【openEuler-1.0-LTS】sched: smart grid: check is active in affinity timer

**【标题描述】smart grid 并发访问cpu.dynamic_affinity_mode出现系统挂死**

**一、缺陷信息**
In the test case like below, there is change going to hang system in
stop affinity timer function.

for i in `seq 1 100000`
do
	echo $1 > /sys/fs/cgroup/cpu/cpu.dynamic_affinity_mode 2> &1
done

[  259.061097] CPU: 0 PID: 10223 Comm: sh Kdump: loaded Not tainted 5.10.0OLK-5.10-SP3_SG+ #102
[  259.061098] Hardware name: Huawei TaiShan 200 (Model 5280)/BC82AMDD, BIOS 1.08 12/14/2019
[  259.061098] pstate: 60400089 (nZCv daIf +PAN -UAO -TCO BTYPE=--)
[  259.061099] pc : hrtimer_active+0x2c/0x7c
[  259.061099] lr : hrtimer_cancel+0x3c/0x60
[  259.061100] sp : ffff800167f33c10
[  259.061100] x29: ffff800167f33c10 x28: ffff003006bde040
[  259.061101] x27: 0000000000000000 x26: 0000000000000000
[  259.061102] x25: 0000000000000000 x24: ffff0020b2cdea20
[  259.061103] x23: ffff800167f33d48 x22: ffff800011cc6100
[  259.061105] x21: ffff80001170a120 x20: ffff800011728d88
[  259.061106] x19: ffff00208e53c418 x18: 0000000000000000
[  259.061107] x17: 0000000000000000 x16: 0000000000000000
[  259.061108] x15: 0000aaab02369e80 x14: 0000000000000000
[  259.061109] x13: 0000000000000000 x12: 0000000000000000
[  259.061110] x11: 0000000000000000 x10: 0000000000000008
[  259.061111] x9 : ffff80001017c6bc x8 : 00000000ffffffc9
[  259.061112] x7 : ffff0020cb082581 x6 : 0000000000000000
[  259.061114] x5 : ffff0020cb082582 x4 : 0000000000000000
[  259.061115] x3 : ffff202fffb9adc0 x2 : ffff202fffb9ae00
[  259.061116] x1 : 0000000000003b82 x0 : ffff00208e53c418
[  259.061117] Call trace:
[  259.061117]  hrtimer_active+0x2c/0x7c
[  259.061118]  stop_auto_affinity+0xf0/0x170
[  259.061118]  cpu_affinity_mode_write_u64+0x2c/0x60
[  259.061119]  cgroup_file_write+0x128/0x1b0
[  259.061119]  kernfs_fop_write_iter+0x130/0x1c0
[  259.061120]  new_sync_write+0xec/0x18c
[  259.061121]  vfs_write+0x214/0x2ac
[  259.061121]  ksys_write+0x70/0xfc
[  259.061122]  __arm64_sys_write+0x24/0x30
[  259.061122]  invoke_syscall+0x50/0x11c
[  259.061123]  el0_svc_common.constprop.0+0x158/0x164
[  259.061123]  do_el0_svc+0x2c/0xac
[  259.061123]  el0_svc+0x20/0x30
[  259.061124]  el0_sync_handler+0xb0/0xb4
[  259.061124]  el0_sync+0x160/0x180

The root cause was that hrtimer_cancel are holding spin_lock, which the
timer are running.

Thread:				hrtimer:

acqurie lock			acqurie lock
cancel hrtimer sync		...		// deadlock
...
release lock			release lock

Thread will wait hrtimer exit forever, and the hrtimer are waiting spin_
lock forever.

**内核信息：**
openEuler-1.0-LTS

**缺陷归属组件：**
smart grid
**缺陷归属的版本：**
4.19

Hi zouyipeng, welcome to the openEuler Community.
I'm the Bot here serving you. You can find the instructions on how to interact with me at Here.
If you have any questions, please contact the SIG: Kernel, and any of the maintainers.

GVP openEuler/kernel

内容风险标识

评论 (1)

GVPopenEuler/kernel

内容风险标识