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authorAlex Williamson <alex.williamson@redhat.com>2023-10-03 01:43:25 +0300
committerAlex Williamson <alex.williamson@redhat.com>2023-10-10 00:56:09 +0300
commitbd885fcf28da7da6a2244d30cd45630303c781ed (patch)
treec10f395203c517f97c0a4a983a509bb5a992ecf2 /drivers/vfio
parentf9af5ad0f5b599fadf6fc7c9c2153d7919c7691e (diff)
downloadlinux-bd885fcf28da7da6a2244d30cd45630303c781ed.tar.xz
vfio: Fix smatch errors in vfio_combine_iova_ranges()
smatch reports: vfio_combine_iova_ranges() error: uninitialized symbol 'last'. vfio_combine_iova_ranges() error: potentially dereferencing uninitialized 'comb_end'. vfio_combine_iova_ranges() error: potentially dereferencing uninitialized 'comb_start'. These errors are only reachable via invalid input, in the case of @last when we receive an empty rb-tree or for @comb_{start,end} if the rb-tree is empty or otherwise fails to produce a second node that reduces the gap. Add tests with warnings for these cases. Reported-by: Cong Liu <liucong2@kylinos.cn> Link: https://lore.kernel.org/all/20230920095532.88135-1-liucong2@kylinos.cn Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Brett Creeley <brett.creeley@amd.com> Link: https://lore.kernel.org/r/20231002224325.3150842-1-alex.williamson@redhat.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'drivers/vfio')
-rw-r--r--drivers/vfio/vfio_main.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
index 40732e8ed4c6..e31e1952d7b8 100644
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -946,6 +946,11 @@ void vfio_combine_iova_ranges(struct rb_root_cached *root, u32 cur_nodes,
unsigned long last;
comb_start = interval_tree_iter_first(root, 0, ULONG_MAX);
+
+ /* Empty list */
+ if (WARN_ON_ONCE(!comb_start))
+ return;
+
curr = comb_start;
while (curr) {
last = curr->last;
@@ -975,6 +980,11 @@ void vfio_combine_iova_ranges(struct rb_root_cached *root, u32 cur_nodes,
prev = curr;
curr = interval_tree_iter_next(curr, 0, ULONG_MAX);
}
+
+ /* Empty list or no nodes to combine */
+ if (WARN_ON_ONCE(min_gap == ULONG_MAX))
+ break;
+
comb_start->last = comb_end->last;
interval_tree_remove(comb_end, root);
cur_nodes--;