| From | Greg Kroah-Hartman <> | Subject | [ 143/171] libceph: (re)initialize bio_iter on start of message receive | Date | Wed, 21 Nov 2012 16:41:29 -0800 |
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3.4-stable review patch. If anyone has any objections, please let me know.
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From: Sage Weil <sage@inktank.com>
(cherry picked from commit a4107026976f06c9a6ce8cc84a763564ee39d901)
Previously, we were opportunistically initializing the bio_iter if it appeared to be uninitialized in the middle of the read path. The problem is that a sequence like:
- start reading message - initialize bio_iter - read half a message - messenger fault, reconnect - restart reading message - ** bio_iter now non-NULL, not reinitialized ** - read past end of bio, crash
Instead, initialize the bio_iter unconditionally when we allocate/claim the message for read.
Signed-off-by: Sage Weil <sage@inktank.com> Reviewed-by: Alex Elder <elder@inktank.com> Reviewed-by: Yehuda Sadeh <yehuda@inktank.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/ceph/messenger.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
--- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -1872,6 +1872,11 @@ static int read_partial_message(struct c else con->in_msg_pos.page_pos = 0; con->in_msg_pos.data_pos = 0; + +#ifdef CONFIG_BLOCK + if (m->bio) + init_bio_iter(m->bio, &m->bio_iter, &m->bio_seg); +#endif } /* front */ @@ -1888,10 +1893,6 @@ static int read_partial_message(struct c if (ret <= 0) return ret; } -#ifdef CONFIG_BLOCK - if (m->bio && !m->bio_iter) - init_bio_iter(m->bio, &m->bio_iter, &m->bio_seg); -#endif /* (page) data */ while (con->in_msg_pos.data_pos < data_len) { @@ -1902,7 +1903,7 @@ static int read_partial_message(struct c return ret; #ifdef CONFIG_BLOCK } else if (m->bio) { - + BUG_ON(!m->bio_iter); ret = read_partial_message_bio(con, &m->bio_iter, &m->bio_seg, data_len, do_datacrc);
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