Commit 597675e3 authored by Andreas Schwab's avatar Andreas Schwab Committed by Wentao Guan
Browse files

riscv/futex: sign extend compare value in atomic cmpxchg 

stable inclusion
from stable-v6.6.81
commit 06316f435b0f248815291ba210f5f2ed8f6244da
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IBYZED

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=06316f435b0f248815291ba210f5f2ed8f6244da



--------------------------------

commit 599c44cd21f4967774e0acf58f734009be4aea9a upstream.

Make sure the compare value in the lr/sc loop is sign extended to match
what lr.w does.  Fortunately, due to the compiler keeping the register
contents sign extended anyway the lack of the explicit extension didn't
result in wrong code so far, but this cannot be relied upon.

Fixes: b90edb33 ("RISC-V: Add futex support.")
Signed-off-by: default avatarAndreas Schwab <schwab@suse.de>
Reviewed-by: default avatarAlexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: default avatarBjörn Töpel <bjorn@rivosinc.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/mvmfrkv2vhz.fsf@suse.de


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 06316f435b0f248815291ba210f5f2ed8f6244da)
Signed-off-by: default avatarWentao Guan <guanwentao@uniontech.com>
parent 2b87d769

arch/riscv/include/asm/futex.h

+1 −1
Original line number Diff line number Diff line
@@ -93,7 +93,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, 
		_ASM_EXTABLE_UACCESS_ERR(1b, 3b, %[r])	\

		_ASM_EXTABLE_UACCESS_ERR(2b, 3b, %[r])	\

	: [r] "+r" (ret), [v] "=&r" (val), [u] "+m" (*uaddr), [t] "=&r" (tmp)

	: [ov] "Jr" (oldval), [nv] "Jr" (newval)

	: [ov] "Jr" ((long)(int)oldval), [nv] "Jr" (newval)

	: "memory");

	__disable_user_access();