Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

On Wed, Feb 21, 2018 at 01:39:52PM -0800, Linus Torvalds wrote: > which are actually about the crash. The rest is almost entirely useless. > > Do I know what the corrent answer is? No. Ok, I hear ya. I finally have some time to poke at this. So here's a new splat, see below. Incremental diff at

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

On Wed, Feb 21, 2018 at 01:39:52PM -0800, Linus Torvalds wrote: > which are actually about the crash. The rest is almost entirely useless. > > Do I know what the corrent answer is? No. Ok, I hear ya. I finally have some time to poke at this. So here's a new splat, see below. Incremental diff at

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

Josh Poimboeuf writes: > On Thu, Feb 22, 2018 at 10:42:52AM -0800, Linus Torvalds wrote: >> So what we could perhaps do is: >> >> - make console_verbose() actually reset things to at least LOGLEVEL_DEBUG >> >> - make sure the *default* loglevel be LOGLEVEL_WARNING >>

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

Josh Poimboeuf writes: > On Thu, Feb 22, 2018 at 10:42:52AM -0800, Linus Torvalds wrote: >> So what we could perhaps do is: >> >> - make console_verbose() actually reset things to at least LOGLEVEL_DEBUG >> >> - make sure the *default* loglevel be LOGLEVEL_WARNING >> >> - now you can use

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

On Thu, Feb 22, 2018 at 10:42:52AM -0800, Linus Torvalds wrote: > So what we could perhaps do is: > > - make console_verbose() actually reset things to at least LOGLEVEL_DEBUG > > - make sure the *default* loglevel be LOGLEVEL_WARNING > > - now you can use pr_debug() in the oops code to

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

On Thu, Feb 22, 2018 at 10:42:52AM -0800, Linus Torvalds wrote: > So what we could perhaps do is: > > - make console_verbose() actually reset things to at least LOGLEVEL_DEBUG > > - make sure the *default* loglevel be LOGLEVEL_WARNING > > - now you can use pr_debug() in the oops code to

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

On Thu, Feb 22, 2018 at 1:23 AM, Peter Zijlstra wrote: > > So being one to only use machines that have a serial line this does not > really affect me; but it would appear to me that it might make sense to > try and reverse the entire dump. In theory yes. But while you

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

On Thu, Feb 22, 2018 at 1:23 AM, Peter Zijlstra wrote: > > So being one to only use machines that have a serial line this does not > really affect me; but it would appear to me that it might make sense to > try and reverse the entire dump. In theory yes. But while you mention the buffering

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

On Wed, Feb 21, 2018 at 01:39:52PM -0800, Linus Torvalds wrote: > showing with a hung kernel. And most of the above is actually > completely useless. Those are the *usermode* registers it shows, not > the kernel registers at the time of the crash (the final rip/rsp/code > lines are for the actual

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

On Wed, Feb 21, 2018 at 01:39:52PM -0800, Linus Torvalds wrote: > showing with a hung kernel. And most of the above is actually > completely useless. Those are the *usermode* registers it shows, not > the kernel registers at the time of the crash (the final rip/rsp/code > lines are for the actual

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

On Wed, Feb 21, 2018 at 9:54 AM, Borislav Petkov wrote: > > Ok, lemme run it by Linus too as he probably stares at this part of the > output a *lot* :-) Less than I used to, since there are others who are pretty good at decoding them, but yes... > Anyway, here's a 64-bit splat.

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

On Wed, Feb 21, 2018 at 9:54 AM, Borislav Petkov wrote: > > Ok, lemme run it by Linus too as he probably stares at this part of the > output a *lot* :-) Less than I used to, since there are others who are pretty good at decoding them, but yes... > Anyway, here's a 64-bit splat. I'm basically

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

On Wed, Feb 21, 2018 at 10:15:53AM +0100, Ingo Molnar wrote: > That looks really useful! Ok, lemme run it by Linus too as he probably stares at this part of the output a *lot* :-) Combined patch at the end. I'll split it later. @Linus: also, pls have a look at

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

On Wed, Feb 21, 2018 at 10:15:53AM +0100, Ingo Molnar wrote: > That looks really useful! Ok, lemme run it by Linus too as he probably stares at this part of the output a *lot* :-) Combined patch at the end. I'll split it later. @Linus: also, pls have a look at

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

* Borislav Petkov wrote: > On Tue, Feb 20, 2018 at 01:29:56PM -0600, Josh Poimboeuf wrote: > > > Maybe this series already has this side-effect, but I'd really love to > > > see oopses show the code bytes for each kernel entry, not just the > > > innermode one. We already dump

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

* Borislav Petkov wrote: > On Tue, Feb 20, 2018 at 01:29:56PM -0600, Josh Poimboeuf wrote: > > > Maybe this series already has this side-effect, but I'd really love to > > > see oopses show the code bytes for each kernel entry, not just the > > > innermode one. We already dump full regs

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

On Tue, Feb 20, 2018 at 01:29:56PM -0600, Josh Poimboeuf wrote: > > Maybe this series already has this side-effect, but I'd really love to > > see oopses show the code bytes for each kernel entry, not just the > > innermode one. We already dump full regs including RIP -- adding > > Code: should

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

On Tue, Feb 20, 2018 at 01:29:56PM -0600, Josh Poimboeuf wrote: > > Maybe this series already has this side-effect, but I'd really love to > > see oopses show the code bytes for each kernel entry, not just the > > innermode one. We already dump full regs including RIP -- adding > > Code: should

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

On Tue, Feb 20, 2018 at 07:14:00PM +, Andy Lutomirski wrote: > On Mon, Feb 19, 2018 at 8:28 PM, Borislav Petkov wrote: > > From: Borislav Petkov > > > > Hi, > > > > so I've been thinking about doing this for a while now: be able to dump > > the opcode bytes

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

On Tue, Feb 20, 2018 at 07:14:00PM +, Andy Lutomirski wrote: > On Mon, Feb 19, 2018 at 8:28 PM, Borislav Petkov wrote: > > From: Borislav Petkov > > > > Hi, > > > > so I've been thinking about doing this for a while now: be able to dump > > the opcode bytes around the user rIP just like we

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

On Mon, Feb 19, 2018 at 8:28 PM, Borislav Petkov wrote: > From: Borislav Petkov > > Hi, > > so I've been thinking about doing this for a while now: be able to dump > the opcode bytes around the user rIP just like we do for kernel faults. > > Why? > > See patch 5's

Re: [PATCH 0/5] x86/dumpstack: Cleanups and user opcode bytes Code: section

On Mon, Feb 19, 2018 at 8:28 PM, Borislav Petkov wrote: > From: Borislav Petkov > > Hi, > > so I've been thinking about doing this for a while now: be able to dump > the opcode bytes around the user rIP just like we do for kernel faults. > > Why? > > See patch 5's commit message. That's why I've