[BUG REPORT] softlock up in net/core cleanup_net
From: jiangheng (G) <hidden>
Date: 2023-05-16 13:30:06
Hi all, on linux 5.10, we want to use isula interactively when testing an internal feature. When isula restarts the container, it will call cleanup_net and a crash will occur. [ 843.330515] CPU: 0 PID: 158 Comm: kworker/u8:2 Kdump: loaded Tainted: G B OEL #1 [ 843.330516] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 [ 843.330523] Workqueue: netns cleanup_net [ 843.330526] pstate: 60400085 (nZCv daIf +PAN -UAO -TCO BTYPE=--) [ 843.330529] pc : machine_kexec+0x48/0x2b0 [ 843.330531] lr : machine_kexec+0x48/0x2b0 [ 843.330531] sp : ffff80010284bb10 [ 843.330533] x29: ffff80010284bb10 x28: ffff0000ff851cf8 [ 843.330535] x27: ffff0000ff851d78 x26: ffff80010284bda0 [ 843.330537] x25: ffff800101d9c000 x24: 0000000000000001 [ 843.330539] x23: ffff800101d9c650 x22: ffff800101eb6000 [ 843.330541] x21: ffff800101eb6000 x20: ffff0000cba23c00 [ 843.330543] x19: ffff0000cba23c00 x18: 0000000000000020 [ 843.330545] x17: 0000000000000000 x16: ffff800100d27a3c [ 843.330548] x15: ffffffffffffffff x14: 0000000060000085 [ 843.330550] x13: ffff8001001c090c x12: 0000000000000040 [ 843.330552] x11: ffff800101aad158 x10: 00000000ffff8000 [ 843.330554] x9 : ffff800100157654 x8 : 0000000000000000 [ 843.330556] x7 : ffff8001017ed158 x6 : 0000000000017ffd [ 843.330559] x5 : ffff0000ff84b410 x4 : ffff80010284b910 [ 843.330561] x3 : 0000000000000001 x2 : 0000000000000000 [ 843.330563] x1 : 0000000000000000 x0 : ffff0000c09eb9c0 [ 843.330566] Call trace: [ 843.330569] machine_kexec+0x48/0x2b0 [ 843.330573] __crash_kexec+0x90/0x13c [ 843.330578] panic+0x314/0x4d8 [ 843.330582] watchdog_timer_fn+0x26c/0x2f0 [ 843.330585] __run_hrtimer+0x98/0x2b4 [ 843.330586] __hrtimer_run_queues+0xbc/0x130 [ 843.330588] hrtimer_interrupt+0x150/0x3e4 [ 843.330592] arch_timer_handler_virt+0x3c/0x50 [ 843.330596] handle_percpu_devid_irq+0x90/0x1f4 [ 843.330599] __handle_domain_irq+0x84/0x100 [ 843.330601] gic_handle_irq+0x88/0x2b0 [ 843.330603] el1_irq+0xb8/0x140 [ 843.330605] smp_call_function_single+0x1b8/0x1dc [ 843.330608] rcu_barrier+0x1c4/0x2d0 [ 843.330612] netdev_run_todo+0x7c/0x330 [ 843.330615] rtnl_unlock+0x18/0x24 [ 843.330616] default_device_exit_batch+0x15c/0x190 [ 843.330621] ops_exit_list+0x70/0x84 [ 843.330622] cleanup_net+0x184/0x2e0 [ 843.330625] process_one_work+0x1d4/0x4bc [ 843.330627] worker_thread+0x150/0x400 [ 843.330629] kthread+0x108/0x134 [ 843.330631] ret_from_fork+0x10/0x18 [ 843.330633] ---[ end trace 8378c01c76c90cc4 ]--- [ 843.330637] Bye! Crash:bt -l PID: 158 TASK: ffff0000c09eb9c0 CPU: 0 COMMAND: "kworker/u8:2" PID: 158 TASK: ffff0000c09eb9c0 CPU: 0 COMMAND: "kworker/u8:2" bt: invalid kernel virtual address: 0 type: "IRQ stack contents" bt: read of IRQ stack at 0 failed #0 [ffff80010284bb60] __crash_kexec at ffff8001001c0908 /usr/src/debug/kernel/./arch/arm64/include/asm/kexec.h: 57 #1 [ffff80010284bcf0] panic at ffff800100d256a4 /usr/src/debug/kernel/kernel/panic.c: 392 #2 [ffff80010284bde0] watchdog_timer_fn at ffff80010020a5c8 /usr/src/debug/kernel/kernel/watchdog.c: 578 #3 [ffff80010284be30] __run_hrtimer at ffff800100191d24 /usr/src/debug/kernel/kernel/time/hrtimer.c: 1586 #4 [ffff80010284be80] __hrtimer_run_queues at ffff800100191ffc /usr/src/debug/kernel/kernel/time/hrtimer.c: 1650 #5 [ffff80010284bee0] hrtimer_interrupt at ffff80010019267c /usr/src/debug/kernel/kernel/time/hrtimer.c: 1712 #6 [ffff80010284bf50] arch_timer_handler_virt at ffff800100aa9a38 /usr/src/debug/kernel/drivers/clocksource/arm_arch_timer.c: 674 #7 [ffff80010284bf60] handle_percpu_devid_irq at ffff80010016500c /usr/src/debug/kernel/./arch/arm64/include/asm/percpu.h: 45 #8 [ffff80010284bf90] __handle_domain_irq at ffff80010015b840 /usr/src/debug/kernel/./include/linux/irqdesc.h: 153 #9 [ffff80010284bfd0] gic_handle_irq at ffff800100010144 /usr/src/debug/kernel/./include/linux/irqdesc.h: 171
--- <IRQ stack> ---#10 [ffff800102d4bb20] el1_irq at ffff800100012374
/usr/src/debug/kernel/arch/arm64/kernel/entry.S: 672
#11 [ffff800102d4bb40] smp_call_function_single at ffff8001001b1e68
/usr/src/debug/kernel/./arch/arm64/include/asm/cmpxchg.h: 278
#12 [ffff800102d4bba0] rcu_barrier at ffff800100178ba0
/usr/src/debug/kernel/kernel/rcu/tree.c: 3920
#13 [ffff800102d4bc00] netdev_run_todo at ffff800100b3f768
/usr/src/debug/kernel/net/core/dev.c: 10313
#14 [ffff800102d4bc80] rtnl_unlock at ffff800100b4cb54
/usr/src/debug/kernel/net/core/rtnetlink.c: 114
#15 [ffff800102d4bc90] default_device_exit_batch at ffff800100b378d8
/usr/src/debug/kernel/net/core/dev.c: 11287
#16 [ffff800102d4bd00] ops_exit_list at ffff800100b2337c
/usr/src/debug/kernel/net/core/net_namespace.c: 200
#17 [ffff800102d4bd30] cleanup_net at ffff800100b25ab0
/usr/src/debug/kernel/net/core/net_namespace.c: 616
#18 [ffff800102d4bd90] process_one_work at ffff8001000de784
/usr/src/debug/kernel/kernel/workqueue.c: 2354
#19 [ffff800102d4bdf0] worker_thread at ffff8001000df18c
/usr/src/debug/kernel/kernel/workqueue.c: 2500
#20 [ffff800102d4be50] kthread at ffff8001000e75a4
/usr/src/debug/kernel/kernel/kthread.c: 313
The above backtrace seems to be caused func:netdev_run_todo() that the size of list not null.
void netdev_run_todo(void)
{
struct net_device *dev, *tmp;
struct list_head list;
#ifdef CONFIG_LOCKDEP
struct list_head unlink_list;
list_replace_init(&net_unlink_list, &unlink_list);
while (!list_empty(&unlink_list)) {
struct net_device *dev = list_first_entry(&unlink_list,
struct net_device,
unlink_list);
list_del_init(&dev->unlink_list);
dev->nested_level = dev->lower_level - 1;
}
#endif
/* Snapshot list, allow later requests */
list_replace_init(&net_todo_list, &list);
__rtnl_unlock();
/* Wait for rcu callbacks to finish before next phase */
if !(list_empty(&list))
rcu_barrier();
I wonder if softlockup is due to the above code? Please help analyze the possible causes of this.