| Message ID | 20231002224325.3150842-1-alex.williamson@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | vfio: Fix smatch errors in vfio_combine_iova_ranges() | expand |
On 10/2/2023 3:43 PM, Alex Williamson wrote: > Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding. > > > 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 > Cc: Yishai Hadas <yishaih@nvidia.com> > Cc: Brett Creeley <brett.creeley@amd.com> > Signed-off-by: Alex Williamson <alex.williamson@redhat.com> > --- > drivers/vfio/vfio_main.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > 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--; > -- > 2.40.1 > LGTM. Thanks for fixing this. Reviewed-by: Brett Creeley <brett.creeley@amd.com>
On Mon, Oct 02, 2023 at 04:43:25PM -0600, Alex Williamson wrote: > 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 > Cc: Yishai Hadas <yishaih@nvidia.com> > Cc: Brett Creeley <brett.creeley@amd.com> > Signed-off-by: Alex Williamson <alex.williamson@redhat.com> > --- > drivers/vfio/vfio_main.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) Yeah, this is much clearer Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Thanks, Jason
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--;
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 Cc: Yishai Hadas <yishaih@nvidia.com> Cc: Brett Creeley <brett.creeley@amd.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com> --- drivers/vfio/vfio_main.c | 10 ++++++++++ 1 file changed, 10 insertions(+)