[PATCH] drm/nouveau: fix lockdep splat in display
Maarten Lankhorst
maarten.lankhorst at canonical.com
Tue Feb 5 02:29:59 PST 2013
Add a flag NVOBJ_FLAG_CREAT_EXCL, which will make sure that only 1 engctx will be created.
This removes the need of having multiple
Fixes the following lockdep splat:
=============================================
[ INFO: possible recursive locking detected ]
3.8.0-rc6-ninja+ #1 Not tainted
---------------------------------------------
modprobe/585 is trying to acquire lock:
(&subdev->mutex){+.+.+.}, at: [<ffffffffa016c323>]
nouveau_instobj_create_+0x43/0x90 [nouveau]
but task is already holding lock:
(&subdev->mutex){+.+.+.}, at: [<ffffffffa017672d>]
nv50_disp_data_ctor+0x5d/0xd0 [nouveau]
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&subdev->mutex);
lock(&subdev->mutex);
*** DEADLOCK ***
May be due to missing lock nesting notation
4 locks held by modprobe/585:
#0: (&__lockdep_no_validate__){......}, at: [<ffffffff813075f3>]
__driver_attach+0x53/0xb0
#1: (&__lockdep_no_validate__){......}, at: [<ffffffff81307601>]
__driver_attach+0x61/0xb0
#2: (drm_global_mutex){+.+.+.}, at: [<ffffffff812ee59c>]
drm_get_pci_dev+0xbc/0x2b0
#3: (&subdev->mutex){+.+.+.}, at: [<ffffffffa017672d>]
nv50_disp_data_ctor+0x5d/0xd0 [nouveau]
stack backtrace:
Pid: 585, comm: modprobe Not tainted 3.8.0-rc6-expert+ #1
Call Trace:
[<ffffffff8108fde2>] validate_chain.isra.33+0xd72/0x10d0
[<ffffffff8105fa08>] ? __kernel_text_address+0x58/0x80
[<ffffffff8100575d>] ? print_context_stack+0x5d/0xd0
[<ffffffff81090bc1>] __lock_acquire+0x3a1/0xb60
[<ffffffff8108d504>] ? __lock_is_held+0x54/0x80
[<ffffffff8109184a>] lock_acquire+0x5a/0x70
[<ffffffffa016c323>] ? nouveau_instobj_create_+0x43/0x90 [nouveau]
[<ffffffff81558739>] mutex_lock_nested+0x69/0x340
[<ffffffffa016c323>] ? nouveau_instobj_create_+0x43/0x90 [nouveau]
[<ffffffffa0152370>] ? nouveau_object_create_+0x60/0xa0 [nouveau]
[<ffffffffa016c323>] nouveau_instobj_create_+0x43/0x90 [nouveau]
[<ffffffffa016cf8c>] nv50_instobj_ctor+0x4c/0xf0 [nouveau]
[<ffffffffa0152163>] nouveau_object_ctor+0x33/0xc0 [nouveau]
[<ffffffffa016cd51>] nv50_instmem_alloc+0x21/0x30 [nouveau]
[<ffffffffa0150917>] nouveau_gpuobj_create_+0x247/0x2f0 [nouveau]
[<ffffffff8155b35a>] ? _raw_spin_unlock_irqrestore+0x3a/0x70
[<ffffffff810921fd>] ? trace_hardirqs_on_caller+0x10d/0x1a0
[<ffffffffa014f4bc>] nouveau_engctx_create_+0x25c/0x2a0 [nouveau]
[<ffffffffa0176791>] nv50_disp_data_ctor+0xc1/0xd0 [nouveau]
[<ffffffffa0153722>] ? nouveau_subdev_reset+0x52/0x60 [nouveau]
[<ffffffffa0152163>] nouveau_object_ctor+0x33/0xc0 [nouveau]
[<ffffffffa0152a42>] nouveau_object_new+0x112/0x240 [nouveau]
[<ffffffffa01f4b1d>] nv50_display_create+0x18d/0x860 [nouveau]
[<ffffffff8105cb5d>] ? __cancel_work_timer+0x6d/0xc0
[<ffffffffa01db8eb>] nouveau_display_create+0x3cb/0x670 [nouveau]
[<ffffffffa01cb1bf>] nouveau_drm_load+0x26f/0x590 [nouveau]
[<ffffffff81304c99>] ? device_register+0x19/0x20
[<ffffffff812efe91>] ? drm_sysfs_device_add+0x81/0xb0
[<ffffffff812ee65e>] drm_get_pci_dev+0x17e/0x2b0
[<ffffffff81245e56>] ? __pci_set_master+0x26/0x80
[<ffffffffa01cab2a>] nouveau_drm_probe+0x25a/0x2a0 [nouveau]
[<ffffffff8124a386>] local_pci_probe+0x46/0x80
[<ffffffff8124ac11>] pci_device_probe+0x101/0x110
[<ffffffff813073d6>] driver_probe_device+0x76/0x240
[<ffffffff81307643>] __driver_attach+0xa3/0xb0
[<ffffffff813075a0>] ? driver_probe_device+0x240/0x240
[<ffffffff8130564d>] bus_for_each_dev+0x4d/0x90
[<ffffffff81306f39>] driver_attach+0x19/0x20
[<ffffffff81306af0>] bus_add_driver+0x1a0/0x270
[<ffffffffa023d000>] ? 0xffffffffa023cfff
[<ffffffff81307cd2>] driver_register+0x72/0x170
[<ffffffffa023d000>] ? 0xffffffffa023cfff
[<ffffffff8124ad0f>] __pci_register_driver+0x5f/0x70
[<ffffffff812ee8a5>] drm_pci_init+0x115/0x130
[<ffffffffa023d000>] ? 0xffffffffa023cfff
[<ffffffffa023d000>] ? 0xffffffffa023cfff
[<ffffffffa023d04d>] nouveau_drm_init+0x4d/0x1000 [nouveau]
[<ffffffff810002da>] do_one_initcall+0x11a/0x170
[<ffffffff8109d044>] load_module+0xe84/0x1470
[<ffffffff81098c30>] ? in_lock_functions+0x20/0x20
[<ffffffff8122c22e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[<ffffffff8109d6e7>] sys_init_module+0xb7/0xe0
[<ffffffff8155c156>] system_call_fastpath+0x1a/0x1f
Reported-by: Arend van Spriel <arend at broadcom.com>
Reported-by: Peter Hurley <peter at hurleysoftware.com>
Reported-by: Daniel J Blueman <daniel at quora.org>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst at canonical.com>
---
XXX: Add Cc: stable at kernel.org if it applies to 3.7 ?
diff --git a/drivers/gpu/drm/nouveau/core/core/engctx.c b/drivers/gpu/drm/nouveau/core/core/engctx.c
index 84c71fa..4a0ab2b 100644
--- a/drivers/gpu/drm/nouveau/core/core/engctx.c
+++ b/drivers/gpu/drm/nouveau/core/core/engctx.c
@@ -31,12 +31,15 @@
#include <subdev/vm.h>
static inline int
-nouveau_engctx_exists(struct nouveau_object *parent,
+nouveau_engctx_exists(struct nouveau_object *parent, u32 flags,
struct nouveau_engine *engine, void **pobject)
{
struct nouveau_engctx *engctx;
struct nouveau_object *parctx;
+ if ((flags & NVOBJ_FLAG_CREAT_EXCL) && !list_empty(&engine->contexts))
+ return -EBUSY;
+
list_for_each_entry(engctx, &engine->contexts, head) {
parctx = nv_pclass(nv_object(engctx), NV_PARENT_CLASS);
if (parctx == parent) {
@@ -67,7 +70,7 @@ nouveau_engctx_create_(struct nouveau_object *parent,
* and reference it instead of creating a new one
*/
spin_lock_irqsave(&engine->lock, save);
- ret = nouveau_engctx_exists(parent, engine, pobject);
+ ret = nouveau_engctx_exists(parent, flags, engine, pobject);
spin_unlock_irqrestore(&engine->lock, save);
if (ret)
return ret;
@@ -94,7 +97,7 @@ nouveau_engctx_create_(struct nouveau_object *parent,
* it's not possible to allocate the object with it held.
*/
spin_lock_irqsave(&engine->lock, save);
- ret = nouveau_engctx_exists(parent, engine, pobject);
+ ret = nouveau_engctx_exists(parent, flags, engine, pobject);
if (ret) {
spin_unlock_irqrestore(&engine->lock, save);
nouveau_object_ref(NULL, &engctx);
diff --git a/drivers/gpu/drm/nouveau/core/engine/disp/nv50.c b/drivers/gpu/drm/nouveau/core/engine/disp/nv50.c
index ca1a7d7..1d3dcd0 100644
--- a/drivers/gpu/drm/nouveau/core/engine/disp/nv50.c
+++ b/drivers/gpu/drm/nouveau/core/engine/disp/nv50.c
@@ -695,9 +695,8 @@ nv50_disp_data_ctor(struct nouveau_object *parent,
struct nouveau_oclass *oclass, void *data, u32 size,
struct nouveau_object **pobject)
{
- struct nv50_disp_priv *priv = (void *)engine;
struct nouveau_engctx *ectx;
- int ret = -EBUSY;
+ int ret;
/* no context needed for channel objects... */
if (nv_mclass(parent) != NV_DEVICE_CLASS) {
@@ -707,14 +706,10 @@ nv50_disp_data_ctor(struct nouveau_object *parent,
}
/* allocate display hardware to client */
- mutex_lock(&nv_subdev(priv)->mutex);
- if (list_empty(&nv_engine(priv)->contexts)) {
- ret = nouveau_engctx_create(parent, engine, oclass, NULL,
- 0x10000, 0x10000,
- NVOBJ_FLAG_HEAP, &ectx);
- *pobject = nv_object(ectx);
- }
- mutex_unlock(&nv_subdev(priv)->mutex);
+ ret = nouveau_engctx_create(parent, engine, oclass, NULL, 0x10000, 0x10000,
+ NVOBJ_FLAG_HEAP | NVOBJ_FLAG_CREAT_EXCL, &ectx);
+
+ *pobject = nv_object(ectx);
return ret;
}
diff --git a/drivers/gpu/drm/nouveau/core/include/core/gpuobj.h b/drivers/gpu/drm/nouveau/core/include/core/gpuobj.h
index b3b9ce4..9d47d51 100644
--- a/drivers/gpu/drm/nouveau/core/include/core/gpuobj.h
+++ b/drivers/gpu/drm/nouveau/core/include/core/gpuobj.h
@@ -12,6 +12,7 @@ struct nouveau_vm;
#define NVOBJ_FLAG_ZERO_ALLOC 0x00000001
#define NVOBJ_FLAG_ZERO_FREE 0x00000002
#define NVOBJ_FLAG_HEAP 0x00000004
+#define NVOBJ_FLAG_CREAT_EXCL 0x00000008
struct nouveau_gpuobj {
struct nouveau_object base;
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