Release 4.10 lib/bug.c
/*
Generic support for BUG()
This respects the following config options:
CONFIG_BUG - emit BUG traps. Nothing happens without this.
CONFIG_GENERIC_BUG - enable this code.
CONFIG_GENERIC_BUG_RELATIVE_POINTERS - use 32-bit pointers relative to
the containing struct bug_entry for bug_addr and file.
CONFIG_DEBUG_BUGVERBOSE - emit full file+line information for each BUG
CONFIG_BUG and CONFIG_DEBUG_BUGVERBOSE are potentially user-settable
(though they're generally always on).
CONFIG_GENERIC_BUG is set by each architecture using this code.
To use this, your architecture must:
1. Set up the config options:
- Enable CONFIG_GENERIC_BUG if CONFIG_BUG
2. Implement BUG (and optionally BUG_ON, WARN, WARN_ON)
- Define HAVE_ARCH_BUG
- Implement BUG() to generate a faulting instruction
- NOTE: struct bug_entry does not have "file" or "line" entries
when CONFIG_DEBUG_BUGVERBOSE is not enabled, so you must generate
the values accordingly.
3. Implement the trap
- In the illegal instruction trap handler (typically), verify
that the fault was in kernel mode, and call report_bug()
- report_bug() will return whether it was a false alarm, a warning,
or an actual bug.
- You must implement the is_valid_bugaddr(bugaddr) callback which
returns true if the eip is a real kernel address, and it points
to the expected BUG trap instruction.
Jeremy Fitzhardinge <jeremy@goop.org> 2006
*/
#define pr_fmt(fmt) fmt
#include <linux/list.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/bug.h>
#include <linux/sched.h>
extern const struct bug_entry __start___bug_table[], __stop___bug_table[];
static inline unsigned long bug_addr(const struct bug_entry *bug)
{
#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
return bug->bug_addr;
#else
return (unsigned long)bug + bug->bug_addr_disp;
#endif
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| jan beulich | jan beulich | 37 | 100.00% | 1 | 100.00% |
| Total | 37 | 100.00% | 1 | 100.00% |
#ifdef CONFIG_MODULES
/* Updates are protected by module mutex */
static LIST_HEAD(module_bug_list);
static const struct bug_entry *module_find_bug(unsigned long bugaddr)
{
struct module *mod;
const struct bug_entry *bug = NULL;
rcu_read_lock_sched();
list_for_each_entry_rcu(mod, &module_bug_list, bug_list) {
unsigned i;
bug = mod->bug_table;
for (i = 0; i < mod->num_bugs; ++i, ++bug)
if (bugaddr == bug_addr(bug))
goto out;
}
bug = NULL;
out:
rcu_read_unlock_sched();
return bug;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| jeremy fitzhardinge | jeremy fitzhardinge | 57 | 63.33% | 1 | 25.00% |
| masami hiramatsu | masami hiramatsu | 28 | 31.11% | 1 | 25.00% |
| jan beulich | jan beulich | 3 | 3.33% | 1 | 25.00% |
| peter zijlstra | peter zijlstra | 2 | 2.22% | 1 | 25.00% |
| Total | 90 | 100.00% | 4 | 100.00% |
void module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
struct module *mod)
{
char *secstrings;
unsigned int i;
lockdep_assert_held(&module_mutex);
mod->bug_table = NULL;
mod->num_bugs = 0;
/* Find the __bug_table section, if present */
secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
for (i = 1; i < hdr->e_shnum; i++) {
if (strcmp(secstrings+sechdrs[i].sh_name, "__bug_table"))
continue;
mod->bug_table = (void *) sechdrs[i].sh_addr;
mod->num_bugs = sechdrs[i].sh_size / sizeof(struct bug_entry);
break;
}
/*
* Strictly speaking this should have a spinlock to protect against
* traversals, but since we only traverse on BUG()s, a spinlock
* could potentially lead to deadlock and thus be counter-productive.
* Thus, this uses RCU to safely manipulate the bug list, since BUG
* must run in non-interruptive state.
*/
list_add_rcu(&mod->bug_list, &module_bug_list);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| jeremy fitzhardinge | jeremy fitzhardinge | 134 | 93.71% | 1 | 25.00% |
| peter zijlstra | peter zijlstra | 6 | 4.20% | 1 | 25.00% |
| masami hiramatsu | masami hiramatsu | 2 | 1.40% | 1 | 25.00% |
| linus torvalds | linus torvalds | 1 | 0.70% | 1 | 25.00% |
| Total | 143 | 100.00% | 4 | 100.00% |
void module_bug_cleanup(struct module *mod)
{
lockdep_assert_held(&module_mutex);
list_del_rcu(&mod->bug_list);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| jeremy fitzhardinge | jeremy fitzhardinge | 17 | 70.83% | 1 | 33.33% |
| peter zijlstra | peter zijlstra | 6 | 25.00% | 1 | 33.33% |
| masami hiramatsu | masami hiramatsu | 1 | 4.17% | 1 | 33.33% |
| Total | 24 | 100.00% | 3 | 100.00% |
#else
static inline const struct bug_entry *module_find_bug(unsigned long bugaddr)
{
return NULL;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| jeremy fitzhardinge | jeremy fitzhardinge | 17 | 100.00% | 1 | 100.00% |
| Total | 17 | 100.00% | 1 | 100.00% |
#endif
const struct bug_entry *find_bug(unsigned long bugaddr)
{
const struct bug_entry *bug;
for (bug = __start___bug_table; bug < __stop___bug_table; ++bug)
if (bugaddr == bug_addr(bug))
return bug;
return module_find_bug(bugaddr);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| jeremy fitzhardinge | jeremy fitzhardinge | 46 | 93.88% | 1 | 50.00% |
| jan beulich | jan beulich | 3 | 6.12% | 1 | 50.00% |
| Total | 49 | 100.00% | 2 | 100.00% |
enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs)
{
const struct bug_entry *bug;
const char *file;
unsigned line, warning;
if (!is_valid_bugaddr(bugaddr))
return BUG_TRAP_TYPE_NONE;
bug = find_bug(bugaddr);
file = NULL;
line = 0;
warning = 0;
if (bug) {
#ifdef CONFIG_DEBUG_BUGVERBOSE
#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
file = bug->file;
#else
file = (const char *)bug + bug->file_disp;
#endif
line = bug->line;
#endif
warning = (bug->flags & BUGFLAG_WARNING) != 0;
}
if (warning) {
/* this is a WARN_ON rather than BUG/BUG_ON */
__warn(file, line, (void *)bugaddr, BUG_GET_TAINT(bug), regs,
NULL);
return BUG_TRAP_TYPE_WARN;
}
printk(KERN_DEFAULT "------------[ cut here ]------------\n");
if (file)
pr_crit("kernel BUG at %s:%u!\n", file, line);
else
pr_crit("Kernel BUG at %p [verbose debug info unavailable]\n",
(void *)bugaddr);
return BUG_TRAP_TYPE_BUG;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| jeremy fitzhardinge | jeremy fitzhardinge | 135 | 74.18% | 1 | 10.00% |
| jan beulich | jan beulich | 20 | 10.99% | 1 | 10.00% |
| anton blanchard | anton blanchard | 6 | 3.30% | 1 | 10.00% |
| josh poimboeuf | josh poimboeuf | 5 | 2.75% | 1 | 10.00% |
| heiko carstens | heiko carstens | 5 | 2.75% | 1 | 10.00% |
| ben hutchings | ben hutchings | 4 | 2.20% | 1 | 10.00% |
| fabian frederick | fabian frederick | 3 | 1.65% | 1 | 10.00% |
| paul mundt | paul mundt | 2 | 1.10% | 1 | 10.00% |
| prarit bhargava | prarit bhargava | 1 | 0.55% | 1 | 10.00% |
| rusty russell | rusty russell | 1 | 0.55% | 1 | 10.00% |
| Total | 182 | 100.00% | 10 | 100.00% |
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| jeremy fitzhardinge | jeremy fitzhardinge | 438 | 74.36% | 1 | 7.14% |
| jan beulich | jan beulich | 64 | 10.87% | 1 | 7.14% |
| masami hiramatsu | masami hiramatsu | 31 | 5.26% | 1 | 7.14% |
| peter zijlstra | peter zijlstra | 14 | 2.38% | 1 | 7.14% |
| fabian frederick | fabian frederick | 10 | 1.70% | 1 | 7.14% |
| heiko carstens | heiko carstens | 8 | 1.36% | 1 | 7.14% |
| anton blanchard | anton blanchard | 6 | 1.02% | 1 | 7.14% |
| paul mundt | paul mundt | 5 | 0.85% | 1 | 7.14% |
| josh poimboeuf | josh poimboeuf | 5 | 0.85% | 1 | 7.14% |
| ben hutchings | ben hutchings | 4 | 0.68% | 1 | 7.14% |
| rusty russell | rusty russell | 2 | 0.34% | 2 | 14.29% |
| linus torvalds | linus torvalds | 1 | 0.17% | 1 | 7.14% |
| prarit bhargava | prarit bhargava | 1 | 0.17% | 1 | 7.14% |
| Total | 589 | 100.00% | 14 | 100.00% |
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