update the fix.
On 2018年01月24日 11:09, Chunming Zhou wrote:
Hi Tom,
Your change looks ok, as Roger suggested, you can send both dri and
amd mail lists.
In addition, when I review your patches, I found a bug as the
attached, you can send it together with yours if you think that's a
right fix.
Regards,
David Zhou
On 2018年01月24日 03:25, Tom St Denis wrote:
On 22/01/18 01:42 AM, Chunming Zhou wrote:
On 2018年01月20日 02:23, Tom St Denis wrote:
On 19/01/18 01:14 PM, Tom St Denis wrote:
Hi all,
In the function ttm_bo_cleanup_refs() it seems possible to get to
line 551 without entering the block on 516 which means you'll be
unlocking a mutex that wasn't locked.
Now it might be that in the course of the API this pattern cannot
be expressed but it's not clear from the function alone that that
is the case.
Looking further it seems the behaviour depends on locking in parent
callers. That's kinda a no-no right? Shouldn't the lock be
taken/released in the same function ideally?
Same feelings
Regards,
David Zhou
Attached is a patch that addresses this.
I can't see any obvious race in functions that call
ttm_bo_cleanup_refs() between the time they let go of the lock and
the time it's taken again in the call.
Running it on my system doesn't produce anything notable though the
KASAN with DRI_PRIME=1 issue is still there (this patch neither
causes that nor fixes it).
Tom
>From 9f06e6619b47c506fc87471e38de4640c9879a9f Mon Sep 17 00:00:00 2001
From: Chunming Zhou <david1.z...@amd.com>
Date: Wed, 24 Jan 2018 10:59:05 +0800
Subject: [PATCH] ttm: fix double trylock reservation
Change-Id: Ie2d7af8b6ce4df8bb575f7959e17e36ac81092e5
Signed-off-by: Chunming Zhou <david1.z...@amd.com>
---
drivers/gpu/drm/ttm/ttm_bo.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index d33a6bb742a1..e737515405fd 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -530,7 +530,7 @@ static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo,
return -EBUSY;
spin_lock(&glob->lru_lock);
- if (unlock_resv && !reservation_object_trylock(bo->resv)) {
+ if (!unlock_resv && !reservation_object_trylock(bo->resv)) {
/*
* We raced, and lost, someone else holds the reservation now,
* and is probably busy in ttm_bo_cleanup_memtype_use.
@@ -542,6 +542,7 @@ static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo,
spin_unlock(&glob->lru_lock);
return 0;
}
+ unlock_resv = true;
ret = 0;
}
--
2.14.1
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