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Message-Id: <20190729190747.977638588@linuxfoundation.org>
Date: Mon, 29 Jul 2019 21:20:39 +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 5.2 043/215] 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 00e743153e94..1a6a5b78e30f 100644
--- a/drivers/gpu/drm/drm_debugfs_crc.c
+++ b/drivers/gpu/drm/drm_debugfs_crc.c
@@ -389,8 +389,9 @@ 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) {
@@ -421,7 +422,7 @@ 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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