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 887E4C25B06 for ; Sun, 14 Aug 2022 16:38:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243057AbiHNQiA (ORCPT ); Sun, 14 Aug 2022 12:38:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51220 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242940AbiHNQgD (ORCPT ); Sun, 14 Aug 2022 12:36:03 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A62161088; Sun, 14 Aug 2022 09:28:00 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 3735B60FC1; Sun, 14 Aug 2022 16:28:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0EEABC433C1; Sun, 14 Aug 2022 16:27:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660494479; bh=1HZL6Ii0eYbpxdGWodcz3JnCT22+06EimcngsnMDASM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jycde2CoHIPMWxe870XnKJzM+rASJtlz/BedpahpQ8JKhSoW0K5l/wXlDaOj1mlk3 Y56hFG7Qx0C3gVqcxmrU60wpfm+393tGFrzRul7SJgPvioP2mezj5+2QPQe9cP/ffK QDO4q2DlKaWjqLMll0jhyg6K8/sbwOoqLCR2VLBXn67EJsYQ5uzAkGtWiKq6EaLUNO 1DqCx7/sFdMt4mjt3M+RM9RYuRp1/DUPo/tdnC0tOvfHfDyuXa6/4EmjyzAPzBllrB XSGy9Zde+9dSSxGKeXV8znrfv5uibqbdwYrWAdbexE/rxOcjEO9qdpM6GcyquWnamj OEUVIsrLx2G9Q== 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, akpm@linux-foundation.org, philipp.tomsich@vrull.eu, wangkefeng.wang@huawei.com, heiko@sntech.de, ebiederm@xmission.com, linux-riscv@lists.infradead.org Subject: [PATCH AUTOSEL 5.10 08/19] RISC-V: Add fast call path of crash_kexec() Date: Sun, 14 Aug 2022 12:27:27 -0400 Message-Id: <20220814162739.2398217-8-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220814162739.2398217-1-sashal@kernel.org> References: <20220814162739.2398217-1-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: linux-kernel@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 ad14f4466d92..c1a13011fb8e 100644 --- a/arch/riscv/kernel/traps.c +++ b/arch/riscv/kernel/traps.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include @@ -43,6 +44,9 @@ 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