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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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19
configure vendored
View File

@ -296,6 +296,7 @@ libiscsi=""
libnfs=""
coroutine=""
coroutine_pool=""
debug_stack_usage="no"
seccomp=""
glusterfs=""
glusterfs_xlator_opt="no"
@ -1004,6 +1005,8 @@ for opt do
;;
--enable-coroutine-pool) coroutine_pool="yes"
;;
--enable-debug-stack-usage) debug_stack_usage="yes"
;;
--disable-docs) docs="no"
;;
--enable-docs) docs="yes"
@ -4331,6 +4334,17 @@ if test "$coroutine" = "gthread" -a "$coroutine_pool" = "yes"; then
error_exit "'gthread' coroutine backend does not support pool (use --disable-coroutine-pool)"
fi
if test "$debug_stack_usage" = "yes"; then
if test "$cpu" = "ia64" -o "$cpu" = "hppa"; then
error_exit "stack usage debugging is not supported for $cpu"
fi
if test "$coroutine_pool" = "yes"; then
echo "WARN: disabling coroutine pool for stack usage debugging"
coroutine_pool=no
fi
fi
##########################################
# check if we have open_by_handle_at
@ -4916,6 +4930,7 @@ echo "QGA MSI support $guest_agent_msi"
echo "seccomp support $seccomp"
echo "coroutine backend $coroutine"
echo "coroutine pool $coroutine_pool"
echo "debug stack usage $debug_stack_usage"
echo "GlusterFS support $glusterfs"
echo "Archipelago support $archipelago"
echo "gcov $gcov_tool"
@ -5384,6 +5399,10 @@ else
echo "CONFIG_COROUTINE_POOL=0" >> $config_host_mak
fi
if test "$debug_stack_usage" = "yes" ; then
echo "CONFIG_DEBUG_STACK_USAGE=y" >> $config_host_mak
fi
if test "$open_by_handle_at" = "yes" ; then
echo "CONFIG_OPEN_BY_HANDLE=y" >> $config_host_mak
fi

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);
}