The patch titled
Add generic exit-time stack-depth checking to CONFIG_DEBUG_STACK_USAGE
has been added to the -mm tree. Its filename is
add-generic-exit-time-stack-depth-checking-to-config_debug_stack_usage.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: Add generic exit-time stack-depth checking to CONFIG_DEBUG_STACK_USAGE
From: Jeff Dike <jdike@xxxxxxxxxxx>
Add generic exit-time stack-depth checking to CONFIG_DEBUG_STACK_USAGE.
This also adds UML support.
Tested on UML and i386.
Signed-off-by: Jeff Dike <jdike@xxxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/um/Kconfig.debug | 9 +++++++++
arch/um/defconfig | 1 +
include/asm-um/thread_info.h | 9 +++++++++
kernel/exit.c | 24 ++++++++++++++++++++++++
4 files changed, 43 insertions(+)
diff -puN arch/um/Kconfig.debug~add-generic-exit-time-stack-depth-checking-to-config_debug_stack_usage arch/um/Kconfig.debug
--- a/arch/um/Kconfig.debug~add-generic-exit-time-stack-depth-checking-to-config_debug_stack_usage
+++ a/arch/um/Kconfig.debug
@@ -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
diff -puN arch/um/defconfig~add-generic-exit-time-stack-depth-checking-to-config_debug_stack_usage arch/um/defconfig
--- a/arch/um/defconfig~add-generic-exit-time-stack-depth-checking-to-config_debug_stack_usage
+++ a/arch/um/defconfig
@@ -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
diff -puN include/asm-um/thread_info.h~add-generic-exit-time-stack-depth-checking-to-config_debug_stack_usage include/asm-um/thread_info.h
--- a/include/asm-um/thread_info.h~add-generic-exit-time-stack-depth-checking-to-config_debug_stack_usage
+++ a/include/asm-um/thread_info.h
@@ -52,10 +52,19 @@ static inline struct thread_info *curren
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)
diff -puN kernel/exit.c~add-generic-exit-time-stack-depth-checking-to-config_debug_stack_usage kernel/exit.c
--- a/kernel/exit.c~add-generic-exit-time-stack-depth-checking-to-config_debug_stack_usage
+++ a/kernel/exit.c
@@ -868,6 +868,27 @@ static void exit_notify(struct task_stru
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), free;
+
+ while (*n == 0)
+ n++;
+ free = (unsigned long)n - (unsigned long)end_of_stack(current);
+
+ spin_lock(&low_water_lock);
+ if (free < lowest_to_date) {
+ printk(KERN_WARNING "Greatest stack depth - %ld bytes left\n",
+ free);
+ lowest_to_date = free;
+ }
+ spin_unlock(&low_water_lock);
+}
+#endif
+
fastcall NORET_TYPE void do_exit(long code)
{
struct task_struct *tsk = current;
@@ -959,6 +980,9 @@ fastcall NORET_TYPE void do_exit(long co
exit_sem(tsk);
__exit_files(tsk);
__exit_fs(tsk);
+#ifdef CONFIG_DEBUG_STACK_USAGE
+ check_stack_usage();
+#endif
exit_thread();
cpuset_exit(tsk);
exit_keys(tsk);
_
Patches currently in -mm which might be from jdike@xxxxxxxxxxx are
hostfs-convert-to-new-aops.patch
uml-fix-request-sector-update.patch
uml-use-get_free_pages-to-allocate-kernel-stacks.patch
add-generic-exit-time-stack-depth-checking-to-config_debug_stack_usage.patch
add-generic-exit-time-stack-depth-checking-to-config_debug_stack_usage-fix.patch
uml-add-stack-usage-monitoring.patch
-
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
