What a library version did you try? In my environment 1.5 stable and master
branches seem broken for mips/mipsel (at least for O32 ABI give empty
traces).
Try this branch https://github.com/keenetic/libunwind/commits/v1.4-rc1-ndm
(v1.4-rc1-ndm-4 tag).
Also try to add
CFLAGS += -fasynchronous-unwind-tables
чт, 17 июн. 2021 г. в 01:51, Story, Lenny <lst...@irobot.com>:
> Greetings,
>
> Thanks again for your detailed responses.
>
>
> Our system is indeed, MIPS + MUSL, and we rebuilt it with the options you
> provided. I am still at a loss as to why we only get 2 levels.
>
> I am attempting to overload "malloc" and get backtraces for when certain
> threads allocate memory. The interesting thing is that the 2 levels i am
> getting are "malloc" and my internal malloc which are located in the same
> file. I am not using LD_PRELOAD to do this, so the linked image has the
> internal malloc and not the MUSL one.
>
> Since this is an embedded linux system, i cant really run the image with
> full dwarf info, but rather a stripped one. I confirmed that the .eh_frame
> section is there, and not stripped.
>
> I enabled and set the UNW_DEBUG_LEVEL, the output is below.
>
> It appears to find the eh_frame data (i think), searches and finds on CIE,
> then stops. But i dont see an indication as to why it stopped.
>
> Is there anything you can discern from this trace that offers any clues ?
>
> Thanks Again,
> -Lenny
>
>
> My backtrace test print code :
> =========================================================
>
>
> #define BT_ARRAY_SIZE (10)
> void *bt[BT_ARRAY_SIZE];
> int Count;
>
> memset(&bt, 0, sizeof(bt));
> Count = unw_backtrace((void **)&bt, BT_ARRAY_SIZE);
>
> if(Count)
> {
> fprintf(stdout, "[ALLOC] Alloc : %d bytes : %d : %p,%p,%p,%p,%p,%p,%p
> \n",
> Size, Count, bt[0], bt[1], bt[2], bt[3], bt[4], bt[5], bt[6]);
> }
>
>
>
> My image shows the following sections :
> =======================================================
>
> There are 32 section headers, starting at offset 0x12ecbe8:
>
> Section Headers:
> [Nr] Name Type Addr Off Size ES Flg Lk
> Inf Al
> [ 0] NULL 00000000 000000 000000 00 0
> 0 0
> [ 1] .interp PROGBITS 00000174 000174 00000d 00 A 0
> 0 1
> [ 2] .MIPS.abiflags MIPS_ABIFLAGS 00000188 000188 000018 18 A 0
> 0 8
> [ 3] .note.gnu.build-i NOTE 000001a0 0001a0 000024 00 A 0
> 0 4
> [ 4] .dynamic DYNAMIC 000001c4 0001c4 000158 08 A 7
> 0 4
> [ 5] .hash HASH 0000031c 00031c 016da8 04 A 6
> 0 4
> [ 6] .dynsym DYNSYM 000170c4 0170c4 0476d0 10 A 7
> 2 4
> [ 7] .dynstr STRTAB 0005e794 05e794 1bf709 00 A 0
> 0 1
> [ 8] .gnu.version VERSYM 0021de9e 21de9e 008eda 02 A 6
> 0 2
> [ 9] .gnu.version_r VERNEED 00226d78 226d78 0001b0 00 A 7
> 3 4
> [10] .rel.dyn REL 00226f28 226f28 031880 08 A 6
> 0 4
> [11] .init PROGBITS 00295b40 295b40 00001c 00 AX 0
> 0 4
> [12] .text PROGBITS 00295b60 295b60 dea060 00 AX 0
> 0 16
> [13] .MIPS.stubs PROGBITS 0107fbc0 107fbc0 001680 00 AX 0
> 0 4
> [14] .fini PROGBITS 01081240 1081240 00001c 00 AX 0
> 0 4
> [15] .rodata PROGBITS 01081260 1081260 10d1f0 00 A 0
> 0 16
> [16] .eh_frame_hdr PROGBITS 0118e450 118e450 017ae4 00 A 0
> 0 4
> [17] .eh_frame PROGBITS 011b6000 11a6000 0da0e0 00 WA 0
> 0 4
> [18] .gcc_except_table PROGBITS 012900e0 12800e0 03383f 00 WA 0
> 0 4
> [19] .init_array INIT_ARRAY 012c3920 12b3920 000bec 04 WA 0
> 0 4
> [20] .fini_array FINI_ARRAY 012c450c 12b450c 000004 04 WA 0
> 0 4
> [21] .data.rel.ro PROGBITS 012c4510 12b4510 021bbc 00 WA
> 0 0 8
> [22] .data PROGBITS 012e60d0 12d60d0 002860 00 WA 0
> 0 16
> [23] .rld_map PROGBITS 012e8930 12d8930 000004 00 WA 0
> 0 4
> [24] .got PROGBITS 012e8940 12d8940 014148 04 WAp 0
> 0 16
> [25] .sdata PROGBITS 012fca88 12eca88 000004 00 WAp 0
> 0 4
> [26] .sbss NOBITS 012fca8c 12eca8c 000014 00 WAp 0
> 0 4
> [27] .bss NOBITS 012fcaa0 12eca8c 0dc0ac 00 WA 0
> 0 16
> [28] .comment PROGBITS 00000000 12eca8c 000011 01 MS 0
> 0 1
> [29] .gnu.attributes GNU_ATTRIBUTES 00000000 12eca9d 000010 00 0
> 0 1
> [30] .mdebug.abi32 PROGBITS 00000000 12ecaad 000000 00 0
> 0 1
> [31] .shstrtab STRTAB 00000000 12ecaad 00013b 00 0
> 0 1
> Key to Flags:
> W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
> L (link order), O (extra OS processing required), G (group), T (TLS),
> C (compressed), x (unknown), o (OS specific), E (exclude),
> p (processor specific)
>
>
>
> Enabling libunwind debug (Level=20) :
> =======================================================
>
>
> >unw_init_local_common: (cursor=0x775b7328)
> >unw_init_local_common: (cursor=0x775b3328)
> >access_mem: mem[55e737a0] -> 2002825
> >get_rs_cache: acquiring lock
> >put_rs_cache: unmasking signals/interrupts and releasing
> lock
> >access_mem: mem[55869edc] -> 1040ffdf
> >get_rs_cache: acquiring lock
> >put_rs_cache: unmasking signals/interrupts and releasing
> lock
> >access_mem: mem[5586a100] -> 10400009
> >get_rs_cache: acquiring lock
> >_ULmips_dwarf_find_proc_info: looking for IP=0x5586a0fb
> >_ULmips_dwarf_callback: checking /opt/app/bin/myapp,
> base=0x555d3000)
> >_ULmips_dwarf_callback: found table `/opt/app/bin/myapp':
> segbase=0x56761450, len=24246, gp=0x12e8940, table_data=0x5676145c
> >lookup: e->start_ip_offset = ff6015d8
> >lookup: e->start_ip_offset = ff327780
> >lookup: e->start_ip_offset = ff1f9fc4
> >lookup: e->start_ip_offset = ff1780f4
> >lookup: e->start_ip_offset = ff148794
> >lookup: e->start_ip_offset = ff12bcf8
> >lookup: e->start_ip_offset = ff11ddc8
> >lookup: e->start_ip_offset = ff113068
> >lookup: e->start_ip_offset = ff10aa00
> >lookup: e->start_ip_offset = ff108b38
> >lookup: e->start_ip_offset = ff109a98
> >lookup: e->start_ip_offset = ff1092c8
> >lookup: e->start_ip_offset = ff108f70
> >lookup: e->start_ip_offset = ff108bb0
> >_ULmips_dwarf_search_unwind_table: ip=0x5586a0fb,
> start_ip=0xff108bb0
> >_ULmips_dwarf_search_unwind_table: e->fde_offset = 27ebc, segbase =
> 56761450, debug_frame_base = 0, fde_addr = 5678930c
> >_ULmips_dwarf_extract_proc_info_from_fde: FDE @ 0x5678930c
> >_ULmips_dwarf_extract_proc_info_from_fde: looking for CIE
> at address 56789000
> >parse_cie: CIE parsed OK, augmentation = "zR", handler=0x0
> >_ULmips_dwarf_extract_proc_info_from_fde: FDE covers IP
> 0x5586a000-0x5586a0b0, LSDA=0x0
> >put_rs_cache: unmasking signals/interrupts and releasing
> lock
>
> [ALLOC] Alloc : 35 bytes : 2 : 0x55869ed8,0x5586a0fc,0,0,0,0,0
>
>
> ------------------------------
> *From:* Sergey Korolev <s.koro...@ndmsystems.com>
> *Sent:* Monday, June 14, 2021 5:34 PM
> *To:* Story, Lenny <lst...@irobot.com>
> *Cc:* libunwind-devel@nongnu.org <libunwind-devel@nongnu.org>
> *Subject:* Re: MIPS unwind only backtraces 2 local levels...
>
> You should build your sources with
>
> CFLAGS += -g1 -fno-omit-frame-pointer ...
> LDFLAGS += -g1 -fno-omit-frame-pointer ... (if you are using LTO)
>
> and then split executables (and libraries) to files with DWARF unwind
> tables
> and files with debug symbols only; for each {executable}:
>
> objcopy --only-keep-debug .../root/{executable}
> .../root/usr/lib/debug/{executable}.debug
> objcopy --strip-debug .../root/{executable}
> objcopy --add-gnu-debuglink=.../root/usr/lib/debug/{executable}.debug
> {executable}
>
> where {executable} is a relative root path to a binary file (/usr/bin/exe
> for example).
> You may not copy /usr/lib/debug to a target rootfs but use it to translate
> addresses to symbols on a host.
>
> Check also that you built all linked libraries (including libc) with -g1
> and -fno-omit-frame-pointer
> to get full traces.
>
> If you are using musl for MIPS, make sure you have a patch adding CFI
> directives to assembler sources.
> For example
> https://github.com/keenetic/musl/commit/ee63340090e3261d04bc7e664f352a7e7dd1c32f
> <https://urldefense.com/v3/__https://github.com/keenetic/musl/commit/ee63340090e3261d04bc7e664f352a7e7dd1c32f__;!!LUQzY6E!46-3jfDsccbzlAz7QLXrOjIHdsWw_d6A6yZPzsPgTs9IjgHK2g6XemqCnE88wg$>
> (based on
> http://lists.openwrt.org/pipermail/openwrt-devel/2020-June/029807.html
> <https://urldefense.com/v3/__http://lists.openwrt.org/pipermail/openwrt-devel/2020-June/029807.html__;!!LUQzY6E!46-3jfDsccbzlAz7QLXrOjIHdsWw_d6A6yZPzsPgTs9IjgHK2g6Xempw6UDApA$>
> ).
>
> On Mon, Jun 14, 2021 at 10:29 PM Story, Lenny <lst...@irobot.com> wrote:
>
> Greetings,
>
> The backtraces on my MIPS target are only going two levels, which happen
> to be declared inside my local file.
>
> Because of its size, the target is stripped of the dwarf .debug_ *
> seconds, and the .symtab. Its just too big to load with symbols included.
> I am only looking to get the frame addresses from the target, and plan on
> performing the symbol resolution off target.
>
> What should I look for in trying to see the trace back to main ?
>
> Thanks !
> -Lenny
>
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