On Thu, Dec 10, 2015 at 1:56 PM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > On Thu, Dec 10, 2015 at 01:45:09PM -0800, Kees Cook wrote: >> > but generally you need ->f_lock. And in situations where the bit can >> > go only off->on, check it lockless, skip the whole thing entirely if it's >> > already set and grab the spinlock otherwise. >> >> And I can take f_lock safely under mmap_sem? > > Are you asking whether it's safe to take a spinlock under an rwsem? I keep getting various surprises while trying to implement this change, so yeah, I just want to make sure I won't waste my time adding taking the spinlock to the patch. -Kees -- Kees Cook Chrome OS & Brillo Security -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>