[PATCH 5.5 010/367] net: stmmac: Delete txtimer in suspend()

Greg Kroah-Hartman
2020-02-10T13:09:51Z

From: Nicolin Chen <nicoleotsuka@gmail.com>

[ Upstream commit 14b41a2959fbaa50932699d32ceefd6643abacc6 ]

When running v5.5 with a rootfs on NFS, memory abort may happen in
the system resume stage:
Unable to handle kernel paging request at virtual address dead00000000012a
[dead00000000012a] address between user and kernel address ranges
pc : run_timer_softirq+0x334/0x3d8
lr : run_timer_softirq+0x244/0x3d8
x1 : ffff800011cafe80 x0 : dead000000000122
Call trace:
run_timer_softirq+0x334/0x3d8
efi_header_end+0x114/0x234
irq_exit+0xd0/0xd8
__handle_domain_irq+0x60/0xb0
gic_handle_irq+0x58/0xa8
el1_irq+0xb8/0x180
arch_cpu_idle+0x10/0x18
do_idle+0x1d8/0x2b0
cpu_startup_entry+0x24/0x40
secondary_start_kernel+0x1b4/0x208
Code: f9000693 a9400660 f9000020 b4000040 (f9000401)
---[ end trace bb83ceeb4c482071 ]---
Kernel panic - not syncing: Fatal exception in interrupt
SMP: stopping secondary CPUs
SMP: failed to stop secondary CPUs 2-3
Kernel Offset: disabled
CPU features: 0x00002,2300aa30
Memory Limit: none
---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---

It's found that stmmac_xmit() and stmmac_resume() sometimes might
run concurrently, possibly resulting in a race condition between
mod_timer() and setup_timer(), being called by stmmac_xmit() and
stmmac_resume() respectively.

Since the resume() runs setup_timer() every time, it'd be safer to
have del_timer_sync() in the suspend() as the counterpart.

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -4860,6 +4860,7 @@ int stmmac_suspend(struct device *dev)
{
struct net_device *ndev = dev_get_drvdata(dev);
struct stmmac_priv *priv = netdev_priv(ndev);
+ u32 chan;

if (!ndev || !netif_running(ndev))
return 0;
@@ -4873,6 +4874,9 @@ int stmmac_suspend(struct device *dev)

stmmac_disable_all_queues(priv);

+ for (chan = 0; chan < priv->plat->tx_queues_to_use; chan++)
+ del_timer_sync(&priv->tx_queue[chan].txtimer);
+
/* Stop TX/RX DMA */
stmmac_stop_all_dma(priv);