diff options
| author | Mateusz Nosek <mateusznosek0@gmail.com> | 2021-03-28 22:43:10 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-03-30 14:41:42 +0200 |
| commit | cec1580fb04c83c2d4300843469be2107ca21d04 (patch) | |
| tree | b5a1fb8bde9bf9ab1d00f48fe1ed43944d80eb6c | |
| parent | b90aa237f469c3575190a5e6a855b76ad1d2ce94 (diff) | |
futex: Fix incorrect should_fail_futex() handling
commit 921c7ebd1337d1a46783d7e15a850e12aed2eaa0 upstream.
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 <mateusznosek0@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20200927000858.24219-1-mateusznosek0@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | kernel/futex.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index c55bf3511203..a03952ffc3cb 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1605,8 +1605,10 @@ 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)) { |