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Re: [PATCH 3/6] sysroot: debuginfo lookup with sysroot case do not remove sysroot from file_name
After looking into it, I believe you here. Your patched checked in as
commit b29e448e1.
On Fri, Mar 9, 2018 at 2:20 PM, Victor Kamensky <kamensky@cisco.com> wrote:
>
>
> On Thu, 8 Mar 2018, Victor Kamensky wrote:
>
>> Hi David,
>>
>> On Thu, 8 Mar 2018, David Smith wrote:
>>
>>> Hmm, the problem I have here is the code your patch wants to delete
>>> was added to fix a sysroot problem in the following commit:
>>>
>>> ====
>>> commit df932a3175284fa75a4c6bdb3aa7af1a34c15cd6
>>> Author: Torsten Polle <Torsten.Polle@gmx.de>
>>> Date: Thu Mar 6 21:38:49 2014 +0100
>>>
>>> Fix: Debug links are not found if the sysroot is used.
>>>
>>> Signed-off-by: Torsten Polle <Torsten.Polle@gmx.de>
>>> ====
>>
>>
>> Thank you for bring my attention to it. Unfortunately above
>> commit message is too terse, and it is not clear what was the
>> use case that did not work.
>>
>> But I looked closely into it again, and I think I know what
>> is happening:
>>
>> It boils down to three different types of entries that
>> SYSTEMTAP_DEBUGINFO_PATH environment (or its default) may have.
>> SYSTEMTAP_DEBUGINFO_PATH value is passed through debuginfo_usr_path
>> to mod->dwfl->callbacks.debuginfo_path and that is passed
>> to dwfl_standard_find_debuginfo function of elfutils.
>>
>> Note fila_name passed to function may have sysroot stripped
>> from it (current code), or may include sysroot as it was
>> before df932a3175284 and after my fix.
>>
>> debuginfo_path may contain the following entries, each
>> may preceeded by optional "+" or "-"
>>
>> 1) empty entry, in this case fila_name passed to the function
>> is checked directly. If file_name does not have sysroot in
>> it dwfl_standard_find_debuginfo will try to look for file
>> in current root. Which is clearly very wrong thing to do in
>> case of sysroot build, since it may pick up file with the
>> same name in host. Current code with default debuginfo_path
>> has this issue
>>
>> 2) Local path like ".debug". In this case function will look
>> for `dirname file_name`/.debug/`basename file_name'. Again
>> if file_name does not have sysroot in it, host files system
>> will be looked and it is wrong. That is actually my case,
>> in for /bin/mkdir.coreutils in my sysroot there is
>> /bin/.debug/mkdir.coreutils with symbols. So if file_name
>> does have sysroot in it, correct symbols file is picked and
>> that is what I made this fix.
>>
>> 3) Absolute path like '/<sysroot>/usr/lib/debug'. In this
>> case function will look at
>> '/<sysroot>/usr/lib/debug'/file_name or
>> '/<sysroot>/usr/lib/debug'/`basename file_name`. And in
>> this case if file_name contains sysroot it will not work.
>> I believe it is what df932a317528 has fixed and that is
>> what my fix would break again. But note df932a317528 broke
>> lookup for case 2).
>
>
> I've tried to implement fix as per my understanding
> above, but I discovered
> that I missed important piece yesterday wrt how
> dwfl_standard_find_debuginfo function handles absolute
> entries. It turns out if function receives file_name it
> will try one by one chipping of directories from the front of
> file_name so eventually it comes to short name within
> sysroot. I.e it gets file_name as /my/sys/root/bin/hello.debug
> it will try:
>
> <absolute_debuginfo>/my/sys/root/bin/hello.debug
>
> <absolute_debuginfo>/sys/root/bin/hello.debug
>
> <absolute_debuginfo>/root/bin/hello.debug
>
> <absolute_debuginfo>/bin/hello.debug
>
> <absolute_debuginfo>/hello.debug
>
> So now, I stand by my original patch - df932a317528 should be
> reverted. And reverted case works for all debuginof_path entries
> types. I've unit tested either local or absolute entries all
> work with my originally proposed patch.
>
> df932a317528 was done in 'Thu Mar 6 21:38:49 2014' but
> dwfl_standard_find_debuginfo logic to explore all sub-subdirs
> for absolute entries was added in elfutils in 2015-08-13
> by b901b5e7. I think that explains it.
>
> Please merge my original patch or revert df932a317528.
>
> Here is snipet from 'git blame ./libdwfl/find-debuginfo.c'
> around explore all sub-subdirs in dwfl_standard_find_debuginfo code
>
> b901b5e7 (Dodji Seketeli 2015-08-13 15:59:41 +0200 268) subdir =
> file_dirname;
> b901b5e7 (Dodji Seketeli 2015-08-13 15:59:41 +0200 269) /* We
> want to explore all sub-subdirs. Chop off one slash
> b901b5e7 (Dodji Seketeli 2015-08-13 15:59:41 +0200 270) at a time. */
> b901b5e7 (Dodji Seketeli 2015-08-13 15:59:41 +0200 271) explore_dir:
> b901b5e7 (Dodji Seketeli 2015-08-13 15:59:41 +0200 272) subdir = strchr
> (subdir, '/');
> b901b5e7 (Dodji Seketeli 2015-08-13 15:59:41 +0200 273) if
> (subdir != NULL)
> b901b5e7 (Dodji Seketeli 2015-08-13 15:59:41 +0200 274) subdir = subdir + 1;
> b901b5e7 (Dodji Seketeli 2015-08-13 15:59:41 +0200 275) if
> (subdir && *subdir == 0)
> b901b5e7 (Dodji Seketeli 2015-08-13 15:59:41 +0200 276) continue;
>
> Thanks,
> Victor
>
>
>> I am not sure how to fix it to work in all cases. I will
>> think about it tomorrow. Any suggestions are welcome.
>>
>> For now it is clear in sysroot case, passing empty entry
>> is wrong. Instead sysroot itself should be passed.
>>
>> Local path and absolute path debuginfo_path contradict
>> each other wrt expectation whether file_name contains
>> sysroot or not. Maybe debuginfo_path in case of
>> non-empty sysroot should be split into two diferent
>> sets: one with absolute entries and other with local entries
>> and dwfl_standard_find_debuginfo should be called twice
>> with different variants of file_name.
>>
>> If interseted please find below my gdb session that
>> illustrates behavior of dwfl_standard_find_debuginfo described
>> above. Gdb session has run against current code.
>>
>> Thanks,
>> Victor
>>
>> In this example /bin/hello executable compiled in such way that it's
>> .gnu_debuglink has value hello.debug, so it could be distingushable
>> from executable itself.
>>
>> (gdb) show args
>> Argument list to give program being debugged when it is started is
>> "--sysroot=/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs
>> -a x86_64 -r
>> /home/wd8/yocto/20180128/build_x86_64/tmp/work/corei7-64-intel-common-poky-linux/linux-yocto/4.9.78+gitAUTOINC+ef2f5d9a0a_f7a6d45fff-r0/linux-corei7-64-intel-common-standard-build
>> -B
>> CROSS_COMPILE=/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/usr/bin/x86_64-poky-linux-
>> --sysenv=PATH=/usr/bin:/bin:/usr/sbin:/sbin
>> --sysenv=LD_LIBRARY_PATH=/lib:/usr/lib -v -l
>> 'process("/bin/hello").function("*")'".
>> ...
>>
>> (gdb) bt
>> #0 find_debuginfo_in_path (mod=mod@entry=0x62d6950,
>> file_name=file_name@entry=0x62d6bf2 "/bin/hello",
>> debuglink_file=debuglink_file@entry=0x7ffff7fed044 "hello.debug",
>> debuglink_crc=debuglink_crc@entry=611974856,
>> debuginfo_file_name=debuginfo_file_name@entry=0x62d69a8) at
>> find-debuginfo.c:165
>> #1 0x00007ffff7bb2855 in dwfl_standard_find_debuginfo (mod=0x62d6950,
>> userdata=<optimized out>, modname=<optimized out>, base=<optimized out>,
>> file_name=0x62d6bf2 "/bin/hello",
>> debuglink_file=0x7ffff7fed044 "hello.debug", debuglink_crc=611974856,
>> debuginfo_file_name=0x62d69a8) at find-debuginfo.c:383
>> #2 0x0000000000657719 in internal_find_debuginfo (mod=0x62d6950,
>> userdata=0x62d6960,
>> modname=0x62d6af0
>> "/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/bin/hello",
>> base=65536,
>> file_name=0x62d6bf2 "/bin/hello", debuglink_file=0x7ffff7fed044
>> "hello.debug", debuglink_crc=611974856, debuginfo_file_name=0x62d69a8) at
>> ../systemtap/setupdwfl.cxx:645
>> #3 0x00007ffff7bb0153 in find_debuginfo (mod=0x62d6950) at
>> dwfl_module_getdwarf.c:539
>> #4 0x00007ffff7bb1393 in find_dw (mod=0x62d6950) at
>> dwfl_module_getdwarf.c:1400
>> #5 dwfl_module_getdwarf (mod=0x62d6950, bias=0x7fffffff79d8) at
>> dwfl_module_getdwarf.c:1434
>> #6 0x0000000000530b2c in validate_module_elf (mod=0x62d6950,
>> name=0x62d6af0
>> "/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/bin/hello",
>> q=0x7fffffff8110)
>> at ../systemtap/tapsets.cxx:2471
>> #7 0x000000000053169e in query_module (mod=0x62d6950,
>> name=0x62d6af0
>> "/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/bin/hello",
>> addr=65536, q=0x7fffffff8110)
>> at ../systemtap/tapsets.cxx:2605
>> #8 0x00007ffff7baed71 in dwfl_getmodules (dwfl=0x62d5020,
>> callback=0x53137c <query_module(Dwfl_Module*, void**, char const*,
>> Dwarf_Addr, base_query*)>, arg=0x7fffffff8110, offset=0)
>> at dwfl_getmodules.c:86
>> #9 0x0000000000623215 in dwflpp::iterate_over_modules<void>
>> (this=0x62d4b80, callback=0x53137c <query_module(Dwfl_Module*, void**, char
>> const*, Dwarf_Addr, base_query*)>,
>> data=0x7fffffff8110) at ../systemtap/dwflpp.cxx:409
>> #10 0x000000000058b7a3 in dwflpp::iterate_over_modules<base_query>
>> (this=0x62d4b80, callback=0x53137c <query_module(Dwfl_Module*, void**, char
>> const*, Dwarf_Addr, base_query*)>,
>> data=0x7fffffff8110) at ../systemtap/dwflpp.h:238
>> #11 0x00000000005664f7 in dwarf_builder::build (this=0x62c7960, sess=...,
>> base=0x4b538d0, location=0x1028eb0, parameters=std::map with 2 elements =
>> {...},
>> finished_results=std::vector of length 0, capacity 0) at
>> ../systemtap/tapsets.cxx:8616
>> #12 0x000000000049dcbf in match_node::find_and_build (this=0x62cc660,
>> s=..., p=0x4b538d0, loc=0x1028eb0, pos=2, results=std::vector of length 0,
>> capacity 0, builders=std::set with 0 elements)
>> at ../systemtap/elaborate.cxx:474
>> #13 0x000000000049ee12 in match_node::find_and_build (this=0x4b4d920,
>> s=..., p=0x4b538d0, loc=0x1028eb0, pos=1, results=std::vector of length 0,
>> capacity 0, builders=std::set with 0 elements)
>> at ../systemtap/elaborate.cxx:648
>> #14 0x000000000049ee12 in match_node::find_and_build (this=0xa1b2d0,
>> s=..., p=0x4b538d0, loc=0x1028eb0, pos=0, results=std::vector of length 0,
>> capacity 0, builders=std::set with 0 elements)
>> at ../systemtap/elaborate.cxx:648
>> #15 0x00000000004a0ca5 in derive_probes (s=..., p=0x4b538d0,
>> dps=std::vector of length 0, capacity 0, optional=false,
>> rethrow_errors=false) at ../systemtap/elaborate.cxx:1022
>> #16 0x00000000004a4332 in semantic_pass_symbols (s=...) at
>> ../systemtap/elaborate.cxx:1890
>> #17 0x00000000004a88c5 in semantic_pass (s=...) at
>> ../systemtap/elaborate.cxx:2441
>> #18 0x0000000000413a48 in passes_0_4 (s=...) at ../systemtap/main.cxx:914
>> #19 0x00000000004161a8 in main (argc=13, argv=0x7fffffffdd68) at
>> ../systemtap/main.cxx:1381
>> (gdb) p *mod
>> $43 = {dwfl = 0x62d5020, next = 0x0, userdata = 0x0,
>> name = 0x62d6af0
>> "/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/bin/hello",
>> low_addr = 65536, high_addr = 2166840,
>> main = {name = 0x62d6b80
>> "/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/bin/hello",
>> fd = -1, valid = false,
>> relocated = false, elf = 0x62d50b0, vaddr = 0, address_sync = 2304},
>> debug = {name = 0x0, fd = 0, valid = false, relocated = false, elf = 0x0,
>> vaddr = 0, address_sync = 0}, aux_sym = {
>> name = 0x0, fd = 0, valid = false, relocated = false, elf = 0x0, vaddr
>> = 0, address_sync = 0}, main_bias = 65536, ebl = 0x0, e_type = 3, elferr =
>> DWFL_E_NOERROR, reloc_info = 0x0,
>> symfile = 0x0, symdata = 0x0, aux_symdata = 0x0, syments = 0, aux_syments
>> = 0, first_global = 0, aux_first_global = 0, symstrdata = 0x0,
>> aux_symstrdata = 0x0, symxndxdata = 0x0,
>> aux_symxndxdata = 0x0, dw = 0x0, alt = 0x0, alt_fd = 0, alt_elf = 0x0,
>> symerr = DWFL_E_NOERROR, dwerr = DWFL_E_NO_DWARF, first_cu = 0x0, cu = 0x0,
>> lazy_cu_root = 0x0, aranges = 0x0,
>> build_id_bits = 0x62d4b60, build_id_vaddr = 66180, build_id_len = 20, ncu
>> = 0, lazycu = 0, naranges = 0, dwarf_cfi = 0x0, eh_cfi = 0x0, segment = 0,
>> gc = false, is_executable = false}
>> (gdb) p *mod->dwfl->callbacks
>> $44 = {find_elf = 0x0, find_debuginfo = 0x657103
>> <internal_find_debuginfo(Dwfl_Module*, void**, char const*, unsigned long,
>> char const*, char const*, unsigned int, char**)>,
>> section_address = 0x0, debuginfo_path = 0xa07db8 <debuginfo_usr_path>}
>> (gdb) p debuginfo_usr_path
>> $45 = 0xa28bc0
>> "+:.debug:/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/usr/lib/debug:/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/var/cache/abrt-di/usr/lib/debug"
>> (gdb) c
>>
>> Breakpoint 5, try_open (dir=dir@entry=0x62d8c50 "/bin",
>> subdir=subdir@entry=0x0, debuglink=debuglink@entry=0x7ffff7fed044
>> "hello.debug",
>> debuginfo_file_name=debuginfo_file_name@entry=0x7fffffff7340,
>> main_stat=<optimized out>, main_stat=<optimized out>) at find-debuginfo.c:44
>> 44 try_open (const struct stat *main_stat,
>> (gdb) c
>> Continuing.
>>
>> Breakpoint 6, try_open (dir=dir@entry=0x62d8c50 "/bin",
>> subdir=subdir@entry=0x0, debuglink=debuglink@entry=0x7ffff7fed044
>> "hello.debug",
>> debuginfo_file_name=debuginfo_file_name@entry=0x7fffffff7340,
>> main_stat=<optimized out>, main_stat=<optimized out>) at find-debuginfo.c:61
>> 61 int fd = TEMP_FAILURE_RETRY (open (fname, O_RDONLY));
>> (gdb) p fname
>> $46 = 0x62d9320 "/bin/hello.debug"
>> (gdb) c
>> Continuing.
>>
>> Breakpoint 5, try_open (dir=dir@entry=0x62d8c50 "/bin",
>> subdir=subdir@entry=0xa28e42 ".debug",
>> debuglink=debuglink@entry=0x7ffff7fed044 "hello.debug",
>> debuginfo_file_name=debuginfo_file_name@entry=0x7fffffff7340,
>> main_stat=<optimized out>, main_stat=<optimized out>) at find-debuginfo.c:44
>> 44 try_open (const struct stat *main_stat,
>> (gdb) c
>> Continuing.
>>
>> Breakpoint 6, try_open (dir=dir@entry=0x62d8c50 "/bin",
>> subdir=subdir@entry=0xa28e42 ".debug",
>> debuglink=debuglink@entry=0x7ffff7fed044 "hello.debug",
>> debuginfo_file_name=debuginfo_file_name@entry=0x7fffffff7340,
>> main_stat=<optimized out>, main_stat=<optimized out>) at find-debuginfo.c:61
>> 61 int fd = TEMP_FAILURE_RETRY (open (fname, O_RDONLY));
>> (gdb) p fname
>> $47 = 0x62d9320 "/bin/.debug/hello.debug"
>> (gdb) c
>> Continuing.
>>
>> Breakpoint 5, try_open (dir=dir@entry=0x62d8c50 "/bin",
>> subdir=subdir@entry=0x0, debuglink=debuglink@entry=0x7ffff7fed044
>> "hello.debug",
>> debuginfo_file_name=debuginfo_file_name@entry=0x7fffffff7340,
>> main_stat=<optimized out>, main_stat=<optimized out>) at find-debuginfo.c:44
>> 44 try_open (const struct stat *main_stat,
>> (gdb) c
>> Continuing.
>>
>> Breakpoint 6, try_open (dir=dir@entry=0x62d8c50 "/bin",
>> subdir=subdir@entry=0x0, debuglink=debuglink@entry=0x7ffff7fed044
>> "hello.debug",
>> debuginfo_file_name=debuginfo_file_name@entry=0x7fffffff7340,
>> main_stat=<optimized out>, main_stat=<optimized out>) at find-debuginfo.c:61
>> 61 int fd = TEMP_FAILURE_RETRY (open (fname, O_RDONLY));
>> (gdb) p fname
>> $48 = 0x62d9320 "/bin/hello.debug"
>> (gdb) c
>> Continuing.
>>
>> Breakpoint 5, try_open (dir=dir@entry=0xa28e49
>> "/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/usr/lib/debug",
>> subdir=subdir@entry=0x62d8c51 "bin",
>> debuglink=debuglink@entry=0x7ffff7fed044 "hello.debug",
>> debuginfo_file_name=debuginfo_file_name@entry=0x7fffffff7340,
>> main_stat=<optimized out>,
>> main_stat=<optimized out>) at find-debuginfo.c:44
>> 44 try_open (const struct stat *main_stat,
>> (gdb) c
>> Continuing.
>>
>> Breakpoint 6, try_open (dir=dir@entry=0xa28e49
>> "/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/usr/lib/debug",
>> subdir=subdir@entry=0x62d8c51 "bin",
>> debuglink=debuglink@entry=0x7ffff7fed044 "hello.debug",
>> debuginfo_file_name=debuginfo_file_name@entry=0x7fffffff7340,
>> main_stat=<optimized out>,
>> main_stat=<optimized out>) at find-debuginfo.c:61
>> 61 int fd = TEMP_FAILURE_RETRY (open (fname, O_RDONLY));
>> (gdb) p fname
>> $49 = 0x62d9fd0
>> "/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/usr/lib/debug/bin/hello.debug"
>> (gdb) c
>> Continuing.
>>
>> Breakpoint 5, try_open (dir=dir@entry=0xa28e49
>> "/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/usr/lib/debug",
>> subdir=subdir@entry=0x0, debuglink=debuglink@entry=0x7ffff7fed044
>> "hello.debug", debuginfo_file_name=debuginfo_file_name@entry=0x7fffffff7340,
>> main_stat=<optimized out>,
>> main_stat=<optimized out>) at find-debuginfo.c:44
>> 44 try_open (const struct stat *main_stat,
>> (gdb) c
>> Continuing.
>>
>> Breakpoint 6, try_open (dir=dir@entry=0xa28e49
>> "/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/usr/lib/debug",
>> subdir=subdir@entry=0x0, debuglink=debuglink@entry=0x7ffff7fed044
>> "hello.debug", debuginfo_file_name=debuginfo_file_name@entry=0x7fffffff7340,
>> main_stat=<optimized out>,
>> main_stat=<optimized out>) at find-debuginfo.c:61
>> 61 int fd = TEMP_FAILURE_RETRY (open (fname, O_RDONLY));
>> (gdb) p fname
>> $50 = 0x62d9fd0
>> "/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/usr/lib/debug/hello.debug"
>> (gdb) c
>> Continuing.
>>
>> Breakpoint 5, try_open (
>> dir=dir@entry=0xa28eca
>> "/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/var/cache/abrt-di/usr/lib/debug",
>> subdir=subdir@entry=0x62d8c51 "bin",
>> debuglink=debuglink@entry=0x7ffff7fed044 "hello.debug",
>> debuginfo_file_name=debuginfo_file_name@entry=0x7fffffff7340,
>> main_stat=<optimized out>,
>> main_stat=<optimized out>) at find-debuginfo.c:44
>> 44 try_open (const struct stat *main_stat,
>> (gdb) c
>> Continuing.
>>
>> Breakpoint 6, try_open (
>> dir=dir@entry=0xa28eca
>> "/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/var/cache/abrt-di/usr/lib/debug",
>> subdir=subdir@entry=0x62d8c51 "bin",
>> debuglink=debuglink@entry=0x7ffff7fed044 "hello.debug",
>> debuginfo_file_name=debuginfo_file_name@entry=0x7fffffff7340,
>> main_stat=<optimized out>,
>> main_stat=<optimized out>) at find-debuginfo.c:61
>> 61 int fd = TEMP_FAILURE_RETRY (open (fname, O_RDONLY));
>> (gdb) p fname
>> $51 = 0x62d9e90
>> "/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/var/cache/abrt-di/usr/lib/debug/bin/hello.debug"
>> (gdb) c
>> Continuing.
>>
>> Breakpoint 5, try_open (
>> dir=dir@entry=0xa28eca
>> "/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/var/cache/abrt-di/usr/lib/debug",
>> subdir=subdir@entry=0x0, debuglink=debuglink@entry=0x7ffff7fed044
>> "hello.debug", debuginfo_file_name=debuginfo_file_name@entry=0x7fffffff7340,
>> main_stat=<optimized out>,
>> main_stat=<optimized out>) at find-debuginfo.c:44
>> 44 try_open (const struct stat *main_stat,
>> (gdb) c
>> Continuing.
>>
>> Breakpoint 6, try_open (
>> dir=dir@entry=0xa28eca
>> "/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/var/cache/abrt-di/usr/lib/debug",
>> subdir=subdir@entry=0x0, debuglink=debuglink@entry=0x7ffff7fed044
>> "hello.debug", debuginfo_file_name=debuginfo_file_name@entry=0x7fffffff7340,
>> main_stat=<optimized out>,
>> main_stat=<optimized out>) at find-debuginfo.c:61
>> 61 int fd = TEMP_FAILURE_RETRY (open (fname, O_RDONLY));
>> (gdb) p fname
>> $52 = 0x62da070
>> "/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/var/cache/abrt-di/usr/lib/debug/hello.debug"
>>
>>
>>> Torsten, have you tried using --sysroot recently?
>>>
>>> On Mon, Mar 5, 2018 at 11:37 AM, Victor Kamensky <kamensky@cisco.com>
>>> wrote:
>>>>
>>>> If sysroot option is passed, and debug symbols reside in sysroot along
>>>> with executable <foo> in <foo_dir>/.debug/<foo_file> directory, stap
>>>> fails to find debuginfo because it strips out sysroot path from
>>>> file_name
>>>> so dwfl_standard_find_debuginfo ends up looking at host
>>>> <foo_dir>/.debug/<foo_file> rather then checking
>>>> <sysroot>/<foo_dir>/.debug/<foo_file>.
>>>>
>>>> Note in cross compile environment, it is good idea to set and export
>>>> proper SYSTEMTAP_DEBUGINFO_PATH variable because usual built defaults
>>>> that
>>>> work for native distros very often not applicable to cross sysroot
>>>> based environment. For example for yocto poky/OE build the following
>>>> setting seems proper "+:.debug:build".
>>>>
>>>> Here are steps how to reproduce the issue. Note <sysroot> is produced by
>>>> yocto poky build.
>>>>
>>>> [kamensky@coreos-lnx2 tests]$ ls
>>>> /home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/bin/mkdir.coreutils
>>>>
>>>> /home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/bin/mkdir.coreutils
>>>> [kamensky@coreos-lnx2 tests]$ ls
>>>> /home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/bin/.debug/mkdir.coreutils
>>>>
>>>> /home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs/bin/.debug/mkdir.coreutils
>>>> [kamensky@coreos-lnx2 tests]$
>>>> /home/wd8/systemtap/20180208_2/packages/bin/stap
>>>> --sysroot=/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs
>>>> -a x86_64 -r 4.9.78-yocto-standard -B CROSS_COMPILE=x86_64-poky-linux-
>>>> --sysenv=PATH=/usr/bin:/bin:/usr/sbin:/sbin
>>>> --sysenv=LD_LIBRARY_PATH=/lib:/usr/lib -v -l
>>>> 'process("/bin/mkdir.coreutils").function("*")'
>>>> Pass 1: parsed user script and 480 library scripts using
>>>> 230184virt/93416res/5344shr/88612data kb, in 350usr/30sys/378real ms.
>>>> process("/bin/mkdir.coreutils").function("_fini")
>>>> process("/bin/mkdir.coreutils").function("_init")
>>>> process("/bin/mkdir.coreutils").function("fts_children")
>>>> process("/bin/mkdir.coreutils").function("fts_close")
>>>> process("/bin/mkdir.coreutils").function("fts_open")
>>>> process("/bin/mkdir.coreutils").function("fts_read")
>>>> process("/bin/mkdir.coreutils").function("fts_set")
>>>> Pass 2: analyzed script: 7 probes, 0 functions, 0 embeds, 0 globals
>>>> using 233484virt/97928res/6212shr/91912data kb, in 20usr/0sys/26real ms.
>>>>
>>>> running above example under strace shows that stap tries to access
>>>> /bin/.debug/mkdir.coreutils on host, rather then sysroot
>>>>
>>>> 13064 openat(AT_FDCWD, "/bin/mkdir.coreutils", O_RDONLY) = -1 ENOENT (No
>>>> such file or directory)
>>>> 13064 openat(AT_FDCWD, "/bin/.debug/mkdir.coreutils", O_RDONLY) = -1
>>>> ENOENT (No such file or directory)
>>>> 13064 openat(AT_FDCWD, "/bin/mkdir.coreutils", O_RDONLY) = -1 ENOENT (No
>>>> such file or directory)
>>>> 13064 openat(AT_FDCWD, "/bin/build/mkdir.coreutils", O_RDONLY) = -1
>>>> ENOENT (No such file or directory)
>>>> 13064 openat(AT_FDCWD, "/bin/mkdir.coreutils", O_RDONLY) = -1 ENOENT (No
>>>> such file or directory)
>>>>
>>>> After fix applied stap is able to find /bin/.debug/mkdir.coreutils under
>>>> sysroot:
>>>>
>>>> [kamensky@coreos-lnx2 tests]$
>>>> /home/wd8/systemtap/20180208_2/packages/bin/stap
>>>> --sysroot=/home/wd8/yocto/20180128/build_x86_64/tmp/work/intel_corei7_64-poky-linux/kdevel-console-devel-image/1.0-r0/rootfs
>>>> -a x86_64 -r 4.9.78-yocto-standard -B CROSS_COMPILE=x86_64-poky-linux-
>>>> --sysenv=PATH=/usr/bin:/bin:/usr/sbin:/sbin
>>>> --sysenv=LD_LIBRARY_PATH=/lib:/usr/lib -v -l
>>>> 'process("/bin/mkdir.coreutils").function("*")' | wc
>>>> Pass 1: parsed user script and 480 library scripts using
>>>> 230184virt/93440res/5368shr/88612data kb, in 330usr/40sys/371real ms.
>>>> Pass 2: analyzed script: 401 probes, 0 functions, 0 embeds, 0 globals
>>>> using 235092virt/99484res/6256shr/93520data kb, in 30usr/0sys/35real ms.
>>>> 249 249 29671
>>>>
>>>> Also verified on target that script like example below, once compiled
>>>> against sysroot on host and copied back on target can trace 'mkdir'
>>>> invocation functions:
>>>>
>>>> [kamensky@coreos-lnx2 tests]$ cat mkdir1.stp
>>>> probe process("/bin/mkdir.coreutils").function("*").call {
>>>> printf ("%s -> %s\n", thread_indent(1), ppfunc())
>>>> }
>>>> probe process("/bin/mkdir.coreutils").function("*").return {
>>>> printf ("%s <- %s\n", thread_indent(-1), ppfunc())
>>>> }
>>>>
>>>> Signed-off-by: Victor Kamensky <kamensky@cisco.com>
>>>> ---
>>>> setupdwfl.cxx | 12 ------------
>>>> 1 file changed, 12 deletions(-)
>>>>
>>>> diff --git a/setupdwfl.cxx b/setupdwfl.cxx
>>>> index f00cf755b..e5bfa28f0 100644
>>>> --- a/setupdwfl.cxx
>>>> +++ b/setupdwfl.cxx
>>>> @@ -637,18 +637,6 @@ internal_find_debuginfo (Dwfl_Module *mod,
>>>>
>>>> call_dwfl_standard_find_debuginfo:
>>>>
>>>> - if (current_session_for_find_debuginfo)
>>>> - {
>>>> - string sysroot = current_session_for_find_debuginfo->sysroot +
>>>> "/*";
>>>> - int found = fnmatch(sysroot.c_str(), file_name, 0);
>>>> -
>>>> - if (found)
>>>> - {
>>>> - file_name = file_name
>>>> - + current_session_for_find_debuginfo->sysroot.length() - 1;
>>>> - }
>>>> - }
>>>> -
>>>> /* Call the original dwfl_standard_find_debuginfo */
>>>> return dwfl_standard_find_debuginfo(mod, userdata, modname, base,
>>>> file_name, debuglink_file,
>>>> --
>>>> 2.14.3
>>>>
>>>
>>>
>>>
>>> --
>>> David Smith
>>> Associate Manager
>>> Red Hat
>>>
>>
>
--
David Smith
Associate Manager
Red Hat