[PATCH net 3/7] net/mlx5e: Fix soft lockup when HW Timestamping is enabled
From: Saeed Mahameed <hidden>
Date: 2016-02-24 11:19:25
Subsystem:
mellanox ethernet driver (mlx5e), mellanox mlx5 core vpi driver, networking drivers, the rest · Maintainers:
Saeed Mahameed, Tariq Toukan, Mark Bloch, Leon Romanovsky, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Eran Ben Elisha <redacted>
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.
Fixes: ef9814deafd0 ('net/mlx5e: Add HW timestamping (TS) support')
Signed-off-by: Eran Ben Elisha <redacted>
Signed-off-by: Saeed Mahameed <redacted>
---
drivers/net/ethernet/mellanox/mlx5/core/en_clock.c | 30 ++++++++++++--------
1 files changed, 18 insertions(+), 12 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..86f9f29 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_clock.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_clock.c@@ -41,10 +41,11 @@ void mlx5e_fill_hwstamp(struct mlx5e_tstamp *tstamp, u64 timestamp, struct skb_shared_hwtstamps *hwts) { u64 nsec; + unsigned long flags; - read_lock(&tstamp->lock); + read_lock_irqsave(&tstamp->lock, flags); nsec = timecounter_cyc2time(&tstamp->clock, timestamp); - read_unlock(&tstamp->lock); + read_unlock_irqrestore(&tstamp->lock, flags); hwts->hwtstamp = ns_to_ktime(nsec); }
@@ -62,10 +63,11 @@ 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 +138,11 @@ 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 +153,11 @@ 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 +168,11 @@ 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 +181,7 @@ 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 +195,11 @@ 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