The pintosm from ryanphuang

Booting fails due to 'struct integer_base' in stdio.c

First, thank you very much for your work. I found it is really helpful.

Symptom

On this command,

PintosM/src/threads $ make qemu-nox

I cannot get 'boot complete' sign. It just loops forever like this:

(...)
Pintos hda1
Loading............
Kernel command line:
Pintos booting with Pintos hda1
Loading............
Kernel command line:
Pintos booting with Pintos hda1
Loading............
Kernel command line:
Pintos booting with Pintos hda1
Loading............
(...)

Reason of the Symptom

After some debugging using gdb, I found running pintos on qemu makes error on formatting integer on printf function, for example in upper case, this line does not work properly:

PintosM/src/threads/init.c

Line 94 in a19f2a6

printf ("Pintos booting with %'"PRIu32" kB RAM...\n",

And with even more debugging, I found struct integer_base base_* variables in PintosM/src/lib/stdio.c is assigned but do not have desired value in runtime.

They are defined like this in PintosM/src/lib/stdio.c:

struct integer_base 
  {
    int base;                   /* Base. */
    const char *digits;         /* Collection of digits. */
    int x;                      /* `x' character to use, for base 16 only. */
    int group;                  /* Number of digits to group with ' flag. */
  };

static const struct integer_base base_d = {10, "0123456789", 0, 3};
static const struct integer_base base_o = {8, "01234567", 0, 3};
static const struct integer_base base_x = {16, "0123456789abcdef", 'x', 4};
static const struct integer_base base_X = {16, "0123456789ABCDEF", 'X', 4};

But in runtime, using gdb:

 (gdb) l
 469     static void
 470     format_integer (uintmax_t value, bool is_signed, bool negative,
 471                     const struct integer_base *b,
 472                     const struct printf_conversion *c,
 473                     void (*output) (char, void *), void *aux)
 474     {
 475       char buf[64], *cp;            /* Buffer and current position. */
 476       int x;                        /* `x' character to use or 0 if none. */
 477       int sign;                     /* Sign character or 0 if none. */
 478       int precision;                /* Rendered precision. */
 (gdb) bt
 #0  format_integer (value=3968, is_signed=is_signed@entry=false, negative=false, b=0xc0039550 <base_d>, c=0xc000ef20, output=0xc002a41d <vprintf_helper>,
     aux=0xc000ef6c) at ../../lib/stdio.c:474
 #1  0xc002700c in __vprintf (format=<optimized out>, args=0xc000efa8 200226003300217004002300304, <incomplete sequence \357>,
     output=<optimized out>, aux=<optimized out>) at ../../lib/stdio.c:279
 #2  0xc002a575 in vprintf (format=0xc002e36c Pintos booting with %u kB RAM...\n", args=0xc000efa4 "\200\017") at ../../lib/kernel/console.c:131
 #3  0xc00268e8 in printf (format=0xc002e36c "Pintos booting with %u kB RAM...n) at ../../lib/stdio.c:85
 #4  0xc00204c0 in pintos_init () at ../../threads/init.c:94
 #5  0xc002015d in start () at ../../threads/start.S:180
 (gdb) p *b
  = {base = 0, digits = 0x0, x = 0, group = 0}
 (gdb) p base_d
  = {base = 0, digits = 0x0, x = 0, group = 0}

base_d is set to zero in runtime, and others too, which yields 'division by 0' error.

I don't know why this happened, and want to fix it properly. My guess is that the bug is from outside of the stdio.c (like assembly codes?) but not sure.

There is a simple work-around which ignores all printf function calls, with which I can successfully boot pintos, but I want to resolve this issue fundamentally.

test environment

$ uname -a
Linux ub-Virtual-Machine 4.15.0-45-generic #48-Ubuntu SMP Tue Jan 29 16:28:13 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

$ cat /etc/os-release 
NAME="Ubuntu"
VERSION="18.04.1 LTS (Bionic Beaver)"
(...)
 
$ gcc --version
gcc (Ubuntu 7.3.0-27ubuntu1~18.04) 7.3.0
(...)
 
$ objdump -i | grep elf32-i386
elf32-i386
         elf64-x86-64 elf32-i386 elf32-iamcu elf32-x86-64 a.out-i386-linux
    i386 elf64-x86-64 elf32-i386 ----------- elf32-x86-64 a.out-i386-linux
 
$ qemu-system-i386 --version
QEMU emulator version 2.11.1(Debian 1:2.11+dfsg-1ubuntu7.9)
Copyright (c) 2003-2017 Fabrice Bellard and the QEMU Project developers

It is ubuntu VM on windows, but the symptom was exactly same in another ubuntu 18.04 host PC.

ryanphuang / pintosm Goto Github PK

pintosm's People

Contributors

Stargazers

Watchers

pintosm's Issues

Booting fails due to 'struct integer_base' in stdio.c

Symptom

Reason of the Symptom

test environment

Recommend Projects

React

Vue.js

Typescript

TensorFlow

Django

Laravel

D3

Recommend Topics

javascript

web

server

Machine learning

Visualization

Game

Recommend Org

Facebook

Microsoft

Google

Alibaba

D3

Tencent