From 907241dccb4ce5d9413cf3c030b32b0cfc184914 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Fri, 23 Sep 2016 18:24:07 +0100 Subject: [PATCH] thread_info: Use unsigned long for flags The generic THREAD_INFO_IN_TASK definition of thread_info::flags is a u32, matching x86 prior to the introduction of THREAD_INFO_IN_TASK. However, common helpers like test_ti_thread_flag() implicitly assume that thread_info::flags has at least the size and alignment of unsigned long, and relying on padding and alignment provided by other elements of task_struct is somewhat fragile. Additionally, some architectures use more that 32 bits for thread_info::flags, and others may need to in future. With THREAD_INFO_IN_TASK, task struct follows thread_info with a long field, and thus we no longer save any space as we did back in commit: affa219b60a11b32 ("x86: change thread_info's flag field back to 32 bits") Given all this, it makes more sense for the generic thread_info::flags to be an unsigned long. In fact given contains/uses the helpers mentioned above, BE arches *must* use unsigned long (or something of the same size) today, or they wouldn't work. Make it so. Signed-off-by: Mark Rutland Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Kees Cook Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1474651447-30447-1-git-send-email-mark.rutland@arm.com Signed-off-by: Ingo Molnar --- include/linux/thread_info.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h index e2d0fd81b1ba..45f004e9cc59 100644 --- a/include/linux/thread_info.h +++ b/include/linux/thread_info.h @@ -15,7 +15,7 @@ struct compat_timespec; #ifdef CONFIG_THREAD_INFO_IN_TASK struct thread_info { - u32 flags; /* low level flags */ + unsigned long flags; /* low level flags */ }; #define INIT_THREAD_INFO(tsk) \ -- 2.20.1