Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1637059

Re: [PATCH 7/7] DWARF: add the config option

Show all headers | View raw

On May 7, 2017 10:59:16 AM PDT, Ingo Molnar <mingo@kernel.org> wrote:
>
>* Josh Poimboeuf <jpoimboe@redhat.com> wrote:
>
>> One instance of the structure would exist for each time the stack
>> pointer changes, e.g. for every function entry, push/pop, and rsp
>> add/subtract.  The data could be assembled and sorted offline,
>possibly
>> derived from DWARF, or more likely, generated by objtool.  After
>doing
>> some rough calculations, I think the section size would be comparable
>to
>> the sizes of the DWARF .eh_frame sections it would replace.
>
>That's something I've been thinking about as well: if objtool generates
>the 
>unwinder data structures then the kernel is not directly exposed to
>tooling bugs 
>anymore.
>
>A fair chunk of the fragility of DWARF comes from the fact that it's
>generated by 
>a tool chain that we cannot fix as part of the kernel project. If GCC
>generates 
>crap debuginfo, and GDB happens to work with it but the kernel not,
>we'll have to 
>work it around in the kernel. If GCC starts bloating debuginfo in the
>future we 
>are screwed as well, etc.
>
>If objtool generates debuginfo then it's _our_ responsibility to have
>sane 
>unwinder info and we obviously manage its structure and size as well.
>Win-win.
>
>The unwinder itself should still do sanity checks, etc. (like all good
>debugging 
>infrastructure code) - but the nature of the kernel's exposure to tool
>chain 
>details changes in a very fundamental way.
>
>So yes, I think this is a very good idea, assuming it works in
>practice! ;-)
>
>Thanks,
>
>	Ingo

Can objtool verify the unwinder at each address in the kernel, or is that an AI-complete problem?
-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH 7/7] DWARF: add the config option Jiri Slaby <jslaby@suse.cz> - 2017-05-05 14:30 +0200
  Re: [PATCH 7/7] DWARF: add the config option Linus Torvalds <torvalds@linux-foundation.org> - 2017-05-05 22:00 +0200
    Re: [PATCH 7/7] DWARF: add the config option Ingo Molnar <mingo@kernel.org> - 2017-05-06 09:30 +0200
      Re: [PATCH 7/7] DWARF: add the config option Jiri Slaby <jslaby@suse.cz> - 2017-05-10 09:50 +0200
    Re: [PATCH 7/7] DWARF: add the config option Jiri Kosina <jikos@kernel.org> - 2017-05-06 16:30 +0200
    Re: [PATCH 7/7] DWARF: add the config option Ingo Molnar <mingo@kernel.org> - 2017-05-07 23:50 +0200
      Re: [PATCH 7/7] DWARF: add the config option Josh Poimboeuf <jpoimboe@redhat.com> - 2017-05-07 23:50 +0200
        Re: [PATCH 7/7] DWARF: add the config option Vojtech Pavlik <vojtech@suse.com> - 2017-05-08 10:20 +0200
          Re: [PATCH 7/7] DWARF: add the config option Josh Poimboeuf <jpoimboe@redhat.com> - 2017-05-08 15:20 +0200
      Re: [PATCH 7/7] DWARF: add the config option hpa@zytor.com - 2017-05-08 00:10 +0200
    Re: [PATCH 7/7] DWARF: add the config option Josh Poimboeuf <jpoimboe@redhat.com> - 2017-05-07 23:50 +0200
      Re: [PATCH 7/7] DWARF: add the config option Andy Lutomirski <luto@amacapital.net> - 2017-05-08 07:40 +0200
        Re: [PATCH 7/7] DWARF: add the config option Ingo Molnar <mingo@kernel.org> - 2017-05-08 08:20 +0200
        Re: [PATCH 7/7] DWARF: add the config option Josh Poimboeuf <jpoimboe@redhat.com> - 2017-05-08 16:50 +0200
          Re: [PATCH 7/7] DWARF: add the config option hpa@zytor.com - 2017-05-08 21:10 +0200
      Re: [PATCH 7/7] DWARF: add the config option Andy Lutomirski <luto@kernel.org> - 2017-05-09 02:30 +0200
        Re: [PATCH 7/7] DWARF: add the config option Josh Poimboeuf <jpoimboe@redhat.com> - 2017-05-09 03:40 +0200
          Re: [PATCH 7/7] DWARF: add the config option Andy Lutomirski <luto@kernel.org> - 2017-05-09 04:40 +0200
            Re: [PATCH 7/7] DWARF: add the config option Josh Poimboeuf <jpoimboe@redhat.com> - 2017-05-09 05:40 +0200
              Re: [PATCH 7/7] DWARF: add the config option hpa@zytor.com - 2017-05-09 12:10 +0200
                Re: [PATCH 7/7] DWARF: add the config option Josh Poimboeuf <jpoimboe@redhat.com> - 2017-05-09 17:00 +0200
                Re: [PATCH 7/7] DWARF: add the config option "H.J. Lu" <hjl.tools@gmail.com> - 2017-05-09 18:50 +0200
                Re: [PATCH 7/7] DWARF: add the config option Jiri Slaby <jslaby@suse.cz> - 2017-05-10 10:20 +0200
                Re: [PATCH 7/7] DWARF: add the config option Josh Poimboeuf <jpoimboe@redhat.com> - 2017-05-10 15:10 +0200
                Re: [PATCH 7/7] DWARF: add the config option "H.J. Lu" <hjl.tools@gmail.com> - 2017-05-10 18:30 +0200
      Re: [PATCH 7/7] DWARF: add the config option Jiri Kosina <jikos@kernel.org> - 2017-05-09 20:50 +0200
        Re: [PATCH 7/7] DWARF: add the config option Josh Poimboeuf <jpoimboe@redhat.com> - 2017-05-09 21:30 +0200
          Re: [PATCH 7/7] DWARF: add the config option Jiri Slaby <jslaby@suse.cz> - 2017-05-10 10:40 +0200
            Re: [PATCH 7/7] DWARF: add the config option Josh Poimboeuf <jpoimboe@redhat.com> - 2017-05-10 15:20 +0200
    Re: [PATCH 7/7] DWARF: add the config option Jiri Slaby <jslaby@suse.cz> - 2017-05-10 09:50 +0200
      Re: [PATCH 7/7] DWARF: add the config option Josh Poimboeuf <jpoimboe@redhat.com> - 2017-05-10 14:50 +0200
        Re: [PATCH 7/7] DWARF: add the config option Jiri Slaby <jslaby@suse.cz> - 2017-05-10 14:50 +0200
      Re: [PATCH 7/7] DWARF: add the config option Linus Torvalds <torvalds@linux-foundation.org> - 2017-05-10 20:20 +0200

csiph-web