[-tip,v11,06/27] kprobes: treewide: Cleanup the error messages for kprobes

Message ID	163163036568.489837.14085396178727185469.stgit@devnote2 (mailing list archive)
State	Not Applicable
Delegated to:	BPF
Headers	show Return-Path: <bpf-owner@kernel.org> From: Masami Hiramatsu <mhiramat@kernel.org> To: Steven Rostedt <rostedt@goodmis.org>, Josh Poimboeuf <jpoimboe@redhat.com>, Ingo Molnar <mingo@kernel.org> Cc: X86 ML <x86@kernel.org>, Masami Hiramatsu <mhiramat@kernel.org>, Daniel Xu <dxu@dxuuu.xyz>, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, kuba@kernel.org, mingo@redhat.com, ast@kernel.org, Thomas Gleixner <tglx@linutronix.de>, Borislav Petkov <bp@alien8.de>, Peter Zijlstra <peterz@infradead.org>, kernel-team@fb.com, yhs@fb.com, linux-ia64@vger.kernel.org, Abhishek Sagar <sagar.abhishek@gmail.com>, Andrii Nakryiko <andrii.nakryiko@gmail.com>, Paul McKenney <paulmck@kernel.org> Subject: [PATCH -tip v11 06/27] kprobes: treewide: Cleanup the error messages for kprobes Date: Tue, 14 Sep 2021 23:39:25 +0900 Message-Id: <163163036568.489837.14085396178727185469.stgit@devnote2> In-Reply-To: <163163030719.489837.2236069935502195491.stgit@devnote2> References: <163163030719.489837.2236069935502195491.stgit@devnote2> User-Agent: StGit/0.19 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Precedence: bulk
Series	kprobes: Fix stacktrace with kretprobes on x86 \| expand [-tip,v11,00/27] kprobes: Fix stacktrace with kretprobes on x86 [-tip,v11,01/27] kprobes: Do not use local variable when creating debugfs file [-tip,v11,02/27] kprobes: Use helper to parse boolean input from userspace [-tip,v11,03/27] kprobe: Simplify prepare_kprobe() by dropping redundant version [-tip,v11,04/27] csky: ftrace: Drop duplicate implementation of arch_check_ftrace_location() [-tip,v11,05/27] kprobes: Make arch_check_ftrace_location static [-tip,v11,06/27] kprobes: treewide: Cleanup the error messages for kprobes [-tip,v11,07/27] kprobes: Fix coding style issues [-tip,v11,08/27] kprobes: Use IS_ENABLED() instead of kprobes_built_in() [-tip,v11,09/27] kprobes: Add assertions for required lock [-tip,v11,10/27] kprobes: treewide: Use 'kprobe_opcode_t *' for the code address in get_optimized_k… [-tip,v11,11/27] kprobes: Use bool type for functions which returns boolean value [-tip,v11,12/27] ia64: kprobes: Fix to pass correct trampoline address to the handler [-tip,v11,13/27] kprobes: treewide: Replace arch_deref_entry_point() with dereference_symbol_descri… [-tip,v11,14/27] kprobes: treewide: Remove trampoline_address from kretprobe_trampoline_handler() [-tip,v11,15/27] kprobes: treewide: Make it harder to refer kretprobe_trampoline directly [-tip,v11,16/27] kprobes: Add kretprobe_find_ret_addr() for searching return address [-tip,v11,17/27] objtool: Add frame-pointer-specific function ignore [-tip,v11,18/27] objtool: Ignore unwind hints for ignored functions [-tip,v11,19/27] x86/kprobes: Add UNWIND_HINT_FUNC on kretprobe_trampoline() [-tip,v11,20/27] ARC: Add instruction_pointer_set() API [-tip,v11,21/27] ia64: Add instruction_pointer_set() API [-tip,v11,22/27] arm: kprobes: Make space for instruction pointer on stack [-tip,v11,23/27] kprobes: Enable stacktrace from pt_regs in kretprobe handler [-tip,v11,24/27] x86/kprobes: Push a fake return address at kretprobe_trampoline [-tip,v11,25/27] x86/unwind: Recover kretprobe trampoline entry [-tip,v11,26/27] tracing: Show kretprobe unknown indicator only for kretprobe_trampoline [-tip,v11,27/27] x86/kprobes: Fixup return address in generic trampoline handler

Context	Check	Description
netdev/tree_selection	success	Not a local patch

diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c index 27e0af78e88b..a59e38de4a03 100644 --- a/arch/arm/probes/kprobes/core.c +++ b/arch/arm/probes/kprobes/core.c @@ -11,6 +11,8 @@ * Copyright (C) 2007 Marvell Ltd. */ +#define pr_fmt(fmt) "kprobes: " fmt + #include <linux/kernel.h> #include <linux/kprobes.h> #include <linux/module.h> @@ -278,7 +280,7 @@ void __kprobes kprobe_handler(struct pt_regs *regs) break; case KPROBE_REENTER: /* A nested probe was hit in FIQ, it is a BUG */ - pr_warn("Unrecoverable kprobe detected.\n"); + pr_warn("Failed to recover from reentered kprobes.\n"); dump_kprobe(p); fallthrough; default: diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c index 6dbcc89f6662..ce429cbacd35 100644 --- a/arch/arm64/kernel/probes/kprobes.c +++ b/arch/arm64/kernel/probes/kprobes.c @@ -7,6 +7,9 @@ * Copyright (C) 2013 Linaro Limited. * Author: Sandeepa Prabhu <sandeepa.prabhu@linaro.org> */ + +#define pr_fmt(fmt) "kprobes: " fmt + #include <linux/extable.h> #include <linux/kasan.h> #include <linux/kernel.h> @@ -218,7 +221,7 @@ static int __kprobes reenter_kprobe(struct kprobe *p, break; case KPROBE_HIT_SS: case KPROBE_REENTER: - pr_warn("Unrecoverable kprobe detected.\n"); + pr_warn("Failed to recover from reentered kprobes.\n"); dump_kprobe(p); BUG(); break; diff --git a/arch/csky/kernel/probes/kprobes.c b/arch/csky/kernel/probes/kprobes.c index 8fffa34d4e1c..632407bf45d5 100644 --- a/arch/csky/kernel/probes/kprobes.c +++ b/arch/csky/kernel/probes/kprobes.c @@ -1,5 +1,7 @@ // SPDX-License-Identifier: GPL-2.0+ +#define pr_fmt(fmt) "kprobes: " fmt + #include <linux/kprobes.h> #include <linux/extable.h> #include <linux/slab.h> @@ -77,10 +79,8 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) { unsigned long probe_addr = (unsigned long)p->addr; - if (probe_addr & 0x1) { - pr_warn("Address not aligned.\n"); - return -EINVAL; - } + if (probe_addr & 0x1) + return -EILSEQ; /* copy instruction */ p->opcode = le32_to_cpu(*p->addr); @@ -225,7 +225,7 @@ static int __kprobes reenter_kprobe(struct kprobe *p, break; case KPROBE_HIT_SS: case KPROBE_REENTER: - pr_warn("Unrecoverable kprobe detected.\n"); + pr_warn("Failed to recover from reentered kprobes.\n"); dump_kprobe(p); BUG(); break; diff --git a/arch/mips/kernel/kprobes.c b/arch/mips/kernel/kprobes.c index 75bff0f77319..b0934a0d7aed 100644 --- a/arch/mips/kernel/kprobes.c +++ b/arch/mips/kernel/kprobes.c @@ -11,6 +11,8 @@ * Copyright (C) IBM Corporation, 2002, 2004 */ +#define pr_fmt(fmt) "kprobes: " fmt + #include <linux/kprobes.h> #include <linux/preempt.h> #include <linux/uaccess.h> @@ -80,8 +82,7 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) insn = p->addr[0]; if (insn_has_ll_or_sc(insn)) { - pr_notice("Kprobes for ll and sc instructions are not" - "supported\n"); + pr_notice("Kprobes for ll and sc instructions are not supported\n"); ret = -EINVAL; goto out; } @@ -219,7 +220,7 @@ static int evaluate_branch_instruction(struct kprobe *p, struct pt_regs *regs, return 0; unaligned: - pr_notice("%s: unaligned epc - sending SIGBUS.\n", current->comm); + pr_notice("Failed to emulate branch instruction because of unaligned epc - sending SIGBUS to %s.\n", current->comm); force_sig(SIGBUS); return -EFAULT; @@ -238,10 +239,8 @@ static void prepare_singlestep(struct kprobe *p, struct pt_regs *regs, regs->cp0_epc = (unsigned long)p->addr; else if (insn_has_delayslot(p->opcode)) { ret = evaluate_branch_instruction(p, regs, kcb); - if (ret < 0) { - pr_notice("Kprobes: Error in evaluating branch\n"); + if (ret < 0) return; - } } regs->cp0_epc = (unsigned long)&p->ainsn.insn[0]; } diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c index 00088dc6da4b..cab6f874358e 100644 --- a/arch/riscv/kernel/probes/kprobes.c +++ b/arch/riscv/kernel/probes/kprobes.c @@ -1,5 +1,7 @@ // SPDX-License-Identifier: GPL-2.0+ +#define pr_fmt(fmt) "kprobes: " fmt + #include <linux/kprobes.h> #include <linux/extable.h> #include <linux/slab.h> @@ -50,11 +52,8 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) { unsigned long probe_addr = (unsigned long)p->addr; - if (probe_addr & 0x1) { - pr_warn("Address not aligned.\n"); - - return -EINVAL; - } + if (probe_addr & 0x1) + return -EILSEQ; /* copy instruction */ p->opcode = *p->addr; @@ -191,7 +190,7 @@ static int __kprobes reenter_kprobe(struct kprobe *p, break; case KPROBE_HIT_SS: case KPROBE_REENTER: - pr_warn("Unrecoverable kprobe detected.\n"); + pr_warn("Failed to recover from reentered kprobes.\n"); dump_kprobe(p); BUG(); break; diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c index 52d056a5f89f..952d44b0610b 100644 --- a/arch/s390/kernel/kprobes.c +++ b/arch/s390/kernel/kprobes.c @@ -7,6 +7,8 @@ * s390 port, used ppc64 as template. Mike Grundy <grundym@us.ibm.com> */ +#define pr_fmt(fmt) "kprobes: " fmt + #include <linux/moduleloader.h> #include <linux/kprobes.h> #include <linux/ptrace.h> @@ -259,7 +261,7 @@ static void kprobe_reenter_check(struct kprobe_ctlblk *kcb, struct kprobe *p) * is a BUG. The code path resides in the .kprobes.text * section and is executed with interrupts disabled. */ - pr_err("Invalid kprobe detected.\n"); + pr_err("Failed to recover from reentered kprobes.\n"); dump_kprobe(p); BUG(); } diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 30199bfcc74a..7663c8a51889 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -18,6 +18,9 @@ * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi * <prasanna@in.ibm.com> added function-return probes. */ + +#define pr_fmt(fmt) "kprobes: " fmt + #include <linux/kprobes.h> #include <linux/hash.h> #include <linux/init.h> @@ -892,7 +895,7 @@ static void optimize_all_kprobes(void) optimize_kprobe(p); } cpus_read_unlock(); - printk(KERN_INFO "Kprobes globally optimized\n"); + pr_info("kprobe jump-optimization is enabled. All kprobes are optimized if possible.\n"); out: mutex_unlock(&kprobe_mutex); } @@ -925,7 +928,7 @@ static void unoptimize_all_kprobes(void) /* Wait for unoptimizing completion */ wait_for_kprobe_optimizer(); - printk(KERN_INFO "Kprobes globally unoptimized\n"); + pr_info("kprobe jump-optimization is disabled. All kprobes are based on software breakpoint.\n"); } static DEFINE_MUTEX(kprobe_sysctl_mutex); @@ -1003,7 +1006,7 @@ static int reuse_unused_kprobe(struct kprobe *ap) * unregistered. * Thus there should be no chance to reuse unused kprobe. */ - printk(KERN_ERR "Error: There should be no unused kprobe here.\n"); + WARN_ON_ONCE(1); return -EINVAL; } @@ -1040,18 +1043,13 @@ static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops, int ret = 0; ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 0, 0); - if (ret) { - pr_debug("Failed to arm kprobe-ftrace at %pS (%d)\n", - p->addr, ret); + if (WARN_ONCE(ret < 0, "Failed to arm kprobe-ftrace at %pS (error %d)\n", p->addr, ret)) return ret; - } if (*cnt == 0) { ret = register_ftrace_function(ops); - if (ret) { - pr_debug("Failed to init kprobe-ftrace (%d)\n", ret); + if (WARN(ret < 0, "Failed to register kprobe-ftrace (error %d)\n", ret)) goto err_ftrace; - } } (*cnt)++; @@ -1083,14 +1081,14 @@ static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops, if (*cnt == 1) { ret = unregister_ftrace_function(ops); - if (WARN(ret < 0, "Failed to unregister kprobe-ftrace (%d)\n", ret)) + if (WARN(ret < 0, "Failed to unregister kprobe-ftrace (error %d)\n", ret)) return ret; } (*cnt)--; ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0); - WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (%d)\n", + WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (error %d)\n", p->addr, ret); return ret; } @@ -1880,7 +1878,7 @@ unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs, node = node->next; } - pr_err("Oops! Kretprobe fails to find correct return address.\n"); + pr_err("kretprobe: Return address not found, not execute handler. Maybe there is a bug in the kernel.\n"); BUG_ON(1); found: @@ -2209,8 +2207,7 @@ EXPORT_SYMBOL_GPL(enable_kprobe); /* Caller must NOT call this in usual path. This is only for critical case */ void dump_kprobe(struct kprobe *kp) { - pr_err("Dumping kprobe:\n"); - pr_err("Name: %s\nOffset: %x\nAddress: %pS\n", + pr_err("Dump kprobe:\n.symbol_name = %s, .offset = %x, .addr = %pS\n", kp->symbol_name, kp->offset, kp->addr); } NOKPROBE_SYMBOL(dump_kprobe); @@ -2473,8 +2470,7 @@ static int __init init_kprobes(void) err = populate_kprobe_blacklist(__start_kprobe_blacklist, __stop_kprobe_blacklist); if (err) { - pr_err("kprobes: failed to populate blacklist: %d\n", err); - pr_err("Please take care of using kprobes.\n"); + pr_err("Failed to populate blacklist (error %d), kprobes not restricted, be careful using them!\n", err); } if (kretprobe_blacklist_size) { @@ -2483,7 +2479,7 @@ static int __init init_kprobes(void) kretprobe_blacklist[i].addr = kprobe_lookup_name(kretprobe_blacklist[i].name, 0); if (!kretprobe_blacklist[i].addr) - printk("kretprobe: lookup failed: %s\n", + pr_err("Failed to lookup symbol '%s' for kretprobe blacklist. Maybe the target function is removed or renamed.\n", kretprobe_blacklist[i].name); } } @@ -2687,7 +2683,7 @@ static int arm_all_kprobes(void) } if (errors) - pr_warn("Kprobes globally enabled, but failed to arm %d out of %d probes\n", + pr_warn("Kprobes globally enabled, but failed to enable %d out of %d probes. Please check which kprobes are kept disabled via debugfs.\n", errors, total); else pr_info("Kprobes globally enabled\n"); @@ -2730,7 +2726,7 @@ static int disarm_all_kprobes(void) } if (errors) - pr_warn("Kprobes globally disabled, but failed to disarm %d out of %d probes\n", + pr_warn("Kprobes globally disabled, but failed to disable %d out of %d probes. Please check which kprobes are kept enabled via debugfs.\n", errors, total); else pr_info("Kprobes globally disabled\n");

[-tip,v11,06/27] kprobes: treewide: Cleanup the error messages for kprobes

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