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sh: fix futex FUTEX_OP_SET op on userspace addresses 

Commit 00b73d8d1b ("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>
This commit is contained in:
Aurelien Jarno 2017-05-02 13:00:12 +00:00 committed by Rich Felker
parent 0adb32858b
commit 9b7e30ab97
1 changed files with 1 additions and 4 deletions
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5
arch/sh/include/asm/futex.h
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@ -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;