[PATCH net-next v4 01/15] net: page_pool: Don't recycle into cache on PREEMPT_RT
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: 2025-05-12 09:27:44
Also in:
linux-rt-devel
Subsystem:
networking [general], page pool, the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Jesper Dangaard Brouer, Ilias Apalodimas, Linus Torvalds
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> --- 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 7745ad924ae2d..ba8803c2c0b20 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c@@ -805,6 +805,10 @@ 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;
--
2.49.0