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 9C94AC32792 for ; Tue, 23 Aug 2022 11:05:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356721AbiHWLFF (ORCPT ); Tue, 23 Aug 2022 07:05:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39438 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357480AbiHWLC3 (ORCPT ); Tue, 23 Aug 2022 07:02:29 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A80C9B2758; Tue, 23 Aug 2022 02:15:04 -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 3D4D8B81C66; Tue, 23 Aug 2022 09:15:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 74FD3C433D6; Tue, 23 Aug 2022 09:15:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1661246101; bh=tJ4/GjcFTOYm1eHzzFoim4ZayD31016TtBq0nigveEE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sEJc8e3UNwILZbpGkJwonc/Z6Bp2t09SMtQBZEb3y+p2V/QeHvc9oEwdlnZed2fUQ zU8V4LKgAL+gFn3aA7Y1To0S7eG4Y2GQdnSN6kjX4A+Xr0Rgl4zDvIa7aJSChqmtSF pqF1Xx2jQN+q8dLdga9qmP6b96BwlHmAhgUwjQyM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Guo Ren , Xianting Tian , Palmer Dabbelt , Sasha Levin Subject: [PATCH 4.19 275/287] RISC-V: Add fast call path of crash_kexec() Date: Tue, 23 Aug 2022 10:27:24 +0200 Message-Id: <20220823080110.667293814@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220823080100.268827165@linuxfoundation.org> References: <20220823080100.268827165@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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 24a9333dda2c..7c65750508f2 100644 --- a/arch/riscv/kernel/traps.c +++ b/arch/riscv/kernel/traps.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include @@ -50,6 +51,9 @@ void die(struct pt_regs *regs, const char *str) ret = notify_die(DIE_OOPS, str, regs, 0, regs->scause, 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