From e35df62e04cc6fc4b9d90d054732f138349ff9b1 Mon Sep 17 00:00:00 2001 From: Sven Van Asbroeck Date: Thu, 12 Nov 2020 13:59:49 -0500 Subject: [PATCH] lan743x: fix issue causing intermittent kernel log warnings When running this chip on arm imx6, we intermittently observe the following kernel warning in the log, especially when the system is under high load: [ 50.119484] ------------[ cut here ]------------ [ 50.124377] WARNING: CPU: 0 PID: 303 at kernel/softirq.c:169 __local_bh_enable_ip+0x100/0x184 [ 50.132925] IRQs not enabled as expected [ 50.159250] CPU: 0 PID: 303 Comm: rngd Not tainted 5.7.8 #1 [ 50.164837] Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree) [ 50.171395] [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [ 50.179162] [] (show_stack) from [] (dump_stack+0xac/0xd8) [ 50.186408] [] (dump_stack) from [] (__warn+0xd0/0x10c) [ 50.193391] [] (__warn) from [] (warn_slowpath_fmt+0x98/0xc4) [ 50.200892] [] (warn_slowpath_fmt) from [] (__local_bh_enable_ip+0x100/0x184) [ 50.209860] [] (__local_bh_enable_ip) from [] (destroy_conntrack+0x48/0xd8 [nf_conntrack]) [ 50.220038] [] (destroy_conntrack [nf_conntrack]) from [] (nf_conntrack_destroy+0x94/0x168) [ 50.230160] [] (nf_conntrack_destroy) from [] (skb_release_head_state+0xa0/0xd0) [ 50.239314] [] (skb_release_head_state) from [] (skb_release_all+0xc/0x24) [ 50.247946] [] (skb_release_all) from [] (consume_skb+0x74/0x17c) [ 50.255796] [] (consume_skb) from [] (lan743x_tx_release_desc+0x120/0x124) [ 50.264428] [] (lan743x_tx_release_desc) from [] (lan743x_tx_napi_poll+0x5c/0x18c) [ 50.273755] [] (lan743x_tx_napi_poll) from [] (net_rx_action+0x118/0x4a4) [ 50.282306] [] (net_rx_action) from [] (__do_softirq+0x13c/0x53c) [ 50.290157] [] (__do_softirq) from [] (irq_exit+0x150/0x17c) [ 50.297575] [] (irq_exit) from [] (__handle_domain_irq+0x60/0xb0) [ 50.305423] [] (__handle_domain_irq) from [] (gic_handle_irq+0x4c/0x90) [ 50.313790] [] (gic_handle_irq) from [] (__irq_usr+0x54/0x80) [ 50.321287] Exception stack(0xecd99fb0 to 0xecd99ff8) [ 50.326355] 9fa0: 1cf1aa74 00000001 00000001 00000000 [ 50.334547] 9fc0: 00000001 00000000 00000000 00000000 00000000 00000000 00004097 b6d17d14 [ 50.342738] 9fe0: 00000001 b6d17c60 00000000 b6e71f94 800b0010 ffffffff [ 50.349364] irq event stamp: 2525027 [ 50.352955] hardirqs last enabled at (2525026): [] net_rx_action+0xb4/0x4a4 [ 50.360892] hardirqs last disabled at (2525027): [] _raw_spin_lock_irqsave+0x1c/0x50 [ 50.369517] softirqs last enabled at (2524660): [] __do_softirq+0x38c/0x53c [ 50.377446] softirqs last disabled at (2524693): [] irq_exit+0x150/0x17c [ 50.385027] ---[ end trace c0b571db4bc8087d ]--- The driver is calling dev_kfree_skb() from code inside a spinlock, where h/w interrupts are disabled. This is forbidden, as documented in include/linux/netdevice.h. The correct function to use dev_kfree_skb_irq(), or dev_kfree_skb_any(). Fix by using the correct dev_kfree_skb_xxx() functions: in lan743x_tx_release_desc(): called by lan743x_tx_release_completed_descriptors() called by in lan743x_tx_napi_poll() which holds a spinlock called by lan743x_tx_release_all_descriptors() called by lan743x_tx_close() which can-sleep conclusion: use dev_kfree_skb_any() in lan743x_tx_xmit_frame(): which holds a spinlock conclusion: use dev_kfree_skb_irq() in lan743x_tx_close(): which can-sleep conclusion: use dev_kfree_skb() in lan743x_rx_release_ring_element(): called by lan743x_rx_close() which can-sleep called by lan743x_rx_open() which can-sleep conclusion: use dev_kfree_skb() Fixes: 23f0703c125b ("lan743x: Add main source files for new lan743x driver") Signed-off-by: Sven Van Asbroeck Link: https://lore.kernel.org/r/20201112185949.11315-1-TheSven73@gmail.com Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/microchip/lan743x_main.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/net/ethernet/microchip/lan743x_main.c b/drivers/net/ethernet/microchip/lan743x_main.c index e2c99d9..18c053b8 100644 --- a/drivers/net/ethernet/microchip/lan743x_main.c +++ b/drivers/net/ethernet/microchip/lan743x_main.c @@ -1307,13 +1307,13 @@ clean_up_data_descriptor: goto clear_active; if (!(buffer_info->flags & TX_BUFFER_INFO_FLAG_TIMESTAMP_REQUESTED)) { - dev_kfree_skb(buffer_info->skb); + dev_kfree_skb_any(buffer_info->skb); goto clear_skb; } if (cleanup) { lan743x_ptp_unrequest_tx_timestamp(tx->adapter); - dev_kfree_skb(buffer_info->skb); + dev_kfree_skb_any(buffer_info->skb); } else { ignore_sync = (buffer_info->flags & TX_BUFFER_INFO_FLAG_IGNORE_SYNC) != 0; @@ -1623,7 +1623,7 @@ static netdev_tx_t lan743x_tx_xmit_frame(struct lan743x_tx *tx, if (required_number_of_descriptors > lan743x_tx_get_avail_desc(tx)) { if (required_number_of_descriptors > (tx->ring_size - 1)) { - dev_kfree_skb(skb); + dev_kfree_skb_irq(skb); } else { /* save to overflow buffer */ tx->overflow_skb = skb; @@ -1656,7 +1656,7 @@ static netdev_tx_t lan743x_tx_xmit_frame(struct lan743x_tx *tx, start_frame_length, do_timestamp, skb->ip_summed == CHECKSUM_PARTIAL)) { - dev_kfree_skb(skb); + dev_kfree_skb_irq(skb); goto unlock; } @@ -1675,7 +1675,7 @@ static netdev_tx_t lan743x_tx_xmit_frame(struct lan743x_tx *tx, * frame assembler clean up was performed inside * lan743x_tx_frame_add_fragment */ - dev_kfree_skb(skb); + dev_kfree_skb_irq(skb); goto unlock; } } -- 2.7.4