Messages in this thread | | | Date | Wed, 30 Apr 2008 00:24:27 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] x86: endless page faults in mount_block_root for Linux 2.6 |
| |
* Pekka Enberg <penberg@cs.helsinki.fi> wrote:
> On Tue, Apr 29, 2008 at 5:33 PM, Ingo Molnar <mingo@elte.hu> wrote: > > btw., i have a kmemcheck-reported bug fixed in this same area with the > > patch below. I dont remember the details anymore, but the root mount > > code did something really, really weird here. > > > > Subject: init: root mount fix > > From: Ingo Molnar <mingo@elte.hu> > > Date: Tue Apr 29 16:31:50 CEST 2008 > > > > Signed-off-by: Ingo Molnar <mingo@elte.hu> > > --- > > init/do_mounts.c | 8 ++++++-- > > 1 file changed, 6 insertions(+), 2 deletions(-) > > > > Index: linux/init/do_mounts.c > > =================================================================== > > --- linux.orig/init/do_mounts.c > > +++ linux/init/do_mounts.c > > @@ -201,9 +201,13 @@ static int __init do_mount_root(char *na > > return 0; > > } > > > > +#if PAGE_SIZE < PATH_MAX > > +# error increase the fs_names allocation size here > > +#endif > > > > + > > void __init mount_block_root(char *name, int flags) > > { > > - char *fs_names = __getname(); > > + char *fs_names = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1); > > > > char *p; > > #ifdef CONFIG_BLOCK > > char b[BDEVNAME_SIZE]; > > @@ -251,7 +255,7 @@ retry: > > > > #endif > > panic("VFS: Unable to mount root fs on %s", b); > > out: > > - putname(fs_names); > > + free_pages((unsigned long)fs_names, 1); > > } > > > > #ifdef CONFIG_ROOT_NFS > > It could have been a bug in early kmemcheck too. We don't check memory > allocated with the page allocator, only slab, so this shouldn't > trigger anything.
no, i tracked it down and the problem was some genuine weirdness in this code (and not in kmemcheck) but i forgot the details :-)
it was something rather disgusting, the boot parameter parsing stuff.
Ingo
| |