Hello all, I hope this is a reasonable place to post a bug. If I fix it I can post a fix too. I believe there might be a bug in deferred io. In my fb driver I have a block of memory, allocated with kmalloc, that I can mmap, write to, and munmap perfectly fine using my own mmap routine. As soon as I switch to deferred io, there's a problem: >From userspace, I can mmap the framebuffer memory fine and write to it. The deferred io driver routine is called and updates the display perfectly correctly. As soon as I call munmap() I get a repeated kernel messages. This happens on ARM but not under an Ubuntu Virtualbox VM (x86): BUG: Bad page state in process fbtest1 pfn:ad11d page:c0dc03a0 count:0 mapcount:0 mapping:edbf7144 index:0x1d page flags: 0x94(referenced|dirty|slab) Modules linked in: hhlcd28a(O) sysimgblt sysfillrect syscopyarea fb_sys_fops bnep ipv6 mwifiex_sdio mwifiex btmrvl_sdio firmware_class btmrvl cfg80211 bluetooth rfkill [<c0014bc8>] (unwind_backtrace+0x0/0x11c) from [<c00c44d4>] (bad_page+0xd0/0xfc) [<c00c44d4>] (bad_page+0xd0/0xfc) from [<c00c45c0>] (free_pages_prepare+0xc0/0x150) [<c00c45c0>] (free_pages_prepare+0xc0/0x150) from [<c00c5a34>] (free_hot_cold_page+0x20/0x188) [<c00c5a34>] (free_hot_cold_page+0x20/0x188) from [<c00c5dc4>] (free_hot_cold_page_list+0x7c/0x9c) [<c00c5dc4>] (free_hot_cold_page_list+0x7c/0x9c) from [<c00c90c0>] (release_pages+0x1b4/0x1c8) [<c00c90c0>] (release_pages+0x1b4/0x1c8) from [<c00ea854>] (free_pages_and_swap_cache+0x8c/0x9c) [<c00ea854>] (free_pages_and_swap_cache+0x8c/0x9c) from [<c00dfff4>] (unmap_region+0x100/0x154) [<c00dfff4>] (unmap_region+0x100/0x154) from [<c00e116c>] (do_munmap+0x218/0x2a4) [<c00e116c>] (do_munmap+0x218/0x2a4) from [<c00e1234>] (vm_munmap+0x3c/0x50) [<c00e1234>] (vm_munmap+0x3c/0x50) from [<c000dc20>] (ret_fast_syscall+0x0/0x30) [repeated for N pages] root@duovero:~/testdrv# I will now convert to using vmalloc and check to see if this happens too. Thanks, Conor. -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
