6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior bigeasy@linutronix.de
[ Upstream commit 32471b2f481dea8624f27669d36ffd131d24b732 ]
With preemptible softirq and no per-CPU locking in local_bh_disable() on PREEMPT_RT the consumer can be preempted while a skb is returned.
Avoid the race by disabling the recycle into the cache on PREEMPT_RT.
Cc: Jesper Dangaard Brouer hawk@kernel.org Cc: Ilias Apalodimas ilias.apalodimas@linaro.org Signed-off-by: Sebastian Andrzej Siewior bigeasy@linutronix.de Link: https://patch.msgid.link/20250512092736.229935-2-bigeasy@linutronix.de Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/core/page_pool.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/net/core/page_pool.c b/net/core/page_pool.c index 0f23b3126bdaf..b1c3e0ad6dbf4 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -829,6 +829,10 @@ static bool page_pool_napi_local(const struct page_pool *pool) const struct napi_struct *napi; u32 cpuid;
+ /* On PREEMPT_RT the softirq can be preempted by the consumer */ + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + return false; + if (unlikely(!in_softirq())) return false;