* [PATCH] Revert "drm/i915/userptr: Acquire the page lock around set_page_dirty()"
[not found] <CAHk-=wjKv_Zw2zGHduyrQH_VQzxXYzwKdwwzzpsdnsdx=EK30Q@mail.gmail.com>
@ 2019-09-12 12:56 ` Chris Wilson
2019-09-12 14:39 ` [Intel-gfx] " Tvrtko Ursulin
0 siblings, 1 reply; 2+ messages in thread
From: Chris Wilson @ 2019-09-12 12:56 UTC (permalink / raw)
To: intel-gfx, torvalds
Cc: Martin.Wilck, MKoutny, leho, tiwai, linux-kernel, Chris Wilson,
Lionel Landwerlin, Tvrtko Ursulin, Jani Nikula, Joonas Lahtinen,
stable
The userptr put_pages can be called from inside try_to_unmap, and so
enters with the page lock held on one of the object's backing pages. We
cannot take the page lock ourselves for fear of recursion.
Reported-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reported-by: Martin Wilck <Martin.Wilck@suse.com>
Reported-by: Leo Kraav <leho@kraav.com>
Fixes: aa56a292ce62 ("drm/i915/userptr: Acquire the page lock around set_page_dirty()")
References: https://bugzilla.kernel.org/show_bug.cgi?id=203317
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: stable@vger.kernel.org
---
drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 10 +---------
1 file changed, 1 insertion(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
index 74da35611d7c..11b231c187c5 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
@@ -672,15 +672,7 @@ i915_gem_userptr_put_pages(struct drm_i915_gem_object *obj,
for_each_sgt_page(page, sgt_iter, pages) {
if (obj->mm.dirty)
- /*
- * As this may not be anonymous memory (e.g. shmem)
- * but exist on a real mapping, we have to lock
- * the page in order to dirty it -- holding
- * the page reference is not sufficient to
- * prevent the inode from being truncated.
- * Play safe and take the lock.
- */
- set_page_dirty_lock(page);
+ set_page_dirty(page);
mark_page_accessed(page);
put_page(page);
--
2.23.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [Intel-gfx] [PATCH] Revert "drm/i915/userptr: Acquire the page lock around set_page_dirty()"
2019-09-12 12:56 ` [PATCH] Revert "drm/i915/userptr: Acquire the page lock around set_page_dirty()" Chris Wilson
@ 2019-09-12 14:39 ` Tvrtko Ursulin
0 siblings, 0 replies; 2+ messages in thread
From: Tvrtko Ursulin @ 2019-09-12 14:39 UTC (permalink / raw)
To: Chris Wilson, intel-gfx, torvalds
Cc: tiwai, linux-kernel, leho, Jani Nikula, MKoutny, stable, Martin.Wilck
On 12/09/2019 13:56, Chris Wilson wrote:
> The userptr put_pages can be called from inside try_to_unmap, and so
> enters with the page lock held on one of the object's backing pages. We
> cannot take the page lock ourselves for fear of recursion.
>
> Reported-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
> Reported-by: Martin Wilck <Martin.Wilck@suse.com>
> Reported-by: Leo Kraav <leho@kraav.com>
> Fixes: aa56a292ce62 ("drm/i915/userptr: Acquire the page lock around set_page_dirty()")
> References: https://bugzilla.kernel.org/show_bug.cgi?id=203317
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> Cc: Jani Nikula <jani.nikula@intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: stable@vger.kernel.org
> ---
> drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 10 +---------
> 1 file changed, 1 insertion(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
> index 74da35611d7c..11b231c187c5 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
> @@ -672,15 +672,7 @@ i915_gem_userptr_put_pages(struct drm_i915_gem_object *obj,
>
> for_each_sgt_page(page, sgt_iter, pages) {
> if (obj->mm.dirty)
> - /*
> - * As this may not be anonymous memory (e.g. shmem)
> - * but exist on a real mapping, we have to lock
> - * the page in order to dirty it -- holding
> - * the page reference is not sufficient to
> - * prevent the inode from being truncated.
> - * Play safe and take the lock.
> - */
> - set_page_dirty_lock(page);
> + set_page_dirty(page);
>
> mark_page_accessed(page);
> put_page(page);
>
Acked-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Regards,
Tvrtko
^ permalink raw reply [flat|nested] 2+ messages in thread
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2019-09-12 12:56 ` [PATCH] Revert "drm/i915/userptr: Acquire the page lock around set_page_dirty()" Chris Wilson
2019-09-12 14:39 ` [Intel-gfx] " Tvrtko Ursulin
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