Hi, On Sun, Oct 27, 2013 at 07:51:15PM +0800, Ming Lei wrote: > On Sat, 26 Oct 2013 15:36:17 +0100 > Will Deacon <will.dea...@arm.com> wrote: > > > On Thu, Oct 24, 2013 at 09:07:30PM +0100, Aaro Koskinen wrote: > > > > > [ 36.477203] Backtrace: > > > [ 36.535603] [<c009237c>] (page_mapping+0x0/0x50) from [<c0010dd8>] > > > (flush_kernel_dcache_page+0x14/0x98) > > > [ 36.661070] [<c0010dc4>] (flush_kernel_dcache_page+0x0/0x98) from > > > [<c0172b60>] (sg_miter_stop+0xc8/0x10c) > > > [ 36.792813] r4:df8a9a64 r3:00000003 > > > [ 36.857524] [<c0172a98>] (sg_miter_stop+0x0/0x10c) from [<c0172f20>] > > > (sg_miter_next+0x14/0x13c) > > > > ... assumedly for scatter/gather DMA. How is your block driver allocating > > its buffers? If you're using the DMA API, I can't see how this would happen. > > Lots of SCSI commands(inquiry, ...) pass kmalloc buffer to block layer, > then the sg buffer copy helpers and flush_kernel_dcache_page() may see > slab page. > > That has been here from commit b1adaf65ba03( [SCSI] block: add sg buffer copy > helper functions).
On ARM v3.9 or older kernels do not trigger this BUG, at seems it only started to appear with the following commit (bisected): commit 1bc39742aab09248169ef9d3727c9def3528b3f3 Author: Simon Baatz <gmbno...@gmail.com> Date: Mon Jun 10 21:10:12 2013 +0100 ARM: 7755/1: handle user space mapped pages in flush_kernel_dcache_page A. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/