From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Paul Burton , James Hogan , Ralf Baechle , Huacai Chen , linux-mips@linux-mips.org Subject: [PATCH 4.4 26/31] MIPS: Call dump_stack() from show_regs() Date: Fri, 20 Jul 2018 14:13:56 +0200 Message-Id: <20180720121341.095972489@linuxfoundation.org> In-Reply-To: <20180720121340.158484922@linuxfoundation.org> References: <20180720121340.158484922@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paul Burton commit 5a267832c2ec47b2dad0fdb291a96bb5b8869315 upstream. The generic nmi_cpu_backtrace() function calls show_regs() when a struct pt_regs is available, and dump_stack() otherwise. If we were to make use of the generic nmi_cpu_backtrace() with MIPS' current implementation of show_regs() this would mean that we see only register data with no accompanying stack information, in contrast with our current implementation which calls dump_stack() regardless of whether register state is available. In preparation for making use of the generic nmi_cpu_backtrace() to implement arch_trigger_cpumask_backtrace(), have our implementation of show_regs() call dump_stack() and drop the explicit dump_stack() call in arch_dump_stack() which is invoked by arch_trigger_cpumask_backtrace(). This will allow the output we produce to remain the same after a later patch switches to using nmi_cpu_backtrace(). It may mean that we produce extra stack output in other uses of show_regs(), but this: 1) Seems harmless. 2) Is good for consistency between arch_trigger_cpumask_backtrace() and other users of show_regs(). 3) Matches the behaviour of the ARM & PowerPC architectures. Marked for stable back to v4.9 as a prerequisite of the following patch "MIPS: Call dump_stack() from show_regs()". Signed-off-by: Paul Burton Patchwork: https://patchwork.linux-mips.org/patch/19596/ Cc: James Hogan Cc: Ralf Baechle Cc: Huacai Chen Cc: linux-mips@linux-mips.org Cc: stable@vger.kernel.org # v4.9+ Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman --- arch/mips/kernel/process.c | 4 ++-- arch/mips/kernel/traps.c | 1 + 2 files changed, 3 insertions(+), 2 deletions(-) --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -637,8 +637,8 @@ static void arch_dump_stack(void *info) if (regs) show_regs(regs); - - dump_stack(); + else + dump_stack(); } void arch_trigger_all_cpu_backtrace(bool include_self) --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -344,6 +344,7 @@ static void __show_regs(const struct pt_ void show_regs(struct pt_regs *regs) { __show_regs((struct pt_regs *)regs); + dump_stack(); } void show_registers(struct pt_regs *regs)