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 2437D1459F2; Wed, 19 Jun 2024 13:21:48 +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=1718803308; cv=none; b=qYJekahE339CWKmlZxz965hwSpXiQIkoFYVikUkkQlBtLSiKoBfFdLDLFyD6tCa42q/E63tbSVW4NDoCE6vpuwwspcQnx0V5pLA1fYfaF7r3N1nXF0mgsTOKSDc48mJPMnrY6zRFYKIY6MRo9izQdQKL6zmNJG/NmyJbmLjRu1g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718803308; c=relaxed/simple; bh=TcB3JEw8ld6WiI5xC0wzW3QISw5Kp9SuYKqhl/Ag7tU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=d0x/Qzh9VTI5+TQ/cERl3Y7nRO1tLjsZoOx6sMHVlBH7wELDtqdwYdVBLOnDi4g77XgUwFDaOv4n7e9RW9Z4SIWQvbXN4VByZE5hX4HMgO9ZnX/dfGcZIkZ3vl0ma99nTihpqlUw8KXoVA2TugSFzEte11hcbY01rtzWhq9SSf4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=tZqCCJje; 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="tZqCCJje" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 939ADC2BBFC; Wed, 19 Jun 2024 13:21:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1718803308; bh=TcB3JEw8ld6WiI5xC0wzW3QISw5Kp9SuYKqhl/Ag7tU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tZqCCJjeZrOIJFJlR7F1GZWaoSaaOp4u9Q+W7LNUGVkqy42H9i0Tnh02niU6KwmUb fH2kf7O181TpaCu6d8D6jv2iFGEmdUd0BDOTXPpBMt7ajWd4t/hh/VfqICGsrMxVw+ jyWiIjDz14alHK+aX2ZasOkm1gIxeraV3Y6EyacQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= , Nam Cao , =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= , "Mike Rapoport (IBM)" , Palmer Dabbelt Subject: [PATCH 6.9 224/281] riscv: fix overlap of allocated page and PTR_ERR Date: Wed, 19 Jun 2024 14:56:23 +0200 Message-ID: <20240619125618.578259559@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240619125609.836313103@linuxfoundation.org> References: <20240619125609.836313103@linuxfoundation.org> User-Agent: quilt/0.67 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 6.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nam Cao commit 994af1825a2aa286f4903ff64a1c7378b52defe6 upstream. On riscv32, it is possible for the last page in virtual address space (0xfffff000) to be allocated. This page overlaps with PTR_ERR, so that shouldn't happen. There is already some code to ensure memblock won't allocate the last page. However, buddy allocator is left unchecked. Fix this by reserving physical memory that would be mapped at virtual addresses greater than 0xfffff000. Reported-by: Björn Töpel Closes: https://lore.kernel.org/linux-riscv/878r1ibpdn.fsf@all.your.base.are.belong.to.us Fixes: 76d2a0493a17 ("RISC-V: Init and Halt Code") Signed-off-by: Nam Cao Cc: Tested-by: Björn Töpel Reviewed-by: Björn Töpel Reviewed-by: Mike Rapoport (IBM) Link: https://lore.kernel.org/r/20240425115201.3044202-1-namcao@linutronix.de Signed-off-by: Palmer Dabbelt Signed-off-by: Greg Kroah-Hartman --- arch/riscv/mm/init.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -235,18 +235,19 @@ static void __init setup_bootmem(void) kernel_map.va_pa_offset = PAGE_OFFSET - phys_ram_base; /* - * memblock allocator is not aware of the fact that last 4K bytes of - * the addressable memory can not be mapped because of IS_ERR_VALUE - * macro. Make sure that last 4k bytes are not usable by memblock - * if end of dram is equal to maximum addressable memory. For 64-bit - * kernel, this problem can't happen here as the end of the virtual - * address space is occupied by the kernel mapping then this check must - * be done as soon as the kernel mapping base address is determined. + * Reserve physical address space that would be mapped to virtual + * addresses greater than (void *)(-PAGE_SIZE) because: + * - This memory would overlap with ERR_PTR + * - This memory belongs to high memory, which is not supported + * + * This is not applicable to 64-bit kernel, because virtual addresses + * after (void *)(-PAGE_SIZE) are not linearly mapped: they are + * occupied by kernel mapping. Also it is unrealistic for high memory + * to exist on 64-bit platforms. */ if (!IS_ENABLED(CONFIG_64BIT)) { - max_mapped_addr = __pa(~(ulong)0); - if (max_mapped_addr == (phys_ram_end - 1)) - memblock_set_current_limit(max_mapped_addr - 4096); + max_mapped_addr = __va_to_pa_nodebug(-PAGE_SIZE); + memblock_reserve(max_mapped_addr, (phys_addr_t)-max_mapped_addr); } min_low_pfn = PFN_UP(phys_ram_base);