Elfutils, looking for kernel debuginfo file, tries to find it at various places. If elfutils finds /boot/vmlinu*x* file, it checks for debufginfo section. If debuginfo is not present, it saves it as 'main elf' and continue looking for debuginfo file having .debug extension i.e. vmlinux-RELEASE.debug.
'Ubuntu on powerpc' installs kernel as /boot/vmlinux and installs debuginfo without any extension as /usr/lib/debug/boot/vmlinux-RELEASE and hence, elfutils is not able to find the debuginfo file. Here is the lunchpad bug for the same: https://bugs.launchpad.net/ubuntu/+source/systemtap/+bug/1537125 This patch adds functionality to search for file without any extension followed by searching file having .debug extension. I've formatted this patch from elfutils-0.165 Before applying patch: # strace -o out -e open ./stap -v probe.stp Pass 1: parsed user script and 95 library script(s) using 42176virt/32128res/5952shr/25472data kb, in 190usr/20sys/222real ms. WARNING: cannot find module kernel debuginfo: No DWARF information found [man warning::debuginfo] semantic error: while resolving probe point: identifier 'kernel' at probe.stp:1:7 source: probe kernel.function("do_fork") ^ semantic error: no match Pass 2: analyzed script: 0 probe(s), 0 function(s), 0 embed(s), 0 global(s) using 66688virt/34496res/7296shr/26432data kb, in 0usr/0sys/28real ms. Pass 2: analysis failed. [man error::pass2] Tip: /usr/share/doc/systemtap/README.Debian should help you get started. # cat out | grep vmlinu open("/boot/vmlinux-3.13.0-76-generic", O_RDONLY) = 3 open("/lib/modules/3.13.0-76-generic/build/vmlinux.id", O_RDONLY) = -1 ENOENT (No such file or directory) open("/boot/vmlinux-3.13.0-76-generic.debug", O_RDONLY) = -1 ENOENT (No such file or directory) open("/boot/.debug/vmlinux-3.13.0-76-generic.debug", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/lib/debug/boot/vmlinux-3.13.0-76-generic.debug", O_RDONLY) = -1 ENOENT (No such file or directory) open("/var/cache/abrt-di/usr/lib/debug/boot/vmlinux-3.13.0-76-generic.debug", O_RDONLY) = -1 ENOENT (No such file or directory) open("/boot/build/vmlinux-3.13.0-76-generic.debug", O_RDONLY) = -1 ENOENT (No such file or directory) open("/boot/vmlinux-3.13.0-76-generic.debug", O_RDONLY) = -1 ENOENT (No such file or directory) open("/boot/.debug/vmlinux-3.13.0-76-generic.debug", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/lib/debug/boot/vmlinux-3.13.0-76-generic.debug", O_RDONLY) = -1 ENOENT (No such file or directory) open("/var/cache/abrt-di/usr/lib/debug/boot/vmlinux-3.13.0-76-generic.debug", O_RDONLY) = -1 ENOENT (No such file or directory) open("/boot/build/vmlinux-3.13.0-76-generic.debug", O_RDONLY) = -1 ENOENT (No such file or directory) After applying patch: # strace -o out1 -e open ./stap -v probe.stp Pass 1: parsed user script and 95 library script(s) using 41856virt/32128res/5952shr/25472data kb, in 170usr/10sys/189real ms. Pass 2: analyzed script: 1 probe(s), 0 function(s), 0 embed(s), 0 global(s) using 242496virt/166912res/105088shr/60608data kb, in 700usr/100sys/1518real ms. Pass 3: translated to C into "/tmp/stapbbBu6y/stap_a18833407fc7a78b1251d743383f3fef_989_src.c" using 242496virt/167040res/105216shr/60608data kb, in 0usr/0sys/9real ms. Pass 4: compiled C into "stap_a18833407fc7a78b1251d743383f3fef_989.ko" in 6710usr/820sys/8338real ms. Pass 5: starting run. ^CPass 5: run completed in 0usr/10sys/3477real ms. # cat out1 | grep vmlinu open("/boot/vmlinux-3.13.0-76-generic", O_RDONLY) = 3 open("/lib/modules/3.13.0-76-generic/build/vmlinux.id", O_RDONLY) = -1 ENOENT (No such file or directory) open("/boot/vmlinux-3.13.0-76-generic", O_RDONLY) = 4 open("/boot/.debug/vmlinux-3.13.0-76-generic", O_RDONLY) = -1 ENOENT (No such file or directory) open("/boot/vmlinux-3.13.0-76-generic", O_RDONLY) = 4 open("/usr/lib/debug/boot/vmlinux-3.13.0-76-generic", O_RDONLY) = 4 Signed-off-by: Ravi Bangoria <ravi.bango...@linux.vnet.ibm.com> --- libdwfl/dwfl_module_getdwarf.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) diff --git a/libdwfl/dwfl_module_getdwarf.c b/libdwfl/dwfl_module_getdwarf.c index 0e8810b..ad5054b 100644 --- a/libdwfl/dwfl_module_getdwarf.c +++ b/libdwfl/dwfl_module_getdwarf.c @@ -529,11 +529,22 @@ find_debuginfo (Dwfl_Module *mod) debuglink_file = INTUSE(dwelf_elf_gnu_debuglink) (mod->main.elf, &debuglink_crc); - mod->debug.fd = (*mod->dwfl->callbacks->find_debuginfo) (MODCB_ARGS (mod), - mod->main.name, - debuglink_file, - debuglink_crc, - &mod->debug.name); + /* First try to look for vmlinux file */ + if (debuglink_file == NULL) + mod->debug.fd = (*mod->dwfl->callbacks->find_debuginfo) (MODCB_ARGS (mod), + mod->main.name, + basename(mod->main.name), + debuglink_crc, + &mod->debug.name); + + /* Try to look for vmlinux.debug file */ + if (mod->debug.fd <= 0) + mod->debug.fd = (*mod->dwfl->callbacks->find_debuginfo) (MODCB_ARGS (mod), + mod->main.name, + debuglink_file, + debuglink_crc, + &mod->debug.name); + Dwfl_Error result = open_elf (mod, &mod->debug); if (result == DWFL_E_NOERROR && mod->debug.address_sync != 0) result = find_prelink_address_sync (mod, &mod->debug); -- 1.9.1
