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authorMax Filippov <jcmvbkbc@gmail.com>2018-01-05 14:27:58 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-02-16 20:09:47 +0100
commit1c11f153eb35260b3baab5996d7aa9e974dbb5dd (patch)
tree9e763f023b910eb956e25e5ffe776d41383d791b /arch/xtensa
parent4bd9d85ab3db74527d7db46874a93459e6c0cee2 (diff)
xtensa: fix futex_atomic_cmpxchg_inatomic
commit ca47480921587ae30417dd234a9f79af188e3666 upstream. Return 0 if the operation was successful, not the userspace memory value. Check that userspace value equals passed oldval, not itself. Don't update *uval if the value wasn't read from userspace memory. This fixes process hang due to infinite loop in futex_lock_pi. It also fixes a bunch of glibc tests nptl/tst-mutexpi*. Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/xtensa')
-rw-r--r--arch/xtensa/include/asm/futex.h23
1 files changed, 10 insertions, 13 deletions
diff --git a/arch/xtensa/include/asm/futex.h b/arch/xtensa/include/asm/futex.h
index b39531babec0..72bfc1cbc2b5 100644
--- a/arch/xtensa/include/asm/futex.h
+++ b/arch/xtensa/include/asm/futex.h
@@ -109,7 +109,6 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
u32 oldval, u32 newval)
{
int ret = 0;
- u32 prev;
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
return -EFAULT;
@@ -120,26 +119,24 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
__asm__ __volatile__ (
" # futex_atomic_cmpxchg_inatomic\n"
- "1: l32i %1, %3, 0\n"
- " mov %0, %5\n"
- " wsr %1, scompare1\n"
- "2: s32c1i %0, %3, 0\n"
- "3:\n"
+ " wsr %5, scompare1\n"
+ "1: s32c1i %1, %4, 0\n"
+ " s32i %1, %6, 0\n"
+ "2:\n"
" .section .fixup,\"ax\"\n"
" .align 4\n"
- "4: .long 3b\n"
- "5: l32r %1, 4b\n"
- " movi %0, %6\n"
+ "3: .long 2b\n"
+ "4: l32r %1, 3b\n"
+ " movi %0, %7\n"
" jx %1\n"
" .previous\n"
" .section __ex_table,\"a\"\n"
- " .long 1b,5b,2b,5b\n"
+ " .long 1b,4b\n"
" .previous\n"
- : "+r" (ret), "=&r" (prev), "+m" (*uaddr)
- : "r" (uaddr), "r" (oldval), "r" (newval), "I" (-EFAULT)
+ : "+r" (ret), "+r" (newval), "+m" (*uaddr), "+m" (*uval)
+ : "r" (uaddr), "r" (oldval), "r" (uval), "I" (-EFAULT)
: "memory");
- *uval = prev;
return ret;
}