* [PATCH -tip 1/6] kprobes: treewide: Cleanup the error messages for kprobes
2021-07-10 14:55 [PATCH -tip 0/6] kprobes: treewide: Clean up kprobe code Masami Hiramatsu
@ 2021-07-10 14:55 ` Masami Hiramatsu
2021-07-10 14:55 ` [PATCH -tip 2/6] kprobes: Fix coding style issues Masami Hiramatsu
` (4 subsequent siblings)
5 siblings, 0 replies; 9+ messages in thread
From: Masami Hiramatsu @ 2021-07-10 14:55 UTC (permalink / raw)
To: X86 ML, Ingo Molnar
Cc: Steven Rostedt, Josh Poimboeuf, Masami Hiramatsu, Daniel Xu,
linux-kernel, bpf, kuba, mingo, ast, Thomas Gleixner,
Borislav Petkov, Peter Zijlstra, kernel-team, yhs, linux-ia64,
Abhishek Sagar, Andrii Nakryiko
This clean up the error/notification messages in kprobes related code.
Basically this defines 'pr_fmt()' macros for each files and update
the messages which describes
- what happened,
- what is the kernel going to do or not do,
- is the kernel fine,
- what can the user do about it.
Also, if the message is not needed (e.g. the function returns unique
error code, or other error message is already shown.) remove it,
and replace the message with WARN_*() macros if suitable.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
arch/arm/probes/kprobes/core.c | 4 +++-
arch/arm64/kernel/probes/kprobes.c | 5 ++++-
arch/csky/kernel/probes/kprobes.c | 10 +++++-----
arch/mips/kernel/kprobes.c | 11 +++++------
arch/riscv/kernel/probes/kprobes.c | 11 +++++------
arch/s390/kernel/kprobes.c | 4 +++-
kernel/kprobes.c | 36 ++++++++++++++++--------------------
7 files changed, 41 insertions(+), 40 deletions(-)
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 68b22b499aeb..e823c3051b24 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 247e33fa5bc7..dcf7c1f6d136 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;
@@ -208,7 +207,7 @@ 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 528bb31815c3..9bca57fe6b6a 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>
@@ -264,7 +266,7 @@ 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 790a573bbe00..63532991ccb4 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;
}
@@ -1049,18 +1052,13 @@ 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)++;
@@ -1092,14 +1090,14 @@ 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;
}
@@ -1885,7 +1883,7 @@ 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:
@@ -2214,8 +2212,7 @@ 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);
@@ -2478,8 +2475,7 @@ 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) {
@@ -2488,7 +2484,7 @@ 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);
}
}
@@ -2692,7 +2688,7 @@ 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");
@@ -2735,7 +2731,7 @@ 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");
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH -tip 2/6] kprobes: Fix coding style issues
2021-07-10 14:55 [PATCH -tip 0/6] kprobes: treewide: Clean up kprobe code Masami Hiramatsu
2021-07-10 14:55 ` [PATCH -tip 1/6] kprobes: treewide: Cleanup the error messages for kprobes Masami Hiramatsu
@ 2021-07-10 14:55 ` Masami Hiramatsu
2021-07-10 14:55 ` [PATCH -tip 3/6] kprobes: Use IS_ENABLED() instead of kprobes_built_in() Masami Hiramatsu
` (3 subsequent siblings)
5 siblings, 0 replies; 9+ messages in thread
From: Masami Hiramatsu @ 2021-07-10 14:55 UTC (permalink / raw)
To: X86 ML, Ingo Molnar
Cc: Steven Rostedt, Josh Poimboeuf, Masami Hiramatsu, Daniel Xu,
linux-kernel, bpf, kuba, mingo, ast, Thomas Gleixner,
Borislav Petkov, Peter Zijlstra, kernel-team, yhs, linux-ia64,
Abhishek Sagar, Andrii Nakryiko
Fix coding style issues reported by checkpatch.pl and update
comments to quote variable names and add "()" to function
name.
One TODO comment in __disarm_kprobe() is removed because
it has been done by following commit.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
include/linux/kprobes.h | 40 +++++---
kernel/kprobes.c | 238 ++++++++++++++++++++++++-----------------------
2 files changed, 146 insertions(+), 132 deletions(-)
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index e4f3bfe08757..28c04f1f2b73 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -3,7 +3,6 @@
#define _LINUX_KPROBES_H
/*
* Kernel Probes (KProbes)
- * include/linux/kprobes.h
*
* Copyright (C) IBM Corporation, 2002, 2004
*
@@ -39,7 +38,7 @@
#define KPROBE_REENTER 0x00000004
#define KPROBE_HIT_SSDONE 0x00000008
-#else /* CONFIG_KPROBES */
+#else /* !CONFIG_KPROBES */
#include <asm-generic/kprobes.h>
typedef int kprobe_opcode_t;
struct arch_specific_insn {
@@ -228,7 +227,7 @@ static nokprobe_inline struct kretprobe *get_kretprobe(struct kretprobe_instance
return READ_ONCE(ri->rph->rp);
}
-#else /* CONFIG_KRETPROBES */
+#else /* !CONFIG_KRETPROBES */
static inline void arch_prepare_kretprobe(struct kretprobe *rp,
struct pt_regs *regs)
{
@@ -239,11 +238,15 @@ static inline int arch_trampoline_kprobe(struct kprobe *p)
}
#endif /* CONFIG_KRETPROBES */
+/* Markers of '_kprobe_blacklist' section */
+extern unsigned long __start_kprobe_blacklist[];
+extern unsigned long __stop_kprobe_blacklist[];
+
extern struct kretprobe_blackpoint kretprobe_blacklist[];
#ifdef CONFIG_KPROBES_SANITY_TEST
extern int init_test_probes(void);
-#else
+#else /* !CONFIG_KPROBES_SANITY_TEST */
static inline int init_test_probes(void)
{
return 0;
@@ -303,7 +306,7 @@ static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
#define KPROBE_OPTINSN_PAGE_SYM "kprobe_optinsn_page"
int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum,
unsigned long *value, char *type, char *sym);
-#else /* __ARCH_WANT_KPROBES_INSN_SLOT */
+#else /* !__ARCH_WANT_KPROBES_INSN_SLOT */
#define DEFINE_INSN_CACHE_OPS(__name) \
static inline bool is_kprobe_##__name##_slot(unsigned long addr) \
{ \
@@ -345,16 +348,17 @@ extern int sysctl_kprobes_optimization;
extern int proc_kprobes_optimization_handler(struct ctl_table *table,
int write, void *buffer,
size_t *length, loff_t *ppos);
-#endif
+#endif /* CONFIG_SYSCTL */
extern void wait_for_kprobe_optimizer(void);
-#else
+#else /* !CONFIG_OPTPROBES */
static inline void wait_for_kprobe_optimizer(void) { }
#endif /* CONFIG_OPTPROBES */
+
#ifdef CONFIG_KPROBES_ON_FTRACE
extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *ops, struct ftrace_regs *fregs);
extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
-#endif
+#endif /* CONFIG_KPROBES_ON_FTRACE */
int arch_check_ftrace_location(struct kprobe *p);
@@ -364,7 +368,7 @@ struct kprobe *get_kprobe(void *addr);
/* kprobe_running() will just return the current_kprobe on this CPU */
static inline struct kprobe *kprobe_running(void)
{
- return (__this_cpu_read(current_kprobe));
+ return __this_cpu_read(current_kprobe);
}
static inline void reset_current_kprobe(void)
@@ -428,11 +432,11 @@ static inline struct kprobe *kprobe_running(void)
}
static inline int register_kprobe(struct kprobe *p)
{
- return -ENOSYS;
+ return -EOPNOTSUPP;
}
static inline int register_kprobes(struct kprobe **kps, int num)
{
- return -ENOSYS;
+ return -EOPNOTSUPP;
}
static inline void unregister_kprobe(struct kprobe *p)
{
@@ -442,11 +446,11 @@ static inline void unregister_kprobes(struct kprobe **kps, int num)
}
static inline int register_kretprobe(struct kretprobe *rp)
{
- return -ENOSYS;
+ return -EOPNOTSUPP;
}
static inline int register_kretprobes(struct kretprobe **rps, int num)
{
- return -ENOSYS;
+ return -EOPNOTSUPP;
}
static inline void unregister_kretprobe(struct kretprobe *rp)
{
@@ -462,11 +466,11 @@ static inline void kprobe_free_init_mem(void)
}
static inline int disable_kprobe(struct kprobe *kp)
{
- return -ENOSYS;
+ return -EOPNOTSUPP;
}
static inline int enable_kprobe(struct kprobe *kp)
{
- return -ENOSYS;
+ return -EOPNOTSUPP;
}
static inline bool within_kprobe_blacklist(unsigned long addr)
@@ -479,6 +483,7 @@ static inline int kprobe_get_kallsym(unsigned int symnum, unsigned long *value,
return -ERANGE;
}
#endif /* CONFIG_KPROBES */
+
static inline int disable_kretprobe(struct kretprobe *rp)
{
return disable_kprobe(&rp->kp);
@@ -493,13 +498,14 @@ static inline bool is_kprobe_insn_slot(unsigned long addr)
{
return false;
}
-#endif
+#endif /* !CONFIG_KPROBES */
+
#ifndef CONFIG_OPTPROBES
static inline bool is_kprobe_optinsn_slot(unsigned long addr)
{
return false;
}
-#endif
+#endif /* !CONFIG_OPTPROBES */
/* Returns true if kprobes handled the fault */
static nokprobe_inline bool kprobe_page_fault(struct pt_regs *regs,
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 63532991ccb4..e5e1400072c8 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1,7 +1,6 @@
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Kernel Probes (KProbes)
- * kernel/kprobes.c
*
* Copyright (C) IBM Corporation, 2002, 2004
*
@@ -52,18 +51,18 @@
static int kprobes_initialized;
/* kprobe_table can be accessed by
- * - Normal hlist traversal and RCU add/del under kprobe_mutex is held.
+ * - Normal hlist traversal and RCU add/del under 'kprobe_mutex' is held.
* Or
* - RCU hlist traversal under disabling preempt (breakpoint handlers)
*/
static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
-/* NOTE: change this value only with kprobe_mutex held */
+/* NOTE: change this value only with 'kprobe_mutex' held */
static bool kprobes_all_disarmed;
-/* This protects kprobe_table and optimizing_list */
+/* This protects 'kprobe_table' and 'optimizing_list' */
static DEFINE_MUTEX(kprobe_mutex);
-static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
+static DEFINE_PER_CPU(struct kprobe *, kprobe_instance);
kprobe_opcode_t * __weak kprobe_lookup_name(const char *name,
unsigned int __unused)
@@ -71,12 +70,15 @@ kprobe_opcode_t * __weak kprobe_lookup_name(const char *name,
return ((kprobe_opcode_t *)(kallsyms_lookup_name(name)));
}
-/* Blacklist -- list of struct kprobe_blacklist_entry */
+/*
+ * Blacklist -- list of 'struct kprobe_blacklist_entry' to store info where
+ * kprobes can not probe.
+ */
static LIST_HEAD(kprobe_blacklist);
#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
/*
- * kprobe->ainsn.insn points to the copy of the instruction to be
+ * 'kprobe::ainsn.insn' points to the copy of the instruction to be
* single-stepped. x86_64, POWER4 and above have no-exec support and
* stepping on the instruction on a vmalloced/kmalloced/data page
* is a recipe for disaster
@@ -107,6 +109,12 @@ enum kprobe_slot_state {
void __weak *alloc_insn_page(void)
{
+ /*
+ * Use module_alloc() so this page is within +/- 2GB of where the
+ * kernel image and loaded module images reside. This is required
+ * for most of the architectures.
+ * (e.g. x86-64 needs this to handle the %rip-relative fixups.)
+ */
return module_alloc(PAGE_SIZE);
}
@@ -142,6 +150,7 @@ kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c)
list_for_each_entry_rcu(kip, &c->pages, list) {
if (kip->nused < slots_per_page(c)) {
int i;
+
for (i = 0; i < slots_per_page(c); i++) {
if (kip->slot_used[i] == SLOT_CLEAN) {
kip->slot_used[i] = SLOT_USED;
@@ -167,11 +176,6 @@ kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c)
if (!kip)
goto out;
- /*
- * Use module_alloc so this page is within +/- 2GB of where the
- * kernel image and loaded module images reside. This is required
- * so x86_64 can correctly handle the %rip-relative fixups.
- */
kip->insns = c->alloc();
if (!kip->insns) {
kfree(kip);
@@ -233,6 +237,7 @@ static int collect_garbage_slots(struct kprobe_insn_cache *c)
list_for_each_entry_safe(kip, next, &c->pages, list) {
int i;
+
if (kip->ngarbage == 0)
continue;
kip->ngarbage = 0; /* we will collect all garbages */
@@ -313,7 +318,7 @@ int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum,
list_for_each_entry_rcu(kip, &c->pages, list) {
if ((*symnum)--)
continue;
- strlcpy(sym, c->sym, KSYM_NAME_LEN);
+ strscpy(sym, c->sym, KSYM_NAME_LEN);
*type = 't';
*value = (unsigned long)kip->insns;
ret = 0;
@@ -361,9 +366,9 @@ static inline void reset_kprobe_instance(void)
/*
* This routine is called either:
- * - under the kprobe_mutex - during kprobe_[un]register()
- * OR
- * - with preemption disabled - from arch/xxx/kernel/kprobes.c
+ * - under the 'kprobe_mutex' - during kprobe_[un]register().
+ * OR
+ * - with preemption disabled - from architecture specific code.
*/
struct kprobe *get_kprobe(void *addr)
{
@@ -383,22 +388,20 @@ NOKPROBE_SYMBOL(get_kprobe);
static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs);
-/* Return true if the kprobe is an aggregator */
+/* Return true if 'p' is an aggregator */
static inline int kprobe_aggrprobe(struct kprobe *p)
{
return p->pre_handler == aggr_pre_handler;
}
-/* Return true(!0) if the kprobe is unused */
+/* Return true if 'p' is unused */
static inline int kprobe_unused(struct kprobe *p)
{
return kprobe_aggrprobe(p) && kprobe_disabled(p) &&
list_empty(&p->list);
}
-/*
- * Keep all fields in the kprobe consistent
- */
+/* Keep all fields in the kprobe consistent. */
static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p)
{
memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t));
@@ -406,11 +409,11 @@ static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p)
}
#ifdef CONFIG_OPTPROBES
-/* NOTE: change this value only with kprobe_mutex held */
+/* NOTE: This is protected by 'kprobe_mutex'. */
static bool kprobes_allow_optimization;
/*
- * Call all pre_handler on the list, but ignores its return value.
+ * Call all 'kprobe::pre_handler' on the list, but ignores its return value.
* This must be called from arch-dep optimized caller.
*/
void opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
@@ -438,7 +441,7 @@ static void free_aggr_kprobe(struct kprobe *p)
kfree(op);
}
-/* Return true(!0) if the kprobe is ready for optimization. */
+/* Return true if the kprobe is ready for optimization. */
static inline int kprobe_optready(struct kprobe *p)
{
struct optimized_kprobe *op;
@@ -451,7 +454,7 @@ static inline int kprobe_optready(struct kprobe *p)
return 0;
}
-/* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */
+/* Return true if the kprobe is disarmed. Note: p must be on hash list */
static inline int kprobe_disarmed(struct kprobe *p)
{
struct optimized_kprobe *op;
@@ -465,7 +468,7 @@ static inline int kprobe_disarmed(struct kprobe *p)
return kprobe_disabled(p) && list_empty(&op->list);
}
-/* Return true(!0) if the probe is queued on (un)optimizing lists */
+/* Return true if the probe is queued on (un)optimizing lists */
static int kprobe_queued(struct kprobe *p)
{
struct optimized_kprobe *op;
@@ -480,7 +483,7 @@ static int kprobe_queued(struct kprobe *p)
/*
* Return an optimized kprobe whose optimizing code replaces
- * instructions including addr (exclude breakpoint).
+ * instructions including 'addr' (exclude breakpoint).
*/
static struct kprobe *get_optimized_kprobe(unsigned long addr)
{
@@ -501,7 +504,7 @@ static struct kprobe *get_optimized_kprobe(unsigned long addr)
return NULL;
}
-/* Optimization staging list, protected by kprobe_mutex */
+/* Optimization staging list, protected by 'kprobe_mutex' */
static LIST_HEAD(optimizing_list);
static LIST_HEAD(unoptimizing_list);
static LIST_HEAD(freeing_list);
@@ -512,20 +515,20 @@ static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
/*
* Optimize (replace a breakpoint with a jump) kprobes listed on
- * optimizing_list.
+ * 'optimizing_list'.
*/
static void do_optimize_kprobes(void)
{
lockdep_assert_held(&text_mutex);
/*
- * The optimization/unoptimization refers online_cpus via
- * stop_machine() and cpu-hotplug modifies online_cpus.
- * And same time, text_mutex will be held in cpu-hotplug and here.
- * This combination can cause a deadlock (cpu-hotplug try to lock
- * text_mutex but stop_machine can not be done because online_cpus
- * has been changed)
- * To avoid this deadlock, caller must have locked cpu hotplug
- * for preventing cpu-hotplug outside of text_mutex locking.
+ * The optimization/unoptimization refers 'online_cpus' via
+ * stop_machine() and cpu-hotplug modifies the 'online_cpus'.
+ * And same time, 'text_mutex' will be held in cpu-hotplug and here.
+ * This combination can cause a deadlock (cpu-hotplug tries to lock
+ * 'text_mutex' but stop_machine() can not be done because
+ * the 'online_cpus' has been changed)
+ * To avoid this deadlock, caller must have locked cpu-hotplug
+ * for preventing cpu-hotplug outside of 'text_mutex' locking.
*/
lockdep_assert_cpus_held();
@@ -539,7 +542,7 @@ static void do_optimize_kprobes(void)
/*
* Unoptimize (replace a jump with a breakpoint and remove the breakpoint
- * if need) kprobes listed on unoptimizing_list.
+ * if need) kprobes listed on 'unoptimizing_list'.
*/
static void do_unoptimize_kprobes(void)
{
@@ -554,7 +557,7 @@ static void do_unoptimize_kprobes(void)
return;
arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list);
- /* Loop free_list for disarming */
+ /* Loop on 'freeing_list' for disarming */
list_for_each_entry_safe(op, tmp, &freeing_list, list) {
/* Switching from detour code to origin */
op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
@@ -565,7 +568,7 @@ static void do_unoptimize_kprobes(void)
/*
* Remove unused probes from hash list. After waiting
* for synchronization, these probes are reclaimed.
- * (reclaiming is done by do_free_cleaned_kprobes.)
+ * (reclaiming is done by do_free_cleaned_kprobes().)
*/
hlist_del_rcu(&op->kp.hlist);
} else
@@ -573,7 +576,7 @@ static void do_unoptimize_kprobes(void)
}
}
-/* Reclaim all kprobes on the free_list */
+/* Reclaim all kprobes on the 'freeing_list' */
static void do_free_cleaned_kprobes(void)
{
struct optimized_kprobe *op, *tmp;
@@ -645,9 +648,9 @@ void wait_for_kprobe_optimizer(void)
while (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) {
mutex_unlock(&kprobe_mutex);
- /* this will also make optimizing_work execute immmediately */
+ /* This will also make 'optimizing_work' execute immmediately */
flush_delayed_work(&optimizing_work);
- /* @optimizing_work might not have been queued yet, relax */
+ /* 'optimizing_work' might not have been queued yet, relax */
cpu_relax();
mutex_lock(&kprobe_mutex);
@@ -678,7 +681,7 @@ static void optimize_kprobe(struct kprobe *p)
(kprobe_disabled(p) || kprobes_all_disarmed))
return;
- /* kprobes with post_handler can not be optimized */
+ /* kprobes with 'post_handler' can not be optimized */
if (p->post_handler)
return;
@@ -698,7 +701,10 @@ static void optimize_kprobe(struct kprobe *p)
}
op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
- /* On unoptimizing/optimizing_list, op must have OPTIMIZED flag */
+ /*
+ * On the 'unoptimizing_list' and 'optimizing_list',
+ * 'op' must have OPTIMIZED flag
+ */
if (WARN_ON_ONCE(!list_empty(&op->list)))
return;
@@ -768,7 +774,7 @@ static int reuse_unused_kprobe(struct kprobe *ap)
WARN_ON_ONCE(list_empty(&op->list));
/* Enable the probe again */
ap->flags &= ~KPROBE_FLAG_DISABLED;
- /* Optimize it again (remove from op->list) */
+ /* Optimize it again. (remove from 'op->list') */
if (!kprobe_optready(ap))
return -EINVAL;
@@ -818,7 +824,7 @@ static void prepare_optimized_kprobe(struct kprobe *p)
__prepare_optimized_kprobe(op, p);
}
-/* Allocate new optimized_kprobe and try to prepare optimized instructions */
+/* Allocate new optimized_kprobe and try to prepare optimized instructions. */
static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
{
struct optimized_kprobe *op;
@@ -837,19 +843,19 @@ static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p);
/*
- * Prepare an optimized_kprobe and optimize it
- * NOTE: p must be a normal registered kprobe
+ * Prepare an optimized_kprobe and optimize it.
+ * NOTE: 'p' must be a normal registered kprobe.
*/
static void try_to_optimize_kprobe(struct kprobe *p)
{
struct kprobe *ap;
struct optimized_kprobe *op;
- /* Impossible to optimize ftrace-based kprobe */
+ /* Impossible to optimize ftrace-based kprobe. */
if (kprobe_ftrace(p))
return;
- /* For preparing optimization, jump_label_text_reserved() is called */
+ /* For preparing optimization, jump_label_text_reserved() is called. */
cpus_read_lock();
jump_label_lock();
mutex_lock(&text_mutex);
@@ -860,14 +866,14 @@ static void try_to_optimize_kprobe(struct kprobe *p)
op = container_of(ap, struct optimized_kprobe, kp);
if (!arch_prepared_optinsn(&op->optinsn)) {
- /* If failed to setup optimizing, fallback to kprobe */
+ /* If failed to setup optimizing, fallback to kprobe. */
arch_remove_optimized_kprobe(op);
kfree(op);
goto out;
}
init_aggr_kprobe(ap, p);
- optimize_kprobe(ap); /* This just kicks optimizer thread */
+ optimize_kprobe(ap); /* This just kicks optimizer thread. */
out:
mutex_unlock(&text_mutex);
@@ -882,7 +888,7 @@ static void optimize_all_kprobes(void)
unsigned int i;
mutex_lock(&kprobe_mutex);
- /* If optimization is already allowed, just return */
+ /* If optimization is already allowed, just return. */
if (kprobes_allow_optimization)
goto out;
@@ -908,7 +914,7 @@ static void unoptimize_all_kprobes(void)
unsigned int i;
mutex_lock(&kprobe_mutex);
- /* If optimization is already prohibited, just return */
+ /* If optimization is already prohibited, just return. */
if (!kprobes_allow_optimization) {
mutex_unlock(&kprobe_mutex);
return;
@@ -926,7 +932,7 @@ static void unoptimize_all_kprobes(void)
cpus_read_unlock();
mutex_unlock(&kprobe_mutex);
- /* Wait for unoptimizing completion */
+ /* Wait for unoptimizing completion. */
wait_for_kprobe_optimizer();
pr_info("kprobe jump-optimization is disabled. All kprobes are based on software breakpoint.\n");
}
@@ -953,12 +959,12 @@ int proc_kprobes_optimization_handler(struct ctl_table *table, int write,
}
#endif /* CONFIG_SYSCTL */
-/* Put a breakpoint for a probe. Must be called with text_mutex locked */
+/* Put a breakpoint for a probe. Must be called with 'text_mutex' locked. */
static void __arm_kprobe(struct kprobe *p)
{
struct kprobe *_p;
- /* Check collision with other optimized kprobes */
+ /* Find the overlapping optimized kprobes. */
_p = get_optimized_kprobe((unsigned long)p->addr);
if (unlikely(_p))
/* Fallback to unoptimized kprobe */
@@ -968,7 +974,7 @@ static void __arm_kprobe(struct kprobe *p)
optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */
}
-/* Remove the breakpoint of a probe. Must be called with text_mutex locked */
+/* Remove the breakpoint of a probe. Must be called with 'text_mutex' locked. */
static void __disarm_kprobe(struct kprobe *p, bool reopt)
{
struct kprobe *_p;
@@ -978,12 +984,17 @@ static void __disarm_kprobe(struct kprobe *p, bool reopt)
if (!kprobe_queued(p)) {
arch_disarm_kprobe(p);
- /* If another kprobe was blocked, optimize it. */
+ /* If another kprobe was blocked, re-optimize it. */
_p = get_optimized_kprobe((unsigned long)p->addr);
if (unlikely(_p) && reopt)
optimize_kprobe(_p);
}
- /* TODO: reoptimize others after unoptimized this probe */
+ /*
+ * TODO: Since unoptimization and real disarming will be done by
+ * the worker thread, we can not check whether another probe are
+ * unoptimized because of this probe here. It should be re-optimized
+ * by the worker thread.
+ */
}
#else /* !CONFIG_OPTPROBES */
@@ -1036,7 +1047,7 @@ static struct ftrace_ops kprobe_ipmodify_ops __read_mostly = {
static int kprobe_ipmodify_enabled;
static int kprobe_ftrace_enabled;
-/* Must ensure p->addr is really on ftrace */
+/* Must ensure 'p->addr' is really on ftrace. */
static int prepare_kprobe(struct kprobe *p)
{
if (!kprobe_ftrace(p))
@@ -1045,7 +1056,7 @@ static int prepare_kprobe(struct kprobe *p)
return arch_prepare_kprobe_ftrace(p);
}
-/* Caller must lock kprobe_mutex */
+/* Caller must lock 'kprobe_mutex' */
static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
int *cnt)
{
@@ -1082,7 +1093,7 @@ static int arm_kprobe_ftrace(struct kprobe *p)
ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
}
-/* Caller must lock kprobe_mutex */
+/* Caller must lock 'kprobe_mutex'. */
static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
int *cnt)
{
@@ -1127,7 +1138,7 @@ static inline int disarm_kprobe_ftrace(struct kprobe *p)
}
#endif
-/* Arm a kprobe with text_mutex */
+/* Arm a kprobe with 'text_mutex'. */
static int arm_kprobe(struct kprobe *kp)
{
if (unlikely(kprobe_ftrace(kp)))
@@ -1142,7 +1153,7 @@ static int arm_kprobe(struct kprobe *kp)
return 0;
}
-/* Disarm a kprobe with text_mutex */
+/* Disarm a kprobe with 'text_mutex'. */
static int disarm_kprobe(struct kprobe *kp, bool reopt)
{
if (unlikely(kprobe_ftrace(kp)))
@@ -1192,17 +1203,17 @@ static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
}
NOKPROBE_SYMBOL(aggr_post_handler);
-/* Walks the list and increments nmissed count for multiprobe case */
+/* Walks the list and increments 'nmissed' if 'p' has child probes. */
void kprobes_inc_nmissed_count(struct kprobe *p)
{
struct kprobe *kp;
+
if (!kprobe_aggrprobe(p)) {
p->nmissed++;
} else {
list_for_each_entry_rcu(kp, &p->list, list)
kp->nmissed++;
}
- return;
}
NOKPROBE_SYMBOL(kprobes_inc_nmissed_count);
@@ -1220,9 +1231,9 @@ static void recycle_rp_inst(struct kretprobe_instance *ri)
{
struct kretprobe *rp = get_kretprobe(ri);
- if (likely(rp)) {
+ if (likely(rp))
freelist_add(&ri->freelist, &rp->freelist);
- } else
+ else
call_rcu(&ri->rcu, free_rp_inst_rcu);
}
NOKPROBE_SYMBOL(recycle_rp_inst);
@@ -1248,8 +1259,8 @@ void kprobe_busy_end(void)
}
/*
- * This function is called from finish_task_switch when task tk becomes dead,
- * so that we can recycle any function-return probe instances associated
+ * This function is called from finish_task_switch() when task 'tk' becomes
+ * dead, so that we can recycle any kretprobe instances associated
* with this task. These left over instances represent probed functions
* that have been called but will never return.
*/
@@ -1297,7 +1308,7 @@ static inline void free_rp_inst(struct kretprobe *rp)
}
}
-/* Add the new probe to ap->list */
+/* Add the new probe to 'ap->list'. */
static int add_new_kprobe(struct kprobe *ap, struct kprobe *p)
{
if (p->post_handler)
@@ -1311,12 +1322,12 @@ static int add_new_kprobe(struct kprobe *ap, struct kprobe *p)
}
/*
- * Fill in the required fields of the "manager kprobe". Replace the
- * earlier kprobe in the hlist with the manager kprobe
+ * Fill in the required fields of the aggregator kprobe. Replace the
+ * earlier kprobe in the hlist with the aggregator kprobe.
*/
static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
{
- /* Copy p's insn slot to ap */
+ /* Copy the insn slot of 'p' to 'ap'. */
copy_kprobe(p, ap);
flush_insn_slot(ap);
ap->addr = p->addr;
@@ -1334,8 +1345,7 @@ static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
}
/*
- * This is the second or subsequent kprobe at the address - handle
- * the intricacies
+ * This registers the second or subsequent kprobe at the same address.
*/
static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p)
{
@@ -1349,7 +1359,7 @@ static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p)
mutex_lock(&text_mutex);
if (!kprobe_aggrprobe(orig_p)) {
- /* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */
+ /* If 'orig_p' is not an 'aggr_kprobe', create new one. */
ap = alloc_aggr_kprobe(orig_p);
if (!ap) {
ret = -ENOMEM;
@@ -1374,8 +1384,8 @@ static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p)
if (ret)
/*
* Even if fail to allocate new slot, don't need to
- * free aggr_probe. It will be used next time, or
- * freed by unregister_kprobe.
+ * free the 'ap'. It will be used next time, or
+ * freed by unregister_kprobe().
*/
goto out;
@@ -1390,7 +1400,7 @@ static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p)
| KPROBE_FLAG_DISABLED;
}
- /* Copy ap's insn slot to p */
+ /* Copy the insn slot of 'p' to 'ap'. */
copy_kprobe(ap, p);
ret = add_new_kprobe(ap, p);
@@ -1416,7 +1426,7 @@ static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p)
bool __weak arch_within_kprobe_blacklist(unsigned long addr)
{
- /* The __kprobes marked functions and entry code must not be probed */
+ /* The '__kprobes' functions and entry code must not be probed. */
return addr >= (unsigned long)__kprobes_text_start &&
addr < (unsigned long)__kprobes_text_end;
}
@@ -1428,8 +1438,8 @@ static bool __within_kprobe_blacklist(unsigned long addr)
if (arch_within_kprobe_blacklist(addr))
return true;
/*
- * If there exists a kprobe_blacklist, verify and
- * fail any probe registration in the prohibited area
+ * If 'kprobe_blacklist' is defined, check the address and
+ * reject any probe registration in the prohibited area.
*/
list_for_each_entry(ent, &kprobe_blacklist, list) {
if (addr >= ent->start_addr && addr < ent->end_addr)
@@ -1459,7 +1469,7 @@ bool within_kprobe_blacklist(unsigned long addr)
}
/*
- * If we have a symbol_name argument, look it up and add the offset field
+ * If 'symbol_name' is specified, look it up and add the 'offset'
* to it. This way, we can specify a relative address to a symbol.
* This returns encoded errors if it fails to look up symbol or invalid
* combination of parameters.
@@ -1489,7 +1499,10 @@ static kprobe_opcode_t *kprobe_addr(struct kprobe *p)
return _kprobe_addr(p->addr, p->symbol_name, p->offset);
}
-/* Check passed kprobe is valid and return kprobe in kprobe_table. */
+/*
+ * Check the 'p' is valid and return the aggregator kprobe
+ * at the same address.
+ */
static struct kprobe *__get_valid_kprobe(struct kprobe *p)
{
struct kprobe *ap, *list_p;
@@ -1566,7 +1579,7 @@ static int check_kprobe_address_safe(struct kprobe *p,
goto out;
}
- /* Check if are we probing a module */
+ /* Check if 'p' is probing a module. */
*probed_mod = __module_text_address((unsigned long) p->addr);
if (*probed_mod) {
/*
@@ -1579,7 +1592,7 @@ static int check_kprobe_address_safe(struct kprobe *p,
}
/*
- * If the module freed .init.text, we couldn't insert
+ * If the module freed '.init.text', we couldn't insert
* kprobes in there.
*/
if (within_module_init((unsigned long)p->addr, *probed_mod) &&
@@ -1626,7 +1639,7 @@ int register_kprobe(struct kprobe *p)
old_p = get_kprobe(p->addr);
if (old_p) {
- /* Since this may unoptimize old_p, locking text_mutex. */
+ /* Since this may unoptimize 'old_p', locking 'text_mutex'. */
ret = register_aggr_kprobe(old_p, p);
goto out;
}
@@ -1665,7 +1678,7 @@ int register_kprobe(struct kprobe *p)
}
EXPORT_SYMBOL_GPL(register_kprobe);
-/* Check if all probes on the aggrprobe are disabled */
+/* Check if all probes on the 'ap' are disabled. */
static int aggr_kprobe_disabled(struct kprobe *ap)
{
struct kprobe *kp;
@@ -1675,15 +1688,15 @@ static int aggr_kprobe_disabled(struct kprobe *ap)
list_for_each_entry(kp, &ap->list, list)
if (!kprobe_disabled(kp))
/*
- * There is an active probe on the list.
- * We can't disable this ap.
+ * Since there is an active probe on the list,
+ * we can't disable this 'ap'.
*/
return 0;
return 1;
}
-/* Disable one kprobe: Make sure called under kprobe_mutex is locked */
+/* Disable one kprobe: Make sure called under 'kprobe_mutex' is locked. */
static struct kprobe *__disable_kprobe(struct kprobe *p)
{
struct kprobe *orig_p;
@@ -1702,7 +1715,7 @@ static struct kprobe *__disable_kprobe(struct kprobe *p)
/* Try to disarm and disable this/parent probe */
if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
/*
- * If kprobes_all_disarmed is set, orig_p
+ * If 'kprobes_all_disarmed' is set, 'orig_p'
* should have already been disarmed, so
* skip unneed disarming process.
*/
@@ -1989,7 +2002,7 @@ int register_kretprobe(struct kretprobe *rp)
if (ret)
return ret;
- /* If only rp->kp.addr is specified, check reregistering kprobes */
+ /* If only 'rp->kp.addr' is specified, check reregistering kprobes */
if (rp->kp.addr && warn_kprobe_rereg(&rp->kp))
return -EINVAL;
@@ -2094,13 +2107,13 @@ EXPORT_SYMBOL_GPL(unregister_kretprobes);
#else /* CONFIG_KRETPROBES */
int register_kretprobe(struct kretprobe *rp)
{
- return -ENOSYS;
+ return -EOPNOTSUPP;
}
EXPORT_SYMBOL_GPL(register_kretprobe);
int register_kretprobes(struct kretprobe **rps, int num)
{
- return -ENOSYS;
+ return -EOPNOTSUPP;
}
EXPORT_SYMBOL_GPL(register_kretprobes);
@@ -2149,7 +2162,7 @@ static void kill_kprobe(struct kprobe *p)
/*
* The module is going away. We should disarm the kprobe which
* is using ftrace, because ftrace framework is still available at
- * MODULE_STATE_GOING notification.
+ * 'MODULE_STATE_GOING' notification.
*/
if (kprobe_ftrace(p) && !kprobe_disabled(p) && !kprobes_all_disarmed)
disarm_kprobe_ftrace(p);
@@ -2322,13 +2335,13 @@ static int __init populate_kprobe_blacklist(unsigned long *start,
return ret;
}
- /* Symbols in __kprobes_text are blacklisted */
+ /* Symbols in '__kprobes_text' are blacklisted */
ret = kprobe_add_area_blacklist((unsigned long)__kprobes_text_start,
(unsigned long)__kprobes_text_end);
if (ret)
return ret;
- /* Symbols in noinstr section are blacklisted */
+ /* Symbols in 'noinstr' section are blacklisted */
ret = kprobe_add_area_blacklist((unsigned long)__noinstr_text_start,
(unsigned long)__noinstr_text_end);
@@ -2400,9 +2413,9 @@ static int kprobes_module_callback(struct notifier_block *nb,
return NOTIFY_DONE;
/*
- * When MODULE_STATE_GOING was notified, both of module .text and
- * .init.text sections would be freed. When MODULE_STATE_LIVE was
- * notified, only .init.text section would be freed. We need to
+ * When 'MODULE_STATE_GOING' was notified, both of module '.text' and
+ * '.init.text' sections would be freed. When 'MODULE_STATE_LIVE' was
+ * notified, only '.init.text' section would be freed. We need to
* disable kprobes which have been inserted in the sections.
*/
mutex_lock(&kprobe_mutex);
@@ -2419,9 +2432,9 @@ static int kprobes_module_callback(struct notifier_block *nb,
*
* Note, this will also move any optimized probes
* that are pending to be removed from their
- * corresponding lists to the freeing_list and
+ * corresponding lists to the 'freeing_list' and
* will not be touched by the delayed
- * kprobe_optimizer work handler.
+ * kprobe_optimizer() work handler.
*/
kill_kprobe(p);
}
@@ -2437,10 +2450,6 @@ static struct notifier_block kprobe_module_nb = {
.priority = 0
};
-/* Markers of _kprobe_blacklist section */
-extern unsigned long __start_kprobe_blacklist[];
-extern unsigned long __stop_kprobe_blacklist[];
-
void kprobe_free_init_mem(void)
{
void *start = (void *)(&__init_begin);
@@ -2451,7 +2460,7 @@ void kprobe_free_init_mem(void)
mutex_lock(&kprobe_mutex);
- /* Kill all kprobes on initmem */
+ /* Kill all kprobes on initmem because the target code has been freed. */
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
hlist_for_each_entry(p, head, hlist) {
@@ -2474,9 +2483,8 @@ static int __init init_kprobes(void)
err = populate_kprobe_blacklist(__start_kprobe_blacklist,
__stop_kprobe_blacklist);
- if (err) {
+ if (err)
pr_err("Failed to populate blacklist (error %d), kprobes not restricted, be careful using them!\n", err);
- }
if (kretprobe_blacklist_size) {
/* lookup the function address from its name */
@@ -2493,7 +2501,7 @@ static int __init init_kprobes(void)
kprobes_all_disarmed = false;
#if defined(CONFIG_OPTPROBES) && defined(__ARCH_WANT_KPROBES_INSN_SLOT)
- /* Init kprobe_optinsn_slots for allocation */
+ /* Init 'kprobe_optinsn_slots' for allocation */
kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
#endif
@@ -2627,7 +2635,7 @@ static int kprobe_blacklist_seq_show(struct seq_file *m, void *v)
list_entry(v, struct kprobe_blacklist_entry, list);
/*
- * If /proc/kallsyms is not showing kernel address, we won't
+ * If '/proc/kallsyms' is not showing kernel address, we won't
* show them here either.
*/
if (!kallsyms_show_value(m->file->f_cred))
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