| From | Sasha Levin <> | Subject | [PATCH AUTOSEL 4.19 020/101] drm/crc-debugfs: User irqsafe spinlock in drm_crtc_add_crc_entry | Date | Fri, 19 Jul 2019 00:06:11 -0400 |
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From: Daniel Vetter <daniel.vetter@ffwll.ch>
[ Upstream commit 1882018a70e06376234133e69ede9dd743b4dbd9 ]
We can be called from any context, we need to be prepared.
Noticed this while hacking on vkms, which calls this function from a normal worker. Which really upsets lockdep.
Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com> Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com> Cc: Emil Velikov <emil.velikov@collabora.com> Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org> Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190605194556.16744-1-daniel.vetter@ffwll.ch Signed-off-by: Sasha Levin <sashal@kernel.org> --- drivers/gpu/drm/drm_debugfs_crc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_debugfs_crc.c b/drivers/gpu/drm/drm_debugfs_crc.c index 99961192bf03..a334a82fcb36 100644 --- a/drivers/gpu/drm/drm_debugfs_crc.c +++ b/drivers/gpu/drm/drm_debugfs_crc.c @@ -379,8 +379,9 @@ int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame, struct drm_crtc_crc *crc = &crtc->crc; struct drm_crtc_crc_entry *entry; int head, tail; + unsigned long flags; - spin_lock(&crc->lock); + spin_lock_irqsave(&crc->lock, flags); /* Caller may not have noticed yet that userspace has stopped reading */ if (!crc->entries) { @@ -411,7 +412,7 @@ int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame, head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1); crc->head = head; - spin_unlock(&crc->lock); + spin_unlock_irqrestore(&crc->lock, flags); wake_up_interruptible(&crc->wq); -- 2.20.1
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