diff options
author | Trond Myklebust <trond.myklebust@hammerspace.com> | 2020-03-29 19:55:05 -0400 |
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committer | Trond Myklebust <trond.myklebust@hammerspace.com> | 2020-04-01 13:37:56 -0400 |
commit | dc9dc2febb17f72e9878eb540ad3996f7984239a (patch) | |
tree | ebe5d0a572a1584384969fd3612853b1ae776a84 /fs | |
parent | 08ca8b21f760c0ed5034a5c122092eec22ccf8f4 (diff) | |
download | linux-dc9dc2febb17f72e9878eb540ad3996f7984239a.tar.bz2 |
NFS: Fix use-after-free issues in nfs_pageio_add_request()
We need to ensure that we create the mirror requests before calling
nfs_pageio_add_request_mirror() on the request we are adding.
Otherwise, we can end up with a use-after-free if the call to
nfs_pageio_add_request_mirror() triggers I/O.
Fixes: c917cfaf9bbe ("NFS: Fix up NFS I/O subrequest creation")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/nfs/pagelist.c | 48 |
1 files changed, 24 insertions, 24 deletions
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index 0e3f0f241d83..99eb839c5778 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -1191,38 +1191,38 @@ int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc, if (desc->pg_error < 0) goto out_failed; - for (midx = 0; midx < desc->pg_mirror_count; midx++) { - if (midx) { - nfs_page_group_lock(req); - - /* find the last request */ - for (lastreq = req->wb_head; - lastreq->wb_this_page != req->wb_head; - lastreq = lastreq->wb_this_page) - ; - - dupreq = nfs_create_subreq(req, lastreq, - pgbase, offset, bytes); - - nfs_page_group_unlock(req); - if (IS_ERR(dupreq)) { - desc->pg_error = PTR_ERR(dupreq); - goto out_failed; - } - } else - dupreq = req; + /* Create the mirror instances first, and fire them off */ + for (midx = 1; midx < desc->pg_mirror_count; midx++) { + nfs_page_group_lock(req); + + /* find the last request */ + for (lastreq = req->wb_head; + lastreq->wb_this_page != req->wb_head; + lastreq = lastreq->wb_this_page) + ; + + dupreq = nfs_create_subreq(req, lastreq, + pgbase, offset, bytes); + + nfs_page_group_unlock(req); + if (IS_ERR(dupreq)) { + desc->pg_error = PTR_ERR(dupreq); + goto out_failed; + } - if (nfs_pgio_has_mirroring(desc)) - desc->pg_mirror_idx = midx; + desc->pg_mirror_idx = midx; if (!nfs_pageio_add_request_mirror(desc, dupreq)) goto out_cleanup_subreq; } + desc->pg_mirror_idx = 0; + if (!nfs_pageio_add_request_mirror(desc, req)) + goto out_failed; + return 1; out_cleanup_subreq: - if (req != dupreq) - nfs_pageio_cleanup_request(desc, dupreq); + nfs_pageio_cleanup_request(desc, dupreq); out_failed: nfs_pageio_error_cleanup(desc); return 0; |