The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 599c44cd21f4967774e0acf58f734009be4aea9a # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025030419-satin-cogwheel-ae89@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 599c44cd21f4967774e0acf58f734009be4aea9a Mon Sep 17 00:00:00 2001 From: Andreas Schwab schwab@suse.de Date: Mon, 3 Feb 2025 11:06:00 +0100 Subject: [PATCH] riscv/futex: sign extend compare value in atomic cmpxchg MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

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

diff --git a/arch/riscv/include/asm/futex.h b/arch/riscv/include/asm/futex.h index 72be100afa23..90c86b115e00 100644 --- a/arch/riscv/include/asm/futex.h +++ b/arch/riscv/include/asm/futex.h @@ -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();