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Add generic exit-time stack-depth checking to CONFIG_DEBUG_STACK_USAGE

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Add generic exit-time stack-depth checking to CONFIG_DEBUG_STACK_USAGE.

This also adds UML support.

Tested on UML and i386.

[akpm@linux-foundation.org: cleanups, speedups, tweaks]
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jeff Dike 2007-07-15 23:38:48 -07:00 committed by Linus Torvalds
parent 84812217e3
commit e18eecb8b3
4 changed files with 48 additions and 0 deletions
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9
arch/um/Kconfig.debug
View File

@ -47,4 +47,13 @@ config GCOV
If you're involved in UML kernel development and want to use gcov,
say Y. If you're unsure, say N.
config DEBUG_STACK_USAGE
bool "Stack utilization instrumentation"
default N
help
Track the maximum kernel stack usage - this will look at each
kernel stack at process exit and log it if it's the deepest
stack seen so far.
This option will slow down process creation and destruction somewhat.
endmenu

1
arch/um/defconfig
View File

@ -527,3 +527,4 @@ CONFIG_FORCED_INLINING=y
# CONFIG_RCU_TORTURE_TEST is not set
# CONFIG_GPROF is not set
# CONFIG_GCOV is not set
# CONFIG_DEBUG_STACK_USAGE is not set

9
include/asm-um/thread_info.h
View File

@ -52,10 +52,19 @@ static inline struct thread_info *current_thread_info(void)
return ti;
}
#ifdef CONFIG_DEBUG_STACK_USAGE
#define alloc_thread_info(tsk) \
((struct thread_info *) __get_free_pages(GFP_KERNEL | __GFP_ZERO, \
CONFIG_KERNEL_STACK_ORDER))
#else
/* thread information allocation */
#define alloc_thread_info(tsk) \
((struct thread_info *) __get_free_pages(GFP_KERNEL, \
CONFIG_KERNEL_STACK_ORDER))
#endif
#define free_thread_info(ti) \
free_pages((unsigned long)(ti),CONFIG_KERNEL_STACK_ORDER)

29
kernel/exit.c
View File

@ -858,6 +858,34 @@ static void exit_notify(struct task_struct *tsk)
release_task(tsk);
}
#ifdef CONFIG_DEBUG_STACK_USAGE
static void check_stack_usage(void)
{
static DEFINE_SPINLOCK(low_water_lock);
static int lowest_to_date = THREAD_SIZE;
unsigned long *n = end_of_stack(current);
unsigned long free;
while (*n == 0)
n++;
free = (unsigned long)n - (unsigned long)end_of_stack(current);
if (free >= lowest_to_date)
return;
spin_lock(&low_water_lock);
if (free < lowest_to_date) {
printk(KERN_WARNING "%s used greatest stack depth: %lu bytes "
"left\n",
current->comm, free);
lowest_to_date = free;
}
spin_unlock(&low_water_lock);
}
#else
static inline void check_stack_usage(void) {}
#endif
fastcall NORET_TYPE void do_exit(long code)
{
struct task_struct *tsk = current;
@ -949,6 +977,7 @@ fastcall NORET_TYPE void do_exit(long code)
exit_sem(tsk);
__exit_files(tsk);
__exit_fs(tsk);
check_stack_usage();
exit_thread();
cpuset_exit(tsk);
exit_keys(tsk);