Messages in this thread | | | Date | Sun, 22 Jun 2008 23:34:48 -0700 | From | Andrew Morton <> | Subject | Re: Oops when using growisofs |
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On Mon, 23 Jun 2008 00:28:20 +0200 Michael Buesch <mb@bu3sch.de> wrote:
> On Monday 23 June 2008 00:05:51 Michael Buesch wrote: > > > Note: r9 and r3 are both NULL pointers. r3 is the value returned from alloc_page_buffers. > > > R9 is a copy of that, which gets accessed. > > > > Hm, yeah. I looked at that code already, but I can't see how it could return > > a NULL pointer. > > Well, actually, it can return a NULL pointer. > > 928 head = NULL; > 929 offset = PAGE_SIZE; > 930 while ((offset -= size) >= 0) { > ... > 949 } > 950 return head; > > So if size, which is a passed in as parameter, is > PAGE_SIZE it will return NULL. > > The size parameter is calculated by doing > blocksize = 1 << inode->i_blkbits; > in an earlier function in the callchain.
Yes, that's a more likely scenario. isofs has a history of passing garbage into the VFS.
> So, well. I dunno what i_blkbits is. There's no docs in struct inode.
It's log2 of the filesystem blocksize. It'd be interesting to work out what value isofs is setting it to, and why.
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