From: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx> Subject: kmemleak: clear stale pointers from task stacks Kmemleak considers any pointers on task stacks as references. This patch clears newly allocated and reused vmap stacks. Link: http://lkml.kernel.org/r/150728990124.744199.8403409836394318684.stgit@buzz Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx> Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/thread_info.h | 2 +- kernel/fork.c | 4 ++++ 2 files changed, 5 insertions(+), 1 deletion(-) diff -puN include/linux/thread_info.h~kmemleak-clear-stale-pointers-from-task-stacks include/linux/thread_info.h --- a/include/linux/thread_info.h~kmemleak-clear-stale-pointers-from-task-stacks +++ a/include/linux/thread_info.h @@ -42,7 +42,7 @@ enum { #define THREAD_ALIGN THREAD_SIZE #endif -#ifdef CONFIG_DEBUG_STACK_USAGE +#if IS_ENABLED(CONFIG_DEBUG_STACK_USAGE) || IS_ENABLED(CONFIG_DEBUG_KMEMLEAK) # define THREADINFO_GFP (GFP_KERNEL_ACCOUNT | __GFP_NOTRACK | \ __GFP_ZERO) #else diff -puN kernel/fork.c~kmemleak-clear-stale-pointers-from-task-stacks kernel/fork.c --- a/kernel/fork.c~kmemleak-clear-stale-pointers-from-task-stacks +++ a/kernel/fork.c @@ -215,6 +215,10 @@ static unsigned long *alloc_thread_stack if (!s) continue; +#ifdef CONFIG_DEBUG_KMEMLEAK + /* Clear stale pointers from reused stack. */ + memset(s->addr, 0, THREAD_SIZE); +#endif tsk->stack_vm_area = s; return s->addr; } _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
