Hello all I know that I can print stack of function using dump_stack() But I need to find out whether my function y() was called from linux kernel function x().\ I see that kmsg_dump_get_buffer() function can get kernel messages but it is not clear for me should I use it bedore calling dump_stack or I need to do additional setup before calling for these 2 functions? Regards, Lev
On Fri, 03 Aug 2018 15:14:45 +0300, Lev Olshvang said:
But I need to find out whether my function y() was called from linux kernel function x().\
What problem are you trying to solve? If it's your function, don't you already *know* which functions call it? And if being called from code A requires different behavior than if it was called from B, the *right* answer is to create a flag and pass it. That requires less code, is simpler than trying to unwind the stack, and makes it easier if 6 months from now you call a call from routine C. For an example, see the memory-allocation flags GFP_ATOMIC and similar - if you're adding another call site that needs it, you just add GFP_ATOMIC to the flags. And I'm willing to bet that most of those GFP_ flags were *all* originally "we have to do something special if we try to do memory allocation from That One Problem Spot. :)
03.08.2018, 15:42, "valdis.kletnieks@vt.edu" <valdis.kletnieks@vt.edu>:
On Fri, 03 Aug 2018 15:14:45 +0300, Lev Olshvang said:
But I need to find out whether my function y() was called from linux kernel function x().\
What problem are you trying to solve? If it's your function, don't you already *know* which functions call it?
And if being called from code A requires different behavior than if it was called from B, the *right* answer is to create a flag and pass it. That requires less code, is simpler than trying to unwind the stack, and makes it easier if 6 months from now you call a call from routine C.
For an example, see the memory-allocation flags GFP_ATOMIC and similar - if you're adding another call site that needs it, you just add GFP_ATOMIC to the flags.
And I'm willing to bet that most of those GFP_ flags were *all* originally "we have to do something special if we try to do memory allocation from That One Problem Spot. :)
Hi Valdis, Thanks for the reply. Now I see i miised to explain that my function x() in my module might be called from kernel functions foo() or bar() which I do not own ( function my_x() is sort of callback) . Since I can not change foo()) or bar() code and add flags I need to inspect the stack. I am confused to see in kernel code that there is a new to me objects of type kernel dumper who need to be registered in order to get dump_stack() output. Saw I applied yo list wisdom to seek for an advise. Thanks All. Lev
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Lev Olshvang -
valdis.kletnieks＠vt.edu