sh: fix futex FUTEX_OP_SET op on userspace addresses

Commit 00b73d8d1b71 ("sh: add working futex atomic ops on userspace
addresses for smp") changed the futex_atomic_op_inuser function to
use a loop. In case of the FUTEX_OP_SET op with a userspace address
containing a value different of 0, this loop is an endless loop.

Fix that by loading the value of oldval from the userspace before doing
the cmpxchg op, also for the FUTEX_OP_SET case.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Rich Felker <dalias@libc.org>

diff --git a/arch/sh/include/asm/futex.h b/arch/sh/include/asm/futex.h
index 15bf07bfa96bcaea117faa00d64a18cf1f2a378f..6d192f4908a729c5d9d57b58dc060442a362ed49 100644 (file)
--- a/arch/sh/include/asm/futex.h
+++ b/arch/sh/include/asm/futex.h
@@ -37,10 +37,7 @@ static inline int arch_futex_atomic_op_inuser(int op, u32 oparg, int *oval,
        pagefault_disable();
 
        do {
-               if (op == FUTEX_OP_SET)
-                       ret = oldval = 0;
-               else
-                       ret = get_user(oldval, uaddr);
+               ret = get_user(oldval, uaddr);
 
                if (ret) break;