The following nfsd bugfix is available from git://linux-nfs.org/~bfields/linux.git for-2.6.34 Please pull for 2.6.34. Thanks! --b. commit 2bc3c1179c781b359d4f2f3439cb3df72afc17fc Author: Neil Brown <neilb@xxxxxxx> Date: Tue Apr 20 12:16:52 2010 +1000 nfsd4: bug in read_buf When read_buf is called to move over to the next page in the pagelist of an NFSv4 request, it sets argp->end to essentially a random number, certainly not an address within the page which argp->p now points to. So subsequent calls to READ_BUF will think there is much more than a page of spare space (the cast to u32 ensures an unsigned comparison) so we can expect to fall off the end of the second page. We never encountered thsi in testing because typically the only operations which use more than two pages are write-like operations, which have their own decoding logic. Something like a getattr after a write may cross a page boundary, but it would be very unusual for it to cross another boundary after that. Cc: stable@xxxxxxxxxx Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxxxxxx> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index e170317..34ccf81 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -161,10 +161,10 @@ static __be32 *read_buf(struct nfsd4_compoundargs *argp, u32 nbytes) argp->p = page_address(argp->pagelist[0]); argp->pagelist++; if (argp->pagelen < PAGE_SIZE) { - argp->end = p + (argp->pagelen>>2); + argp->end = argp->p + (argp->pagelen>>2); argp->pagelen = 0; } else { - argp->end = p + (PAGE_SIZE>>2); + argp->end = argp->p + (PAGE_SIZE>>2); argp->pagelen -= PAGE_SIZE; } memcpy(((char*)p)+avail, argp->p, (nbytes - avail)); @@ -1426,10 +1426,10 @@ nfsd4_decode_compound(struct nfsd4_compoundargs *argp) argp->p = page_address(argp->pagelist[0]); argp->pagelist++; if (argp->pagelen < PAGE_SIZE) { - argp->end = p + (argp->pagelen>>2); + argp->end = argp->p + (argp->pagelen>>2); argp->pagelen = 0; } else { - argp->end = p + (PAGE_SIZE>>2); + argp->end = argp->p + (PAGE_SIZE>>2); argp->pagelen -= PAGE_SIZE; } } -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html