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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 68AD7C433EF for ; Sun, 10 Oct 2021 10:22:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4FA5460E9B for ; Sun, 10 Oct 2021 10:22:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231535AbhJJKYK (ORCPT ); Sun, 10 Oct 2021 06:24:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:49670 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231508AbhJJKYI (ORCPT ); Sun, 10 Oct 2021 06:24:08 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 20B4F60C51; Sun, 10 Oct 2021 10:22:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1633861330; bh=7y1+yZdeMZC6+bSqxMi4FtFSRgSbABb9frMpif2Gz3g=; h=Subject:To:Cc:From:Date:From; b=FvzWfKwiv8vqXQOXna3Tm+aKWKmnSIdtTUO4G600b1Dd4AifBQRwel5dofa/Iw6CN ED0Pz2+HDXVD7d6bNnvTrJVsWXzGVfZB5cwhhprhOpCecamf9AGZf+iYSJow7SbTNl 9Y2gd8PDb8UmZ65PD+yhvCHSFfuH3Ulugo8EZrCs= Subject: FAILED: patch "[PATCH] riscv: Flush current cpu icache before other cpus" failed to apply to 4.19-stable tree To: alex@ghiti.fr, palmerdabbelt@google.com Cc: From: Date: Sun, 10 Oct 2021 12:22:00 +0200 Message-ID: <1633861320227119@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 4.19-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 . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From bb8958d5dc79acbd071397abb57b8756375fe1ce Mon Sep 17 00:00:00 2001 From: Alexandre Ghiti Date: Sat, 18 Sep 2021 18:02:21 +0200 Subject: [PATCH] riscv: Flush current cpu icache before other cpus On SiFive Unmatched, I recently fell onto the following BUG when booting: [ 0.000000] ftrace: allocating 36610 entries in 144 pages [ 0.000000] Oops - illegal instruction [#1] [ 0.000000] Modules linked in: [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.13.1+ #5 [ 0.000000] Hardware name: SiFive HiFive Unmatched A00 (DT) [ 0.000000] epc : riscv_cpuid_to_hartid_mask+0x6/0xae [ 0.000000] ra : __sbi_rfence_v02+0xc8/0x10a [ 0.000000] epc : ffffffff80007240 ra : ffffffff80009964 sp : ffffffff81803e10 [ 0.000000] gp : ffffffff81a1ea70 tp : ffffffff8180f500 t0 : ffffffe07fe30000 [ 0.000000] t1 : 0000000000000004 t2 : 0000000000000000 s0 : ffffffff81803e60 [ 0.000000] s1 : 0000000000000000 a0 : ffffffff81a22238 a1 : ffffffff81803e10 [ 0.000000] a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000 [ 0.000000] a5 : 0000000000000000 a6 : ffffffff8000989c a7 : 0000000052464e43 [ 0.000000] s2 : ffffffff81a220c8 s3 : 0000000000000000 s4 : 0000000000000000 [ 0.000000] s5 : 0000000000000000 s6 : 0000000200000100 s7 : 0000000000000001 [ 0.000000] s8 : ffffffe07fe04040 s9 : ffffffff81a22c80 s10: 0000000000001000 [ 0.000000] s11: 0000000000000004 t3 : 0000000000000001 t4 : 0000000000000008 [ 0.000000] t5 : ffffffcf04000808 t6 : ffffffe3ffddf188 [ 0.000000] status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000002 [ 0.000000] [] riscv_cpuid_to_hartid_mask+0x6/0xae [ 0.000000] [] sbi_remote_fence_i+0x1e/0x26 [ 0.000000] [] flush_icache_all+0x12/0x1a [ 0.000000] [] patch_text_nosync+0x26/0x32 [ 0.000000] [] ftrace_init_nop+0x52/0x8c [ 0.000000] [] ftrace_process_locs.isra.0+0x29c/0x360 [ 0.000000] [] ftrace_init+0x80/0x130 [ 0.000000] [] start_kernel+0x5c4/0x8f6 [ 0.000000] ---[ end trace f67eb9af4d8d492b ]--- [ 0.000000] Kernel panic - not syncing: Attempted to kill the idle task! [ 0.000000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]--- While ftrace is looping over a list of addresses to patch, it always failed when patching the same function: riscv_cpuid_to_hartid_mask. Looking at the backtrace, the illegal instruction is encountered in this same function. However, patch_text_nosync, after patching the instructions, calls flush_icache_range. But looking at what happens in this function: flush_icache_range -> flush_icache_all -> sbi_remote_fence_i -> __sbi_rfence_v02 -> riscv_cpuid_to_hartid_mask The icache and dcache of the current cpu are never synchronized between the patching of riscv_cpuid_to_hartid_mask and calling this same function. So fix this by flushing the current cpu's icache before asking for the other cpus to do the same. Signed-off-by: Alexandre Ghiti Fixes: fab957c11efe ("RISC-V: Atomic and Locking Code") Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c index 094118663285..89f81067e09e 100644 --- a/arch/riscv/mm/cacheflush.c +++ b/arch/riscv/mm/cacheflush.c @@ -16,6 +16,8 @@ static void ipi_remote_fence_i(void *info) void flush_icache_all(void) { + local_flush_icache_all(); + if (IS_ENABLED(CONFIG_RISCV_SBI)) sbi_remote_fence_i(NULL); else