From: Jonathan Lemon <jonathan.lemon@gmail.com>
To: <netdev@vger.kernel.org>, <davem@davemloft.net>,
<brouer@redhat.com>, <ilias.apalodimas@linaro.org>
Cc: <kernel-team@fb.com>
Subject: [PATCH] page_pool: use irqsave/irqrestore to protect ring access.
Date: Mon, 9 Mar 2020 12:49:29 -0700 [thread overview]
Message-ID: <20200309194929.3889255-1-jonathan.lemon@gmail.com> (raw)
netpoll may be called from IRQ context, which may access the
page pool ring. The current _bh variants do not provide sufficient
protection, so use irqsave/restore instead.
Error observed on a modified mlx4 driver, but the code path exists
for any driver which calls page_pool_recycle from napi poll.
WARNING: CPU: 34 PID: 550248 at /ro/source/kernel/softirq.c:161 __local_bh_enable_ip+0x35/0x50
__page_pool_finish_recycle+0x14f/0x180
mlx4_en_recycle_tx_desc+0x44/0x50
mlx4_en_process_tx_cq+0x19f/0x440
mlx4_en_poll_rx_cq+0xd4/0xf0
netpoll_poll_dev+0xc2/0x190
netpoll_send_skb_on_dev+0xf5/0x230
netpoll_send_udp+0x2b3/0x3cd
write_ext_msg+0x1be/0x1d0
console_unlock+0x22e/0x500
vprintk_emit+0x23a/0x360
printk+0x48/0x4a
hpet_rtc_interrupt.cold.17+0xe/0x1a
__handle_irq_event_percpu+0x43/0x180
handle_irq_event_percpu+0x20/0x60
handle_irq_event+0x2a/0x47
handle_edge_irq+0x8e/0x190
handle_irq+0xbf/0x100
do_IRQ+0x41/0xc0
common_interrupt+0xf/0xf
</IRQ>
Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
---
net/core/page_pool.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index 626db912fce4..df9804e85a40 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -102,6 +102,7 @@ noinline
static struct page *page_pool_refill_alloc_cache(struct page_pool *pool)
{
struct ptr_ring *r = &pool->ring;
+ unsigned long flags;
struct page *page;
int pref_nid; /* preferred NUMA node */
@@ -120,7 +121,7 @@ static struct page *page_pool_refill_alloc_cache(struct page_pool *pool)
#endif
/* Slower-path: Get pages from locked ring queue */
- spin_lock(&r->consumer_lock);
+ spin_lock_irqsave(&r->consumer_lock, flags);
/* Refill alloc array, but only if NUMA match */
do {
@@ -146,7 +147,7 @@ static struct page *page_pool_refill_alloc_cache(struct page_pool *pool)
if (likely(pool->alloc.count > 0))
page = pool->alloc.cache[--pool->alloc.count];
- spin_unlock(&r->consumer_lock);
+ spin_unlock_irqrestore(&r->consumer_lock, flags);
return page;
}
@@ -321,11 +322,8 @@ static void page_pool_return_page(struct page_pool *pool, struct page *page)
static bool page_pool_recycle_in_ring(struct page_pool *pool, struct page *page)
{
int ret;
- /* BH protection not needed if current is serving softirq */
- if (in_serving_softirq())
- ret = ptr_ring_produce(&pool->ring, page);
- else
- ret = ptr_ring_produce_bh(&pool->ring, page);
+
+ ret = ptr_ring_produce_any(&pool->ring, page);
return (ret == 0) ? true : false;
}
@@ -411,7 +409,7 @@ static void page_pool_empty_ring(struct page_pool *pool)
struct page *page;
/* Empty recycle ring */
- while ((page = ptr_ring_consume_bh(&pool->ring))) {
+ while ((page = ptr_ring_consume_any(&pool->ring))) {
/* Verify the refcnt invariant of cached pages */
if (!(page_ref_count(page) == 1))
pr_crit("%s() page_pool refcnt %d violation\n",
--
2.17.1
next reply other threads:[~2020-03-09 19:49 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-09 19:49 Jonathan Lemon [this message]
2020-03-10 0:55 ` [PATCH] page_pool: use irqsave/irqrestore to protect ring access David Miller
2020-03-10 2:30 ` Saeed Mahameed
2020-03-10 10:04 ` Jesper Dangaard Brouer
2020-03-10 17:52 ` Jonathan Lemon
2020-03-10 21:09 ` Jakub Kicinski
2020-03-10 23:53 ` Saeed Mahameed
2020-03-10 17:07 ` Jonathan Lemon
2020-03-10 23:34 ` Saeed Mahameed
2020-03-10 16:52 ` Jonathan Lemon
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