1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
|
// SPDX-License-Identifier: GPL-2.0
#include <linux/bug.h>
#include <linux/io.h>
#include <linux/types.h>
#include <linux/kdebug.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/sched/task_stack.h>
#include <linux/uaccess.h>
#include <linux/hardirq.h>
#include <linux/kernel.h>
#include <linux/kexec.h>
#include <linux/sched/signal.h>
#include <linux/extable.h>
#include <linux/module.h> /* print_modules */
#include <asm/unwinder.h>
#include <asm/traps.h>
static DEFINE_SPINLOCK(die_lock);
void die(const char *str, struct pt_regs *regs, long err)
{
static int die_counter;
oops_enter();
spin_lock_irq(&die_lock);
console_verbose();
bust_spinlocks(1);
printk("%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
print_modules();
show_regs(regs);
printk("Process: %s (pid: %d, stack limit = %p)\n", current->comm,
task_pid_nr(current), task_stack_page(current) + 1);
if (!user_mode(regs) || in_interrupt())
dump_mem("Stack: ", KERN_DEFAULT, regs->regs[15],
THREAD_SIZE + (unsigned long)task_stack_page(current));
notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV);
bust_spinlocks(0);
add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
spin_unlock_irq(&die_lock);
oops_exit();
if (kexec_should_crash(current))
crash_kexec(regs);
if (in_interrupt())
panic("Fatal exception in interrupt");
if (panic_on_oops)
panic("Fatal exception");
do_exit(SIGSEGV);
}
void die_if_kernel(const char *str, struct pt_regs *regs, long err)
{
if (!user_mode(regs))
die(str, regs, err);
}
/*
* try and fix up kernelspace address errors
* - userspace errors just cause EFAULT to be returned, resulting in SEGV
* - kernel/userspace interfaces cause a jump to an appropriate handler
* - other kernel errors are bad
*/
void die_if_no_fixup(const char *str, struct pt_regs *regs, long err)
{
if (!user_mode(regs)) {
const struct exception_table_entry *fixup;
fixup = search_exception_tables(regs->pc);
if (fixup) {
regs->pc = fixup->fixup;
return;
}
die(str, regs, err);
}
}
#ifdef CONFIG_GENERIC_BUG
static void handle_BUG(struct pt_regs *regs)
{
const struct bug_entry *bug;
unsigned long bugaddr = regs->pc;
enum bug_trap_type tt;
if (!is_valid_bugaddr(bugaddr))
goto invalid;
bug = find_bug(bugaddr);
/* Switch unwinders when unwind_stack() is called */
if (bug->flags & BUGFLAG_UNWINDER)
unwinder_faulted = 1;
tt = report_bug(bugaddr, regs);
if (tt == BUG_TRAP_TYPE_WARN) {
regs->pc += instruction_size(bugaddr);
return;
}
invalid:
die("Kernel BUG", regs, TRAPA_BUG_OPCODE & 0xff);
}
int is_valid_bugaddr(unsigned long addr)
{
insn_size_t opcode;
if (addr < PAGE_OFFSET)
return 0;
if (get_kernel_nofault(opcode, (insn_size_t *)addr))
return 0;
if (opcode == TRAPA_BUG_OPCODE)
return 1;
return 0;
}
#endif
/*
* Generic trap handler.
*/
BUILD_TRAP_HANDLER(debug)
{
TRAP_HANDLER_DECL;
/* Rewind */
regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
if (notify_die(DIE_TRAP, "debug trap", regs, 0, vec & 0xff,
SIGTRAP) == NOTIFY_STOP)
return;
force_sig(SIGTRAP);
}
/*
* Special handler for BUG() traps.
*/
BUILD_TRAP_HANDLER(bug)
{
TRAP_HANDLER_DECL;
/* Rewind */
regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
if (notify_die(DIE_TRAP, "bug trap", regs, 0, TRAPA_BUG_OPCODE & 0xff,
SIGTRAP) == NOTIFY_STOP)
return;
#ifdef CONFIG_GENERIC_BUG
if (__kernel_text_address(instruction_pointer(regs))) {
insn_size_t insn = *(insn_size_t *)instruction_pointer(regs);
if (insn == TRAPA_BUG_OPCODE)
handle_BUG(regs);
return;
}
#endif
force_sig(SIGTRAP);
}
#ifdef CONFIG_DYNAMIC_FTRACE
extern void arch_ftrace_nmi_enter(void);
extern void arch_ftrace_nmi_exit(void);
#else
static inline void arch_ftrace_nmi_enter(void) { }
static inline void arch_ftrace_nmi_exit(void) { }
#endif
BUILD_TRAP_HANDLER(nmi)
{
unsigned int cpu = smp_processor_id();
TRAP_HANDLER_DECL;
arch_ftrace_nmi_enter();
nmi_enter();
this_cpu_inc(irq_stat.__nmi_count);
switch (notify_die(DIE_NMI, "NMI", regs, 0, vec & 0xff, SIGINT)) {
case NOTIFY_OK:
case NOTIFY_STOP:
break;
case NOTIFY_BAD:
die("Fatal Non-Maskable Interrupt", regs, SIGINT);
default:
printk(KERN_ALERT "Got NMI, but nobody cared. Ignoring...\n");
break;
}
nmi_exit();
arch_ftrace_nmi_exit();
}
|
