![Ingo Molnar](/assets/img/avatar_default.png)
We are going to split <linux/sched/debug.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/debug.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
318 lines
7.7 KiB
C
318 lines
7.7 KiB
C
/*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
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*/
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#include <linux/kallsyms.h>
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#include <linux/kprobes.h>
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#include <linux/uaccess.h>
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#include <linux/utsname.h>
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#include <linux/hardirq.h>
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#include <linux/kdebug.h>
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#include <linux/module.h>
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#include <linux/ptrace.h>
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#include <linux/sched/debug.h>
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#include <linux/ftrace.h>
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#include <linux/kexec.h>
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#include <linux/bug.h>
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#include <linux/nmi.h>
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#include <linux/sysfs.h>
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#include <asm/stacktrace.h>
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#include <asm/unwind.h>
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int panic_on_unrecovered_nmi;
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int panic_on_io_nmi;
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unsigned int code_bytes = 64;
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static int die_counter;
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bool in_task_stack(unsigned long *stack, struct task_struct *task,
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struct stack_info *info)
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{
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unsigned long *begin = task_stack_page(task);
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unsigned long *end = task_stack_page(task) + THREAD_SIZE;
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if (stack < begin || stack >= end)
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return false;
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info->type = STACK_TYPE_TASK;
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info->begin = begin;
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info->end = end;
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info->next_sp = NULL;
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return true;
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}
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static void printk_stack_address(unsigned long address, int reliable,
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char *log_lvl)
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{
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touch_nmi_watchdog();
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printk("%s %s%pB\n", log_lvl, reliable ? "" : "? ", (void *)address);
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}
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void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
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unsigned long *stack, char *log_lvl)
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{
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struct unwind_state state;
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struct stack_info stack_info = {0};
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unsigned long visit_mask = 0;
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int graph_idx = 0;
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printk("%sCall Trace:\n", log_lvl);
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unwind_start(&state, task, regs, stack);
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stack = stack ? : get_stack_pointer(task, regs);
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/*
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* Iterate through the stacks, starting with the current stack pointer.
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* Each stack has a pointer to the next one.
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*
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* x86-64 can have several stacks:
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* - task stack
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* - interrupt stack
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* - HW exception stacks (double fault, nmi, debug, mce)
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*
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* x86-32 can have up to three stacks:
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* - task stack
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* - softirq stack
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* - hardirq stack
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*/
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for (regs = NULL; stack; stack = stack_info.next_sp) {
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const char *stack_name;
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/*
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* If we overflowed the task stack into a guard page, jump back
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* to the bottom of the usable stack.
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*/
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if (task_stack_page(task) - (void *)stack < PAGE_SIZE)
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stack = task_stack_page(task);
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if (get_stack_info(stack, task, &stack_info, &visit_mask))
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break;
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stack_name = stack_type_name(stack_info.type);
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if (stack_name)
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printk("%s <%s>\n", log_lvl, stack_name);
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/*
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* Scan the stack, printing any text addresses we find. At the
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* same time, follow proper stack frames with the unwinder.
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*
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* Addresses found during the scan which are not reported by
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* the unwinder are considered to be additional clues which are
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* sometimes useful for debugging and are prefixed with '?'.
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* This also serves as a failsafe option in case the unwinder
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* goes off in the weeds.
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*/
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for (; stack < stack_info.end; stack++) {
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unsigned long real_addr;
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int reliable = 0;
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unsigned long addr = READ_ONCE_NOCHECK(*stack);
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unsigned long *ret_addr_p =
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unwind_get_return_address_ptr(&state);
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if (!__kernel_text_address(addr))
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continue;
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/*
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* Don't print regs->ip again if it was already printed
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* by __show_regs() below.
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*/
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if (regs && stack == ®s->ip) {
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unwind_next_frame(&state);
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continue;
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}
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if (stack == ret_addr_p)
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reliable = 1;
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/*
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* When function graph tracing is enabled for a
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* function, its return address on the stack is
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* replaced with the address of an ftrace handler
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* (return_to_handler). In that case, before printing
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* the "real" address, we want to print the handler
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* address as an "unreliable" hint that function graph
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* tracing was involved.
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*/
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real_addr = ftrace_graph_ret_addr(task, &graph_idx,
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addr, stack);
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if (real_addr != addr)
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printk_stack_address(addr, 0, log_lvl);
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printk_stack_address(real_addr, reliable, log_lvl);
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if (!reliable)
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continue;
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/*
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* Get the next frame from the unwinder. No need to
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* check for an error: if anything goes wrong, the rest
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* of the addresses will just be printed as unreliable.
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*/
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unwind_next_frame(&state);
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/* if the frame has entry regs, print them */
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regs = unwind_get_entry_regs(&state);
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if (regs)
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__show_regs(regs, 0);
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}
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if (stack_name)
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printk("%s </%s>\n", log_lvl, stack_name);
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}
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}
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void show_stack(struct task_struct *task, unsigned long *sp)
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{
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task = task ? : current;
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/*
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* Stack frames below this one aren't interesting. Don't show them
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* if we're printing for %current.
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*/
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if (!sp && task == current)
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sp = get_stack_pointer(current, NULL);
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show_trace_log_lvl(task, NULL, sp, KERN_DEFAULT);
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}
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void show_stack_regs(struct pt_regs *regs)
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{
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show_trace_log_lvl(current, regs, NULL, KERN_DEFAULT);
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}
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static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
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static int die_owner = -1;
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static unsigned int die_nest_count;
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unsigned long oops_begin(void)
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{
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int cpu;
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unsigned long flags;
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oops_enter();
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/* racy, but better than risking deadlock. */
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raw_local_irq_save(flags);
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cpu = smp_processor_id();
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if (!arch_spin_trylock(&die_lock)) {
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if (cpu == die_owner)
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/* nested oops. should stop eventually */;
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else
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arch_spin_lock(&die_lock);
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}
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die_nest_count++;
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die_owner = cpu;
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console_verbose();
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bust_spinlocks(1);
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return flags;
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}
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EXPORT_SYMBOL_GPL(oops_begin);
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NOKPROBE_SYMBOL(oops_begin);
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void __noreturn rewind_stack_do_exit(int signr);
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void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
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{
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if (regs && kexec_should_crash(current))
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crash_kexec(regs);
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bust_spinlocks(0);
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die_owner = -1;
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add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
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die_nest_count--;
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if (!die_nest_count)
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/* Nest count reaches zero, release the lock. */
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arch_spin_unlock(&die_lock);
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raw_local_irq_restore(flags);
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oops_exit();
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if (!signr)
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return;
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if (in_interrupt())
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panic("Fatal exception in interrupt");
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if (panic_on_oops)
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panic("Fatal exception");
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/*
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* We're not going to return, but we might be on an IST stack or
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* have very little stack space left. Rewind the stack and kill
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* the task.
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*/
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rewind_stack_do_exit(signr);
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}
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NOKPROBE_SYMBOL(oops_end);
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int __die(const char *str, struct pt_regs *regs, long err)
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{
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#ifdef CONFIG_X86_32
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unsigned short ss;
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unsigned long sp;
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#endif
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printk(KERN_DEFAULT
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"%s: %04lx [#%d]%s%s%s%s\n", str, err & 0xffff, ++die_counter,
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IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT" : "",
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IS_ENABLED(CONFIG_SMP) ? " SMP" : "",
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debug_pagealloc_enabled() ? " DEBUG_PAGEALLOC" : "",
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IS_ENABLED(CONFIG_KASAN) ? " KASAN" : "");
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if (notify_die(DIE_OOPS, str, regs, err,
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current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
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return 1;
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print_modules();
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show_regs(regs);
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#ifdef CONFIG_X86_32
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if (user_mode(regs)) {
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sp = regs->sp;
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ss = regs->ss & 0xffff;
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} else {
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sp = kernel_stack_pointer(regs);
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savesegment(ss, ss);
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}
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printk(KERN_EMERG "EIP: %pS SS:ESP: %04x:%08lx\n",
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(void *)regs->ip, ss, sp);
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#else
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/* Executive summary in case the oops scrolled away */
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printk(KERN_ALERT "RIP: %pS RSP: %016lx\n", (void *)regs->ip, regs->sp);
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#endif
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return 0;
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}
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NOKPROBE_SYMBOL(__die);
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/*
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* This is gone through when something in the kernel has done something bad
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* and is about to be terminated:
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*/
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void die(const char *str, struct pt_regs *regs, long err)
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{
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unsigned long flags = oops_begin();
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int sig = SIGSEGV;
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if (!user_mode(regs))
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report_bug(regs->ip, regs);
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if (__die(str, regs, err))
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sig = 0;
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oops_end(flags, regs, sig);
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}
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static int __init code_bytes_setup(char *s)
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{
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ssize_t ret;
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unsigned long val;
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if (!s)
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return -EINVAL;
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ret = kstrtoul(s, 0, &val);
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if (ret)
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return ret;
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code_bytes = val;
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if (code_bytes > 8192)
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code_bytes = 8192;
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return 1;
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}
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__setup("code_bytes=", code_bytes_setup);
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