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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 /kernel/relay.c
parent27e1f9d1cc87be4e53c6eb7158cafc21c4b85a14 (diff)
downloadvexpress-lsk-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 'kernel/relay.c')
-rw-r--r--kernel/relay.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/relay.c b/kernel/relay.c
index ab56a1764d4..e8cd2027abb 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -1235,6 +1235,7 @@ static ssize_t subbuf_splice_actor(struct file *in,
struct splice_pipe_desc spd = {
.pages = pages,
.nr_pages = 0,
+ .nr_pages_max = PIPE_DEF_BUFFERS,
.partial = partial,
.flags = flags,
.ops = &relay_pipe_buf_ops,
@@ -1302,8 +1303,8 @@ static ssize_t subbuf_splice_actor(struct file *in,
ret += padding;
out:
- splice_shrink_spd(pipe, &spd);
- return ret;
+ splice_shrink_spd(&spd);
+ return ret;
}
static ssize_t relay_file_splice_read(struct file *in,