linux中的内核死锁调试

linux内核死锁调试

使用内核的kernel hacking功能

打开以下配置

CONFIG_PROVE_LOCKING=y CONFIG_LOCK_STAT=y CONFIG_DEBUG_LOCKDEP=y

重新编译内核后，

proc目录下会有lockdep lockdep_stats lockdep_chains说明lockdep模块已经生效

测试code

#include <linux/kernel.h> #include <linux/module.h> #include <linux/init.h> #include <linux/slab.h> static DEFINE_SPINLOCK(hack_spinA); static DEFINE_SPINLOCK(hack_spinB); #ifdef MEMORY_TEST static char* buf; static void create_slue_err(void){ buf = kmalloc(32,GFP_KERNEL); if(buf) { /*memset(buf,0x00,33);*/ /* kfree(buf); printk(“%sn”,”free buf” );*/ /*kfree(buf);*/ memset(buf,0x00,33); } return; } #endif void hack_spinBA(void) { printk(“%sn”,”hack_spin:B=>An” ); spin_lock(&hack_spinA); spin_lock(&hack_spinB); } void hack_spinAB(void) { printk(“%sn”,”hack_spin:A=>Bn” ); spin_lock(&hack_spinB); } static int __init my_test_init(void) { printk(“init %sn”, “my_test_init 1”); #ifdef MEMORY_TEST create_slue_err(); #endif hack_spinBA(); hack_spinAB(); printk(“init %sn”, “my_test_init 2”); return 0; } static void __exit my_test_exit(void) { printk(“%sn”,”my_test_exit” ); return ; } MODULE_LICENSE(“GPL”); module_init(my_test_init); module_exit(my_test_exit);

测试打印：

[  188.596504@1] init my_test_init 1

[  188.596548@1] hack_spin:B=>A

[  188.596548@1] 

[  188.598679@1] hack_spin:A=>B

[  188.598679@1] 

[  189.920389@1] BUG: spinlock lockup suspected on CPU#1, insmod/6999

[  189.920943@1]  lock: hack_spinB+0x0/0xfffffffffffffef4 [slub_test], .magic: dead4ead, .owner: insmod/6999, .owner_cpu: 1

[  189.931758@1] CPU: 1 PID: 6999 Comm: insmod Tainted: G           O 3.14.29 #6

[  189.938784@1] Call trace:

[  189.941406@1] [] dump_backtrace+0x0/0x144

[  189.946896@1] [] show_stack+0x1c/0x28

[  189.952120@1] [] dump_stack+0x74/0xb8

[  189.957247@1] [] spin_dump+0x78/0x98

[  189.962369@1] [] do_raw_spin_lock+0x170/0x1a8

[  189.968199@1] [] _raw_spin_lock+0x68/0x88

[  189.973764@1] [] hack_spinAB+0x30/0x3c [slub_test]

[  189.980015@1] [] $x+0x28/0x4c [slub_test]

[  189.985566@1] [] do_one_initcall+0xd4/0x13c

[  189.991257@1] [] load_module+0x16d8/0x1e08

[  189.996834@1] [<ffffffc00112cba0>] SyS_finit_module+0x80/0x90

[  211.641019@1] INFO: rcu_sched detected stalls on CPUs/tasks: { 1} (detected by 2, t=2104 jiffies, g=18446744073709551337, c=18446744073709551336, q=4)

[  211.648804@2] Task dump for CPU 1:

[  211.652167@2] insmod          R  running task        0  6999   5821 0x0000000a

[  211.659325@2] Call trace:

[  211.661920@2] [<ffffffc001085f10>] __switch_to+0x74/0x8c

很明显可以看出死锁的发生路径与调用栈

hack_spinAB在申请spin_lock(&hack_spinB)时死锁了

总结

以上为个人经验，希望能给大家一个参考，也希望大家多多支持。