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I am debugging a multi-threaded application with gdb, but when I start the program in gdb I get the warning:

warning: Unable to find libthread_db matching inferior's thread library, thread debugging will not be available.

I can still debug, but I can't debug anything other than the main thread. I have read forums that suggest installing the packages libthread-db1 and glibc-dbg, but this does not correct the problem for me.

On my machine I have the 3 files /lib/libthread_db.so.1, /lib/.debug/libthread_db-1.0.so, and /lib/libthread_db-1.0.so. I tried creating symbolic links in /lib with the name libthread_db.so, one time pointing at the /lib/libthread_db.so.1 file, and another time pointing at the /lib/libthread_db-1.0.so file, and also I created the symbolic link /lib/.debug/libthread_db.so pointing to /lib/.debug/libthread_db-1.0.so, all with no luck.

In gdb I have tried setting libthread-db-search-path to /lib (with the symlink once set to libthread_db.so.1, and once to libthread_db-1.0.so, and also set to /lib/.debug.

Any suggestions? I am using Angstrom Linux v2.6.39 for the BeagleBoard-xm.

Samuel
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  • Note that I started with a root file system from a 2.6.32 kernel (Angstrom-Beagleboard-demo-image-glibc-ipk-2011.1-beagleboard.rootfs.tar.bz2), and copied the linux source into /usr/src, and cross-compiled a new kernel based on 2.6.39. This is likely the reason for the version mismatch. I have the threading shared object files from the cross compiler, and I tried replacing the existing .so files with the ones from the cross compiler, but it caused make to crash. Any ideas? – Samuel Jul 23 '12 at 15:00
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    Hi I'm currently having the exact same issue on angstrom running on a beaglebone. Did you ever figure out the solution? – Brandon Yates Jun 19 '13 at 23:30
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    Also, be sure your version of libpthread is `not stripped` – Pavel Krasavin Jul 04 '16 at 08:22

2 Answers2

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warning: Unable to find libthread_db matching inferior's thread library

This means that your /lib/libthread_db.so.1 does not match your /lib/libpthread.so.0. Such mismatch could be the result of you installing different versions of libc and libthread_db packages, or updating one or the other outside of the package management system. It could also be an error in your packages (i.e. they may not be built correctly).

You should ignore /lib/.debug/* -- that is not the library you are looking for.

Employed Russian
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6

You are correct in trying to use 

set libthread-db-search-path [path]

however, it seems you have still not pointed it at a version of libthread_db that is compatible with the pthreads library you're using.

First, check which pthread library you're linked to using ldd:

ldd your_executable

then make sure the libthread-db-search-path points to a location that has a compatible version of libthread_db with whatever libpthread you're getting. It could be that you're dynamic linker path is getting a different pthread library than you expect.

Tony K.
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