On Tue, Feb 15, 2022 at 8:46 AM Helge Deller [off-list ref] wrote:

On 2/15/22 04:03, Al Viro wrote:

quoted

On Mon, Feb 14, 2022 at 05:34:52PM +0100, Arnd Bergmann wrote:

quoted

diff --git a/arch/parisc/include/asm/futex.h b/arch/parisc/include/asm/futex.h
index b5835325d44b..2f4a1b1ef387 100644
--- a/arch/parisc/include/asm/futex.h
+++ b/arch/parisc/include/asm/futex.h

@@ -99,7 +99,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
     /* futex.c wants to do a cmpxchg_inatomic on kernel NULL, which is
      * our gateway page, and causes no end of trouble...
      */
-    if (uaccess_kernel() && !uaddr)
+    if (!uaddr)
             return -EFAULT;

      Huh?  uaccess_kernel() is removed since it becomes always false now,
so this looks odd.

      AFAICS, the comment above that check refers to futex_detect_cmpxchg()
-> cmpxchg_futex_value_locked() -> futex_atomic_cmpxchg_inatomic() call chain.
Which had been gone since commit 3297481d688a (futex: Remove futex_cmpxchg
detection).  The comment *and* the check should've been killed off back
then.
      Let's make sure to get both now...

Right. Arnd, can you drop this if() and the comment above it?

Done.

       Arnd