From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D0103330B28; Fri, 17 Oct 2025 15:48:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760716137; cv=none; b=e6JHFG9mYcb+FquPpYOLWT6R0EpYbzCWOfYxI68X2rpc938oQY9G49rSk0/1bRv7FUZRujg0bHsaxifWD+kRZfQcVgG691pCsCfPRYzJ76xH+2pW/A3pxFXXAvT4tlCWJfEpgPwAdCbz639zYDZ1NK6ixb9jI5+SwDr3UUY0abc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760716137; c=relaxed/simple; bh=vAtW9AklGZGhem25t1BSMoyo66plGjHbru/ACfKxtbc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=BKIY6JSXnx4plpkFa4IxvS0z01mSiPPhkHcjiJK6iFV0kgp8nvTAsUtjA0slQMFd/B8YZpzR6E/S1BTlkEgD+8wg4CulfzP2VPaZnrcR7nPJa8J97pVngb+RP8j5/o+oMVsaJLCKRdGQn/h+p/xA0mpMczdJWjUGeBNaKhFv8PM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=QJMrn1Hs; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="QJMrn1Hs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A640C4CEE7; Fri, 17 Oct 2025 15:48:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1760716137; bh=vAtW9AklGZGhem25t1BSMoyo66plGjHbru/ACfKxtbc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QJMrn1HskLyfhGNf79E79TIw10kluKXDIeLmnGPEmKJLgh2lh1wtqNTqOTUjEpL3w l+OBnSM2u4t1wwsxIHU1C5lbaRPU63AB5woKaAKQq5en51Z2xnWS8yovnoFhbqp3md tMUd5SXWAbembHxWPMVHqG4hKg+fix1jVSZEg19g= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Anthony Yznaga , Michael Karcher , Andreas Larsson , Sasha Levin , John Paul Adrian Glaubitz , =?UTF-8?q?Ren=C3=A9=20Rebe?= Subject: [PATCH 5.15 087/276] sparc: fix accurate exception reporting in copy_{from_to}_user for UltraSPARC III Date: Fri, 17 Oct 2025 16:53:00 +0200 Message-ID: <20251017145145.662054810@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251017145142.382145055@linuxfoundation.org> References: <20251017145142.382145055@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michael Karcher [ Upstream commit 47b49c06eb62504075f0f2e2227aee2e2c2a58b3 ] Anthony Yznaga tracked down that a BUG_ON in ext4 code with large folios enabled resulted from copy_from_user() returning impossibly large values greater than the size to be copied. This lead to __copy_from_iter() returning impossible values instead of the actual number of bytes it was able to copy. The BUG_ON has been reported in https://lore.kernel.org/r/b14f55642207e63e907965e209f6323a0df6dcee.camel@physik.fu-berlin.de The referenced commit introduced exception handlers on user-space memory references in copy_from_user and copy_to_user. These handlers return from the respective function and calculate the remaining bytes left to copy using the current register contents. The exception handlers expect that %o2 has already been masked during the bulk copy loop, but the masking was performed after that loop. This will fix the return value of copy_from_user and copy_to_user in the faulting case. The behaviour of memcpy stays unchanged. Fixes: ee841d0aff64 ("sparc64: Convert U3copy_{from,to}_user to accurate exception reporting.") Tested-by: John Paul Adrian Glaubitz # on Sun Netra 240 Reviewed-by: Anthony Yznaga Tested-by: René Rebe # on UltraSparc III+ and UltraSparc IIIi Signed-off-by: Michael Karcher Reviewed-by: Andreas Larsson Link: https://lore.kernel.org/r/20250905-memcpy_series-v4-2-1ca72dda195b@mkarcher.dialup.fu-berlin.de Signed-off-by: Andreas Larsson Signed-off-by: Sasha Levin --- arch/sparc/lib/U3memcpy.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/sparc/lib/U3memcpy.S b/arch/sparc/lib/U3memcpy.S index 9248d59c734ce..bace3a18f836f 100644 --- a/arch/sparc/lib/U3memcpy.S +++ b/arch/sparc/lib/U3memcpy.S @@ -267,6 +267,7 @@ FUNC_NAME: /* %o0=dst, %o1=src, %o2=len */ faligndata %f10, %f12, %f26 EX_LD_FP(LOAD(ldd, %o1 + 0x040, %f0), U3_retl_o2) + and %o2, 0x3f, %o2 subcc GLOBAL_SPARE, 0x80, GLOBAL_SPARE add %o1, 0x40, %o1 bgu,pt %XCC, 1f @@ -336,7 +337,6 @@ FUNC_NAME: /* %o0=dst, %o1=src, %o2=len */ * Also notice how this code is careful not to perform a * load past the end of the src buffer. */ - and %o2, 0x3f, %o2 andcc %o2, 0x38, %g2 be,pn %XCC, 2f subcc %g2, 0x8, %g2 -- 2.51.0