On Wed, Mar 25, 2015 at 08:03:31PM +0000, David Woodhouse wrote: > On Wed, 2015-03-25 at 19:45 +0000, Richard W.M. Jones wrote: > > On Wed, Mar 25, 2015 at 06:30:25PM +0000, David Woodhouse wrote: > > > If the compiler is single-threaded, and increasing the stack ulimit > > > fixes the problem, that implies that the default stack ulimit is less > > > than the 8MiB-64KiB that it takes to reach the guard page... > > > > Just so I'm clear, is the stack supposed to grow down automatically > > (ie. does the stack automatically use MAP_GROWSDOWN), or is OCaml > > supposed to do something when the stack hits the guard page? > > > > I guess it's also possible that an OCaml stack frame is so big that it > > skips the guard page, or that GCC does some kind of stack "filling" to > > trigger the guard page which OCaml does not do. > > This is easy to trigger, right? Can you catch it in gdb and 't a a bt' I won't bore you with the full stack trace, but the top and bottom and some interesting registers are below. It confirms a few things: - Stack is overflowing because of a highly recursive function (which does eventually bottom-out, if you give it a big enough stack). - Compiler is single threaded. - %r1 (at top) - %r1 (at bottom) is approximately 8 MB - Avg. size of each stack frame is ~ 168 bytes. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com Fedora Windows cross-compiler. Compile Windows programs, test, and build Windows installers. Over 100 libraries supported. http://fedoraproject.org/wiki/MinGW
GNU gdb (GDB) Fedora 7.7.1-17.fc20 Copyright (C) 2014 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "ppc64-redhat-linux-gnu". Type "show configuration" for configuration details. For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>. Find the GDB manual and other documentation resources online at: <http://www.gnu.org/software/gdb/documentation/>. For help, type "help". Type "apropos word" to search for commands related to "word"... Reading symbols from /home/rjones/local/bin/ocamlopt.opt...(no debugging symbols found)...done. [?1034h(gdb) run Starting program: /home/rjones/local/bin/ocamlopt.opt -c -g -w a -I camlp4/import -warn-error A-3 -I camlp4/config -I camlp4/boot -o camlp4/boot/camlp4boot.cmx camlp4/boot/camlp4boot.ml Program received signal SIGSEGV, Segmentation fault. 0x00000000100587cc in .camlCSEgen__compare_1011 () Missing separate debuginfos, use: debuginfo-install glibc-2.18-12.fc20.ppc64p7 (gdb) t a a bt Thread 1 (process 48132): #0 0x00000000100587cc in .camlCSEgen__compare_1011 () #1 0x0000000010007b48 in .caml_apply2 () #2 0x0000000010263e44 in .camlMap__find_1091 () #3 0x0000000010058d4c in .camlCSEgen__find_equation_1124 () #4 0x0000000010057624 in .camlCSEgen__fun_1397 () #5 0x0000000010007a84 in .caml_apply3 () #6 0x0000000010057c5c in .camlCSEgen__fun_1397 () #7 0x0000000010007a84 in .caml_apply3 () #8 0x0000000010057c5c in .camlCSEgen__fun_1397 () #9 0x0000000010007a84 in .caml_apply3 () #10 0x000000001005799c in .camlCSEgen__fun_1397 () [these two stack frames are repeated over and over] #49873 0x0000000010007a85 in .caml_apply3 () #49874 0x0000000010057d51 in .camlCSEgen__fun_1397 () #49875 0x0000000010007a85 in .caml_apply3 () #49876 0x0000000010057d51 in .camlCSEgen__fun_1397 () #49877 0x0000000010007a85 in .caml_apply3 () #49878 0x0000000010057315 in .camlCSEgen__fun_1406 () #49879 0x0000000010006a41 in .caml_send1 () #49880 0x0000000010059ea9 in .camlCSE__fundecl_1029 () #49881 0x000000001007c59d in .camlAsmgen__compile_fundecl_1050 () #49882 0x000000001007c895 in .camlAsmgen__compile_phrase_1053 () #49883 0x000000001007bbe9 in .camlAsmgen__fun_1285 () #49884 0x0000000010258a01 in .camlList__iter_1061 () #49885 0x000000001007bc2d in .camlAsmgen__fun_1290 () #49886 0x000000001007cc49 in .camlAsmgen__compile_implementation_1063 () #49887 0x0000000010082da9 in .camlOptcompile__fun_1274 () #49888 0x0000000010083525 in .camlOptcompile__comp_1048 () #49889 0x0000000010083de1 in .camlOptcompile__implementation_1040 () #49890 0x0000000010007cd9 in .camlOptmain__process_implementation_file_1011 () #49891 0x0000000010008445 in .camlOptmain__process_file_1016 () #49892 0x00000000100084c5 in .camlOptmain__anonymous_1022 () #49893 0x0000000010283ec5 in .camlArg__parse_argv_dynamic_1078 () #49894 0x0000000010284161 in .camlArg__parse_1140 () #49895 0x00000000100092bd in .camlOptmain__main_1474 () #49896 0x000000001000a785 in .camlOptmain__entry () #49897 0x0000000010003439 in caml_startup.code_begin () #49898 0x00000000102b633d in .caml_start_program () #49899 0x00000000102b6a30 in .caml_main () #49900 0x000000001029da60 in .main () (gdb) info registers r0 0x10007b48 268467016 r1 0x3fffff800030 70368735789104 r2 0x1048c4e0 273204448 r3 0x3fffb7fa8fc0 70367535861696 r4 0x3fffb7fa9810 70367535863824 r5 0x103a5f34 272260916 r6 0x5 5 r7 0x3fffb7d0f750 70367533135696 r8 0x1 1 r9 0x3fffb7fa8fd8 70367535861720 r10 0xc00 3072 r11 0x10007b18 268466968 r12 0x0 0 r13 0x803935c3e0 550715638752 r14 0x100587c4 268797892 r15 0x3fffb7fa8fc0 70367535861696 r16 0x800 2048 r17 0x1005737c 268792700 r18 0xc00 3072 r19 0x9 9 r20 0x3fffb7fa9268 70367535862376 r21 0x3fffb7fa9158 70367535862104 r22 0x3fffb7fa9120 70367535862048 r23 0x13 19 r24 0x13 19 r25 0x4c 76 r26 0x9 9 r27 0x3fffa63f3f18 70367238373144 r28 0x3fffb7fa9048 70367535861832 r29 0x3fffff8001e0 70368735789536 r30 0x3fffb7dd1000 70367533928448 r31 0x3fffb7fa8fb8 70367535861688 pc 0x100587cc 0x100587cc <.camlCSEgen__compare_1011+8> msr 0x900000000000d032 10376293541461676082 cr 0x22000824 570427428 lr 0x10007b48 0x10007b48 <.caml_apply2+48> ctr 0x100587c4 268797892 xer 0x20000000 536870912 orig_r3 0x10007b44 268467012 trap 0x300 768 (gdb) frame 49878 #49878 0x0000000010057315 in .camlCSEgen__fun_1406 () (gdb) info registers r0 0x10007b48 268467016 r1 0x3fffffffdbd0 70368744168400 r2 0x1048c4e0 273204448 r3 0x3fffb7fa8fc0 70367535861696 r4 0x3fffb7fa9810 70367535863824 r5 0x103a5f34 272260916 r6 0x5 5 r7 0x3fffb7d0f750 70367533135696 r8 0x1 1 r9 0x3fffb7fa8fd8 70367535861720 r10 0xc00 3072 r11 0x10007b18 268466968 r12 0x0 0 r13 0x803935c3e0 550715638752 r14 0x100587c4 268797892 r15 0x3fffb7fa8fc0 70367535861696 r16 0x800 2048 r17 0x1005737c 268792700 r18 0xc00 3072 r19 0x9 9 r20 0x3fffb7fa9268 70367535862376 r21 0x3fffb7fa9158 70367535862104 r22 0x3fffb7fa9120 70367535862048 r23 0x13 19 r24 0x13 19 r25 0x4c 76 r26 0x9 9 r27 0x3fffa63f3f18 70367238373144 r28 0x3fffb7fa9048 70367535861832 r29 0x3fffff8001e0 70368735789536 r30 0x3fffb7dd1000 70367533928448 r31 0x3fffb7fa8fb8 70367535861688 pc 0x10057315 0x10057315 <.camlCSEgen__fun_1406+69> msr 0x900000000000d032 10376293541461676082 cr 0x22000824 570427428 lr 0x10057315 0x10057315 <.camlCSEgen__fun_1406+69> ctr 0x100587c4 268797892 xer 0x20000000 536870912 orig_r3 0x10007b44 268467012 trap 0x300 768 (gdb) frame 49900 #49900 0x000000001029da60 in .main () (gdb) info registers r0 0x10007b48 268467016 r1 0x3fffffffed10 70368744172816 r2 0x1048c4e0 273204448 r3 0x3fffb7fa8fc0 70367535861696 r4 0x3fffb7fa9810 70367535863824 r5 0x103a5f34 272260916 r6 0x5 5 r7 0x3fffb7d0f750 70367533135696 r8 0x1 1 r9 0x3fffb7fa8fd8 70367535861720 r10 0xc00 3072 r11 0x10007b18 268466968 r12 0x0 0 r13 0x803935c3e0 550715638752 r14 0x100587c4 268797892 r15 0x3fffb7fa8fc0 70367535861696 r16 0x800 2048 r17 0x1005737c 268792700 r18 0xc00 3072 r19 0x9 9 r20 0x3fffb7fa9268 70367535862376 r21 0x3fffb7fa9158 70367535862104 r22 0x3fffb7fa9120 70367535862048 r23 0x0 0 r24 0x0 0 r25 0x0 0 r26 0x0 0 r27 0x803934fe00 550715588096 r28 0x8039350d18 550715591960 r29 0x803934f930 550715586864 r30 0x0 0 r31 0x0 0 pc 0x1029da60 0x1029da60 <.main+20> msr 0x900000000000d032 10376293541461676082 cr 0x22000824 570427428 lr 0x1029da60 0x1029da60 <.main+20> ctr 0x100587c4 268797892 xer 0x20000000 536870912 orig_r3 0x10007b44 268467012 trap 0x300 768 (gdb) quit A debugging session is active. Inferior 1 [process 48132] will be killed. Quit anyway? (y or n)
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