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authorEric Dumazet <edumazet@google.com>2012-06-12 15:24:40 +0200
committerJens Axboe <axboe@kernel.dk>2012-06-13 21:16:42 +0200
commit047fe3605235888f3ebcda0c728cb31937eadfe6 (patch)
tree9c33ef4b076bd54f686afe924cee01e21c55f427 /net
parent27e1f9d1cc87be4e53c6eb7158cafc21c4b85a14 (diff)
downloadop-kernel-dev-047fe3605235888f3ebcda0c728cb31937eadfe6.zip
op-kernel-dev-047fe3605235888f3ebcda0c728cb31937eadfe6.tar.gz
splice: fix racy pipe->buffers uses
Dave Jones reported a kernel BUG at mm/slub.c:3474! triggered by splice_shrink_spd() called from vmsplice_to_pipe() commit 35f3d14dbbc5 (pipe: add support for shrinking and growing pipes) added capability to adjust pipe->buffers. Problem is some paths don't hold pipe mutex and assume pipe->buffers doesn't change for their duration. Fix this by adding nr_pages_max field in struct splice_pipe_desc, and use it in place of pipe->buffers where appropriate. splice_shrink_spd() loses its struct pipe_inode_info argument. Reported-by: Dave Jones <davej@redhat.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Tom Herbert <therbert@google.com> Cc: stable <stable@vger.kernel.org> # 2.6.35 Tested-by: Dave Jones <davej@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'net')
-rw-r--r--net/core/skbuff.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 016694d..bac3c57 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1755,6 +1755,7 @@ int skb_splice_bits(struct sk_buff *skb, unsigned int offset,
struct splice_pipe_desc spd = {
.pages = pages,
.partial = partial,
+ .nr_pages_max = MAX_SKB_FRAGS,
.flags = flags,
.ops = &sock_pipe_buf_ops,
.spd_release = sock_spd_release,
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