Fail to mount ubifs

[Jon Ringle]

On Tue, Jan 12, 2010 at 3:23 PM, Jon Ringle <jon at ringle.org> wrote:
> On Mon, Jan 11, 2010 at 11:50 PM, Artem Bityutskiy <dedekind1 at gmail.com> wrote:
>> As this entry suggests:
>> http://www.linux-mtd.infradead.org/doc/ubifs.html#L_how_send_bugreport
>>
>> - validate your flash/driver with the MTD tests - looks like you have a
>> problem there.
>
> Trying to run mtd_readtest I get a seg fault:
> [   67.470000] Unable to handle kernel NULL pointer dereference at
> virtual address 00000000
> [   67.480000] pgd = cf978000
> [   67.480000] [00000000] *pgd=0d49e031, *pte=00000000, *ppte=00000000
> [   67.490000] Internal error: Oops: 0 [#1] PREEMPT
> [   67.490000] Modules linked in: mtd_readtest(+) ixp4xx redboot
> [   67.490000] CPU: 0    Not tainted  (2.6.31.11-isc #3)
> [   67.490000] PC is at 0x0
> [   67.490000] LR is at scan_for_bad_eraseblocks+0x88/0x10c [mtd_readtest]

I patched mtd_readtest.c with this:
diff --git a/drivers/mtd/tests/mtd_readtest.c b/drivers/mtd/tests/mtd_readtest.c
index 79fc453..9edd658 100644
--- a/drivers/mtd/tests/mtd_readtest.c
+++ b/drivers/mtd/tests/mtd_readtest.c
@@ -130,7 +130,7 @@ static int is_block_bad(int ebnum)
        loff_t addr = ebnum * mtd->erasesize;
        int ret;

-       ret = mtd->block_isbad(mtd, addr);
+       ret = mtd->block_isbad ? mtd->block_isbad(mtd, addr) : 0;
        if (ret)
                printk(PRINT_PREF "block %d is bad\n", ebnum);
        return ret;

After this, I ran mtd_readtest and it seemed to complete, but then
hang after it was done:
(initramfs) modprobe mtd_readtest dev=1
[  194.530000]
[  194.530000] =================================================
[  194.540000] mtd_readtest: MTD device: 1
[  194.540000] mtd_readtest: not NAND flash, assume page size is 512 bytes.
[  194.550000] mtd_readtest: MTD device size 32636928, eraseblock size
131072, page size 512, count of eraseblocks 249, pages per eraseblock
131072, OOB size 0
[  194.570000] mtd_readtest: scanning for bad eraseblocks
[  194.570000] mtd_readtest: scanned 249 eraseblocks, 0 are bad
[  194.580000] mtd_readtest: testing page read
[  194.960000] ------------[ cut here ]------------
[  194.960000] WARNING: at kernel/sched.c:5175 do_page_fault+0x16c/0x1ec()
[  194.960000] Modules linked in: mtd_readtest(+)