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Date: Mon, 29 Jul 2019 21:21:47 +0200 From: Greg Kroah-Hartman <gregkh@...uxfoundation.org> To: linux-kernel@...r.kernel.org Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, stable@...r.kernel.org, Rodrigo Siqueira <rodrigosiqueiramelo@...il.com>, Tomeu Vizoso <tomeu.vizoso@...labora.com>, Emil Velikov <emil.velikov@...labora.com>, Benjamin Gaignard <benjamin.gaignard@...aro.org>, Ville Syrjälä <ville.syrjala@...ux.intel.com>, Daniel Vetter <daniel.vetter@...el.com>, Sasha Levin <sashal@...nel.org> Subject: [PATCH 4.19 020/113] drm/crc-debugfs: User irqsafe spinlock in drm_crtc_add_crc_entry [ 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@...il.com> Cc: Tomeu Vizoso <tomeu.vizoso@...labora.com> Cc: Emil Velikov <emil.velikov@...labora.com> Cc: Benjamin Gaignard <benjamin.gaignard@...aro.org> Reviewed-by: Benjamin Gaignard <benjamin.gaignard@...aro.org> Reviewed-by: Ville Syrjälä <ville.syrjala@...ux.intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@...el.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190605194556.16744-1-daniel.vetter@ffwll.ch Signed-off-by: Sasha Levin <sashal@...nel.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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