[PATCH 2/2] Revert "drm/omapdrm: Annotate dma-fence critical section in commit path"
From: Tomi Valkeinen
Date: Wed Sep 20 2023 - 08:58:28 EST
This reverts commit 250aa22920cd5d956a5d3e9c6a43d671c2bae217.
The DMA-fence annotations cause a lockdep warning (see below). As per
https://patchwork.freedesktop.org/patch/462170/ it sounds like the
annotations don't work correctly.
======================================================
WARNING: possible circular locking dependency detected
6.5.0-rc2+ #2 Not tainted
------------------------------------------------------
kmstest/219 is trying to acquire lock:
c4705838 (&hdmi->lock){+.+.}-{3:3}, at: hdmi5_bridge_mode_set+0x1c/0x50
but task is already holding lock:
c11e1128 (dma_fence_map){++++}-{0:0}, at: omap_atomic_commit_tail+0x14/0xbc
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (dma_fence_map){++++}-{0:0}:
__dma_fence_might_wait+0x48/0xb4
dma_resv_lockdep+0x1b8/0x2bc
do_one_initcall+0x68/0x3b0
kernel_init_freeable+0x260/0x34c
kernel_init+0x14/0x140
ret_from_fork+0x14/0x28
-> #1 (fs_reclaim){+.+.}-{0:0}:
fs_reclaim_acquire+0x70/0xa8
__kmem_cache_alloc_node+0x3c/0x368
kmalloc_trace+0x28/0x58
_drm_do_get_edid+0x7c/0x35c
hdmi5_bridge_get_edid+0xc8/0x1ac
drm_bridge_connector_get_modes+0x64/0xc0
drm_helper_probe_single_connector_modes+0x170/0x528
drm_client_modeset_probe+0x208/0x1334
__drm_fb_helper_initial_config_and_unlock+0x30/0x548
omap_fbdev_client_hotplug+0x3c/0x6c
drm_client_register+0x58/0x94
pdev_probe+0x544/0x6b0
platform_probe+0x58/0xbc
really_probe+0xd8/0x3fc
__driver_probe_device+0x94/0x1f4
driver_probe_device+0x2c/0xc4
__device_attach_driver+0xa4/0x11c
bus_for_each_drv+0x84/0xdc
__device_attach+0xac/0x20c
bus_probe_device+0x8c/0x90
device_add+0x588/0x7e0
platform_device_add+0x110/0x24c
platform_device_register_full+0x108/0x15c
dss_bind+0x90/0xc0
try_to_bring_up_aggregate_device+0x1e0/0x2c8
__component_add+0xa4/0x174
hdmi5_probe+0x1c8/0x270
platform_probe+0x58/0xbc
really_probe+0xd8/0x3fc
__driver_probe_device+0x94/0x1f4
driver_probe_device+0x2c/0xc4
__device_attach_driver+0xa4/0x11c
bus_for_each_drv+0x84/0xdc
__device_attach+0xac/0x20c
bus_probe_device+0x8c/0x90
deferred_probe_work_func+0x8c/0xd8
process_one_work+0x2ac/0x6e4
worker_thread+0x30/0x4ec
kthread+0x100/0x124
ret_from_fork+0x14/0x28
-> #0 (&hdmi->lock){+.+.}-{3:3}:
__lock_acquire+0x145c/0x29cc
lock_acquire.part.0+0xb4/0x258
__mutex_lock+0x90/0x950
mutex_lock_nested+0x1c/0x24
hdmi5_bridge_mode_set+0x1c/0x50
drm_bridge_chain_mode_set+0x48/0x5c
crtc_set_mode+0x188/0x1d0
omap_atomic_commit_tail+0x2c/0xbc
commit_tail+0x9c/0x188
drm_atomic_helper_commit+0x158/0x18c
drm_atomic_commit+0xa4/0xe8
drm_mode_atomic_ioctl+0x9a4/0xc38
drm_ioctl+0x210/0x4a8
sys_ioctl+0x138/0xf00
ret_fast_syscall+0x0/0x1c
other info that might help us debug this:
Chain exists of:
&hdmi->lock --> fs_reclaim --> dma_fence_map
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
rlock(dma_fence_map);
lock(fs_reclaim);
lock(dma_fence_map);
lock(&hdmi->lock);
*** DEADLOCK ***
3 locks held by kmstest/219:
#0: f1011de4 (crtc_ww_class_acquire){+.+.}-{0:0}, at: drm_mode_atomic_ioctl+0xf0/0xc38
#1: c47059c8 (crtc_ww_class_mutex){+.+.}-{3:3}, at: modeset_lock+0xf8/0x230
#2: c11e1128 (dma_fence_map){++++}-{0:0}, at: omap_atomic_commit_tail+0x14/0xbc
stack backtrace:
CPU: 1 PID: 219 Comm: kmstest Not tainted 6.5.0-rc2+ #2
Hardware name: Generic DRA74X (Flattened Device Tree)
unwind_backtrace from show_stack+0x10/0x14
show_stack from dump_stack_lvl+0x58/0x70
dump_stack_lvl from check_noncircular+0x164/0x198
check_noncircular from __lock_acquire+0x145c/0x29cc
__lock_acquire from lock_acquire.part.0+0xb4/0x258
lock_acquire.part.0 from __mutex_lock+0x90/0x950
__mutex_lock from mutex_lock_nested+0x1c/0x24
mutex_lock_nested from hdmi5_bridge_mode_set+0x1c/0x50
hdmi5_bridge_mode_set from drm_bridge_chain_mode_set+0x48/0x5c
drm_bridge_chain_mode_set from crtc_set_mode+0x188/0x1d0
crtc_set_mode from omap_atomic_commit_tail+0x2c/0xbc
omap_atomic_commit_tail from commit_tail+0x9c/0x188
commit_tail from drm_atomic_helper_commit+0x158/0x18c
drm_atomic_helper_commit from drm_atomic_commit+0xa4/0xe8
drm_atomic_commit from drm_mode_atomic_ioctl+0x9a4/0xc38
drm_mode_atomic_ioctl from drm_ioctl+0x210/0x4a8
drm_ioctl from sys_ioctl+0x138/0xf00
sys_ioctl from ret_fast_syscall+0x0/0x1c
Exception stack(0xf1011fa8 to 0xf1011ff0)
1fa0: 00466d58 be9ab510 00000003 c03864bc be9ab510 be9ab4e0
1fc0: 00466d58 be9ab510 c03864bc 00000036 00466ef0 00466fc0 00467020 00466f20
1fe0: b6bc7ef4 be9ab4d0 b6bbbb00 b6cb2cc0
Fixes: 250aa22920cd ("drm/omapdrm: Annotate dma-fence critical section in commit path")
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/omapdrm/omap_drv.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/omapdrm/omap_drv.c b/drivers/gpu/drm/omapdrm/omap_drv.c
index afeeb7737552..e000577a95dd 100644
--- a/drivers/gpu/drm/omapdrm/omap_drv.c
+++ b/drivers/gpu/drm/omapdrm/omap_drv.c
@@ -69,7 +69,6 @@ static void omap_atomic_commit_tail(struct drm_atomic_state *old_state)
{
struct drm_device *dev = old_state->dev;
struct omap_drm_private *priv = dev->dev_private;
- bool fence_cookie = dma_fence_begin_signalling();
dispc_runtime_get(priv->dispc);
@@ -92,6 +91,8 @@ static void omap_atomic_commit_tail(struct drm_atomic_state *old_state)
omap_atomic_wait_for_completion(dev, old_state);
drm_atomic_helper_commit_planes(dev, old_state, 0);
+
+ drm_atomic_helper_commit_hw_done(old_state);
} else {
/*
* OMAP3 DSS seems to have issues with the work-around above,
@@ -101,11 +102,9 @@ static void omap_atomic_commit_tail(struct drm_atomic_state *old_state)
drm_atomic_helper_commit_planes(dev, old_state, 0);
drm_atomic_helper_commit_modeset_enables(dev, old_state);
- }
- drm_atomic_helper_commit_hw_done(old_state);
-
- dma_fence_end_signalling(fence_cookie);
+ drm_atomic_helper_commit_hw_done(old_state);
+ }
/*
* Wait for completion of the page flips to ensure that old buffers
--
2.34.1