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"I happen to believe that not having a kernel debugger forces people to think about their problem on a different level than with a debugger. I think that withou

by thras 17y ago

"I happen to believe that not having a kernel debugger forces people to think about their problem on a different level than with a debugger. I think that without a debugger, you don't get into that mindset where you know how it behaves, and then you fix it from there. Without a debugger, you tend to think about problems another way. You want to understand things on a different _level_." This seems to be the most worthwhile part of the post. I've never gotten into the habit of using debuggers myself, so I can't say how strong his argument is.

Deestan 17y ago
I also find that a debugger encourages a technique of just tracing through the code until "a-hah, that's where fooBing get reset to dingy. I should add a clause to reset it to dingy only if barBong is set." Without a debugger, I would have to write tests, clean up the code until it made sense, or design it in such a way that that particular kind of bug could not occur.
- antonovka 17y ago
  I also find that a debugger encourages a technique of just tracing through the code until "a-hah, that's where fooBing get reset to dingy. I should add a clause to reset it to dingy only if barBong is set." Someone actually skilled in their craft would say: "a-hah, that's where fooBing get reset to dingy. now I understand what's happening, let's understand why". Remember, this is kernel code we're talking about here. In user-space, I rarely need to use a debugger because nearly all issues are caught during initial development by unit and regression testing. However, there are still times where something goes terribly wrong -- sometimes in vendor code (or in the case of the kernel, hardware) -- and I wouldn't give up my debugger for the world.
  - Deestan 17y ago
    No disagreement that debuggers are helpful, but they allow unskilled people to do more crap work without having to learn or think or improve, and that is what I believe Linus is going on about. By all means, I don't agree with him that debuggers should be forbidden, but I believe I know where he's coming from.
    - trebor 17y ago
      Do you mean that, only masochistic programmers ought to survive? Or, didn't we all start out as an unskilled programmer before we gained any skill?
      - Deestan 17y ago
        No.
antonovka 17y ago
Sometimes a debugger is simply the fastest route to isolating and solving an issue. I recently had to track down a kernel issue caused by an piece of code unrelated to my current work casting a signed value to unsigned and eventually triggering a kernel panic. Thanks to remote kernel debugging, I could simply step through the code path and track the changes. If I accidentally overstepped the failure point, I just reset the virtual machine back to the snapshot point and reattached the debugger. Did this mean that I didn't know how the code behaved? No -- I had to understand the code, but there was very little chance that I would quickly eyeball a single incorrect cast in a comparison 6 degrees of separation from where my own code was being run without being able to trace the issue a couple times in a debugger as it happened.

by thras 17y ago

Deestan 17y ago

I also find that a debugger encourages a technique of just tracing through the code until "a-hah, that's where fooBing get reset to dingy. I should add a clause to reset it to dingy only if barBong is set." Without a debugger, I would have to write tests, clean up the code until it made sense, or design it in such a way that that particular kind of bug could not occur.

antonovka 17y ago
I also find that a debugger encourages a technique of just tracing through the code until "a-hah, that's where fooBing get reset to dingy. I should add a clause to reset it to dingy only if barBong is set." Someone actually skilled in their craft would say: "a-hah, that's where fooBing get reset to dingy. now I understand what's happening, let's understand why". Remember, this is kernel code we're talking about here. In user-space, I rarely need to use a debugger because nearly all issues are caught during initial development by unit and regression testing. However, there are still times where something goes terribly wrong -- sometimes in vendor code (or in the case of the kernel, hardware) -- and I wouldn't give up my debugger for the world.
- Deestan 17y ago
  No disagreement that debuggers are helpful, but they allow unskilled people to do more crap work without having to learn or think or improve, and that is what I believe Linus is going on about. By all means, I don't agree with him that debuggers should be forbidden, but I believe I know where he's coming from.
  - trebor 17y ago
    Do you mean that, only masochistic programmers ought to survive? Or, didn't we all start out as an unskilled programmer before we gained any skill?
    - Deestan 17y ago
      No.

antonovka 17y ago

Sometimes a debugger is simply the fastest route to isolating and solving an issue. I recently had to track down a kernel issue caused by an piece of code unrelated to my current work casting a signed value to unsigned and eventually triggering a kernel panic. Thanks to remote kernel debugging, I could simply step through the code path and track the changes. If I accidentally overstepped the failure point, I just reset the virtual machine back to the snapshot point and reattached the debugger. Did this mean that I didn't know how the code behaved? No -- I had to understand the code, but there was very little chance that I would quickly eyeball a single incorrect cast in a comparison 6 degrees of separation from where my own code was being run without being able to trace the issue a couple times in a debugger as it happened.