By default gdb-7.2 depends on ust(btw, the recipe of gdb lacks: DEPENDS += " lttng-ust") unless we specify --without-ust. gdb-7.2 works with lttng-ust 0.11 fine. Recently we upgraded lttng-ust to 0.12 that has API changes(http://www.mail-archive.com/ltt-dev@lists.casi.polymtl.ca/msg01839.html) so gdb-7.2 doesn't build now: gdb-7.2/gdb/gdbserver/tracepoint.c: In function 'first_marker': gdb-7.2/gdb/gdbserver/tracepoint.c:7009:3: warning: return from incompatible pointer type. Saul has worked around the build issue by adding --without-ust to gdb-7.2's configure, and we need try to push upstream gdb to fix the issue.
I reported http://sourceware.org/bugzilla/show_bug.cgi?id=12699 in gdb bugzilla. Also reported the issue in gdb and lttng-ust communities: http://sourceware.org/ml/gdb/2011-04/msg00140.html http://lists.casi.polymtl.ca/pipermail/ltt-dev/2011-April/004449.html
A comment from lttng mailing list follows: http://lists.casi.polymtl.ca/pipermail/ltt-dev/2011-April/004450.html ---------------------------- We're currently doing instrumentation API changes in UST. At the moment, it is in the git tree, planned for release in UST 0.13. Our goal is to perform this painful (but required) step sooner than later so that we minimize the amount of pain for our user-base. Also, we should reopen the discussion on the way the UST Markers collect the registers for GDB, because the current way involves a _lot_ of ugly assembly code. It should be possible to only use a volatile inline asm to specify input constraints on the target marker parameters, and keep the instruction pointer address that corresponds to this inline asm in a section known by gdb (so gdb could use the drawf info to fetch data from registers/memory). If you can ensure that this would fit gdb's requirements, I could clean up the marker code and we could resync the APIs together. We could also provide this for UST Tracepoints in the same go, with pretty much the same interface as we'd use for UST Markers. I am aware that this would require change on the GDB side, but I think it's better to synchronise our effort rather than to shoot at different targets. Thanks, Mathieu ----------------------------
Need to wait for the upstream resolution with UST and gdb
LTTNG Update to 0.15 and GDB update fixes this issue http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=d26c9bd80d8ee5fd125a487435e5c976ea13916a and http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=7ae7e7e09a0ecb76413754c70e12fda14d64a0be