not work as expected Fontconfig warning: "~/.fonts.conf", line 69: Having multiple values in <test> isn't supported and may not work as expected Fontconfig warning: "~/.fonts.conf", line 82: Having multiple values in <test> isn't supported and may not work as expected Fontconfig warning: "~/.fonts.conf", line 96: Having multiple values in <test> isn't supported and may not work as expected Fontconfig warning: "~/.fonts.conf", line 109: Having multiple values in <test> isn't supported and may not work as expected Fontconfig warning: "~/.fonts.conf", line 122: Having multiple values in <test> isn't supported and may not work as expected Fontconfig warning: "~/.fonts.conf", line 133: Having multiple values in <test> isn't supported and may not work as expected Fontconfig warning: "~/.fonts.conf", line 164: Having multiple values in <test> isn't supported and may not work as expected Fontconfig warning: "~/.fonts.conf", line 193: Having multiple values in <test> isn't supported and may not work as expected Fontconfig warning: "/home/kbuild/.config/fontconfig/fonts.conf", line 43: Having multiple values in <test> isn't supported and may not work as expected Fontconfig warning: "/home/kbuild/.config/fontconfig/fonts.conf", line 56: Having multiple values in <test> isn't supported and may not work as expected Fontconfig warning: "/home/kbuild/.config/fontconfig/fonts.conf", line 69: Having multiple values in <test> isn't supported and may not work as expected Fontconfig warning: "/home/kbuild/.config/fontconfig/fonts.conf", line 82: Having multiple values in <test> isn't supported and may not work as expected Fontconfig warning: "/home/kbuild/.config/fontconfig/fonts.conf", line 96: Having multiple values in <test> isn't supported and may not work as expected Fontconfig warning: "/home/kbuild/.config/fontconfig/fonts.conf", line 109: Having multiple values in <test> isn't supported and may not work as expected Fontconfig warning: "/home/kbuild/.config/fontconfig/fonts.conf", line 122: Having multiple values in <test> isn't supported and may not work as expected vim +778 include/drm/drm_mode_config.h 28575f16 Daniel Vetter 2016-11-14 @778 :::::: The code at line 778 was first introduced by commit :::::: 28575f165d36051310d7ea2350e2011f8095b6fb drm: Extract drm_mode_config.[hc] :::::: TO: Daniel Vetter <daniel.vetter@ffwll.ch> :::::: CC: Daniel Vetter <daniel.vetter@ffwll.ch> --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index 0b7e0974e6da..7620ac1ad1b1 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -161,6 +161,8 @@ static void drm_connector_free_work_fn(struct work_struct *work) drm_mode_object_unregister(dev, &connector->base); connector->funcs->destroy(connector); + atomic_dec(&dev->mode_config.connector_free_works); + wake_up_all(&dev->mode_config.connector_free_queue); } /** @@ -552,8 +554,10 @@ EXPORT_SYMBOL(drm_connector_list_iter_begin); static void drm_connector_put_safe(struct drm_connector *conn) { - if (refcount_dec_and_test(&conn->base.refcount.refcount)) + if (refcount_dec_and_test(&conn->base.refcount.refcount)) { + atomic_inc(&conn->dev->mode_config.connector_free_works); schedule_work(&conn->free_work); + } } /** diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c index 6ffe952142e6..cca443faebd8 100644 --- a/drivers/gpu/drm/drm_mode_config.c +++ b/drivers/gpu/drm/drm_mode_config.c @@ -381,6 +381,7 @@ void drm_mode_config_init(struct drm_device *dev) idr_init(&dev->mode_config.tile_idr); ida_init(&dev->mode_config.connector_ida); spin_lock_init(&dev->mode_config.connector_list_lock); + init_waitqueue_head(&dev->mode_config.connector_free_queue); drm_mode_create_standard_properties(dev); @@ -431,8 +432,11 @@ 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(); + wait_event(dev->mode_config.connector_free_queue, + !atomic_read(&dev->mode_config.connector_free_works)); + 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) diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h index a0afeb591dcb..83a7db997e83 100644 --- a/include/drm/drm_mode_config.h +++ b/include/drm/drm_mode_config.h @@ -413,6 +413,19 @@ struct drm_mode_config { * &struct drm_connector_list_iter to walk this list. */ struct list_head connector_list; + /** + * @pending_connector_free_works: + * + * Number of scheduled connector->free_work instances, see + * drm_connector_put_safe(). + */ + atomic_t connector_free_works; + /** + * @pending_connector_free_queue: + * + * Wait queue for waiting until connector->free_work is finished. + */ + wait_queue_head_t connector_free_queue; /** * @num_encoder: *
drm_mode_config_cleanup() might be called from a workqueue context (for example in error path handling of deferred probe), so it must not call flush_scheduled_work(), because it would deadlock in such case. Replace that call with explicit counting of the scheduled connector free works and waiting until it reaches zero. Fixes: a703c55004e1 ("drm: safely free connectors from connector_iter") Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> --- This fixes the issue discussed in the following thread: https://www.spinics.net/lists/arm-kernel/msg622332.html --- drivers/gpu/drm/drm_connector.c | 6 +++++- drivers/gpu/drm/drm_mode_config.c | 6 +++++- include/drm/drm_mode_config.h | 13 +++++++++++++ 3 files changed, 23 insertions(+), 2 deletions(-)