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[PATCH] lockdep: i386 remove multi entry backtraces

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Remove CONFIG_STACK_BACKTRACE_COLS.

This feature didnt work out: instead of making kernel debugging more
efficient, it produces much harder to read stacktraces!  Check out this trace
for example:

  http://static.flickr.com/47/158326090_35d0129147_b_d.jpg

That backtrace could have been printed much nicer as a one-entry-per-line
thing, taking the same amount of screen real-estate.

Plus we remove 30 lines of kernel code as well.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Ingo Molnar 2006-07-03 00:24:37 -07:00 • committed by Linus Torvalds
parent c9ca1ba5bd
commit f0a5c315eb
2 changed files with 9 additions and 39 deletions
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9
arch/i386/Kconfig.debug
View file

@ -31,15 +31,6 @@ config DEBUG_STACK_USAGE
This option will slow down process creation somewhat. This option will slow down process creation somewhat.
config STACK_BACKTRACE_COLS
int "Stack backtraces per line" if DEBUG_KERNEL
range 1 3
default 2
help
Selects how many stack backtrace entries per line to display.
This can save screen space when displaying traces.
comment "Page alloc debug is incompatible with Software Suspend on i386" comment "Page alloc debug is incompatible with Software Suspend on i386"
depends on DEBUG_KERNEL && SOFTWARE_SUSPEND depends on DEBUG_KERNEL && SOFTWARE_SUSPEND

39
arch/i386/kernel/traps.c
View file

@ -115,28 +115,13 @@ static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
} }
/* /*
* Print CONFIG_STACK_BACKTRACE_COLS address/symbol entries per line. * Print one address/symbol entries per line.
*/ */
static inline int print_addr_and_symbol(unsigned long addr, char *log_lvl, static inline void print_addr_and_symbol(unsigned long addr, char *log_lvl)
int printed)
{ {
if (!printed)
printk(log_lvl);
#if CONFIG_STACK_BACKTRACE_COLS == 1
printk(" [<%08lx>] ", addr); printk(" [<%08lx>] ", addr);
#else
printk(" <%08lx> ", addr);
#endif
print_symbol("%s", addr);
printed = (printed + 1) % CONFIG_STACK_BACKTRACE_COLS; print_symbol("%s\n", addr);
if (printed)
printk(" ");
else
printk("\n");
return printed;
} }
static inline unsigned long print_context_stack(struct thread_info *tinfo, static inline unsigned long print_context_stack(struct thread_info *tinfo,
@ -144,12 +129,11 @@ static inline unsigned long print_context_stack(struct thread_info *tinfo,
char *log_lvl) char *log_lvl)
{ {
unsigned long addr; unsigned long addr;
int printed = 0; /* nr of entries already printed on current line */
#ifdef CONFIG_FRAME_POINTER #ifdef CONFIG_FRAME_POINTER
while (valid_stack_ptr(tinfo, (void *)ebp)) { while (valid_stack_ptr(tinfo, (void *)ebp)) {
addr = *(unsigned long *)(ebp + 4); addr = *(unsigned long *)(ebp + 4);
printed = print_addr_and_symbol(addr, log_lvl, printed); print_addr_and_symbol(addr, log_lvl);
/* /*
* break out of recursive entries (such as * break out of recursive entries (such as
* end_of_stack_stop_unwind_function): * end_of_stack_stop_unwind_function):
@ -162,28 +146,23 @@ static inline unsigned long print_context_stack(struct thread_info *tinfo,
while (valid_stack_ptr(tinfo, stack)) { while (valid_stack_ptr(tinfo, stack)) {
addr = *stack++; addr = *stack++;
if (__kernel_text_address(addr)) if (__kernel_text_address(addr))
printed = print_addr_and_symbol(addr, log_lvl, printed); print_addr_and_symbol(addr, log_lvl);
} }
#endif #endif
if (printed)
printk("\n");
return ebp; return ebp;
} }
static asmlinkage int show_trace_unwind(struct unwind_frame_info *info, void *log_lvl) static asmlinkage int
show_trace_unwind(struct unwind_frame_info *info, void *log_lvl)
{ {
int n = 0; int n = 0;
int printed = 0; /* nr of entries already printed on current line */
while (unwind(info) == 0 && UNW_PC(info)) { while (unwind(info) == 0 && UNW_PC(info)) {
++n; n++;
printed = print_addr_and_symbol(UNW_PC(info), log_lvl, printed); print_addr_and_symbol(UNW_PC(info), log_lvl);
if (arch_unw_user_mode(info)) if (arch_unw_user_mode(info))
break; break;
} }
if (printed)
printk("\n");
return n; return n;
} }