November 2013 - Darwin-kernel

Re: How to get the parameters for calls on an arbitrary stack in the kernel
by Alexander Holodny 27 Nov '13

27 Nov '13

GDB/LLDB in order to find out all function's arguments in 'bt' output requires binary to be compiled without most optimizations. I use following debug-proven optimization level: -O2 for Release and -O0 for Debug builds. Xcode defaults to non debug friendly setting -Os. On Nov 26, 2013, at 3:42 AM, Timothy Standing <tstanding(a)mac.com> wrote: > I am trying to debug a hang in our kext. I have been using gdb and the kgmacro command showallstacks to get a dump of all the stacks in the kernel. Using the output from showallstacks and the gdb list command, I can map the return address in every frame in every stack to a location in the source code (as long as it's in our driver). > > What I would like to do is get a listing of each threads stack which included the parameters for each call. I would like something similar to the backtrace command, but for all stacks. Is this possible in gdb? Is it possible to get a list of the parameters for all the calls on a particular stack? > > Thanks, > > Tim Standing > SoftRAID, Inc. > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/darwin-kernel/alexander.holodny%40g… > > This email sent to alexander.holodny(a)gmail.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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How to get the parameters for calls on an arbitrary stack in the kernel
by Steve Modica 26 Nov '13

26 Nov '13

In the olden days, you'd look at the error frame and the assembly for the particular call and see where it stored its args. Usually, it would write them into a cpu register you could see in the error frame (s0, s1 etc), or an offset to something in a cpu register. This was all MIPS specific. (you kids get off my lawn) -- Steve Modica CTO - Small Tree Communications www.small-tree.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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Re: How to get the parameters for calls on an arbitrary stack in the kernel
by Ken Hornstein 26 Nov '13

26 Nov '13

>You may be looking for âshowallstacksâ. I'm familiar with that, but (from memory, it's been a few months) if you switched to a particular thread the backtrace command was, in general, a lot more complete. >Function arguments canât always be recovered; if there is no symbol >information the debugger cannot know the arguments that were passed to >the function, or if the function has been optimised or simply generated >in certain ways the argument values may no longer exist anywhere by the >time a call is made to the next frame down your stack. No argument there; booting with a debug kernel certainly made the backtrace more useful. --Ken _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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Re: How to get the parameters for calls on an arbitrary stack in the kernel
by Ken Hornstein 26 Nov '13

26 Nov '13

> What I would like to do is get a listing of each threads stack > which included the parameters for each call. I would like > something similar to the backtrace command, but for all stacks. > Is this possible in gdb? Is it possible to get a list of the > parameters for all the calls on a particular stack? >From memory, there was a kgmacro that let you switch to a particular thread's context. From there, you could run a backtrace command. Should be possible to make it work for all threads with only a little bit of work. (Ah, okay. The command is "switchtoact", but if you're working from a Corefile it's "switchtocorethread"). --Ken _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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How to get the parameters for calls on an arbitrary stack in the kernel
by Timothy Standing 26 Nov '13

26 Nov '13

I am trying to debug a hang in our kext. I have been using gdb and the kgmacro command showallstacks to get a dump of all the stacks in the kernel. Using the output from showallstacks and the gdb list command, I can map the return address in every frame in every stack to a location in the source code (as long as it's in our driver). What I would like to do is get a listing of each threads stack which included the parameters for each call. I would like something similar to the backtrace command, but for all stacks. Is this possible in gdb? Is it possible to get a list of the parameters for all the calls on a particular stack? Thanks, Tim Standing SoftRAID, Inc. _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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