Put in a check in read subreq termination to detect more data being read for a subrequest than was requested.
Signed-off-by: David Howells <[email protected]> cc: Paulo Alcantara <[email protected]> cc: [email protected] cc: [email protected] --- fs/netfs/read_collect.c | 18 ++++++++++++++++++ include/trace/events/netfs.h | 1 + 2 files changed, 19 insertions(+) diff --git a/fs/netfs/read_collect.c b/fs/netfs/read_collect.c index 802d1c40cce5..c0170f80d67f 100644 --- a/fs/netfs/read_collect.c +++ b/fs/netfs/read_collect.c @@ -227,6 +227,8 @@ static void netfs_collect_read_results(struct netfs_io_request *rreq) notes |= HIT_PENDING; smp_rmb(); /* Read counters after IN_PROGRESS flag. */ transferred = READ_ONCE(front->transferred); + if (transferred > front->len) + transferred = front->len; /* If we can now collect the next folio, do so. We don't want * to defer this as we have to decide whether we need to copy @@ -543,6 +545,22 @@ void netfs_read_subreq_terminated(struct netfs_io_subrequest *subreq) break; } + /* If the subrequest read more than it was supposed to, abort + * the request with EIO as we may have clobbered other parts + * of the buffer that are already read. + */ + if (subreq->transferred > subreq->len) { + trace_netfs_sreq(subreq, netfs_sreq_trace_too_much); + __set_bit(NETFS_SREQ_FAILED, &subreq->flags); + __clear_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags); + subreq->transferred = 0; + subreq->error = -EIO; + trace_netfs_failure(rreq, subreq, subreq->error, netfs_fail_read); + trace_netfs_rreq(rreq, netfs_rreq_trace_set_pause); + set_bit(NETFS_RREQ_PAUSE, &rreq->flags); + goto skip_error_checks; + } + /* Deal with retry requests, short reads and errors. If we retry * but don't make progress, we abandon the attempt. */ diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h index 071d20e80f13..723cb7315308 100644 --- a/include/trace/events/netfs.h +++ b/include/trace/events/netfs.h @@ -132,6 +132,7 @@ EM(netfs_sreq_trace_submit, "SUBMT") \ EM(netfs_sreq_trace_superfluous, "SPRFL") \ EM(netfs_sreq_trace_terminated, "TERM ") \ + EM(netfs_sreq_trace_too_much, "!TOOM") \ EM(netfs_sreq_trace_wait_for, "_WAIT") \ EM(netfs_sreq_trace_write, "WRITE") \ EM(netfs_sreq_trace_write_skip, "SKIP ") \
