futex: Fix inode life-time issue
As reported by Jann, ihold() does not in fact guarantee inode
persistence. And instead of making it so, replace the usage of inode
pointers with a per boot, machine wide, unique inode identifier.
This sequence number is global, but shared (file backed) futexes are
rare enough that this should not become a performance issue.
Reported-by: Jann Horn <firstname.lastname@example.org>
Suggested-by: Linus Torvalds <email@example.com>
Signed-off-by: Peter Zijlstra (Intel) <firstname.lastname@example.org>
4 files changed