TipsAndTricks/DebugNativeRecipeWithGdb - Revision history

Alexander Kanavin: update by Alex

2017-02-15T14:16:59Z

update by Alex

← Older revision		Revision as of 14:16, 15 February 2017
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	I recently had the need to debug a crash in a native binary that a layer I was working on invokes during the build.		I recently had the need to debug a crash in a native binary that a layer I was working on invokes during the build.

	To debug the crash with gdb I had to do two things; 1) have the build system generate a binary with debug symbols and 2) ~~teach gdb where~~ to ~~look for files~~.		To debug the crash with gdb I had to do two things; 1) have the build system generate a binary with debug symbols and 2) not have them stripped during installation to sysroot.

	To debug ~~a native binary with gdb~~ you ~~first~~ need to ensure that the binaries in the sysroot don't have their debugging symbols stripped.		To enable debug symbols, usually one needs to add "-g" to the list of compiler flags. Unforunately how this is done is specific to each project - you need to inspect the
	~~You can do this for all staged binaries by setting~~ <code>INHIBIT_SYSROOT_STRIP = "1"</code> in your local.conf		source code tree and look for clues. For autoconf-based projects adding to CFLAGS environment variable is enough.

			After the build has completed, inspect the compilation log to verify that -g is indeed there.

			To ensure that the binaries in the sysroot don't have their debugging symbols stripped you need to set <code>INHIBIT_SYSROOT_STRIP = "1"</code> in your local.conf

	Alternatively you might want to only inhibit stripping for specific recipes, this can be achieved using recipe OVERRIDES such as:		Alternatively you might want to only inhibit stripping for specific recipes, this can be achieved using recipe OVERRIDES such as:
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	Note: you'll need to ensure any binaries you wish to debug are (re-)staged into the sysroot after changing this setting.		Note: you'll need to ensure any binaries you wish to debug are (re-)staged into the sysroot after changing this setting.

	~~Once you have binaries with debugging symbols you can start a gdb session and teach it where to look for files.~~

	~~I pointed gdb at our native sysroot with (from within a gsb session):~~

	~~set sysroot /path/to/build/tmp/sysroots/x86_64-linux~~

	~~As native binaries can also link to host libraries, especially libc, I also told gdb to look in both the sysroot and the host for shared libraries:~~

	~~set solib-search-path /path/to/build/tmp/sysroots/x86_64-linux/usr/lib:/usr/lib64/:/lib~~

	~~With those commands run I was ready to operate gbd as usual and quickly narrowed down the cause of the crash.~~

	For more information on the gdb commands above see the gdb manual section [https://sourceware.org/gdb/current/onlinedocs/gdb/Files.html#Files "Commands to Specify Files"]		For more information on the gdb commands above see the gdb manual section [https://sourceware.org/gdb/current/onlinedocs/gdb/Files.html#Files "Commands to Specify Files"]

	~~= To Do =~~

	* Verify whether solib-search-path should include sysroot and host paths, or just add host paths.
	* test it still works

Joshua Lock: Add To Do

2016-06-27T13:43:08Z

Add To Do

← Older revision		Revision as of 13:43, 27 June 2016
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	For more information on the gdb commands above see the gdb manual section [https://sourceware.org/gdb/current/onlinedocs/gdb/Files.html#Files "Commands to Specify Files"]		For more information on the gdb commands above see the gdb manual section [https://sourceware.org/gdb/current/onlinedocs/gdb/Files.html#Files "Commands to Specify Files"]

			= To Do =

			* Verify whether solib-search-path should include sysroot and host paths, or just add host paths.
			* test it still works

Joshua Lock: Tweak formatting

2016-06-27T11:58:00Z

Tweak formatting

← Older revision		Revision as of 11:58, 27 June 2016
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	To debug a native binary with gdb you first need to ensure that the binaries in the sysroot don't have their debugging symbols stripped.		To debug a native binary with gdb you first need to ensure that the binaries in the sysroot don't have their debugging symbols stripped.
	You can do this for all staged binaries by setting <code>INHIBIT_SYSROOT_STRIP = "1"</code> in your ~~<pre>~~local.conf~~</pre>~~		You can do this for all staged binaries by setting <code>INHIBIT_SYSROOT_STRIP = "1"</code> in your local.conf

	Alternatively you might want to only inhibit stripping for specific recipes, this can be achieved using recipe ~~<pre>~~OVERRIDES~~</pre>~~ such as:		Alternatively you might want to only inhibit stripping for specific recipes, this can be achieved using recipe OVERRIDES such as:

	INHIBIT_SYSROOT_STRIP_pn-swupd-server-native = "1"		INHIBIT_SYSROOT_STRIP_pn-swupd-server-native = "1"

Joshua Lock at 11:57, 27 June 2016

2016-06-27T11:57:16Z

← Older revision		Revision as of 11:57, 27 June 2016
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	=How to debug native recipes with gdb=		=How to debug native recipes with gdb=

	I recently had the need to debug a crash in a native binary that a layer was ~~calling~~ during the build.		I recently had the need to debug a crash in a native binary that a layer I was working on invokes during the build.

	To debug the crash with gdb I had to do two things; 1) have the build system generate a binary with debug symbols and 2) teach gdb where to look for files.		To debug the crash with gdb I had to do two things; 1) have the build system generate a binary with debug symbols and 2) teach gdb where to look for files.

	To debug a native binary with gdb you first need to ensure that the binaries in the sysroot don't have their debugging symbols stripped.		To debug a native binary with gdb you first need to ensure that the binaries in the sysroot don't have their debugging symbols stripped.
	You can do this for all staged binaries by setting INHIBIT_SYSROOT_STRIP = "1" in your local.conf		You can do this for all staged binaries by setting <code>INHIBIT_SYSROOT_STRIP = "1"</code> in your <pre>local.conf</pre>

	Alternatively you might want to only inhibit stripping for specific recipes, this can be achieved using recipe OVERRIDES such as:		Alternatively you might want to only inhibit stripping for specific recipes, this can be achieved using recipe <pre>OVERRIDES</pre> such as:

	INHIBIT_SYSROOT_STRIP_pn-swupd-server-native = "1"		INHIBIT_SYSROOT_STRIP_pn-swupd-server-native = "1"
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	set solib-search-path /path/to/build/tmp/sysroots/x86_64-linux/usr/lib:/usr/lib64/:/lib		set solib-search-path /path/to/build/tmp/sysroots/x86_64-linux/usr/lib:/usr/lib64/:/lib

			With those commands run I was ready to operate gbd as usual and quickly narrowed down the cause of the crash.

	For more information on the gdb commands above see the gdb manual section [https://sourceware.org/gdb/current/onlinedocs/gdb/Files.html#Files "Commands to Specify Files"]		For more information on the gdb commands above see the gdb manual section [https://sourceware.org/gdb/current/onlinedocs/gdb/Files.html#Files "Commands to Specify Files"]

Joshua Lock: /* How to debug native recipes with gdb */

2016-06-27T10:49:08Z

How to debug native recipes with gdb

← Older revision		Revision as of 10:49, 27 June 2016
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	As native binaries can also link to host libraries, especially libc, I also told gdb to look in both the sysroot and the host for shared libraries:		As native binaries can also link to host libraries, especially libc, I also told gdb to look in both the sysroot and the host for shared libraries:

	set solib-search-path /~~srv~~/~~builds~~/~~oecore~~/tmp~~-glibc~~/sysroots/x86_64-linux/usr/lib:/usr/lib64/:/lib		set solib-search-path /path/to/build/tmp/sysroots/x86_64-linux/usr/lib:/usr/lib64/:/lib

	For more information on the gdb commands above see the gdb manual section [https://sourceware.org/gdb/current/onlinedocs/gdb/Files.html#Files "Commands to Specify Files"]		For more information on the gdb commands above see the gdb manual section [https://sourceware.org/gdb/current/onlinedocs/gdb/Files.html#Files "Commands to Specify Files"]

Joshua Lock: Add tip for debugging binaries produced by native recipes with gdb

2016-06-27T10:48:40Z

Add tip for debugging binaries produced by native recipes with gdb

New page

=How to debug native recipes with gdb=

I recently had the need to debug a crash in a native binary that a layer was calling during the build.

To debug the crash with gdb I had to do two things; 1) have the build system generate a binary with debug symbols and 2) teach gdb where to look for files.

To debug a native binary with gdb you first need to ensure that the binaries in the sysroot don't have their debugging symbols stripped.
You can do this for all staged binaries by setting INHIBIT_SYSROOT_STRIP = "1" in your local.conf

Alternatively you might want to only inhibit stripping for specific recipes, this can be achieved using recipe OVERRIDES such as:

INHIBIT_SYSROOT_STRIP_pn-swupd-server-native = "1"

I used the former as it allowed me to be certain of having all debugging symbols available.

Note: you'll need to ensure any binaries you wish to debug are (re-)staged into the sysroot after changing this setting.

Once you have binaries with debugging symbols you can start a gdb session and teach it where to look for files.

I pointed gdb at our native sysroot with (from within a gsb session):

set sysroot /path/to/build/tmp/sysroots/x86_64-linux

As native binaries can also link to host libraries, especially libc, I also told gdb to look in both the sysroot and the host for shared libraries:

set solib-search-path /srv/builds/oecore/tmp-glibc/sysroots/x86_64-linux/usr/lib:/usr/lib64/:/lib

For more information on the gdb commands above see the gdb manual section [https://sourceware.org/gdb/current/onlinedocs/gdb/Files.html#Files "Commands to Specify Files"]