This is a note to let you know that I've just added the patch titled net: stmmac: don't attach interface until resume finishes to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-stmmac-don-t-attach-interface-until-resume-finishes.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 31096c3e8b1163c6e966bf4d1f36d8b699008f84 Mon Sep 17 00:00:00 2001 From: Leon Yu <leoyu@xxxxxxxxxx> Date: Fri, 22 May 2020 23:29:43 +0800 Subject: net: stmmac: don't attach interface until resume finishes From: Leon Yu <leoyu@xxxxxxxxxx> commit 31096c3e8b1163c6e966bf4d1f36d8b699008f84 upstream. Commit 14b41a2959fb ("net: stmmac: Delete txtimer in suspend") was the first attempt to fix a race between mod_timer() and setup_timer() during stmmac_resume(). However the issue still exists as the commit only addressed half of the issue. Same race can still happen as stmmac_resume() re-attaches interface way too early - even before hardware is fully initialized. Worse, doing so allows network traffic to restart and stmmac_tx_timer_arm() being called in the middle of stmmac_resume(), which re-init tx timers in stmmac_init_coalesce(). timer_list will be corrupted and system crashes as a result of race between mod_timer() and setup_timer(). systemd--1995 2.... 552950018us : stmmac_suspend: 4994 ksoftirq-9 0..s2 553123133us : stmmac_tx_timer_arm: 2276 systemd--1995 0.... 553127896us : stmmac_resume: 5101 systemd--320 7...2 553132752us : stmmac_tx_timer_arm: 2276 (sd-exec-1999 5...2 553135204us : stmmac_tx_timer_arm: 2276 --------------------------------- pc : run_timer_softirq+0x468/0x5e0 lr : run_timer_softirq+0x570/0x5e0 Call trace: run_timer_softirq+0x468/0x5e0 __do_softirq+0x124/0x398 irq_exit+0xd8/0xe0 __handle_domain_irq+0x6c/0xc0 gic_handle_irq+0x60/0xb0 el1_irq+0xb8/0x180 arch_cpu_idle+0x38/0x230 default_idle_call+0x24/0x3c do_idle+0x1e0/0x2b8 cpu_startup_entry+0x28/0x48 secondary_start_kernel+0x1b4/0x208 Fix this by deferring netif_device_attach() to the end of stmmac_resume(). Signed-off-by: Leon Yu <leoyu@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Cc: Macpaul Lin <macpaul.lin@xxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -4855,8 +4855,6 @@ int stmmac_resume(struct device *dev) stmmac_mdio_reset(priv->mii); } - netif_device_attach(ndev); - mutex_lock(&priv->lock); stmmac_reset_queues_param(priv); @@ -4880,6 +4878,8 @@ int stmmac_resume(struct device *dev) phylink_mac_change(priv->phylink, true); + netif_device_attach(ndev); + return 0; } EXPORT_SYMBOL_GPL(stmmac_resume); Patches currently in stable-queue which might be from leoyu@xxxxxxxxxx are queue-5.4/net-stmmac-don-t-attach-interface-until-resume-finishes.patch