From 3e8db7e56082156a37b71d7334860c10fcea8025 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Tue, 1 Oct 2019 21:58:19 +0300 Subject: net: dsa: sja1105: Fix sleeping while atomic in .port_hwtstamp_set Currently this stack trace can be seen with CONFIG_DEBUG_ATOMIC_SLEEP=y: [ 41.568348] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:909 [ 41.576757] in_atomic(): 1, irqs_disabled(): 0, pid: 208, name: ptp4l [ 41.583212] INFO: lockdep is turned off. [ 41.587123] CPU: 1 PID: 208 Comm: ptp4l Not tainted 5.3.0-rc6-01445-ge950f2d4bc7f-dirty #1827 [ 41.599873] [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [ 41.607584] [] (show_stack) from [] (dump_stack+0xd4/0x100) [ 41.614863] [] (dump_stack) from [] (___might_sleep+0x1c8/0x2b4) [ 41.622574] [] (___might_sleep) from [] (__mutex_lock+0x48/0xab8) [ 41.630368] [] (__mutex_lock) from [] (mutex_lock_nested+0x1c/0x24) [ 41.638340] [] (mutex_lock_nested) from [] (sja1105_static_config_reload+0x30/0x27c) [ 41.647779] [] (sja1105_static_config_reload) from [] (sja1105_hwtstamp_set+0x108/0x1cc) [ 41.657562] [] (sja1105_hwtstamp_set) from [] (dev_ifsioc+0x18c/0x330) [ 41.665788] [] (dev_ifsioc) from [] (dev_ioctl+0x320/0x6e8) [ 41.673064] [] (dev_ioctl) from [] (sock_ioctl+0x334/0x5e8) [ 41.680340] [] (sock_ioctl) from [] (do_vfs_ioctl+0xb0/0xa10) [ 41.687789] [] (do_vfs_ioctl) from [] (ksys_ioctl+0x34/0x58) [ 41.695151] [] (ksys_ioctl) from [] (ret_fast_syscall+0x0/0x28) [ 41.702768] Exception stack(0xe8495fa8 to 0xe8495ff0) [ 41.707796] 5fa0: beff4a8c 00000001 00000011 000089b0 beff4a8c beff4a80 [ 41.715933] 5fc0: beff4a8c 00000001 0000000c 00000036 b6fa98c8 004e19c1 00000001 00000000 [ 41.724069] 5fe0: 004dcedc beff4a6c 004c0738 b6e7af4c [ 41.729860] BUG: scheduling while atomic: ptp4l/208/0x00000002 [ 41.735682] INFO: lockdep is turned off. Enabling RX timestamping will logically disturb the fastpath (processing of meta frames). Replace bool hwts_rx_en with a bit that is checked atomically from the fastpath and temporarily unset from the sleepable context during a change of the RX timestamping process (a destructive operation anyways, requires switch reset). If found unset, the fastpath (net/dsa/tag_sja1105.c) will just drop any received meta frame and not take the meta_lock at all. Fixes: a602afd200f5 ("net: dsa: sja1105: Expose PTP timestamping ioctls to userspace") Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller --- drivers/net/dsa/sja1105/sja1105_main.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) (limited to 'drivers/net/dsa') diff --git a/drivers/net/dsa/sja1105/sja1105_main.c b/drivers/net/dsa/sja1105/sja1105_main.c index ea2e7f4f96d0..7687ddcae159 100644 --- a/drivers/net/dsa/sja1105/sja1105_main.c +++ b/drivers/net/dsa/sja1105/sja1105_main.c @@ -1897,7 +1897,9 @@ static int sja1105_set_ageing_time(struct dsa_switch *ds, return sja1105_static_config_reload(priv); } -/* Caller must hold priv->tagger_data.meta_lock */ +/* Must be called only with priv->tagger_data.state bit + * SJA1105_HWTS_RX_EN cleared + */ static int sja1105_change_rxtstamping(struct sja1105_private *priv, bool on) { @@ -1954,16 +1956,17 @@ static int sja1105_hwtstamp_set(struct dsa_switch *ds, int port, break; } - if (rx_on != priv->tagger_data.hwts_rx_en) { - spin_lock(&priv->tagger_data.meta_lock); + if (rx_on != test_bit(SJA1105_HWTS_RX_EN, &priv->tagger_data.state)) { + clear_bit(SJA1105_HWTS_RX_EN, &priv->tagger_data.state); + rc = sja1105_change_rxtstamping(priv, rx_on); - spin_unlock(&priv->tagger_data.meta_lock); if (rc < 0) { dev_err(ds->dev, "Failed to change RX timestamping: %d\n", rc); - return -EFAULT; + return rc; } - priv->tagger_data.hwts_rx_en = rx_on; + if (rx_on) + set_bit(SJA1105_HWTS_RX_EN, &priv->tagger_data.state); } if (copy_to_user(ifr->ifr_data, &config, sizeof(config))) @@ -1982,7 +1985,7 @@ static int sja1105_hwtstamp_get(struct dsa_switch *ds, int port, config.tx_type = HWTSTAMP_TX_ON; else config.tx_type = HWTSTAMP_TX_OFF; - if (priv->tagger_data.hwts_rx_en) + if (test_bit(SJA1105_HWTS_RX_EN, &priv->tagger_data.state)) config.rx_filter = HWTSTAMP_FILTER_PTP_V2_L2_EVENT; else config.rx_filter = HWTSTAMP_FILTER_NONE; @@ -2031,7 +2034,7 @@ static bool sja1105_port_rxtstamp(struct dsa_switch *ds, int port, struct sja1105_private *priv = ds->priv; struct sja1105_tagger_data *data = &priv->tagger_data; - if (!data->hwts_rx_en) + if (!test_bit(SJA1105_HWTS_RX_EN, &data->state)) return false; /* We need to read the full PTP clock to reconstruct the Rx -- cgit v1.2.3-59-g8ed1b