Commit 87d918d6 authored Dec 04, 2006 by J. Bruce Fields Committed by Trond Myklebust Dec 06, 2006

rpc: gss: fix a kmap_atomic race in krb5 code



This code is never called from interrupt context; it's always run by either
a user thread or rpciod.  So KM_SKB_SUNRPC_DATA is inappropriate here.

Thanks to Aimé Le Rouzic for capturing an oops which showed the kernel
taking an interrupt while we were in this piece of code, resulting in a
nested kmap_atomic(.,KM_SKB_SUNRPC_DATA) call from
xdr_partial_copy_from_skb().

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

parent 8fc7500b

net/sunrpc/auth_gss/gss_krb5_wrap.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -57,9 +57,9 @@ gss_krb5_remove_padding(struct xdr_buf *buf, int blocksize)
		>>PAGE_CACHE_SHIFT;
		int offset = (buf->page_base + len - 1)
		& (PAGE_CACHE_SIZE - 1);
		ptr = kmap_atomic(buf->pages[last], KM_SKB_SUNRPC_DATA);
		ptr = kmap_atomic(buf->pages[last], KM_USER0);
		pad = *(ptr + offset);
		kunmap_atomic(ptr, KM_SKB_SUNRPC_DATA);
		kunmap_atomic(ptr, KM_USER0);
		goto out;
		} else
		len -= buf->page_len;

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