net: stmmac: Delete txtimer in suspend()
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: