From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: netdev@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>,
Thomas Gleixner <tglx@linutronix.de>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Eric Dumazet <edumazet@google.com>
Subject: [PATCH net 2/2] net: gro: Let the timeout timer expire in softirq context with `threadirqs'
Date: Tue, 26 Nov 2019 23:20:13 +0100 [thread overview]
Message-ID: <20191126222013.1904785-3-bigeasy@linutronix.de> (raw)
In-Reply-To: <20191126222013.1904785-1-bigeasy@linutronix.de>
The timer callback (napi_watchdog()) invokes __napi_schedule_irqoff()
with disabled interrupts. With the `threadirqs' commandline option all
interrupt handler are threaded and using __napi_schedule_irqoff() is not
an issue because everyone is using it in threaded context which is
synchronised with local_bh_disable().
The napi_watchdog() timer is still expiring in hardirq context and may
interrupt a threaded handler which is in the middle of
__napi_schedule_irqoff() leading to list corruption.
Let the napi_watchdog() expire in softirq context if `threadirqs' is
used.
Fixes: 3b47d30396bae ("net: gro: add a per device gro flush timer")
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
net/core/dev.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/net/core/dev.c b/net/core/dev.c
index 99ac84ff398f4..ec533d20931bc 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5994,6 +5994,8 @@ bool napi_complete_done(struct napi_struct *n, int work_done)
napi_gro_flush(n, !!timeout);
if (timeout)
hrtimer_start(&n->timer, ns_to_ktime(timeout),
+ force_irqthreads ?
+ HRTIMER_MODE_REL_PINNED_SOFT :
HRTIMER_MODE_REL_PINNED);
}
if (unlikely(!list_empty(&n->poll_list))) {
@@ -6225,7 +6227,9 @@ void netif_napi_add(struct net_device *dev, struct napi_struct *napi,
int (*poll)(struct napi_struct *, int), int weight)
{
INIT_LIST_HEAD(&napi->poll_list);
- hrtimer_init(&napi->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_PINNED);
+ hrtimer_init(&napi->timer, CLOCK_MONOTONIC,
+ force_irqthreads ?
+ HRTIMER_MODE_REL_PINNED_SOFT : HRTIMER_MODE_REL_PINNED);
napi->timer.function = napi_watchdog;
init_gro_hash(napi);
napi->skb = NULL;
--
2.24.0
next prev parent reply other threads:[~2019-11-26 22:20 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-26 22:20 [PATCH net 0/2] __napi_schedule_irqoff() used in wrong context Sebastian Andrzej Siewior
2019-11-26 22:20 ` [PATCH net 1/2] amd-xgbe: Use __napi_schedule() in BH context Sebastian Andrzej Siewior
2019-12-02 17:19 ` Tom Lendacky
2020-04-16 13:52 ` Sebastian Andrzej Siewior
2020-04-16 15:19 ` Eric Dumazet
2019-11-26 22:20 ` Sebastian Andrzej Siewior [this message]
2019-11-26 22:39 ` [PATCH net 2/2] net: gro: Let the timeout timer expire in softirq context with `threadirqs' Eric Dumazet
2019-11-27 9:35 ` Sebastian Andrzej Siewior
[not found] ` <CANn89iL=q2wwjdSj1=veBE0hDATm_K=akKhz3Dyddnk28DRJhg@mail.gmail.com>
2019-11-27 17:11 ` Eric Dumazet
2019-11-27 17:37 ` Sebastian Andrzej Siewior
2020-04-16 13:59 ` Sebastian Andrzej Siewior
2021-03-17 14:10 ` Thomas Gleixner
2021-03-17 14:50 ` Eric Dumazet
2019-11-27 17:22 ` Sebastian Andrzej Siewior
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