From 976a55c0fe427a0084823152447cf5bb9092d24f Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Thu, 18 Aug 2022 18:03:52 -0700 Subject: Revert "linux-user: un-parent OBJECT(cpu) when closing thread" This reverts commit 52f0c1607671293afcdb2acc2f83e9bccbfa74bb. This caused a regression in arm/aarch64. We are hard-coding ARMCPRegInfo pointers into TranslationBlocks, for calling into helper_{get,set}cp_reg{,64}. So we have a race condition between whichever cpu thread translates the code first (encoding the pointer), and that cpu thread exiting, so that the next execution of the TB references a freed data structure. Signed-off-by: Richard Henderson --- linux-user/syscall.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) (limited to 'linux-user') diff --git a/linux-user/syscall.c b/linux-user/syscall.c index bfdd60136b..f409121202 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -8594,13 +8594,7 @@ static abi_long do_syscall1(CPUArchState *cpu_env, int num, abi_long arg1, if (CPU_NEXT(first_cpu)) { TaskState *ts = cpu->opaque; - if (ts->child_tidptr) { - put_user_u32(0, ts->child_tidptr); - do_sys_futex(g2h(cpu, ts->child_tidptr), - FUTEX_WAKE, INT_MAX, NULL, NULL, 0); - } - - object_unparent(OBJECT(cpu)); + object_property_set_bool(OBJECT(cpu), "realized", false, NULL); object_unref(OBJECT(cpu)); /* * At this point the CPU should be unrealized and removed @@ -8610,6 +8604,11 @@ static abi_long do_syscall1(CPUArchState *cpu_env, int num, abi_long arg1, pthread_mutex_unlock(&clone_lock); + if (ts->child_tidptr) { + put_user_u32(0, ts->child_tidptr); + do_sys_futex(g2h(cpu, ts->child_tidptr), + FUTEX_WAKE, INT_MAX, NULL, NULL, 0); + } thread_cpu = NULL; g_free(ts); rcu_unregister_thread(); -- cgit v1.2.3