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Message-Id: <1456773435-16607-4-git-send-email-saeedm@mellanox.com>
Date: Mon, 29 Feb 2016 21:17:11 +0200
From: Saeed Mahameed <saeedm@...lanox.com>
To: "David S. Miller" <davem@...emloft.net>
Cc: netdev@...r.kernel.org, Or Gerlitz <ogerlitz@...lanox.com>,
Eran Ben Elisha <eranbe@...lanox.com>,
Tal Alon <talal@...lanox.com>,
Saeed Mahameed <saeedm@...lanox.com>
Subject: [PATCH net V1 3/7] net/mlx5e: Fix soft lockup when HW Timestamping is enabled
From: Eran Ben Elisha <eranbe@...lanox.com>
Readers/Writers lock for SW timecounter was acquired without disabling
interrupts on local CPU.
The problematic scenario:
* HW timestamping is enabled
* Timestamp overflow periodic service task is running on local CPU and
holding write_lock for SW timecounter
* Completion arrives, triggers interrupt for local CPU.
Interrupt routine calls napi_schedule(), which triggers rx/tx
skb process.
An attempt to read SW timecounter using read_lock is done, which is
already locked by a writer on the same CPU and cause soft lockup.
Add irqsave/irqrestore for when using the readers/writers lock for
writing.
Fixes: ef9814deafd0 ('net/mlx5e: Add HW timestamping (TS) support')
Signed-off-by: Eran Ben Elisha <eranbe@...lanox.com>
Signed-off-by: Saeed Mahameed <saeedm@...lanox.com>
---
drivers/net/ethernet/mellanox/mlx5/core/en_clock.c | 25 ++++++++++++--------
1 files changed, 15 insertions(+), 10 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_clock.c b/drivers/net/ethernet/mellanox/mlx5/core/en_clock.c
index be65435..2018eeb 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_clock.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_clock.c
@@ -62,10 +62,11 @@ static void mlx5e_timestamp_overflow(struct work_struct *work)
struct delayed_work *dwork = to_delayed_work(work);
struct mlx5e_tstamp *tstamp = container_of(dwork, struct mlx5e_tstamp,
overflow_work);
+ unsigned long flags;
- write_lock(&tstamp->lock);
+ write_lock_irqsave(&tstamp->lock, flags);
timecounter_read(&tstamp->clock);
- write_unlock(&tstamp->lock);
+ write_unlock_irqrestore(&tstamp->lock, flags);
schedule_delayed_work(&tstamp->overflow_work, tstamp->overflow_period);
}
@@ -136,10 +137,11 @@ static int mlx5e_ptp_settime(struct ptp_clock_info *ptp,
struct mlx5e_tstamp *tstamp = container_of(ptp, struct mlx5e_tstamp,
ptp_info);
u64 ns = timespec64_to_ns(ts);
+ unsigned long flags;
- write_lock(&tstamp->lock);
+ write_lock_irqsave(&tstamp->lock, flags);
timecounter_init(&tstamp->clock, &tstamp->cycles, ns);
- write_unlock(&tstamp->lock);
+ write_unlock_irqrestore(&tstamp->lock, flags);
return 0;
}
@@ -150,10 +152,11 @@ static int mlx5e_ptp_gettime(struct ptp_clock_info *ptp,
struct mlx5e_tstamp *tstamp = container_of(ptp, struct mlx5e_tstamp,
ptp_info);
u64 ns;
+ unsigned long flags;
- write_lock(&tstamp->lock);
+ write_lock_irqsave(&tstamp->lock, flags);
ns = timecounter_read(&tstamp->clock);
- write_unlock(&tstamp->lock);
+ write_unlock_irqrestore(&tstamp->lock, flags);
*ts = ns_to_timespec64(ns);
@@ -164,10 +167,11 @@ static int mlx5e_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
{
struct mlx5e_tstamp *tstamp = container_of(ptp, struct mlx5e_tstamp,
ptp_info);
+ unsigned long flags;
- write_lock(&tstamp->lock);
+ write_lock_irqsave(&tstamp->lock, flags);
timecounter_adjtime(&tstamp->clock, delta);
- write_unlock(&tstamp->lock);
+ write_unlock_irqrestore(&tstamp->lock, flags);
return 0;
}
@@ -176,6 +180,7 @@ static int mlx5e_ptp_adjfreq(struct ptp_clock_info *ptp, s32 delta)
{
u64 adj;
u32 diff;
+ unsigned long flags;
int neg_adj = 0;
struct mlx5e_tstamp *tstamp = container_of(ptp, struct mlx5e_tstamp,
ptp_info);
@@ -189,11 +194,11 @@ static int mlx5e_ptp_adjfreq(struct ptp_clock_info *ptp, s32 delta)
adj *= delta;
diff = div_u64(adj, 1000000000ULL);
- write_lock(&tstamp->lock);
+ write_lock_irqsave(&tstamp->lock, flags);
timecounter_read(&tstamp->clock);
tstamp->cycles.mult = neg_adj ? tstamp->nominal_c_mult - diff :
tstamp->nominal_c_mult + diff;
- write_unlock(&tstamp->lock);
+ write_unlock_irqrestore(&tstamp->lock, flags);
return 0;
}
--
1.7.1
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