Hi,
I'm having some trouble with using the dma_map/unmap API.
On unmapping a particular page using dma_unmap, it seems that the
PG_dcache_clean flag is set in the page->flags. This is set by the
following statement in __dma_page_dev_to_cpu function in
arch/arm/mm/dma-mapping.c
set_bit(PG_dcache_clean, &page->flags);
Due to this, on any subsequent page allocations using __get_free_pages,
the following BUG gets triggered.
[ 15.267913] BUG: Bad page state in process insmod pfn:acb26
[ 15.274017] page:c151e4c0 count:0 mapcount:0 mapping: (null) index:0x0
[ 15.281097] page flags: 0x200(arch_1)
[ 15.285003] Modules linked in: tcrypt(+)
[ 15.289062] CPU: 0 PID: 1616 Comm: insmod Tainted: G B
3.10.0-00038-gbafd29d-dirty #89
[ 15.298706] [<c001c720>] (unwind_backtrace+0x0/0xfc) from
[<c0018794>] (show_stack+0x20/0x24)
[ 15.307861] [<c0018794>] (show_stack+0x20/0x24) from [<c05a7284>]
(dump_stack+0x20/0x28)
[ 15.316497] [<c05a7284>] (dump_stack+0x20/0x28) from [<c00fa220>]
(bad_page+0xbc/0x11c)
[ 15.325195] [<c00fa220>] (bad_page+0xbc/0x11c) from [<c00fa8c8>]
(get_page_from_freelist+0x4dc/0x620)
[ 15.335083] [<c00fa8c8>] (get_page_from_freelist+0x4dc/0x620) from
[<c00fb57c>] (__alloc_pages_nodemask+0x114/0x8b4)
[ 15.346343] [<c00fb57c>] (__alloc_pages_nodemask+0x114/0x8b4) from
[<c00fbd3c>] (__get_free_pages+0x20/0x3c)
[ 15.356872] [<c00fbd3c>] (__get_free_pages+0x20/0x3c) from
[<c0486bd0>] (omap_aes_copy_sgs+0x48/0x1bc)
If I don't do the unmap and leave the page alone, everything works just
fine.
What is correct way to fix this? Why does the page allocator think its a
BAD page descriptor after the unmap?
Thanks,
-Joel
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
