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 X-Spam-Level: X-Spam-Status: No, score=-10.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DD087CA90AF for ; Wed, 13 May 2020 10:16:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B4F34206D6 for ; Wed, 13 May 2020 10:16:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589364988; bh=27cHpY2S9HvHQKwzfTmdO82WmE54hAfTEifN3f8fcqQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=zGr3U5T3bLDfp0A2Daa1jPBwF5h3BdHR2v4OM5SklkxbOzPSwscHnrjnSiIC4kpr8 mRmyvoIjXP7V7fL6uEbH6kxospqneVzL8y50gvZQpEio4xrs/MR51NTr2iQiqSFgfL FqLKpAY3jZ/VtOCM1PEGLaJafOWKqzeCUVuOccQw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732970AbgEMKQ2 (ORCPT ); Wed, 13 May 2020 06:16:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:46318 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729917AbgEMKQ1 (ORCPT ); Wed, 13 May 2020 06:16:27 -0400 Received: from localhost.localdomain (unknown [42.120.72.94]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DD425206E5; Wed, 13 May 2020 10:16:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589364986; bh=27cHpY2S9HvHQKwzfTmdO82WmE54hAfTEifN3f8fcqQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nAzCc+BgZpNJbSKA2RIknSfJkk0aKWvFsUlVWSXaR5zbNZPw0p+nn/RPYHsnOqtYq Cf6499HSOKeXhxWHoXUmLmwImOpq6YSbtgIVb4n6sSIxXCUyTIwUQFFOSPITB0Bjhx EQALieT9JkwO7nYYFNsbzenDQjxHqYsRI5eUQL8s= From: guoren@kernel.org To: linux-csky@vger.kernel.org Cc: arnd@arndb.de, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, guoren@kernel.org, Guo Ren Subject: [PATCH 2/4] csky: Fixup calltrace panic Date: Wed, 13 May 2020 18:16:15 +0800 Message-Id: <20200513101617.11588-2-guoren@kernel.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20200513101617.11588-1-guoren@kernel.org> References: <20200513101617.11588-1-guoren@kernel.org> Sender: linux-csky-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-csky@vger.kernel.org From: Guo Ren The implementation of show_stack will panic with wrong fp: addr = *fp++; because the fp isn't checked properly. The current implementations of show_stack, wchan and stack_trace haven't been designed properly, so just deprecate them. This patch is a reference to riscv's way, all codes are modified from arm's. The patch is passed with: - cat /proc//stack - cat /proc//wchan - echo c > /proc/sysrq-trigger Signed-off-by: Guo Ren --- arch/csky/Kconfig | 2 + arch/csky/Makefile | 2 +- arch/csky/include/asm/ptrace.h | 10 ++ arch/csky/include/asm/thread_info.h | 6 + arch/csky/kernel/Makefile | 2 +- arch/csky/kernel/dumpstack.c | 49 -------- arch/csky/kernel/process.c | 31 ----- arch/csky/kernel/stacktrace.c | 176 ++++++++++++++++++++++------ 8 files changed, 159 insertions(+), 119 deletions(-) delete mode 100644 arch/csky/kernel/dumpstack.c diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig index 94545d50d40f..bd31ab12f77d 100644 --- a/arch/csky/Kconfig +++ b/arch/csky/Kconfig @@ -8,6 +8,7 @@ config CSKY select ARCH_HAS_SYNC_DMA_FOR_DEVICE select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_QUEUED_RWLOCKS if NR_CPUS>2 + select ARCH_WANT_FRAME_POINTERS if !CPU_CK610 select COMMON_CLK select CLKSRC_MMIO select CSKY_MPINTC if CPU_CK860 @@ -38,6 +39,7 @@ config CSKY select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_AUDITSYSCALL select HAVE_COPY_THREAD_TLS + select HAVE_DEBUG_BUGVERBOSE select HAVE_DYNAMIC_FTRACE select HAVE_DYNAMIC_FTRACE_WITH_REGS select HAVE_FUNCTION_TRACER diff --git a/arch/csky/Makefile b/arch/csky/Makefile index fb1bbbd91954..37f593a4bf53 100644 --- a/arch/csky/Makefile +++ b/arch/csky/Makefile @@ -47,7 +47,7 @@ ifeq ($(CSKYABI),abiv2) KBUILD_CFLAGS += -mno-stack-size endif -ifdef CONFIG_STACKTRACE +ifdef CONFIG_FRAME_POINTER KBUILD_CFLAGS += -mbacktrace endif diff --git a/arch/csky/include/asm/ptrace.h b/arch/csky/include/asm/ptrace.h index aae5aa96cf54..bcfb7070e48d 100644 --- a/arch/csky/include/asm/ptrace.h +++ b/arch/csky/include/asm/ptrace.h @@ -58,6 +58,16 @@ static inline unsigned long kernel_stack_pointer(struct pt_regs *regs) return regs->usp; } +static inline unsigned long frame_pointer(struct pt_regs *regs) +{ + return regs->regs[4]; +} +static inline void frame_pointer_set(struct pt_regs *regs, + unsigned long val) +{ + regs->regs[4] = val; +} + extern int regs_query_register_offset(const char *name); extern unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n); diff --git a/arch/csky/include/asm/thread_info.h b/arch/csky/include/asm/thread_info.h index 5d33fcfd7f2a..d381a5752f0e 100644 --- a/arch/csky/include/asm/thread_info.h +++ b/arch/csky/include/asm/thread_info.h @@ -40,6 +40,12 @@ struct thread_info { #define thread_saved_fp(tsk) \ ((unsigned long)(((struct switch_stack *)(tsk->thread.ksp))->r8)) +#define thread_saved_sp(tsk) \ + ((unsigned long)(tsk->thread.ksp)) + +#define thread_saved_lr(tsk) \ + ((unsigned long)(((struct switch_stack *)(tsk->thread.ksp))->r15)) + static inline struct thread_info *current_thread_info(void) { unsigned long sp; diff --git a/arch/csky/kernel/Makefile b/arch/csky/kernel/Makefile index fd6d9dc8b7f3..37f37c0e934a 100644 --- a/arch/csky/kernel/Makefile +++ b/arch/csky/kernel/Makefile @@ -3,7 +3,7 @@ extra-y := head.o vmlinux.lds obj-y += entry.o atomic.o signal.o traps.o irq.o time.o vdso.o obj-y += power.o syscall.o syscall_table.o setup.o -obj-y += process.o cpu-probe.o ptrace.o dumpstack.o +obj-y += process.o cpu-probe.o ptrace.o stacktrace.o obj-y += probes/ obj-$(CONFIG_MODULES) += module.o diff --git a/arch/csky/kernel/dumpstack.c b/arch/csky/kernel/dumpstack.c deleted file mode 100644 index d67f9777cfd9..000000000000 --- a/arch/csky/kernel/dumpstack.c +++ /dev/null @@ -1,49 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. - -#include - -int kstack_depth_to_print = 48; - -void show_trace(unsigned long *stack) -{ - unsigned long *stack_end; - unsigned long *stack_start; - unsigned long *fp; - unsigned long addr; - - addr = (unsigned long) stack & THREAD_MASK; - stack_start = (unsigned long *) addr; - stack_end = (unsigned long *) (addr + THREAD_SIZE); - - fp = stack; - pr_info("\nCall Trace:"); - - while (fp > stack_start && fp < stack_end) { -#ifdef CONFIG_STACKTRACE - addr = fp[1]; - fp = (unsigned long *) fp[0]; -#else - addr = *fp++; -#endif - if (__kernel_text_address(addr)) - pr_cont("\n[<%08lx>] %pS", addr, (void *)addr); - } - pr_cont("\n"); -} - -void show_stack(struct task_struct *task, unsigned long *stack) -{ - if (!stack) { - if (task) - stack = (unsigned long *)thread_saved_fp(task); - else -#ifdef CONFIG_STACKTRACE - asm volatile("mov %0, r8\n":"=r"(stack)::"memory"); -#else - stack = (unsigned long *)&stack; -#endif - } - - show_trace(stack); -} diff --git a/arch/csky/kernel/process.c b/arch/csky/kernel/process.c index f7b231ca269a..4ad6db56c3cd 100644 --- a/arch/csky/kernel/process.c +++ b/arch/csky/kernel/process.c @@ -98,37 +98,6 @@ int dump_task_regs(struct task_struct *tsk, elf_gregset_t *pr_regs) return 1; } -unsigned long get_wchan(struct task_struct *p) -{ - unsigned long lr; - unsigned long *fp, *stack_start, *stack_end; - int count = 0; - - if (!p || p == current || p->state == TASK_RUNNING) - return 0; - - stack_start = (unsigned long *)end_of_stack(p); - stack_end = (unsigned long *)(task_stack_page(p) + THREAD_SIZE); - - fp = (unsigned long *) thread_saved_fp(p); - do { - if (fp < stack_start || fp > stack_end) - return 0; -#ifdef CONFIG_STACKTRACE - lr = fp[1]; - fp = (unsigned long *)fp[0]; -#else - lr = *fp++; -#endif - if (!in_sched_functions(lr) && - __kernel_text_address(lr)) - return lr; - } while (count++ < 16); - - return 0; -} -EXPORT_SYMBOL(get_wchan); - #ifndef CONFIG_CPU_PM_NONE void arch_cpu_idle(void) { diff --git a/arch/csky/kernel/stacktrace.c b/arch/csky/kernel/stacktrace.c index fec777a643f1..92809e1da723 100644 --- a/arch/csky/kernel/stacktrace.c +++ b/arch/csky/kernel/stacktrace.c @@ -1,57 +1,159 @@ // SPDX-License-Identifier: GPL-2.0 -/* Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. */ #include #include #include #include +#include -void save_stack_trace(struct stack_trace *trace) +#ifdef CONFIG_FRAME_POINTER + +struct stackframe { + unsigned long fp; + unsigned long ra; +}; + +void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs, + bool (*fn)(unsigned long, void *), void *arg) { - save_stack_trace_tsk(current, trace); + unsigned long fp, sp, pc; + + if (regs) { + fp = frame_pointer(regs); + sp = user_stack_pointer(regs); + pc = instruction_pointer(regs); + } else if (task == NULL || task == current) { + const register unsigned long current_sp __asm__ ("sp"); + const register unsigned long current_fp __asm__ ("r8"); + fp = current_fp; + sp = current_sp; + pc = (unsigned long)walk_stackframe; + } else { + /* task blocked in __switch_to */ + fp = thread_saved_fp(task); + sp = thread_saved_sp(task); + pc = thread_saved_lr(task); + } + + for (;;) { + unsigned long low, high; + struct stackframe *frame; + + if (unlikely(!__kernel_text_address(pc) || fn(pc, arg))) + break; + + /* Validate frame pointer */ + low = sp; + high = ALIGN(sp, THREAD_SIZE); + if (unlikely(fp < low || fp > high || fp & 0x3)) + break; + /* Unwind stack frame */ + frame = (struct stackframe *)fp; + sp = fp; + fp = frame->fp; + pc = ftrace_graph_ret_addr(current, NULL, frame->ra, + (unsigned long *)(fp - 8)); + } } -EXPORT_SYMBOL_GPL(save_stack_trace); -void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) +#else /* !CONFIG_FRAME_POINTER */ + +static void notrace walk_stackframe(struct task_struct *task, + struct pt_regs *regs, bool (*fn)(unsigned long, void *), void *arg) { - unsigned long *fp, *stack_start, *stack_end; - unsigned long addr; - int skip = trace->skip; - int savesched; - int graph_idx = 0; + unsigned long sp, pc; + unsigned long *ksp; - if (tsk == current) { - asm volatile("mov %0, r8\n":"=r"(fp)); - savesched = 1; + if (regs) { + sp = user_stack_pointer(regs); + pc = instruction_pointer(regs); + } else if (task == NULL || task == current) { + const register unsigned long current_sp __asm__ ("sp"); + sp = current_sp; + pc = (unsigned long)walk_stackframe; } else { - fp = (unsigned long *)thread_saved_fp(tsk); - savesched = 0; + /* task blocked in __switch_to */ + sp = thread_saved_sp(task); + pc = thread_saved_lr(task); } - addr = (unsigned long) fp & THREAD_MASK; - stack_start = (unsigned long *) addr; - stack_end = (unsigned long *) (addr + THREAD_SIZE); - - while (fp > stack_start && fp < stack_end) { - unsigned long lpp, fpp; + if (unlikely(sp & 0x3)) + return; - fpp = fp[0]; - lpp = fp[1]; - if (!__kernel_text_address(lpp)) + ksp = (unsigned long *)sp; + while (!kstack_end(ksp)) { + if (__kernel_text_address(pc) && unlikely(fn(pc, arg))) break; - else - lpp = ftrace_graph_ret_addr(tsk, &graph_idx, lpp, NULL); - - if (savesched || !in_sched_functions(lpp)) { - if (skip) { - skip--; - } else { - trace->entries[trace->nr_entries++] = lpp; - if (trace->nr_entries >= trace->max_entries) - break; - } - } - fp = (unsigned long *)fpp; + pc = (*ksp++) - 0x4; } } +#endif /* CONFIG_FRAME_POINTER */ + +static bool print_trace_address(unsigned long pc, void *arg) +{ + print_ip_sym(pc); + return false; +} + +void show_stack(struct task_struct *task, unsigned long *sp) +{ + pr_cont("Call Trace:\n"); + walk_stackframe(task, NULL, print_trace_address, NULL); +} + +static bool save_wchan(unsigned long pc, void *arg) +{ + if (!in_sched_functions(pc)) { + unsigned long *p = arg; + *p = pc; + return true; + } + return false; +} + +unsigned long get_wchan(struct task_struct *task) +{ + unsigned long pc = 0; + + if (likely(task && task != current && task->state != TASK_RUNNING)) + walk_stackframe(task, NULL, save_wchan, &pc); + return pc; +} + +#ifdef CONFIG_STACKTRACE +static bool __save_trace(unsigned long pc, void *arg, bool nosched) +{ + struct stack_trace *trace = arg; + + if (unlikely(nosched && in_sched_functions(pc))) + return false; + if (unlikely(trace->skip > 0)) { + trace->skip--; + return false; + } + + trace->entries[trace->nr_entries++] = pc; + return (trace->nr_entries >= trace->max_entries); +} + +static bool save_trace(unsigned long pc, void *arg) +{ + return __save_trace(pc, arg, false); +} + +/* + * Save stack-backtrace addresses into a stack_trace buffer. + */ +void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) +{ + walk_stackframe(tsk, NULL, save_trace, trace); +} EXPORT_SYMBOL_GPL(save_stack_trace_tsk); + +void save_stack_trace(struct stack_trace *trace) +{ + save_stack_trace_tsk(NULL, trace); +} +EXPORT_SYMBOL_GPL(save_stack_trace); + +#endif /* CONFIG_STACKTRACE */ -- 2.17.0