---------- Forwarded message ---------- From: t cheney <cdmalord@xxxxxxxxx> Date: Sun, 11 Dec 2011 21:19:22 +0800 Subject: Re: [PATCH 1/1] x86: Add process memory layout to coredump file To: Andi Kleen <andi@xxxxxxxxxxxxxx> Cc: linux-kernel@xxxxxxxxxxxxxxx, viro@xxxxxxxxxxxxxxxxxx, linux-fsdevel@xxxxxxxxxxxxxxx This is readelf's patch which can retrieve maps in coredump file, and it is based on binutils-2.21.1. Usage: ./readelf -m coredumpfile https://github.com/cdma/coredumpmap/blob/dev/readelf.c https://github.com/cdma/coredumpmap/blob/dev/common.h Alternately, following is diff's result: changed files: ./binutils-2.21.1/binutils/readelf.c ./binutils-2.21.1/include/elf/common.h diff -u ./binutils-2.21.1/binutils/readelf.c ./binutils-2.21.1/binutils/readelf.c.orig --- ./binutils-2.21.1/binutils/readelf.c 2011-12-07 14:54:45.000000000 -0500 +++ ./binutils-2.21.1/binutils/readelf.c.orig 2011-12-07 14:53:43.000000000 -0500 @@ -196,7 +196,6 @@ static int do_notes; static int do_archive_index; static int is_32bit_elf; -static int do_maps; struct group_list { @@ -3072,7 +3071,6 @@ {"dyn-syms", no_argument, 0, OPTION_DYN_SYMS}, {"relocs", no_argument, 0, 'r'}, {"notes", no_argument, 0, 'n'}, - {"maps", no_argument, 0, 'm'}, {"dynamic", no_argument, 0, 'd'}, {"arch-specific", no_argument, 0, 'A'}, {"version-info", no_argument, 0, 'V'}, @@ -3112,7 +3110,6 @@ --symbols An alias for --syms\n\ --dyn-syms Display the dynamic symbol table\n\ -n --notes Display the core notes (if present)\n\ - -m --maps Display the core maps (if present)\n\ -r --relocs Display the relocations (if present)\n\ -u --unwind Display the unwind info (if present)\n\ -d --dynamic Display the dynamic section (if present)\n\ @@ -3231,7 +3228,7 @@ usage (stderr); while ((c = getopt_long - (argc, argv, "ADHINR:SVWacdeghi:lnp:rstuvw::x:m", options, NULL)) != EOF) + (argc, argv, "ADHINR:SVWacdeghi:lnp:rstuvw::x:", options, NULL)) != EOF) { switch (c) { @@ -3354,9 +3351,6 @@ case 'W': do_wide++; break; - case 'm': - do_maps++; - break; default: /* xgettext:c-format */ error (_("Invalid option '-%c'\n"), c); @@ -3370,7 +3364,7 @@ && !do_segments && !do_header && !do_dump && !do_version && !do_histogram && !do_debugging && !do_arch && !do_notes && !do_section_groups && !do_archive_index - && !do_dyn_syms && !do_maps) + && !do_dyn_syms) usage (stderr); else if (argc < 3) { @@ -11855,8 +11849,6 @@ return _("NT_LWPSINFO (lwpsinfo_t structure)"); case NT_WIN32PSTATUS: return _("NT_WIN32PSTATUS (win32_pstatus structure)"); - case NT_MAPS: - return _("NT_MAPS (maps info)"); default: break; } @@ -11970,9 +11962,6 @@ { const char * name = pnote->namesz ? pnote->namedata : "(NONE)"; const char * nt; - - if (do_maps && pnote->type != NT_MAPS) - return 0; if (pnote->namesz == 0) /* If there is no note name, then use the default set of @@ -12000,13 +11989,6 @@ nt = get_note_type (pnote->type); printf (" %s\t\t0x%08lx\t%s\n", name, pnote->descsz, nt); - if (do_maps && pnote->type == NT_MAPS) - { - pnote->descdata[pnote->descsz] = 0; - printf("Maps is following:\n"); - printf("%s\n",pnote->descdata); - } - return 1; } @@ -12093,6 +12075,7 @@ } res &= process_note (& inote); + if (temp != NULL) { free (temp); @@ -12150,7 +12133,7 @@ process_notes (FILE * file) { /* If we have not been asked to display the notes then do nothing. */ - if (! do_notes && !do_maps) + if (! do_notes) return 1; if (elf_header.e_type != ET_CORE) diff -u ./binutils-2.21.1/include/elf/common.h ./binutils-2.21.1/include/elf/common.h.orig --- ./binutils-2.21.1/include/elf/common.h 2011-12-07 14:56:02.000000000 -0500 +++ ./binutils-2.21.1/include/elf/common.h.orig 2011-12-07 14:55:45.000000000 -0500 @@ -518,7 +518,6 @@ #define NT_PRPSINFO 3 /* Contains copy of prpsinfo struct */ #define NT_TASKSTRUCT 4 /* Contains copy of task struct */ #define NT_AUXV 6 /* Contains copy of Elfxx_auxv_t */ -#define NT_MAPS 7 /* Contains copy of maps*/ #define NT_PRXFPREG 0x46e62b7f /* Contains a user_xfpregs_struct; */ /* note name must be "LINUX". */ #define NT_PPC_VMX 0x100 /* PowerPC Altivec/VMX registers */ On 12/11/11, t cheney <cdmalord@xxxxxxxxx> wrote: > On 12/11/11, Andi Kleen <andi@xxxxxxxxxxxxxx> wrote: >> t cheney <cdmalord@xxxxxxxxx> writes: >> >>> This patch just add memory layout(same as /proc/pid/maps) to >>> coredump file. The layout is appended to corenote segment with >>> flag NT_MAPS=7. >> >> Seems like a reasonable idea, but can you please share code with >> the proc implementation? > Yes, I will post it in following mail. >> >> It's a bit unusal to have ASCII in a coredump, but I suppose expressing >> this in binary would be somewhat ugly. >> >>> + char *buf = notes->data; >>> + size_t core_limit = notes->datasz; >>> + gate_vma = get_gate_vma(current->mm); >>> + > The maps info is appended to core notes segment in which there are all > ASCII text such as regs,signal and thread info. >> >> It seems a bit dubious to do this without locking even in a core dump. >> >>> + for (vma = first_vma(current, gate_vma); vma != NULL; >>> + vma = next_vma(vma, gate_vma)) { >>> + flags = vma->vm_flags; >>> + maps_size += len; >>> + if (file) { >>> + if (maps_size > core_limit) >>> + break; >> >> You have a one-off bug here. Also below. >> >>> + DUMP_WRITE(buf, len, foffset); >>> + } >> > Because proceses that could change vma pages are blocked in do_exit, > here vma pages are safe. >> >> -Andi >> -- >> ak@xxxxxxxxxxxxxxx -- Speaking for myself only >> > -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
