nouveau: use an rwlock for the event lock.

airlied · dakr · commit a2e36cd56041 · 2023-11-14T22:40:32.000+01:00
This allows it to break the following circular locking dependency. Aug 10 07:01:29 dg1test kernel: ====================================================== Aug 10 07:01:29 dg1test kernel: WARNING: possible circular locking dependency detected Aug 10 07:01:29 dg1test kernel: 6.4.0-rc7+ #10 Not tainted Aug 10 07:01:29 dg1test kernel: ------------------------------------------------------ Aug 10 07:01:29 dg1test kernel: wireplumber/2236 is trying to acquire lock: Aug 10 07:01:29 dg1test kernel: ffff8fca5320da18 (&fctx->lock){-...}-{2:2}, at: nouveau_fence_wait_uevent_handler+0x2b/0x100 [nouveau] Aug 10 07:01:29 dg1test kernel: but task is already holding lock: Aug 10 07:01:29 dg1test kernel: ffff8fca41208610 (&event->list_lock#2){-...}-{2:2}, at: nvkm_event_ntfy+0x50/0xf0 [nouveau] Aug 10 07:01:29 dg1test kernel: which lock already depends on the new lock. Aug 10 07:01:29 dg1test kernel: the existing dependency chain (in reverse order) is: Aug 10 07:01:29 dg1test kernel: -> #3 (&event->list_lock#2){-...}-{2:2}: Aug 10 07:01:29 dg1test kernel: _raw_spin_lock_irqsave+0x4b/0x70 Aug 10 07:01:29 dg1test kernel: nvkm_event_ntfy+0x50/0xf0 [nouveau] Aug 10 07:01:29 dg1test kernel: ga100_fifo_nonstall_intr+0x24/0x30 [nouveau] Aug 10 07:01:29 dg1test kernel: nvkm_intr+0x12c/0x240 [nouveau] Aug 10 07:01:29 dg1test kernel: __handle_irq_event_percpu+0x88/0x240 Aug 10 07:01:29 dg1test kernel: handle_irq_event+0x38/0x80 Aug 10 07:01:29 dg1test kernel: handle_edge_irq+0xa3/0x240 Aug 10 07:01:29 dg1test kernel: __common_interrupt+0x72/0x160 Aug 10 07:01:29 dg1test kernel: common_interrupt+0x60/0xe0 Aug 10 07:01:29 dg1test kernel: asm_common_interrupt+0x26/0x40 Aug 10 07:01:29 dg1test kernel: -> #2 (&device->intr.lock){-...}-{2:2}: Aug 10 07:01:29 dg1test kernel: _raw_spin_lock_irqsave+0x4b/0x70 Aug 10 07:01:29 dg1test kernel: nvkm_inth_allow+0x2c/0x80 [nouveau] Aug 10 07:01:29 dg1test kernel: nvkm_event_ntfy_state+0x181/0x250 [nouveau] Aug 10 07:01:29 dg1test kernel: nvkm_event_ntfy_allow+0x63/0xd0 [nouveau] Aug 10 07:01:29 dg1test kernel: nvkm_uevent_mthd+0x4d/0x70 [nouveau] Aug 10 07:01:29 dg1test kernel: nvkm_ioctl+0x10b/0x250 [nouveau] Aug 10 07:01:29 dg1test kernel: nvif_object_mthd+0xa8/0x1f0 [nouveau] Aug 10 07:01:29 dg1test kernel: nvif_event_allow+0x2a/0xa0 [nouveau] Aug 10 07:01:29 dg1test kernel: nouveau_fence_enable_signaling+0x78/0x80 [nouveau] Aug 10 07:01:29 dg1test kernel: __dma_fence_enable_signaling+0x5e/0x100 Aug 10 07:01:29 dg1test kernel: dma_fence_add_callback+0x4b/0xd0 Aug 10 07:01:29 dg1test kernel: nouveau_cli_work_queue+0xae/0x110 [nouveau] Aug 10 07:01:29 dg1test kernel: nouveau_gem_object_close+0x1d1/0x2a0 [nouveau] Aug 10 07:01:29 dg1test kernel: drm_gem_handle_delete+0x70/0xe0 [drm] Aug 10 07:01:29 dg1test kernel: drm_ioctl_kernel+0xa5/0x150 [drm] Aug 10 07:01:29 dg1test kernel: drm_ioctl+0x256/0x490 [drm] Aug 10 07:01:29 dg1test kernel: nouveau_drm_ioctl+0x5a/0xb0 [nouveau] Aug 10 07:01:29 dg1test kernel: __x64_sys_ioctl+0x91/0xd0 Aug 10 07:01:29 dg1test kernel: do_syscall_64+0x3c/0x90 Aug 10 07:01:29 dg1test kernel: entry_SYSCALL_64_after_hwframe+0x72/0xdc Aug 10 07:01:29 dg1test kernel: -> #1 (&event->refs_lock#4){....}-{2:2}: Aug 10 07:01:29 dg1test kernel: _raw_spin_lock_irqsave+0x4b/0x70 Aug 10 07:01:29 dg1test kernel: nvkm_event_ntfy_state+0x37/0x250 [nouveau] Aug 10 07:01:29 dg1test kernel: nvkm_event_ntfy_allow+0x63/0xd0 [nouveau] Aug 10 07:01:29 dg1test kernel: nvkm_uevent_mthd+0x4d/0x70 [nouveau] Aug 10 07:01:29 dg1test kernel: nvkm_ioctl+0x10b/0x250 [nouveau] Aug 10 07:01:29 dg1test kernel: nvif_object_mthd+0xa8/0x1f0 [nouveau] Aug 10 07:01:29 dg1test kernel: nvif_event_allow+0x2a/0xa0 [nouveau] Aug 10 07:01:29 dg1test kernel: nouveau_fence_enable_signaling+0x78/0x80 [nouveau] Aug 10 07:01:29 dg1test kernel: __dma_fence_enable_signaling+0x5e/0x100 Aug 10 07:01:29 dg1test kernel: dma_fence_add_callback+0x4b/0xd0 Aug 10 07:01:29 dg1test kernel: nouveau_cli_work_queue+0xae/0x110 [nouveau] Aug 10 07:01:29 dg1test kernel: nouveau_gem_object_close+0x1d1/0x2a0 [nouveau] Aug 10 07:01:29 dg1test kernel: drm_gem_handle_delete+0x70/0xe0 [drm] Aug 10 07:01:29 dg1test kernel: drm_ioctl_kernel+0xa5/0x150 [drm] Aug 10 07:01:29 dg1test kernel: drm_ioctl+0x256/0x490 [drm] Aug 10 07:01:29 dg1test kernel: nouveau_drm_ioctl+0x5a/0xb0 [nouveau] Aug 10 07:01:29 dg1test kernel: __x64_sys_ioctl+0x91/0xd0 Aug 10 07:01:29 dg1test kernel: do_syscall_64+0x3c/0x90 Aug 10 07:01:29 dg1test kernel: entry_SYSCALL_64_after_hwframe+0x72/0xdc Aug 10 07:01:29 dg1test kernel: -> #0 (&fctx->lock){-...}-{2:2}: Aug 10 07:01:29 dg1test kernel: __lock_acquire+0x14e3/0x2240 Aug 10 07:01:29 dg1test kernel: lock_acquire+0xc8/0x2a0 Aug 10 07:01:29 dg1test kernel: _raw_spin_lock_irqsave+0x4b/0x70 Aug 10 07:01:29 dg1test kernel: nouveau_fence_wait_uevent_handler+0x2b/0x100 [nouveau] Aug 10 07:01:29 dg1test kernel: nvkm_client_event+0xf/0x20 [nouveau] Aug 10 07:01:29 dg1test kernel: nvkm_event_ntfy+0x9b/0xf0 [nouveau] Aug 10 07:01:29 dg1test kernel: ga100_fifo_nonstall_intr+0x24/0x30 [nouveau] Aug 10 07:01:29 dg1test kernel: nvkm_intr+0x12c/0x240 [nouveau] Aug 10 07:01:29 dg1test kernel: __handle_irq_event_percpu+0x88/0x240 Aug 10 07:01:29 dg1test kernel: handle_irq_event+0x38/0x80 Aug 10 07:01:29 dg1test kernel: handle_edge_irq+0xa3/0x240 Aug 10 07:01:29 dg1test kernel: __common_interrupt+0x72/0x160 Aug 10 07:01:29 dg1test kernel: common_interrupt+0x60/0xe0 Aug 10 07:01:29 dg1test kernel: asm_common_interrupt+0x26/0x40 Aug 10 07:01:29 dg1test kernel: other info that might help us debug this: Aug 10 07:01:29 dg1test kernel: Chain exists of: &fctx->lock --> &device->intr.lock --> &event->list_lock#2 Aug 10 07:01:29 dg1test kernel: Possible unsafe locking scenario: Aug 10 07:01:29 dg1test kernel: CPU0 CPU1 Aug 10 07:01:29 dg1test kernel: ---- ---- Aug 10 07:01:29 dg1test kernel: lock(&event->list_lock#2); Aug 10 07:01:29 dg1test kernel: lock(&device->intr.lock); Aug 10 07:01:29 dg1test kernel: lock(&event->list_lock#2); Aug 10 07:01:29 dg1test kernel: lock(&fctx->lock); Aug 10 07:01:29 dg1test kernel: *** DEADLOCK *** Aug 10 07:01:29 dg1test kernel: 2 locks held by wireplumber/2236: Aug 10 07:01:29 dg1test kernel: #0: ffff8fca53177bf8 (&device->intr.lock){-...}-{2:2}, at: nvkm_intr+0x29/0x240 [nouveau] Aug 10 07:01:29 dg1test kernel: #1: ffff8fca41208610 (&event->list_lock#2){-...}-{2:2}, at: nvkm_event_ntfy+0x50/0xf0 [nouveau] Aug 10 07:01:29 dg1test kernel: stack backtrace: Aug 10 07:01:29 dg1test kernel: CPU: 6 PID: 2236 Comm: wireplumber Not tainted 6.4.0-rc7+ #10 Aug 10 07:01:29 dg1test kernel: Hardware name: Gigabyte Technology Co., Ltd. Z390 I AORUS PRO WIFI/Z390 I AORUS PRO WIFI-CF, BIOS F8 11/05/2021 Aug 10 07:01:29 dg1test kernel: Call Trace: Aug 10 07:01:29 dg1test kernel: <TASK> Aug 10 07:01:29 dg1test kernel: dump_stack_lvl+0x5b/0x90 Aug 10 07:01:29 dg1test kernel: check_noncircular+0xe2/0x110 Aug 10 07:01:29 dg1test kernel: __lock_acquire+0x14e3/0x2240 Aug 10 07:01:29 dg1test kernel: lock_acquire+0xc8/0x2a0 Aug 10 07:01:29 dg1test kernel: ? nouveau_fence_wait_uevent_handler+0x2b/0x100 [nouveau] Aug 10 07:01:29 dg1test kernel: ? lock_acquire+0xc8/0x2a0 Aug 10 07:01:29 dg1test kernel: _raw_spin_lock_irqsave+0x4b/0x70 Aug 10 07:01:29 dg1test kernel: ? nouveau_fence_wait_uevent_handler+0x2b/0x100 [nouveau] Aug 10 07:01:29 dg1test kernel: nouveau_fence_wait_uevent_handler+0x2b/0x100 [nouveau] Aug 10 07:01:29 dg1test kernel: nvkm_client_event+0xf/0x20 [nouveau] Aug 10 07:01:29 dg1test kernel: nvkm_event_ntfy+0x9b/0xf0 [nouveau] Aug 10 07:01:29 dg1test kernel: ga100_fifo_nonstall_intr+0x24/0x30 [nouveau] Aug 10 07:01:29 dg1test kernel: nvkm_intr+0x12c/0x240 [nouveau] Aug 10 07:01:29 dg1test kernel: __handle_irq_event_percpu+0x88/0x240 Aug 10 07:01:29 dg1test kernel: handle_irq_event+0x38/0x80 Aug 10 07:01:29 dg1test kernel: handle_edge_irq+0xa3/0x240 Aug 10 07:01:29 dg1test kernel: __common_interrupt+0x72/0x160 Aug 10 07:01:29 dg1test kernel: common_interrupt+0x60/0xe0 Aug 10 07:01:29 dg1test kernel: asm_common_interrupt+0x26/0x40 Aug 10 07:01:29 dg1test kernel: RIP: 0033:0x7fb66174d700 Aug 10 07:01:29 dg1test kernel: Code: c1 e2 05 29 ca 8d 0c 10 0f be 07 84 c0 75 eb 89 c8 c3 0f 1f 84 00 00 00 00 00 f3 0f 1e fa e9 d7 0f fc ff 0f 1f 80 00 00 00 00 <f3> 0f 1e fa e9 c7 0f fc> Aug 10 07:01:29 dg1test kernel: RSP: 002b:00007ffdd3c48438 EFLAGS: 00000206 Aug 10 07:01:29 dg1test kernel: RAX: 000055bb758763c0 RBX: 000055bb758752c0 RCX: 00000000000028b0 Aug 10 07:01:29 dg1test kernel: RDX: 000055bb758752c0 RSI: 000055bb75887490 RDI: 000055bb75862950 Aug 10 07:01:29 dg1test kernel: RBP: 00007ffdd3c48490 R08: 000055bb75873b10 R09: 0000000000000001 Aug 10 07:01:29 dg1test kernel: R10: 0000000000000004 R11: 000055bb7587f000 R12: 000055bb75887490 Aug 10 07:01:29 dg1test kernel: R13: 000055bb757f6280 R14: 000055bb758875c0 R15: 000055bb757f6280 Aug 10 07:01:29 dg1test kernel: </TASK> Signed-off-by: Dave Airlie <airlied@redhat.com> Tested-by: Danilo Krummrich <dakr@redhat.com> Reviewed-by: Danilo Krummrich <dakr@redhat.com> Signed-off-by: Danilo Krummrich <dakr@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20231107053255.2257079-1-airlied@gmail.com
diff --git a/drivers/gpu/drm/nouveau/include/nvkm/core/event.h b/drivers/gpu/drm/nouveau/include/nvkm/core/event.h
@@ -14,7 +14,7 @@ struct nvkm_event {
 	int index_nr;
 
 	spinlock_t refs_lock;
-	spinlock_t list_lock;
+	rwlock_t list_lock;
 	int *refs;
 
 	struct list_head ntfy;
@@ -38,7 +38,7 @@ nvkm_event_init(const struct nvkm_event_func *func, struct nvkm_subdev *subdev,
 		int types_nr, int index_nr, struct nvkm_event *event)
 {
 	spin_lock_init(&event->refs_lock);
-	spin_lock_init(&event->list_lock);
+	rwlock_init(&event->list_lock);
 	return __nvkm_event_init(func, subdev, types_nr, index_nr, event);
 }
 
diff --git a/drivers/gpu/drm/nouveau/nvkm/core/event.c b/drivers/gpu/drm/nouveau/nvkm/core/event.c
@@ -81,17 +81,17 @@ nvkm_event_ntfy_state(struct nvkm_event_ntfy *ntfy)
 static void
 nvkm_event_ntfy_remove(struct nvkm_event_ntfy *ntfy)
 {
-	spin_lock_irq(&ntfy->event->list_lock);
+	write_lock_irq(&ntfy->event->list_lock);
 	list_del_init(&ntfy->head);
-	spin_unlock_irq(&ntfy->event->list_lock);
+	write_unlock_irq(&ntfy->event->list_lock);
 }
 
 static void
 nvkm_event_ntfy_insert(struct nvkm_event_ntfy *ntfy)
 {
-	spin_lock_irq(&ntfy->event->list_lock);
+	write_lock_irq(&ntfy->event->list_lock);
 	list_add_tail(&ntfy->head, &ntfy->event->ntfy);
-	spin_unlock_irq(&ntfy->event->list_lock);
+	write_unlock_irq(&ntfy->event->list_lock);
 }
 
 static void
@@ -176,7 +176,7 @@ nvkm_event_ntfy(struct nvkm_event *event, int id, u32 bits)
 		return;
 
 	nvkm_trace(event->subdev, "event: ntfy %08x on %d\n", bits, id);
-	spin_lock_irqsave(&event->list_lock, flags);
+	read_lock_irqsave(&event->list_lock, flags);
 
 	list_for_each_entry_safe(ntfy, ntmp, &event->ntfy, head) {
 		if (ntfy->id == id && ntfy->bits & bits) {
@@ -185,7 +185,7 @@ nvkm_event_ntfy(struct nvkm_event *event, int id, u32 bits)
 		}
 	}
 
-	spin_unlock_irqrestore(&event->list_lock, flags);
+	read_unlock_irqrestore(&event->list_lock, flags);
 }
 
 void

Original file line number	Diff line number	Diff line change
`@@ -14,7 +14,7 @@ struct nvkm_event {`
`14`	`14`	`int index_nr;`
`15`	`15`
`16`	`16`	`spinlock_t refs_lock;`
`17`		`- spinlock_t list_lock;`
	`17`	`+ rwlock_t list_lock;`
`18`	`18`	`int *refs;`
`19`	`19`
`20`	`20`	`struct list_head ntfy;`
`@@ -38,7 +38,7 @@ nvkm_event_init(const struct nvkm_event_func func, struct nvkm_subdev subdev,`
`38`	`38`	`int types_nr, int index_nr, struct nvkm_event *event)`
`39`	`39`	`{`
`40`	`40`	`spin_lock_init(&event->refs_lock);`
`41`		`- spin_lock_init(&event->list_lock);`
	`41`	`+ rwlock_init(&event->list_lock);`
`42`	`42`	`return __nvkm_event_init(func, subdev, types_nr, index_nr, event);`
`43`	`43`	`}`
`44`	`44`
Original file line number	Diff line number	Diff line change
`@@ -81,17 +81,17 @@ nvkm_event_ntfy_state(struct nvkm_event_ntfy *ntfy)`
`81`	`81`	`static void`
`82`	`82`	`nvkm_event_ntfy_remove(struct nvkm_event_ntfy *ntfy)`
`83`	`83`	`{`
`84`		`- spin_lock_irq(&ntfy->event->list_lock);`
	`84`	`+ write_lock_irq(&ntfy->event->list_lock);`
`85`	`85`	`list_del_init(&ntfy->head);`
`86`		`- spin_unlock_irq(&ntfy->event->list_lock);`
	`86`	`+ write_unlock_irq(&ntfy->event->list_lock);`
`87`	`87`	`}`
`88`	`88`
`89`	`89`	`static void`
`90`	`90`	`nvkm_event_ntfy_insert(struct nvkm_event_ntfy *ntfy)`
`91`	`91`	`{`
`92`		`- spin_lock_irq(&ntfy->event->list_lock);`
	`92`	`+ write_lock_irq(&ntfy->event->list_lock);`
`93`	`93`	`list_add_tail(&ntfy->head, &ntfy->event->ntfy);`
`94`		`- spin_unlock_irq(&ntfy->event->list_lock);`
	`94`	`+ write_unlock_irq(&ntfy->event->list_lock);`
`95`	`95`	`}`
`96`	`96`
`97`	`97`	`static void`
`@@ -176,7 +176,7 @@ nvkm_event_ntfy(struct nvkm_event *event, int id, u32 bits)`
`176`	`176`	`return;`
`177`	`177`
`178`	`178`	`nvkm_trace(event->subdev, "event: ntfy %08x on %d\n", bits, id);`
`179`		`- spin_lock_irqsave(&event->list_lock, flags);`
	`179`	`+ read_lock_irqsave(&event->list_lock, flags);`
`180`	`180`
`181`	`181`	`list_for_each_entry_safe(ntfy, ntmp, &event->ntfy, head) {`
`182`	`182`	`if (ntfy->id == id && ntfy->bits & bits) {`
`@@ -185,7 +185,7 @@ nvkm_event_ntfy(struct nvkm_event *event, int id, u32 bits)`
`185`	`185`	`}`
`186`	`186`	`}`
`187`	`187`
`188`		`- spin_unlock_irqrestore(&event->list_lock, flags);`
	`188`	`+ read_unlock_irqrestore(&event->list_lock, flags);`
`189`	`189`	`}`
`190`	`190`
`191`	`191`	`void`