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 5ED80C25B0E for ; Sun, 14 Aug 2022 16:34:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242678AbiHNQdo (ORCPT ); Sun, 14 Aug 2022 12:33:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39678 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243135AbiHNQcI (ORCPT ); Sun, 14 Aug 2022 12:32:08 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 56A972497C; Sun, 14 Aug 2022 09:26:53 -0700 (PDT) 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 ams.source.kernel.org (Postfix) with ESMTPS id 30BC1B80B7C; Sun, 14 Aug 2022 16:26:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 56450C433C1; Sun, 14 Aug 2022 16:26:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660494410; bh=rjjCfkyDLgishq46C0BsFbiiIVJXO157qW9QTrr4C8Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=D5bA8akNIEwG2piRlj2O5QQU1wXIJ/J6hmOvvsr8eW2lX4sSrw1IP6Pd9t+Vr4eTR B20JW9IgoFqrzAljUAjh2Lt8Pc8KjYGa4dPcUM6HD3w/xBwc1koeU5q54iXbNzdk86 JJS4AzvO3v4Q6JlE3dxgM7qkMZioYWCmwWu9+l+rhFTb//Fn13ed/LoIeOHcr1sJgp VK9Jc7yEi0/S+gA1sW2XDVl1hnNo6VsxeCEqww3LIOGuutYJpMaK8UD3s+dJeGvJp5 mbyB99JfYu+rnEXrdXbIajruzdiiJk57XWL0ws20kPAoRuPY9LLdc5Q7VgGbeZ8/Qj uSNDDFSVdaH6w== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Xianting Tian , Guo Ren , Palmer Dabbelt , Sasha Levin , paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, ebiederm@xmission.com, rmk+kernel@armlinux.org.uk, akpm@linux-foundation.org, wangkefeng.wang@huawei.com, heiko@sntech.de, linux-riscv@lists.infradead.org Subject: [PATCH AUTOSEL 5.15 13/28] RISC-V: Add fast call path of crash_kexec() Date: Sun, 14 Aug 2022 12:25:53 -0400 Message-Id: <20220814162610.2397644-13-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220814162610.2397644-1-sashal@kernel.org> References: <20220814162610.2397644-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Xianting Tian [ Upstream commit 3f1901110a89b0e2e13adb2ac8d1a7102879ea98 ] Currently, almost all archs (x86, arm64, mips...) support fast call of crash_kexec() when "regs && kexec_should_crash()" is true. But RISC-V not, it can only enter crash system via panic(). However panic() doesn't pass the regs of the real accident scene to crash_kexec(), it caused we can't get accurate backtrace via gdb, $ riscv64-linux-gnu-gdb vmlinux vmcore Reading symbols from vmlinux... [New LWP 95] #0 console_unlock () at kernel/printk/printk.c:2557 2557 if (do_cond_resched) (gdb) bt #0 console_unlock () at kernel/printk/printk.c:2557 #1 0x0000000000000000 in ?? () With the patch we can get the accurate backtrace, $ riscv64-linux-gnu-gdb vmlinux vmcore Reading symbols from vmlinux... [New LWP 95] #0 0xffffffe00063a4e0 in test_thread (data=) at drivers/test_crash.c:81 81 *(int *)p = 0xdead; (gdb) (gdb) bt #0 0xffffffe00064d5c0 in test_thread (data=) at drivers/test_crash.c:81 #1 0x0000000000000000 in ?? () Test code to produce NULL address dereference in test_crash.c, void *p = NULL; *(int *)p = 0xdead; Reviewed-by: Guo Ren Tested-by: Xianting Tian Signed-off-by: Xianting Tian Link: https://lore.kernel.org/r/20220606082308.2883458-1-xianting.tian@linux.alibaba.com Signed-off-by: Palmer Dabbelt Signed-off-by: Sasha Levin --- arch/riscv/kernel/traps.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c index 0daaa3e4630d..b938ffe129d6 100644 --- a/arch/riscv/kernel/traps.c +++ b/arch/riscv/kernel/traps.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include @@ -44,6 +45,9 @@ void die(struct pt_regs *regs, const char *str) ret = notify_die(DIE_OOPS, str, regs, 0, regs->cause, SIGSEGV); + if (regs && kexec_should_crash(current)) + crash_kexec(regs); + bust_spinlocks(0); add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); spin_unlock_irq(&die_lock); -- 2.35.1