Linux:ftrace: 为什么有些函数没有在available_filter_functions
作者：互联网
文章目录
例如：__run_hrtimer
这个函数其实有被用到，在函数__hrtimer_run_queues 中，有调用__run_hrtimer
但是在available_filter_functions 文件中就是没有
<sbc2048-fwp-a:root>/sys/kernel/debug/tracing:
# grep __run_hrtimer av*
<sbc2048-fwp-a:root>/sys/kernel/debug/tracing:
汇编
看看汇编，发现确实没有调用，原因可能就是void 函数被inline 优化了。
(gdb) disass __hrtimer_run_queues
Dump of assembler code for function __hrtimer_run_queues:
0xffffffff8117d200 <+0>: callq 0xffffffff81a01900 <__fentry__>
0xffffffff8117d205 <+5>: push %r15
0xffffffff8117d207 <+7>: push %r14
0xffffffff8117d209 <+9>: push %r13
0xffffffff8117d20b <+11>: push %r12
0xffffffff8117d20d <+13>: push %rbp
0xffffffff8117d20e <+14>: push %rbx
0xffffffff8117d20f <+15>: sub $0x28,%rsp
0xffffffff8117d213 <+19>: mov %rsi,0x10(%rsp)
0xffffffff8117d218 <+24>: mov %rdx,(%rsp)
0xffffffff8117d21c <+28>: mov %gs:0x28,%rax
0xffffffff8117d225 <+37>: mov %rax,0x20(%rsp)
0xffffffff8117d22a <+42>: xor %eax,%eax
0xffffffff8117d22c <+44>: and 0x8(%rdi),%ecx rdi cpu_base， lockdep_assert_held(&cpu_base->lock);
0xffffffff8117d22f <+47>: je 0xffffffff8117d455 <__hrtimer_run_queues+597> /// stack check failure
0xffffffff8117d235 <+53>: mov %ecx,%eax
0xffffffff8117d237 <+55>: mov %rdi,%r13
0xffffffff8117d23a <+58>: tzcnt %rax,%rax
0xffffffff8117d23f <+63>: mov %eax,%ebp
0xffffffff8117d241 <+65>: btr %eax,%ecx
0xffffffff8117d244 <+68>: mov %eax,%r12d
0xffffffff8117d247 <+71>: add $0x1,%rbp
0xffffffff8117d24b <+75>: mov %ecx,0xc(%rsp)
0xffffffff8117d24f <+79>: shl $0x6,%rbp
0xffffffff8117d253 <+83>: add %rdi,%rbp
0xffffffff8117d256 <+86>: je 0xffffffff8117d455 <__hrtimer_run_queues+597>
0xffffffff8117d25c <+92>: shl $0x6,%r12
0xffffffff8117d260 <+96>: mov 0x28(%rbp),%rbx
0xffffffff8117d264 <+100>: mov 0x10(%rsp),%rax
0xffffffff8117d269 <+105>: add %r13,%r12
0xffffffff8117d26c <+108>: add 0x78(%r12),%rax
0xffffffff8117d271 <+113>: mov %rax,0x18(%rsp)
0xffffffff8117d276 <+118>: test %rbx,%rbx
0xffffffff8117d279 <+121>: je 0xffffffff8117d41e <__hrtimer_run_queues+542>
0xffffffff8117d27f <+127>: cmp 0x20(%rbx),%rax
0xffffffff8117d283 <+131>: jge 0xffffffff8117d2c2 <__hrtimer_run_queues+194>
0xffffffff8117d285 <+133>: jmpq 0xffffffff8117d41e <__hrtimer_run_queues+542>
0xffffffff8117d28a <+138>: addl $0x1,0x10(%rbp)
0xffffffff8117d28e <+142>: addl $0x1,0x10(%rbp)
0xffffffff8117d292 <+146>: cmp %rbx,0x58(%r12)
0xffffffff8117d297 <+151>: jne 0xffffffff8117d343 <__hrtimer_run_queues+323>
0xffffffff8117d29d <+157>: movq $0x0,0x58(%r12)
0xffffffff8117d2a6 <+166>: mov 0x28(%rbp),%rbx
0xffffffff8117d2aa <+170>: test %rbx,%rbx
0xffffffff8117d2ad <+173>: je 0xffffffff8117d41e <__hrtimer_run_queues+542>
0xffffffff8117d2b3 <+179>: mov 0x20(%rbx),%rax
0xffffffff8117d2b7 <+183>: cmp %rax,0x18(%rsp)
0xffffffff8117d2bc <+188>: jl 0xffffffff8117d41e <__hrtimer_run_queues+542>
0xffffffff8117d2c2 <+194>: nopl 0x0(%rax,%rax,1)
0xffffffff8117d2c7 <+199>: mov %rbx,0x58(%r12)
0xffffffff8117d2cc <+204>: addl $0x1,0x10(%rbp)
0xffffffff8117d2d0 <+208>: addl $0x1,0x10(%rbp)
0xffffffff8117d2d4 <+212>: mov %rbp,%rsi
0xffffffff8117d2d7 <+215>: mov %rbx,%rdi
0xffffffff8117d2da <+218>: xor %ecx,%ecx
0xffffffff8117d2dc <+220>: xor %edx,%edx
0xffffffff8117d2de <+222>: callq 0xffffffff8117cd40 <__remove_hrtimer>
0xffffffff8117d2e3 <+227>: mov (%rsp),%rsi
0xffffffff8117d2e7 <+231>: mov %r13,%rdi
0xffffffff8117d2ea <+234>: mov 0x28(%rbx),%r14
0xffffffff8117d2ee <+238>: callq 0xffffffff8197f1d0 <_raw_spin_unlock_irqrestore>
0xffffffff8117d2f3 <+243>: nopl 0x0(%rax,%rax,1)
0xffffffff8117d2f8 <+248>: mov %rbx,%rdi
0xffffffff8117d2fb <+251>: callq 0xffffffff81c015f0 <__x86_indirect_thunk_r14>
0xffffffff8117d300 <+256>: mov %eax,%r14d
0xffffffff8117d303 <+259>: nopl 0x0(%rax,%rax,1)
0xffffffff8117d308 <+264>: mov %r13,%rdi
0xffffffff8117d30b <+267>: callq 0xffffffff8197f560 <_raw_spin_lock_irq>
0xffffffff8117d310 <+272>: test %r14d,%r14d
0xffffffff8117d313 <+275>: je 0xffffffff8117d28a <__hrtimer_run_queues+138>
0xffffffff8117d319 <+281>: testb $0x1,0x38(%rbx)
0xffffffff8117d31d <+285>: jne 0xffffffff8117d28a <__hrtimer_run_queues+138>
0xffffffff8117d323 <+291>: xor %edx,%edx
0xffffffff8117d325 <+293>: mov %rbp,%rsi
0xffffffff8117d328 <+296>: mov %rbx,%rdi
0xffffffff8117d32b <+299>: callq 0xffffffff8117ce80 <enqueue_hrtimer>
0xffffffff8117d330 <+304>: addl $0x1,0x10(%rbp)
0xffffffff8117d334 <+308>: addl $0x1,0x10(%rbp)
0xffffffff8117d338 <+312>: cmp %rbx,0x58(%r12)
0xffffffff8117d33d <+317>: je 0xffffffff8117d29d <__hrtimer_run_queues+157>
0xffffffff8117d343 <+323>: ud2
0xffffffff8117d345 <+325>: jmpq 0xffffffff8117d29d <__hrtimer_run_queues+157>
0xffffffff8117d34a <+330>: mov %gs:0x7ee9224f(%rip),%eax # 0xf5a0 <cpu_number>
0xffffffff8117d351 <+337>: mov %eax,%eax
0xffffffff8117d353 <+339>: bt %rax,0x16ab7e5(%rip) # 0xffffffff82828b40 <__cpu_online_mask>
0xffffffff8117d35b <+347>: jae 0xffffffff8117d2c7 <__hrtimer_run_queues+199>
0xffffffff8117d361 <+353>: mov 0x165f5a0(%rip),%r14 # 0xffffffff827dc908 <__tracepoint_hrtimer_cancel+40>
0xffffffff8117d368 <+360>: test %r14,%r14
0xffffffff8117d36b <+363>: je 0xffffffff8117d388 <__hrtimer_run_queues+392>
0xffffffff8117d36d <+365>: mov (%r14),%rax
0xffffffff8117d370 <+368>: mov 0x8(%r14),%rdi
0xffffffff8117d374 <+372>: add $0x18,%r14
0xffffffff8117d378 <+376>: mov %rbx,%rsi
0xffffffff8117d37b <+379>: callq 0xffffffff81c01450 <__x86_indirect_thunk_rax>
0xffffffff8117d380 <+384>: mov (%r14),%rax
0xffffffff8117d383 <+387>: test %rax,%rax
0xffffffff8117d386 <+390>: jne 0xffffffff8117d370 <__hrtimer_run_queues+368>
0xffffffff8117d388 <+392>: jmpq 0xffffffff8117d2c7 <__hrtimer_run_queues+199>
0xffffffff8117d38d <+397>: mov %gs:0x7ee9220c(%rip),%eax # 0xf5a0 <cpu_number>
0xffffffff8117d394 <+404>: mov %eax,%eax
0xffffffff8117d396 <+406>: bt %rax,0x16ab7a2(%rip) # 0xffffffff82828b40 <__cpu_online_mask>
0xffffffff8117d39e <+414>: jae 0xffffffff8117d308 <__hrtimer_run_queues+264>
0xffffffff8117d3a4 <+420>: mov 0x165f59d(%rip),%rax # 0xffffffff827dc948 <__tracepoint_hrtimer_expire_exit+40>
0xffffffff8117d3ab <+427>: test %rax,%rax
0xffffffff8117d3ae <+430>: je 0xffffffff8117d3ce <__hrtimer_run_queues+462>
0xffffffff8117d3b0 <+432>: mov (%rax),%rdx
0xffffffff8117d3b3 <+435>: mov %rax,%r15
0xffffffff8117d3b6 <+438>: mov 0x8(%r15),%rdi
0xffffffff8117d3ba <+442>: add $0x18,%r15
0xffffffff8117d3be <+446>: mov %rbx,%rsi
0xffffffff8117d3c1 <+449>: callq 0xffffffff81c014b0 <__x86_indirect_thunk_rdx>
0xffffffff8117d3c6 <+454>: mov (%r15),%rdx
0xffffffff8117d3c9 <+457>: test %rdx,%rdx
0xffffffff8117d3cc <+460>: jne 0xffffffff8117d3b6 <__hrtimer_run_queues+438>
0xffffffff8117d3ce <+462>: jmpq 0xffffffff8117d308 <__hrtimer_run_queues+264>
0xffffffff8117d3d3 <+467>: mov %gs:0x7ee921c6(%rip),%eax # 0xf5a0 <cpu_number>
0xffffffff8117d3da <+474>: mov %eax,%eax
0xffffffff8117d3dc <+476>: bt %rax,0x16ab75c(%rip) # 0xffffffff82828b40 <__cpu_online_mask>
0xffffffff8117d3e4 <+484>: jae 0xffffffff8117d2f8 <__hrtimer_run_queues+248>
0xffffffff8117d3ea <+490>: mov 0x165f597(%rip),%rax # 0xffffffff827dc988 <__tracepoint_hrtimer_expire_entry+40>
0xffffffff8117d3f1 <+497>: test %rax,%rax
0xffffffff8117d3f4 <+500>: je 0xffffffff8117d419 <__hrtimer_run_queues+537>
0xffffffff8117d3f6 <+502>: mov (%rax),%rcx
0xffffffff8117d3f9 <+505>: mov %rax,%r15
0xffffffff8117d3fc <+508>: mov 0x8(%r15),%rdi
0xffffffff8117d400 <+512>: add $0x18,%r15
0xffffffff8117d404 <+516>: lea 0x18(%rsp),%rdx
0xffffffff8117d409 <+521>: mov %rbx,%rsi
0xffffffff8117d40c <+524>: callq 0xffffffff81c01490 <__x86_indirect_thunk_rcx>
0xffffffff8117d411 <+529>: mov (%r15),%rcx
0xffffffff8117d414 <+532>: test %rcx,%rcx
0xffffffff8117d417 <+535>: jne 0xffffffff8117d3fc <__hrtimer_run_queues+508>
0xffffffff8117d419 <+537>: jmpq 0xffffffff8117d2f8 <__hrtimer_run_queues+248>
0xffffffff8117d41e <+542>: mov 0xc(%rsp),%eax
0xffffffff8117d422 <+546>: test %eax,%eax
0xffffffff8117d424 <+548>: je 0xffffffff8117d455 <__hrtimer_run_queues+597>
0xffffffff8117d426 <+550>: mov 0xc(%rsp),%ecx
0xffffffff8117d42a <+554>: mov $0xfffffffe,%eax
0xffffffff8117d42f <+559>: mov %rcx,%rsi
0xffffffff8117d432 <+562>: tzcnt %rcx,%rcx
0xffffffff8117d437 <+567>: mov %ecx,%ebp
0xffffffff8117d439 <+569>: rol %cl,%eax
0xffffffff8117d43b <+571>: mov %ecx,%r12d
0xffffffff8117d43e <+574>: add $0x1,%rbp
0xffffffff8117d442 <+578>: and %eax,%esi
0xffffffff8117d444 <+580>: shl $0x6,%rbp
0xffffffff8117d448 <+584>: mov %esi,0xc(%rsp)
0xffffffff8117d44c <+588>: add %r13,%rbp
0xffffffff8117d44f <+591>: jne 0xffffffff8117d25c <__hrtimer_run_queues+92>
0xffffffff8117d455 <+597>: mov 0x20(%rsp),%rax
0xffffffff8117d45a <+602>: xor %gs:0x28,%rax
0xffffffff8117d463 <+611>: jne 0xffffffff8117d474 <__hrtimer_run_queues+628>
0xffffffff8117d465 <+613>: add $0x28,%rsp
0xffffffff8117d469 <+617>: pop %rbx
0xffffffff8117d46a <+618>: pop %rbp
0xffffffff8117d46b <+619>: pop %r12
0xffffffff8117d46d <+621>: pop %r13
0xffffffff8117d46f <+623>: pop %r14
0xffffffff8117d471 <+625>: pop %r15
0xffffffff8117d473 <+627>: retq
0xffffffff8117d474 <+628>: callq 0xffffffff810ebdb0 <__stack_chk_fail>
标签：available,functions,ftrace,rbx,mov,rbp,eax,rsp,rax 来源： https://blog.csdn.net/qq_36428903/article/details/122297361