On Thu, Mar 14, 2013 at 09:38:02AM +0800, Hillf Danton wrote: > [cc Russell] > On Wed, Mar 13, 2013 at 11:04 PM, Mark Jackson <mpfj-list@xxxxxxxxxx> wrote: > > Can any help diagnose what my userspace task is doing to get the followings oops ? > > > > [ 42.587772] Unable to handle kernel paging request at virtual address bfac6004 > > [ 42.595431] pgd = cf748000 > > [ 42.598291] [bfac6004] *pgd=00000000 > > None pgd, why is pgd_none_or_clear_bad() not triggered? I think you're misunderstanding what's happened here. > > [ 42.602079] Internal error: Oops: 5 [#1] ARM > > [ 42.606592] CPU: 0 Not tainted (3.8.0-next-20130225-00001-g2d0ce24-dirty #38) > > [ 42.614509] PC is at unmap_single_vma+0x2d8/0x5bc > > [ 42.619476] LR is at unmap_single_vma+0x29c/0x5bc > > [ 42.624447] pc : [<c00aed0c>] lr : [<c00aecd0>] psr: 60000013 > > [ 42.624447] sp : cf685d88 ip : 8f9523cd fp : cf680004 > > [ 42.636567] r10: 00000000 r9 : bfac6000 r8 : 00200000 > > [ 42.642079] r7 : cf685e00 r6 : cf5e93a8 r5 : cf5e93ac r4 : 000ea000 > > [ 42.648969] r3 : 00000001 r2 : 00000000 r1 : 00000040 r0 : 00000000 ... > > [ 42.935472] Code: 0affffa4 e59d000c e3500000 1a0000a2 (e5993004) That disassembles to this: 0: 0affffa4 beq 0xfffffe98 4: e59d000c ldr r0, [sp, #12] 8: e3500000 cmp r0, #0 c: 1a0000a2 bne 0x29c 10: e5993004 ldr r3, [r9, #4] and r9 = 0xbfac6000, which is _not_ the address of a page table. Unfortunately, the above doesn't tie up with the output from my compiler, so I've no idea what that corresponds with in unmap_single_vma(). The other surprising thing about this oops dump is the lack of backtrace... I think I need to see the disassembly of this function before there can be any further diagnosis of what's going on here. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>