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oslib-posix: add a configure switch to debug stack usage

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this adds a knob to track the maximum stack usage of stacks
created by qemu_alloc_stack.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Peter Lieven 2016-09-27 11:58:45 +02:00 • committed by Kevin Wolf
parent 2f4aa23299
commit 7d992e4d5a
2 changed files with 54 additions and 0 deletions
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35
util/oslib-posix.c
View file

@ -50,6 +50,10 @@
#include "qemu/mmap-alloc.h"
#ifdef CONFIG_DEBUG_STACK_USAGE
#include "qemu/error-report.h"
#endif
int qemu_get_thread_id(void)
{
#if defined(__linux__)
@ -503,6 +507,9 @@ pid_t qemu_fork(Error **errp)
void *qemu_alloc_stack(size_t *sz)
{
void *ptr, *guardpage;
#ifdef CONFIG_DEBUG_STACK_USAGE
void *ptr2;
#endif
size_t pagesz = getpagesize();
#ifdef _SC_THREAD_STACK_MIN
/* avoid stacks smaller than _SC_THREAD_STACK_MIN */
@ -534,10 +541,38 @@ void *qemu_alloc_stack(size_t *sz)
abort();
}
#ifdef CONFIG_DEBUG_STACK_USAGE
for (ptr2 = ptr + pagesz; ptr2 < ptr + *sz; ptr2 += sizeof(uint32_t)) {
*(uint32_t *)ptr2 = 0xdeadbeaf;
}
#endif
return ptr;
}
#ifdef CONFIG_DEBUG_STACK_USAGE
static __thread unsigned int max_stack_usage;
#endif
void qemu_free_stack(void *stack, size_t sz)
{
#ifdef CONFIG_DEBUG_STACK_USAGE
unsigned int usage;
void *ptr;
for (ptr = stack + getpagesize(); ptr < stack + sz;
ptr += sizeof(uint32_t)) {
if (*(uint32_t *)ptr != 0xdeadbeaf) {
break;
}
}
usage = sz - (uintptr_t) (ptr - stack);
if (usage > max_stack_usage) {
error_report("thread %d max stack usage increased from %u to %u",
qemu_get_thread_id(), max_stack_usage, usage);
max_stack_usage = usage;
}
#endif
munmap(stack, sz);
}