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authorRui Wang <rui.y.wang@intel.com>2014-12-15 11:28:26 -0800
committerDave Airlie <airlied@redhat.com>2015-01-21 09:26:15 +1000
commit9aa609e1a3846d3c17087b62579867bab0f488de (patch)
treef71359659439c5fe60588610c7963c74d9be09b4
parente902027a64589e53b6d6d7851438ffb4c65a572b (diff)
downloadlinux-9aa609e1a3846d3c17087b62579867bab0f488de.tar.gz
drm: fb helper should avoid sleeping in panic context
There are still some places in the fb helper that need to avoid sleeping in panic context. Here's an example: [ 65.615496] bad: scheduling from the idle thread! [ 65.620747] CPU: 92 PID: 0 Comm: swapper/92 Tainted: G M E 3.18.0-rc4-7-default+ #20 [ 65.630364] Hardware name: Intel Corporation BRICKLAND/BRICKLAND, BIOS BRHSXSD1.86B.0056.R01.1409242327 09/24/2014 [ 65.641923] ffff88087f693d80 ffff88087f689878 ffffffff81566db9 0000000000000000 [ 65.650226] ffff88087f693d80 ffff88087f689898 ffffffff810871ff ffff88046eb3e0d0 [ 65.658527] ffff88087f693d80 ffff88087f6898c8 ffffffff8107c1fa 000000017f6898b8 [ 65.666830] Call Trace: [ 65.669557] <#MC> [<ffffffff81566db9>] dump_stack+0x46/0x58 [ 65.675994] [<ffffffff810871ff>] dequeue_task_idle+0x2f/0x40 [ 65.682412] [<ffffffff8107c1fa>] dequeue_task+0x5a/0x80 [ 65.688345] [<ffffffff810804f3>] deactivate_task+0x23/0x30 [ 65.694569] [<ffffffff81569050>] __schedule+0x580/0x7f0 [ 65.700502] [<ffffffff81569739>] schedule_preempt_disabled+0x29/0x70 [ 65.707696] [<ffffffff8156abb6>] __ww_mutex_lock_slowpath+0xb8/0x162 [ 65.714891] [<ffffffff8156acb3>] __ww_mutex_lock+0x53/0x85 [ 65.721125] [<ffffffffa00b3a5d>] drm_modeset_lock+0x3d/0x110 [drm] [ 65.728132] [<ffffffffa00b3c2a>] __drm_modeset_lock_all+0x8a/0x120 [drm] [ 65.735721] [<ffffffffa00b3cd0>] drm_modeset_lock_all+0x10/0x30 [drm] [ 65.743015] [<ffffffffa01af8bf>] drm_fb_helper_pan_display+0x2f/0xf0 [drm_kms_helper] [ 65.751857] [<ffffffff8132bd21>] fb_pan_display+0xd1/0x1a0 [ 65.758081] [<ffffffff81326010>] bit_update_start+0x20/0x50 [ 65.764400] [<ffffffff813259f2>] fbcon_switch+0x3a2/0x550 [ 65.770528] [<ffffffff813a01c9>] redraw_screen+0x189/0x240 [ 65.776750] [<ffffffff81322f8a>] fbcon_blank+0x20a/0x2d0 [ 65.782778] [<ffffffff8137d359>] ? erst_writer+0x209/0x330 [ 65.789002] [<ffffffff810ba2f3>] ? internal_add_timer+0x63/0x80 [ 65.795710] [<ffffffff810bc137>] ? mod_timer+0x127/0x1e0 [ 65.801740] [<ffffffff813a0cd8>] do_unblank_screen+0xa8/0x1d0 [ 65.808255] [<ffffffff813a0e10>] unblank_screen+0x10/0x20 [ 65.814381] [<ffffffff812ca0d9>] bust_spinlocks+0x19/0x40 [ 65.820508] [<ffffffff81561ca7>] panic+0x106/0x1f5 [ 65.825955] [<ffffffff8102336c>] mce_panic+0x2ac/0x2e0 [ 65.831789] [<ffffffff812c796a>] ? delay_tsc+0x4a/0x80 [ 65.837625] [<ffffffff81024e1f>] do_machine_check+0xbaf/0xbf0 [ 65.844138] [<ffffffff813365d7>] ? intel_idle+0xc7/0x150 [ 65.850166] [<ffffffff8156f03f>] machine_check+0x1f/0x30 [ 65.856195] [<ffffffff813365d7>] ? intel_idle+0xc7/0x150 [ 65.862222] <<EOE>> [<ffffffff814283d5>] cpuidle_enter_state+0x55/0x170 [ 65.869823] [<ffffffff814285a7>] cpuidle_enter+0x17/0x20 [ 65.875852] [<ffffffff81097b08>] cpu_startup_entry+0x2d8/0x370 [ 65.882467] [<ffffffff8102fe29>] start_secondary+0x159/0x180 There's __drm_modeset_lock_all() which Daniel Vetter introduced for this purpose. We can leverage that without reinventing anything. This patch works with the latest kernel. Reviewed-by: Rob Clark <robdclark@gmail.com> Tested-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Rui Wang <rui.y.wang@intel.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
-rw-r--r--drivers/gpu/drm/drm_fb_helper.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 52ce26d6b4f..cf775a4449c 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -741,7 +741,9 @@ int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
int i, j, rc = 0;
int start;
- drm_modeset_lock_all(dev);
+ if (__drm_modeset_lock_all(dev, !!oops_in_progress)) {
+ return -EBUSY;
+ }
if (!drm_fb_helper_is_bound(fb_helper)) {
drm_modeset_unlock_all(dev);
return -EBUSY;
@@ -915,7 +917,9 @@ int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
int ret = 0;
int i;
- drm_modeset_lock_all(dev);
+ if (__drm_modeset_lock_all(dev, !!oops_in_progress)) {
+ return -EBUSY;
+ }
if (!drm_fb_helper_is_bound(fb_helper)) {
drm_modeset_unlock_all(dev);
return -EBUSY;