6.12-stable review patch. If anyone has any objections, please let me know.
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From: Andreas Schwab schwab@suse.de
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: b90edb33010b ("RISC-V: Add futex support.") Signed-off-by: Andreas Schwab schwab@suse.de Reviewed-by: Alexandre Ghiti alexghiti@rivosinc.com Reviewed-by: Björn Töpel bjorn@rivosinc.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/mvmfrkv2vhz.fsf@suse.de Signed-off-by: Palmer Dabbelt palmer@rivosinc.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/riscv/include/asm/futex.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/riscv/include/asm/futex.h +++ b/arch/riscv/include/asm/futex.h @@ -93,7 +93,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, _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();