[BLOCK2MTD] WARNING: at kernel/lockdep.c:2331 lockdep_init_map()

[Jörn Engel]

On Fri, 19 October 2007 13:53:40 -0400, Erez Zadok wrote:
>
> I've been having this problem for some time with mtd, which I use to mount
> jffs2 images (for unionfs testing).  I've seen it in several recent major
> kernels, including 2.6.24.  Here's the sequence of ops I perform:

Since when roughly?  2.6.20ish?  Before?

> # cp jffs2-empty.img /tmp/foo
> # losetup /dev/loop0 /tmp/foo
> # modprobe mtdblock
> # modprobe block2mtd block2mtd=/dev/loop0,128ki
> # mount -t jffs2 /dev/mtdblock0 /n/lower/b0

Side note: you don't need mtdblock:
# cp jffs2-empty.img /tmp/foo
# losetup /dev/loop0 /tmp/foo
# modprobe block2mtd block2mtd=/dev/loop0,128ki
# mount -t jffs2 mtd0 /n/lower/b0

It doesn't really hurt, 'tis just superfluous.

> The jffs2-empty.img is a small jffs2 image, of an empty directory, created
> w/ the jffs2 utils.  At the point I modprobe block2mtd, I get the following
> lockdep warning and a "BUG" message:
> 
> BUG: key f88e1340 not in .data!
> WARNING: at kernel/lockdep.c:2331 lockdep_init_map()
>  [<c0102bc2>] show_trace_log_lvl+0x1a/0x2f
>  [<c0103692>] show_trace+0x12/0x14
>  [<c01037b2>] dump_stack+0x15/0x17
>  [<c0125432>] lockdep_init_map+0x94/0x3e4
>  [<c0125001>] debug_mutex_init+0x2c/0x3c
>  [<c01210d4>] __mutex_init+0x38/0x40
>  [<f88e01d3>] 0xf88e01d3
>  [<c011dda7>] parse_args+0x123/0x200
>  [<c012b725>] sys_init_module+0xdd0/0x122c
>  [<c0102586>] sysenter_past_esp+0x5f/0x91
>  =======================
> block2mtd: mtd0: [d: /dev/loop0] erase_size = 128KiB [131072]
> block2mtd: version $Revision: 1.30 $

Could be my problem.  I'll see if I can reproduce it.  Can you send me
your .config or a link to it?

Jörn

-- 
/* Keep these two variables together */
int bar;