From: Tejun Heo <tj@kernel.org> mainline inclusion from mainline-v6.15-rc7 commit 428dc9fc0873989d73918d4a9cc22745b7bbc799 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/ID7HLY Reference: https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commi... -------------------------------- BPF programs may call next() and destroy() on BPF iterators even after new() returns an error value (e.g. bpf_for_each() macro ignores error returns from new()). bpf_iter_scx_dsq_new() could leave the iterator in an uninitialized state after an error return causing bpf_iter_scx_dsq_next() to dereference garbage data. Make bpf_iter_scx_dsq_new() always clear $kit->dsq so that next() and destroy() become noops. Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: 650ba21b131e ("sched_ext: Implement DSQ iterator") Cc: stable@vger.kernel.org # v6.12+ Acked-by: Andrea Righi <arighi@nvidia.com> Signed-off-by: Zicheng Qu <quzicheng@huawei.com> Signed-off-by: cheliequan <cheliequan@inspur.com> Signed-off-by: Luo Gengkun <luogengkun2@huawei.com> --- kernel/sched/ext.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index b2c397934b27..c55b949281dc 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -6650,6 +6650,12 @@ __bpf_kfunc int bpf_iter_scx_dsq_new(struct bpf_iter_scx_dsq *it, u64 dsq_id, BUILD_BUG_ON(__alignof__(struct bpf_iter_scx_dsq_kern) != __alignof__(struct bpf_iter_scx_dsq)); + /* + * next() and destroy() will be called regardless of the return value. + * Always clear $kit->dsq. + */ + kit->dsq = NULL; + if (flags & ~__SCX_DSQ_ITER_USER_FLAGS) return -EINVAL; -- 2.34.1