From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 675F3C6FD1A for ; Tue, 7 Mar 2023 16:01:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230182AbjCGQBb (ORCPT ); Tue, 7 Mar 2023 11:01:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43434 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231636AbjCGQBI (ORCPT ); Tue, 7 Mar 2023 11:01:08 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 220C094755 for ; Tue, 7 Mar 2023 07:58:50 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 740E3CE1B9A for ; Tue, 7 Mar 2023 15:58:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0EE62C433EF; Tue, 7 Mar 2023 15:58:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1678204725; bh=/aLO3prxmyONbS4/ndPV5hci1ZmOPTSE9//Kfqt++qQ=; h=Subject:To:Cc:From:Date:From; b=wI2zTdB0a0Ra9b8jnXzd3C6Z0kdgm964KWzLRlp8tVDigv0IcjXtx9Fyc30G16kLm ppIvJhL4EBwULbG13//9bR2HRvTCE0pHF/0Ku5OVz4iQlw4nu62muq18VWWpf99hUm 7pTCitvmBq6JWHvSgH5G8MKU2pBApTXDDFZPtWsM= Subject: FAILED: patch "[PATCH] riscv: ftrace: Fixup panic by disabling preemption" failed to apply to 5.15-stable tree To: andy.chiu@sifive.com, guoren@kernel.org, palmer@rivosinc.com Cc: From: Date: Tue, 07 Mar 2023 16:58:34 +0100 Message-ID: <167820471419475@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 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 . 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 8547649981e6631328cd64f583667501ae385531 # git commit -s git send-email --to '' --in-reply-to '167820471419475@kroah.com' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: 8547649981e6 ("riscv: ftrace: Fixup panic by disabling preemption") f32b4b467ebd ("RISC-V: enable dynamic ftrace for RV32I") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 8547649981e6631328cd64f583667501ae385531 Mon Sep 17 00:00:00 2001 From: Andy Chiu Date: Thu, 12 Jan 2023 04:05:57 -0500 Subject: [PATCH] riscv: ftrace: Fixup panic by disabling preemption In RISCV, we must use an AUIPC + JALR pair to encode an immediate, forming a jump that jumps to an address over 4K. This may cause errors if we want to enable kernel preemption and remove dependency from patching code with stop_machine(). For example, if a task was switched out on auipc. And, if we changed the ftrace function before it was switched back, then it would jump to an address that has updated 11:0 bits mixing with previous XLEN:12 part. p: patched area performed by dynamic ftrace ftrace_prologue: p| REG_S ra, -SZREG(sp) p| auipc ra, 0x? ------------> preempted ... change ftrace function ... p| jalr -?(ra) <------------- switched back p| REG_L ra, -SZREG(sp) func: xxx ret Fixes: afc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT") Signed-off-by: Andy Chiu Signed-off-by: Guo Ren Link: https://lore.kernel.org/r/20230112090603.1295340-2-guoren@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index e2b656043abf..ee0d39b26794 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -138,7 +138,7 @@ config RISCV select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL select HAVE_FUNCTION_GRAPH_TRACER - select HAVE_FUNCTION_TRACER if !XIP_KERNEL + select HAVE_FUNCTION_TRACER if !XIP_KERNEL && !PREEMPTION config ARCH_MMAP_RND_BITS_MIN default 18 if 64BIT