diff options
| -rw-r--r-- | arch/x86/kernel/shstk.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/x86/kernel/shstk.c b/arch/x86/kernel/shstk.c index ad63252ebebc..59e15dd8d0f8 100644 --- a/arch/x86/kernel/shstk.c +++ b/arch/x86/kernel/shstk.c @@ -426,7 +426,18 @@ void shstk_free(struct task_struct *tsk) if (!shstk->base) return; + /* + * shstk->base is NULL for CLONE_VFORK child tasks, and so is + * normal. But size = 0 on a shstk->base is not normal and + * indicated an attempt to free the thread shadow stack twice. + * Warn about it. + */ + if (WARN_ON(!shstk->size)) + return; + unmap_shadow_stack(shstk->base, shstk->size); + + shstk->size = 0; } static int wrss_control(bool enable) |