The following commit has been merged into the locking/urgent branch of tip:
Commit-ID: 921c7ebd1337d1a46783d7e15a850e12aed2eaa0 Gitweb: https://git.kernel.org/tip/921c7ebd1337d1a46783d7e15a850e12aed2eaa0 Author: Mateusz Nosek <mateusznos...@gmail.com> AuthorDate: Sun, 27 Sep 2020 02:08:58 +02:00 Committer: Thomas Gleixner <t...@linutronix.de> CommitterDate: Wed, 28 Oct 2020 15:48:51 +01:00 futex: Fix incorrect should_fail_futex() handling If should_futex_fail() returns true in futex_wake_pi(), then the 'ret' variable is set to -EFAULT and then immediately overwritten. So the failure injection is non-functional. Fix it by actually leaving the function and returning -EFAULT. The Fixes tag is kinda blury because the initial commit which introduced failure injection was already sloppy, but the below mentioned commit broke it completely. [ tglx: Massaged changelog ] Fixes: 6b4f4bc9cb22 ("locking/futex: Allow low-level atomic operations to return -EAGAIN") Signed-off-by: Mateusz Nosek <mateusznos...@gmail.com> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Link: https://lore.kernel.org/r/20200927000858.24219-1-mateusznos...@gmail.com --- kernel/futex.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/futex.c b/kernel/futex.c index a587669..39681bf 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1502,8 +1502,10 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_pi_state *pi_ */ newval = FUTEX_WAITERS | task_pid_vnr(new_owner); - if (unlikely(should_fail_futex(true))) + if (unlikely(should_fail_futex(true))) { ret = -EFAULT; + goto out_unlock; + } ret = cmpxchg_futex_value_locked(&curval, uaddr, uval, newval); if (!ret && (curval != uval)) {
