From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5A3554432 for ; Wed, 15 Mar 2023 12:25:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D2DD6C433EF; Wed, 15 Mar 2023 12:25:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1678883156; bh=oxZq7lq2Z5LRxuZx6TyZO40tToDw9pNkvhhU5kEbxZU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OUEGY8AGViUFCpERFgMQPvaPo0xqPq0G/VvM8XAslOJnQmXZTNI6T2T8woeTfLisn 7Mw6dHyLFZQtodPLQCEEzRkz5hi8Y0GlN73meD3eMIZGLmwbkgtmuHM+2zfyh1L/kg XIuhCPesb0RznqtJMOL38mkz1DL8CVvNVd/KwrjY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, kernel test robot , Dan Carpenter , Conor Dooley , Palmer Dabbelt , Sasha Levin Subject: [PATCH 5.15 035/145] RISC-V: Avoid dereferening NULL regs in die() Date: Wed, 15 Mar 2023 13:11:41 +0100 Message-Id: <20230315115740.231245322@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230315115738.951067403@linuxfoundation.org> References: <20230315115738.951067403@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Palmer Dabbelt [ Upstream commit f2913d006fcdb61719635e093d1b5dd0dafecac7 ] I don't think we can actually die() without a regs pointer, but the compiler was warning about a NULL check after a dereference. It seems prudent to just avoid the possibly-NULL dereference, given that when die()ing the system is already toast so who knows how we got there. Reported-by: kernel test robot Reported-by: Dan Carpenter Reviewed-by: Conor Dooley Link: https://lore.kernel.org/r/20220920200037.6727-1-palmer@rivosinc.com Signed-off-by: Palmer Dabbelt Stable-dep-of: 130aee3fd998 ("riscv: Avoid enabling interrupts in die()") Signed-off-by: Sasha Levin --- arch/riscv/kernel/traps.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c index 6084bd93d2f58..502cba5029ca4 100644 --- a/arch/riscv/kernel/traps.c +++ b/arch/riscv/kernel/traps.c @@ -33,6 +33,7 @@ void die(struct pt_regs *regs, const char *str) { static int die_counter; int ret; + long cause; oops_enter(); @@ -42,11 +43,13 @@ void die(struct pt_regs *regs, const char *str) pr_emerg("%s [#%d]\n", str, ++die_counter); print_modules(); - show_regs(regs); + if (regs) + show_regs(regs); - ret = notify_die(DIE_OOPS, str, regs, 0, regs->cause, SIGSEGV); + cause = regs ? regs->cause : -1; + ret = notify_die(DIE_OOPS, str, regs, 0, cause, SIGSEGV); - if (regs && kexec_should_crash(current)) + if (kexec_should_crash(current)) crash_kexec(regs); bust_spinlocks(0); -- 2.39.2