4 * Copyright (C) 1991, 1992 Linus Torvalds
8 * This function is used through-out the kernel (including mm and fs)
9 * to indicate a major problem.
11 #include <linux/module.h>
12 #include <linux/sched.h>
13 #include <linux/delay.h>
14 #include <linux/reboot.h>
15 #include <linux/notifier.h>
16 #include <linux/init.h>
17 #include <linux/sysrq.h>
18 #include <linux/interrupt.h>
19 #include <linux/nmi.h>
20 #include <linux/kexec.h>
21 #include <linux/debug_locks.h>
22 #include <linux/random.h>
23 #include <linux/kallsyms.h>
27 static int pause_on_oops;
28 static int pause_on_oops_flag;
29 static DEFINE_SPINLOCK(pause_on_oops_lock);
33 ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
35 EXPORT_SYMBOL(panic_notifier_list);
37 static int __init panic_setup(char *str)
39 panic_timeout = simple_strtoul(str, NULL, 0);
42 __setup("panic=", panic_setup);
44 static long no_blink(long time)
49 /* Returns how long it waited in ms */
50 long (*panic_blink)(long time);
51 EXPORT_SYMBOL(panic_blink);
54 * panic - halt the system
55 * @fmt: The text string to print
57 * Display a message, then perform cleanups.
59 * This function never returns.
62 NORET_TYPE void panic(const char * fmt, ...)
65 static char buf[1024];
67 #if defined(CONFIG_S390)
68 unsigned long caller = (unsigned long) __builtin_return_address(0);
72 * It's possible to come here directly from a panic-assertion and not
73 * have preempt disabled. Some functions called from here want
74 * preempt to be disabled. No point enabling it later though...
80 vsnprintf(buf, sizeof(buf), fmt, args);
82 printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf);
83 #ifdef CONFIG_DEBUG_BUGVERBOSE
89 * If we have crashed and we have a crash kernel loaded let it handle
91 * Do we want to call this before we try to display a message?
97 * Note smp_send_stop is the usual smp shutdown function, which
98 * unfortunately means it may not be hardened to work in a panic
104 atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
107 panic_blink = no_blink;
109 if (panic_timeout > 0) {
111 * Delay timeout seconds before rebooting the machine.
112 * We can't use the "normal" timers since we just panicked..
114 printk(KERN_EMERG "Rebooting in %d seconds..",panic_timeout);
115 for (i = 0; i < panic_timeout*1000; ) {
116 touch_nmi_watchdog();
121 /* This will not be a clean reboot, with everything
122 * shutting down. But if there is a chance of
123 * rebooting the system it will be rebooted.
129 extern int stop_a_enabled;
130 /* Make sure the user can actually press Stop-A (L1-A) */
132 printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n");
135 #if defined(CONFIG_S390)
136 disabled_wait(caller);
140 touch_softlockup_watchdog();
147 EXPORT_SYMBOL(panic);
150 * print_tainted - return a string to represent the kernel taint state.
152 * 'P' - Proprietary module has been loaded.
153 * 'F' - Module has been forcibly loaded.
154 * 'S' - SMP with CPUs not designed for SMP.
155 * 'R' - User forced a module unload.
156 * 'M' - System experienced a machine check exception.
157 * 'B' - System has hit bad_page.
158 * 'U' - Userspace-defined naughtiness.
159 * 'A' - ACPI table overridden.
160 * 'W' - Taint on warning.
162 * The string is overwritten by the next call to print_taint().
165 const char *print_tainted(void)
169 snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c%c%c%c%c",
170 tainted & TAINT_PROPRIETARY_MODULE ? 'P' : 'G',
171 tainted & TAINT_FORCED_MODULE ? 'F' : ' ',
172 tainted & TAINT_UNSAFE_SMP ? 'S' : ' ',
173 tainted & TAINT_FORCED_RMMOD ? 'R' : ' ',
174 tainted & TAINT_MACHINE_CHECK ? 'M' : ' ',
175 tainted & TAINT_BAD_PAGE ? 'B' : ' ',
176 tainted & TAINT_USER ? 'U' : ' ',
177 tainted & TAINT_DIE ? 'D' : ' ',
178 tainted & TAINT_OVERRIDDEN_ACPI_TABLE ? 'A' : ' ',
179 tainted & TAINT_WARN ? 'W' : ' ');
182 snprintf(buf, sizeof(buf), "Not tainted");
186 void add_taint(unsigned flag)
188 debug_locks = 0; /* can't trust the integrity of the kernel anymore */
191 EXPORT_SYMBOL(add_taint);
193 static int __init pause_on_oops_setup(char *str)
195 pause_on_oops = simple_strtoul(str, NULL, 0);
198 __setup("pause_on_oops=", pause_on_oops_setup);
200 static void spin_msec(int msecs)
204 for (i = 0; i < msecs; i++) {
205 touch_nmi_watchdog();
211 * It just happens that oops_enter() and oops_exit() are identically
214 static void do_oops_enter_exit(void)
217 static int spin_counter;
222 spin_lock_irqsave(&pause_on_oops_lock, flags);
223 if (pause_on_oops_flag == 0) {
224 /* This CPU may now print the oops message */
225 pause_on_oops_flag = 1;
227 /* We need to stall this CPU */
229 /* This CPU gets to do the counting */
230 spin_counter = pause_on_oops;
232 spin_unlock(&pause_on_oops_lock);
233 spin_msec(MSEC_PER_SEC);
234 spin_lock(&pause_on_oops_lock);
235 } while (--spin_counter);
236 pause_on_oops_flag = 0;
238 /* This CPU waits for a different one */
239 while (spin_counter) {
240 spin_unlock(&pause_on_oops_lock);
242 spin_lock(&pause_on_oops_lock);
246 spin_unlock_irqrestore(&pause_on_oops_lock, flags);
250 * Return true if the calling CPU is allowed to print oops-related info. This
253 int oops_may_print(void)
255 return pause_on_oops_flag == 0;
259 * Called when the architecture enters its oops handler, before it prints
260 * anything. If this is the first CPU to oops, and it's oopsing the first time
261 * then let it proceed.
263 * This is all enabled by the pause_on_oops kernel boot option. We do all this
264 * to ensure that oopses don't scroll off the screen. It has the side-effect
265 * of preventing later-oopsing CPUs from mucking up the display, too.
267 * It turns out that the CPU which is allowed to print ends up pausing for the
268 * right duration, whereas all the other CPUs pause for twice as long: once in
269 * oops_enter(), once in oops_exit().
271 void oops_enter(void)
273 debug_locks_off(); /* can't trust the integrity of the kernel anymore */
274 do_oops_enter_exit();
278 * 64-bit random ID for oopses:
282 static int init_oops_id(void)
285 get_random_bytes(&oops_id, sizeof(oops_id));
289 late_initcall(init_oops_id);
291 static void print_oops_end_marker(void)
294 printk(KERN_WARNING "---[ end trace %016llx ]---\n",
295 (unsigned long long)oops_id);
299 * Called when the architecture exits its oops handler, after printing
304 do_oops_enter_exit();
305 print_oops_end_marker();
308 #ifdef WANT_WARN_ON_SLOWPATH
309 void warn_on_slowpath(const char *file, int line)
311 char function[KSYM_SYMBOL_LEN];
312 unsigned long caller = (unsigned long) __builtin_return_address(0);
313 sprint_symbol(function, caller);
315 printk(KERN_WARNING "------------[ cut here ]------------\n");
316 printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file,
320 print_oops_end_marker();
321 add_taint(TAINT_WARN);
323 EXPORT_SYMBOL(warn_on_slowpath);
326 void warn_slowpath(const char *file, int line, const char *fmt, ...)
329 char function[KSYM_SYMBOL_LEN];
330 unsigned long caller = (unsigned long)__builtin_return_address(0);
331 sprint_symbol(function, caller);
333 printk(KERN_WARNING "------------[ cut here ]------------\n");
334 printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file,
342 print_oops_end_marker();
343 add_taint(TAINT_WARN);
345 EXPORT_SYMBOL(warn_slowpath);
348 #ifdef CONFIG_CC_STACKPROTECTOR
351 #warning You have selected the CONFIG_CC_STACKPROTECTOR option, but the gcc used does not support this.
355 * Called when gcc's -fstack-protector feature is used, and
356 * gcc detects corruption of the on-stack canary value
358 void __stack_chk_fail(void)
360 panic("stack-protector: Kernel stack is corrupted in: %p\n",
361 __builtin_return_address(0));
363 EXPORT_SYMBOL(__stack_chk_fail);