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![Linus Torvalds](/assets/img/avatar_default.png)
were added to 3.10, which includes several bug fixes that have been marked for stable. As for new features, there were a few, but nothing to write to LWN about. These include: New function trigger called "dump" and "cpudump" that will cause ftrace to dump its buffer to the console when the function is called. The difference between "dump" and "cpudump" is that "dump" will dump the entire contents of the ftrace buffer, where as "cpudump" will only dump the contents of the ftrace buffer for the CPU that called the function. Another small enhancement is a new sysctl switch called "traceoff_on_warning" which, when enabled, will disable tracing if any WARN_ON() is triggered. This is useful if you want to debug what caused a warning and do not want to risk losing your trace data by the ring buffer overwriting the data before you can disable it. There's also a kernel command line option that will make this enabled at boot up called the same thing. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQEcBAABAgAGBQJR1uF2AAoJEOdOSU1xswtMJ1IH/2LSiZAKTA2QaRgGQC/5Bb9c XSOI1HfD/78lmUvTyb0AX8sLpkzZlvIONEQ/WaZUFo1Zjbrl45zJUwMkTE9uImEg ZqI5x8OiiN6j4XrRbfYn3Ti060H/Jq41pZXa+shh961Vv51ilv/1yyLkoRmnjzuO JTloPdXDV7icOqqiSdgxSdtUSv59Ef1ZdHgvvsb3aqzMC5btVQPi4kIys0ST1Tr1 pMWBY+UgvH0xYm3gvTR+W6jjDlkVZEH2alkmcinfr+uC1tm9DDqK2HA17Pd5yZ5z HNdT76lCzf9iqRF5F8HUvUt+PIp76dNNxAt2qpB6APqAuJTojyguxXHDbY/0kzs= =UvLi -----END PGP SIGNATURE----- Merge tag 'trace-3.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing changes from Steven Rostedt: "The majority of the changes here are cleanups for the large changes that were added to 3.10, which includes several bug fixes that have been marked for stable. As for new features, there were a few, but nothing to write to LWN about. These include: New function trigger called "dump" and "cpudump" that will cause ftrace to dump its buffer to the console when the function is called. The difference between "dump" and "cpudump" is that "dump" will dump the entire contents of the ftrace buffer, where as "cpudump" will only dump the contents of the ftrace buffer for the CPU that called the function. Another small enhancement is a new sysctl switch called "traceoff_on_warning" which, when enabled, will disable tracing if any WARN_ON() is triggered. This is useful if you want to debug what caused a warning and do not want to risk losing your trace data by the ring buffer overwriting the data before you can disable it. There's also a kernel command line option that will make this enabled at boot up called the same thing" * tag 'trace-3.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (34 commits) tracing: Make tracing_open_generic_{tr,tc}() static tracing: Remove ftrace() function tracing: Remove TRACE_EVENT_TYPE enum definition tracing: Make tracer_tracing_{off,on,is_on}() static tracing: Fix irqs-off tag display in syscall tracing uprobes: Fix return value in error handling path tracing: Fix race between deleting buffer and setting events tracing: Add trace_array_get/put() to event handling tracing: Get trace_array ref counts when accessing trace files tracing: Add trace_array_get/put() to handle instance refs better tracing: Protect ftrace_trace_arrays list in trace_events.c tracing: Make trace_marker use the correct per-instance buffer ftrace: Do not run selftest if command line parameter is set tracing/kprobes: Don't pass addr=ip to perf_trace_buf_submit() tracing: Use flag buffer_disabled for irqsoff tracer tracing/kprobes: Turn trace_probe->files into list_head tracing: Fix disabling of soft disable tracing: Add missing syscall_metadata comment tracing: Simplify code for showing of soft disabled flag tracing/kprobes: Kill probe_enable_lock ...
478 lines
11 KiB
C
478 lines
11 KiB
C
/*
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* linux/kernel/panic.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*/
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/*
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* This function is used through-out the kernel (including mm and fs)
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* to indicate a major problem.
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*/
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#include <linux/debug_locks.h>
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#include <linux/interrupt.h>
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#include <linux/kmsg_dump.h>
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#include <linux/kallsyms.h>
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#include <linux/notifier.h>
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#include <linux/module.h>
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#include <linux/random.h>
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#include <linux/ftrace.h>
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#include <linux/reboot.h>
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#include <linux/delay.h>
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#include <linux/kexec.h>
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#include <linux/sched.h>
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#include <linux/sysrq.h>
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#include <linux/init.h>
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#include <linux/nmi.h>
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#define PANIC_TIMER_STEP 100
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#define PANIC_BLINK_SPD 18
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int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE;
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static unsigned long tainted_mask;
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static int pause_on_oops;
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static int pause_on_oops_flag;
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static DEFINE_SPINLOCK(pause_on_oops_lock);
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int panic_timeout;
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EXPORT_SYMBOL_GPL(panic_timeout);
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ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
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EXPORT_SYMBOL(panic_notifier_list);
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static long no_blink(int state)
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{
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return 0;
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}
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/* Returns how long it waited in ms */
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long (*panic_blink)(int state);
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EXPORT_SYMBOL(panic_blink);
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/*
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* Stop ourself in panic -- architecture code may override this
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*/
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void __weak panic_smp_self_stop(void)
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{
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while (1)
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cpu_relax();
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}
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/**
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* panic - halt the system
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* @fmt: The text string to print
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*
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* Display a message, then perform cleanups.
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*
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* This function never returns.
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*/
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void panic(const char *fmt, ...)
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{
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static DEFINE_SPINLOCK(panic_lock);
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static char buf[1024];
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va_list args;
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long i, i_next = 0;
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int state = 0;
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/*
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* Disable local interrupts. This will prevent panic_smp_self_stop
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* from deadlocking the first cpu that invokes the panic, since
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* there is nothing to prevent an interrupt handler (that runs
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* after the panic_lock is acquired) from invoking panic again.
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*/
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local_irq_disable();
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/*
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* It's possible to come here directly from a panic-assertion and
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* not have preempt disabled. Some functions called from here want
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* preempt to be disabled. No point enabling it later though...
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*
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* Only one CPU is allowed to execute the panic code from here. For
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* multiple parallel invocations of panic, all other CPUs either
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* stop themself or will wait until they are stopped by the 1st CPU
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* with smp_send_stop().
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*/
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if (!spin_trylock(&panic_lock))
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panic_smp_self_stop();
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console_verbose();
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bust_spinlocks(1);
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va_start(args, fmt);
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vsnprintf(buf, sizeof(buf), fmt, args);
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va_end(args);
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printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf);
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#ifdef CONFIG_DEBUG_BUGVERBOSE
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/*
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* Avoid nested stack-dumping if a panic occurs during oops processing
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*/
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if (!test_taint(TAINT_DIE) && oops_in_progress <= 1)
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dump_stack();
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#endif
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/*
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* If we have crashed and we have a crash kernel loaded let it handle
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* everything else.
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* Do we want to call this before we try to display a message?
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*/
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crash_kexec(NULL);
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/*
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* Note smp_send_stop is the usual smp shutdown function, which
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* unfortunately means it may not be hardened to work in a panic
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* situation.
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*/
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smp_send_stop();
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kmsg_dump(KMSG_DUMP_PANIC);
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atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
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bust_spinlocks(0);
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if (!panic_blink)
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panic_blink = no_blink;
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if (panic_timeout > 0) {
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/*
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* Delay timeout seconds before rebooting the machine.
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* We can't use the "normal" timers since we just panicked.
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*/
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printk(KERN_EMERG "Rebooting in %d seconds..", panic_timeout);
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for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) {
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touch_nmi_watchdog();
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if (i >= i_next) {
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i += panic_blink(state ^= 1);
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i_next = i + 3600 / PANIC_BLINK_SPD;
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}
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mdelay(PANIC_TIMER_STEP);
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}
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}
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if (panic_timeout != 0) {
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/*
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* This will not be a clean reboot, with everything
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* shutting down. But if there is a chance of
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* rebooting the system it will be rebooted.
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*/
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emergency_restart();
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}
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#ifdef __sparc__
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{
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extern int stop_a_enabled;
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/* Make sure the user can actually press Stop-A (L1-A) */
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stop_a_enabled = 1;
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printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n");
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}
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#endif
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#if defined(CONFIG_S390)
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{
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unsigned long caller;
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caller = (unsigned long)__builtin_return_address(0);
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disabled_wait(caller);
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}
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#endif
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local_irq_enable();
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for (i = 0; ; i += PANIC_TIMER_STEP) {
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touch_softlockup_watchdog();
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if (i >= i_next) {
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i += panic_blink(state ^= 1);
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i_next = i + 3600 / PANIC_BLINK_SPD;
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}
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mdelay(PANIC_TIMER_STEP);
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}
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}
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EXPORT_SYMBOL(panic);
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struct tnt {
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u8 bit;
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char true;
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char false;
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};
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static const struct tnt tnts[] = {
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{ TAINT_PROPRIETARY_MODULE, 'P', 'G' },
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{ TAINT_FORCED_MODULE, 'F', ' ' },
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{ TAINT_UNSAFE_SMP, 'S', ' ' },
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{ TAINT_FORCED_RMMOD, 'R', ' ' },
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{ TAINT_MACHINE_CHECK, 'M', ' ' },
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{ TAINT_BAD_PAGE, 'B', ' ' },
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{ TAINT_USER, 'U', ' ' },
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{ TAINT_DIE, 'D', ' ' },
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{ TAINT_OVERRIDDEN_ACPI_TABLE, 'A', ' ' },
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{ TAINT_WARN, 'W', ' ' },
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{ TAINT_CRAP, 'C', ' ' },
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{ TAINT_FIRMWARE_WORKAROUND, 'I', ' ' },
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{ TAINT_OOT_MODULE, 'O', ' ' },
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};
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/**
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* print_tainted - return a string to represent the kernel taint state.
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*
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* 'P' - Proprietary module has been loaded.
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* 'F' - Module has been forcibly loaded.
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* 'S' - SMP with CPUs not designed for SMP.
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* 'R' - User forced a module unload.
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* 'M' - System experienced a machine check exception.
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* 'B' - System has hit bad_page.
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* 'U' - Userspace-defined naughtiness.
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* 'D' - Kernel has oopsed before
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* 'A' - ACPI table overridden.
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* 'W' - Taint on warning.
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* 'C' - modules from drivers/staging are loaded.
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* 'I' - Working around severe firmware bug.
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* 'O' - Out-of-tree module has been loaded.
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*
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* The string is overwritten by the next call to print_tainted().
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*/
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const char *print_tainted(void)
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{
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static char buf[ARRAY_SIZE(tnts) + sizeof("Tainted: ") + 1];
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if (tainted_mask) {
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char *s;
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int i;
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s = buf + sprintf(buf, "Tainted: ");
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for (i = 0; i < ARRAY_SIZE(tnts); i++) {
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const struct tnt *t = &tnts[i];
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*s++ = test_bit(t->bit, &tainted_mask) ?
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t->true : t->false;
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}
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*s = 0;
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} else
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snprintf(buf, sizeof(buf), "Not tainted");
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return buf;
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}
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int test_taint(unsigned flag)
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{
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return test_bit(flag, &tainted_mask);
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}
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EXPORT_SYMBOL(test_taint);
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unsigned long get_taint(void)
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{
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return tainted_mask;
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}
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/**
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* add_taint: add a taint flag if not already set.
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* @flag: one of the TAINT_* constants.
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* @lockdep_ok: whether lock debugging is still OK.
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*
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* If something bad has gone wrong, you'll want @lockdebug_ok = false, but for
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* some notewortht-but-not-corrupting cases, it can be set to true.
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*/
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void add_taint(unsigned flag, enum lockdep_ok lockdep_ok)
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{
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if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off())
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printk(KERN_WARNING
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"Disabling lock debugging due to kernel taint\n");
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set_bit(flag, &tainted_mask);
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}
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EXPORT_SYMBOL(add_taint);
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static void spin_msec(int msecs)
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{
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int i;
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for (i = 0; i < msecs; i++) {
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touch_nmi_watchdog();
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mdelay(1);
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}
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}
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/*
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* It just happens that oops_enter() and oops_exit() are identically
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* implemented...
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*/
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static void do_oops_enter_exit(void)
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{
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unsigned long flags;
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static int spin_counter;
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if (!pause_on_oops)
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return;
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spin_lock_irqsave(&pause_on_oops_lock, flags);
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if (pause_on_oops_flag == 0) {
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/* This CPU may now print the oops message */
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pause_on_oops_flag = 1;
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} else {
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/* We need to stall this CPU */
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if (!spin_counter) {
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/* This CPU gets to do the counting */
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spin_counter = pause_on_oops;
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do {
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spin_unlock(&pause_on_oops_lock);
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spin_msec(MSEC_PER_SEC);
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spin_lock(&pause_on_oops_lock);
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} while (--spin_counter);
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pause_on_oops_flag = 0;
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} else {
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/* This CPU waits for a different one */
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while (spin_counter) {
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spin_unlock(&pause_on_oops_lock);
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spin_msec(1);
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spin_lock(&pause_on_oops_lock);
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}
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}
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}
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spin_unlock_irqrestore(&pause_on_oops_lock, flags);
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}
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/*
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* Return true if the calling CPU is allowed to print oops-related info.
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* This is a bit racy..
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*/
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int oops_may_print(void)
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{
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return pause_on_oops_flag == 0;
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}
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/*
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* Called when the architecture enters its oops handler, before it prints
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* anything. If this is the first CPU to oops, and it's oopsing the first
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* time then let it proceed.
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*
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* This is all enabled by the pause_on_oops kernel boot option. We do all
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* this to ensure that oopses don't scroll off the screen. It has the
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* side-effect of preventing later-oopsing CPUs from mucking up the display,
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* too.
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*
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* It turns out that the CPU which is allowed to print ends up pausing for
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* the right duration, whereas all the other CPUs pause for twice as long:
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* once in oops_enter(), once in oops_exit().
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*/
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void oops_enter(void)
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{
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tracing_off();
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/* can't trust the integrity of the kernel anymore: */
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debug_locks_off();
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do_oops_enter_exit();
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}
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/*
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* 64-bit random ID for oopses:
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*/
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static u64 oops_id;
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static int init_oops_id(void)
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{
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if (!oops_id)
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get_random_bytes(&oops_id, sizeof(oops_id));
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else
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oops_id++;
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return 0;
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}
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late_initcall(init_oops_id);
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void print_oops_end_marker(void)
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{
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init_oops_id();
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printk(KERN_WARNING "---[ end trace %016llx ]---\n",
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(unsigned long long)oops_id);
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}
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/*
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* Called when the architecture exits its oops handler, after printing
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* everything.
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*/
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void oops_exit(void)
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{
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do_oops_enter_exit();
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print_oops_end_marker();
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kmsg_dump(KMSG_DUMP_OOPS);
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}
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#ifdef WANT_WARN_ON_SLOWPATH
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struct slowpath_args {
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const char *fmt;
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va_list args;
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};
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static void warn_slowpath_common(const char *file, int line, void *caller,
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unsigned taint, struct slowpath_args *args)
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{
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disable_trace_on_warning();
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pr_warn("------------[ cut here ]------------\n");
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pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS()\n",
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raw_smp_processor_id(), current->pid, file, line, caller);
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if (args)
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vprintk(args->fmt, args->args);
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print_modules();
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dump_stack();
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print_oops_end_marker();
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/* Just a warning, don't kill lockdep. */
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add_taint(taint, LOCKDEP_STILL_OK);
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}
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void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
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{
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struct slowpath_args args;
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args.fmt = fmt;
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va_start(args.args, fmt);
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warn_slowpath_common(file, line, __builtin_return_address(0),
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TAINT_WARN, &args);
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va_end(args.args);
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}
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EXPORT_SYMBOL(warn_slowpath_fmt);
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void warn_slowpath_fmt_taint(const char *file, int line,
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unsigned taint, const char *fmt, ...)
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{
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struct slowpath_args args;
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args.fmt = fmt;
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va_start(args.args, fmt);
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warn_slowpath_common(file, line, __builtin_return_address(0),
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taint, &args);
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va_end(args.args);
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}
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EXPORT_SYMBOL(warn_slowpath_fmt_taint);
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void warn_slowpath_null(const char *file, int line)
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{
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warn_slowpath_common(file, line, __builtin_return_address(0),
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TAINT_WARN, NULL);
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}
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EXPORT_SYMBOL(warn_slowpath_null);
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#endif
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#ifdef CONFIG_CC_STACKPROTECTOR
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/*
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* Called when gcc's -fstack-protector feature is used, and
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* gcc detects corruption of the on-stack canary value
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*/
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void __stack_chk_fail(void)
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{
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|
panic("stack-protector: Kernel stack is corrupted in: %p\n",
|
|
__builtin_return_address(0));
|
|
}
|
|
EXPORT_SYMBOL(__stack_chk_fail);
|
|
|
|
#endif
|
|
|
|
core_param(panic, panic_timeout, int, 0644);
|
|
core_param(pause_on_oops, pause_on_oops, int, 0644);
|
|
|
|
static int __init oops_setup(char *s)
|
|
{
|
|
if (!s)
|
|
return -EINVAL;
|
|
if (!strcmp(s, "panic"))
|
|
panic_on_oops = 1;
|
|
return 0;
|
|
}
|
|
early_param("oops", oops_setup);
|