| Message ID | tencent_1A51A82501181FD23618C68685EBC405990A@qq.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915: use READ_ONCE() to read vma->iomap in concurrent environment | expand |
Hi, I want to confirm the status of this patch and whether need any additional information.
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c index d09aad34ba37..9fcc11db0505 100644 --- a/drivers/gpu/drm/i915/i915_vma.c +++ b/drivers/gpu/drm/i915/i915_vma.c @@ -594,7 +594,7 @@ void __iomem *i915_vma_pin_iomap(struct i915_vma *vma) __i915_gem_object_release_map(vma->obj); else io_mapping_unmap(ptr); - ptr = vma->iomap; + ptr = READ_ONCE(vma->iomap); } }
In function i915_vma_pin_iomap(), vma->iomap is read using READ_ONCE() in line 562 562 ptr = READ_ONCE(vma->iomap); while read directly in line 597 592 if (unlikely(cmpxchg(&vma->iomap, NULL, ptr))) { 593 if (page_unmask_bits(ptr)) 594 __i915_gem_object_release_map(vma->obj); 595 else 596 io_mapping_unmap(ptr); 597 ptr = vma->iomap; There is patch similar to this. https://github.com/torvalds/linux/commit/c1c0ce31b2420d5c173228a2132a492ede03d81f This patch find two read of same variable while one is protected, another is not. And READ_ONCE() is added to protect. Signed-off-by: linke li <lilinke99@qq.com> --- drivers/gpu/drm/i915/i915_vma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)