Re: [PATCH] net: stmmac: Delete txtimer in suspend()

[Jakub Kicinski]

On Fri, 31 Jan 2020 18:01:24 -0800, Nicolin Chen wrote:
> 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@xxxxxxxxx>

Applied, and queued for stable, thank you!