6.14-stable review patch. If anyone has any objections, please let me know.
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From: Jake Hillion jake@hillion.co.uk
commit a8897ed8523d4c9d782e282b18005a3779c92714 upstream.
create_dsq and therefore the scx_bpf_create_dsq kfunc currently silently ignore duplicate entries. As a sched_ext scheduler is creating each DSQ for a different purpose this is surprising behaviour.
Replace rhashtable_insert_fast which ignores duplicates with rhashtable_lookup_insert_fast that reports duplicates (though doesn't return their value). The rest of the code is structured correctly and this now returns -EEXIST.
Tested by adding an extra scx_bpf_create_dsq to scx_simple. Previously this was ignored, now init fails with a -17 code. Also ran scx_lavd which continued to work well.
Signed-off-by: Jake Hillion jake@hillion.co.uk Acked-by: Andrea Righi arighi@nvidia.com Fixes: f0e1a0643a59 ("sched_ext: Implement BPF extensible scheduler class") Cc: stable@vger.kernel.org # v6.12+ Signed-off-by: Tejun Heo tj@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/sched/ext.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -4523,8 +4523,8 @@ static struct scx_dispatch_q *create_dsq
init_dsq(dsq, dsq_id);
- ret = rhashtable_insert_fast(&dsq_hash, &dsq->hash_node, - dsq_hash_params); + ret = rhashtable_lookup_insert_fast(&dsq_hash, &dsq->hash_node, + dsq_hash_params); if (ret) { kfree(dsq); return ERR_PTR(ret);