From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58679) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bIWXf-00080h-1x for qemu-devel@nongnu.org; Thu, 30 Jun 2016 03:37:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bIWXd-0007vq-Lt for qemu-devel@nongnu.org; Thu, 30 Jun 2016 03:37:42 -0400 Received: from mx-v6.kamp.de ([2a02:248:0:51::16]:33566 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bIWXd-0007vf-Bu for qemu-devel@nongnu.org; Thu, 30 Jun 2016 03:37:41 -0400 From: Peter Lieven Date: Thu, 30 Jun 2016 09:37:19 +0200 Message-Id: <1467272240-32123-6-git-send-email-pl@kamp.de> In-Reply-To: <1467272240-32123-1-git-send-email-pl@kamp.de> References: <1467272240-32123-1-git-send-email-pl@kamp.de> Subject: [Qemu-devel] [PATCH 5/6] oslib-posix: add a configure switch to debug stack usage List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, mreitz@redhat.com, pbonzini@redhat.com, mst@redhat.com, dgilbert@redhat.com, peter.maydell@linaro.org, eblake@redhat.com, Peter Lieven this adds a knob to track the maximum stack usage of stacks created by qemu_alloc_stack. Signed-off-by: Peter Lieven --- configure | 15 +++++++++++++++ util/oslib-posix.c | 35 ++++++++++++++++++++++++++++++++++- 2 files changed, 49 insertions(+), 1 deletion(-) diff --git a/configure b/configure index 5929aba..ba66916 100755 --- a/configure +++ b/configure @@ -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" @@ -4298,6 +4301,13 @@ fi 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 "$debug_stack_usage" = "yes"; then + if test "$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 @@ -4866,6 +4876,7 @@ 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" @@ -5336,6 +5347,10 @@ 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 diff --git a/util/oslib-posix.c b/util/oslib-posix.c index a567a7d..0a9f2b2 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -50,6 +50,10 @@ #include +#ifdef CONFIG_DEBUG_STACK_USAGE +#include "qemu/error-report.h" +#endif + int qemu_get_thread_id(void) { #if defined(__linux__) @@ -500,6 +504,9 @@ pid_t qemu_fork(Error **errp) void *qemu_alloc_stack(size_t sz) { +#ifdef CONFIG_DEBUG_STACK_USAGE + void *ptr2; +#endif /* allocate sz bytes plus one extra page for a guard * page at the bottom of the stack */ void *ptr = mmap(NULL, sz + getpagesize(), PROT_NONE, @@ -511,11 +518,37 @@ void *qemu_alloc_stack(size_t sz) MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0) == MAP_FAILED) { abort(); } - return ptr + getpagesize(); + ptr += getpagesize(); +#ifdef CONFIG_DEBUG_STACK_USAGE + for (ptr2 = ptr; ptr2 < ptr + sz; ptr2 += sizeof(u_int32_t)) { + *(u_int32_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 + void *ptr; + unsigned int usage; + for (ptr = stack; ptr < stack + sz; ptr += sizeof(u_int32_t)) { + if (*(u_int32_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 + /* unmap the stack plus the extra guard page */ munmap(stack - getpagesize(), sz + getpagesize()); } -- 1.9.1