From 7d992e4d5a95d0b21c6c33bd32cef8671805e39b Mon Sep 17 00:00:00 2001 From: Peter Lieven Date: Tue, 27 Sep 2016 11:58:45 +0200 Subject: oslib-posix: add a configure switch to debug stack usage this adds a knob to track the maximum stack usage of stacks created by qemu_alloc_stack. Signed-off-by: Peter Lieven Signed-off-by: Kevin Wolf --- util/oslib-posix.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) (limited to 'util') diff --git a/util/oslib-posix.c b/util/oslib-posix.c index d950c347e2..aaec1891f5 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -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); } -- cgit v1.2.3