From 748c90c693363d05c6b2f3915edc7999a2f71837 Mon Sep 17 00:00:00 2001 From: Rick Edgecombe Date: Fri, 8 Sep 2023 13:36:54 -0700 Subject: x86/shstk: Remove useless clone error handling When clone fails after the shadow stack is allocated, any allocated shadow stack is cleaned up in exit_thread() in copy_process(). So the logic in copy_thread() is unneeded, and also will not handle failures that happen outside of copy_thread(). In addition, since there is a second attempt to unmap the same shadow stack, there is a race where an newly mapped region could get unmapped. So remove the logic in copy_thread() and rely on exit_thread() to handle clone failure. Fixes: b2926a36b97a ("x86/shstk: Handle thread shadow stack") Signed-off-by: Rick Edgecombe Signed-off-by: Dave Hansen Tested-by: H.J. Lu Link: https://lore.kernel.org/all/20230908203655.543765-3-rick.p.edgecombe%40intel.com --- arch/x86/kernel/process.c | 7 ------- 1 file changed, 7 deletions(-) diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 9f0909142a0a..b6f4e8399fca 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -257,13 +257,6 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) if (!ret && unlikely(test_tsk_thread_flag(current, TIF_IO_BITMAP))) io_bitmap_share(p); - /* - * If copy_thread() if failing, don't leak the shadow stack possibly - * allocated in shstk_alloc_thread_stack() above. - */ - if (ret) - shstk_free(p); - return ret; } -- cgit