Messages in this thread | | | Date | Wed, 13 Mar 2013 11:35:15 +0800 | From | Shuge <> | Subject | Re: [PATCH] bounce:fix bug, avoid to flush dcache on slab page from jbd2. |
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Hi all >>> The bounce accept slab pages from jbd2, and flush dcache on them. >>> When enabling VM_DEBUG, it will tigger VM_BUG_ON in page_mapping(). >>> So, check PageSlab to avoid it in __blk_queue_bounce(). >>> >>> Bug URL: http://lkml.org/lkml/2013/3/7/56 >>> >>> ... >>> >> ...... >> > That sure is strange. I didn't see any obvious reasons why we'd end up with a > ......
Well, this problem not only appear in arm64, but also arm32. And my kernel version is 3.3.0, arch is arm32. Following the newest kernel, the problem shoulde be exist. I agree with Darrick's modification. Hum, if CONFIG_NEED_BOUNCE_POOL is not set, it also flush dcahce on the pages of b_frozen_data, some of them are allocated by kmem_cache_alloc. As we know, jbd2_alloc allocate a buffer from jbd2_xk slab pool, when the size is smaller than PAGE_SIZE. The b_frozen_data is not mapped to usrspace, not aliasing cache. It cat be lazy flush or other. Is it right?
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