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![Eric W. Biederman](/assets/img/avatar_default.png)
There are two big uses of do_exit. The first is it's design use to be the guts of the exit(2) system call. The second use is to terminate a task after something catastrophic has happened like a NULL pointer in kernel code. Add a function make_task_dead that is initialy exactly the same as do_exit to cover the cases where do_exit is called to handle catastrophic failure. In time this can probably be reduced to just a light wrapper around do_task_dead. For now keep it exactly the same so that there will be no behavioral differences introducing this new concept. Replace all of the uses of do_exit that use it for catastraphic task cleanup with make_task_dead to make it clear what the code is doing. As part of this rename rewind_stack_do_exit rewind_stack_and_make_dead. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
228 lines
6.2 KiB
C
228 lines
6.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Stack dumping functions
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*
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* Copyright IBM Corp. 1999, 2013
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*/
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#include <linux/kallsyms.h>
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#include <linux/hardirq.h>
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#include <linux/kprobes.h>
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#include <linux/utsname.h>
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#include <linux/export.h>
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#include <linux/kdebug.h>
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#include <linux/ptrace.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/sched/debug.h>
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#include <linux/sched/task_stack.h>
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#include <asm/processor.h>
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#include <asm/debug.h>
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#include <asm/dis.h>
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#include <asm/ipl.h>
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#include <asm/unwind.h>
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const char *stack_type_name(enum stack_type type)
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{
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switch (type) {
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case STACK_TYPE_TASK:
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return "task";
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case STACK_TYPE_IRQ:
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return "irq";
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case STACK_TYPE_NODAT:
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return "nodat";
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case STACK_TYPE_RESTART:
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return "restart";
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default:
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return "unknown";
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}
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}
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EXPORT_SYMBOL_GPL(stack_type_name);
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static inline bool in_stack(unsigned long sp, struct stack_info *info,
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enum stack_type type, unsigned long low,
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unsigned long high)
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{
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if (sp < low || sp >= high)
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return false;
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info->type = type;
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info->begin = low;
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info->end = high;
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return true;
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}
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static bool in_task_stack(unsigned long sp, struct task_struct *task,
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struct stack_info *info)
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{
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unsigned long stack;
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stack = (unsigned long) task_stack_page(task);
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return in_stack(sp, info, STACK_TYPE_TASK, stack, stack + THREAD_SIZE);
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}
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static bool in_irq_stack(unsigned long sp, struct stack_info *info)
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{
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unsigned long frame_size, top;
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frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
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top = S390_lowcore.async_stack + frame_size;
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return in_stack(sp, info, STACK_TYPE_IRQ, top - THREAD_SIZE, top);
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}
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static bool in_nodat_stack(unsigned long sp, struct stack_info *info)
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{
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unsigned long frame_size, top;
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frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
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top = S390_lowcore.nodat_stack + frame_size;
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return in_stack(sp, info, STACK_TYPE_NODAT, top - THREAD_SIZE, top);
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}
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static bool in_mcck_stack(unsigned long sp, struct stack_info *info)
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{
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unsigned long frame_size, top;
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frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
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top = S390_lowcore.mcck_stack + frame_size;
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return in_stack(sp, info, STACK_TYPE_MCCK, top - THREAD_SIZE, top);
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}
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static bool in_restart_stack(unsigned long sp, struct stack_info *info)
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{
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unsigned long frame_size, top;
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frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
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top = S390_lowcore.restart_stack + frame_size;
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return in_stack(sp, info, STACK_TYPE_RESTART, top - THREAD_SIZE, top);
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}
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int get_stack_info(unsigned long sp, struct task_struct *task,
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struct stack_info *info, unsigned long *visit_mask)
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{
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if (!sp)
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goto unknown;
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/* Sanity check: ABI requires SP to be aligned 8 bytes. */
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if (sp & 0x7)
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goto unknown;
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/* Check per-task stack */
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if (in_task_stack(sp, task, info))
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goto recursion_check;
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if (task != current)
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goto unknown;
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/* Check per-cpu stacks */
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if (!in_irq_stack(sp, info) &&
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!in_nodat_stack(sp, info) &&
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!in_restart_stack(sp, info) &&
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!in_mcck_stack(sp, info))
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goto unknown;
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recursion_check:
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/*
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* Make sure we don't iterate through any given stack more than once.
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* If it comes up a second time then there's something wrong going on:
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* just break out and report an unknown stack type.
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*/
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if (*visit_mask & (1UL << info->type))
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goto unknown;
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*visit_mask |= 1UL << info->type;
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return 0;
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unknown:
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info->type = STACK_TYPE_UNKNOWN;
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return -EINVAL;
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}
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void show_stack(struct task_struct *task, unsigned long *stack,
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const char *loglvl)
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{
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struct unwind_state state;
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printk("%sCall Trace:\n", loglvl);
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unwind_for_each_frame(&state, task, NULL, (unsigned long) stack)
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printk(state.reliable ? "%s [<%016lx>] %pSR \n" :
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"%s([<%016lx>] %pSR)\n",
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loglvl, state.ip, (void *) state.ip);
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debug_show_held_locks(task ? : current);
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}
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static void show_last_breaking_event(struct pt_regs *regs)
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{
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printk("Last Breaking-Event-Address:\n");
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printk(" [<%016lx>] %pSR\n", regs->last_break, (void *)regs->last_break);
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}
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void show_registers(struct pt_regs *regs)
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{
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struct psw_bits *psw = &psw_bits(regs->psw);
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char *mode;
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mode = user_mode(regs) ? "User" : "Krnl";
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printk("%s PSW : %px %px", mode, (void *)regs->psw.mask, (void *)regs->psw.addr);
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if (!user_mode(regs))
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pr_cont(" (%pSR)", (void *)regs->psw.addr);
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pr_cont("\n");
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printk(" R:%x T:%x IO:%x EX:%x Key:%x M:%x W:%x "
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"P:%x AS:%x CC:%x PM:%x", psw->per, psw->dat, psw->io, psw->ext,
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psw->key, psw->mcheck, psw->wait, psw->pstate, psw->as, psw->cc, psw->pm);
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pr_cont(" RI:%x EA:%x\n", psw->ri, psw->eaba);
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printk("%s GPRS: %016lx %016lx %016lx %016lx\n", mode,
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regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
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printk(" %016lx %016lx %016lx %016lx\n",
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regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
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printk(" %016lx %016lx %016lx %016lx\n",
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regs->gprs[8], regs->gprs[9], regs->gprs[10], regs->gprs[11]);
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printk(" %016lx %016lx %016lx %016lx\n",
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regs->gprs[12], regs->gprs[13], regs->gprs[14], regs->gprs[15]);
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show_code(regs);
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}
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void show_regs(struct pt_regs *regs)
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{
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show_regs_print_info(KERN_DEFAULT);
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show_registers(regs);
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/* Show stack backtrace if pt_regs is from kernel mode */
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if (!user_mode(regs))
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show_stack(NULL, (unsigned long *) regs->gprs[15], KERN_DEFAULT);
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show_last_breaking_event(regs);
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}
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static DEFINE_SPINLOCK(die_lock);
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void __noreturn die(struct pt_regs *regs, const char *str)
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{
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static int die_counter;
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oops_enter();
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lgr_info_log();
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debug_stop_all();
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console_verbose();
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spin_lock_irq(&die_lock);
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bust_spinlocks(1);
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printk("%s: %04x ilc:%d [#%d] ", str, regs->int_code & 0xffff,
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regs->int_code >> 17, ++die_counter);
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#ifdef CONFIG_PREEMPT
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pr_cont("PREEMPT ");
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#elif defined(CONFIG_PREEMPT_RT)
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pr_cont("PREEMPT_RT ");
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#endif
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pr_cont("SMP ");
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if (debug_pagealloc_enabled())
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pr_cont("DEBUG_PAGEALLOC");
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pr_cont("\n");
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notify_die(DIE_OOPS, str, regs, 0, regs->int_code & 0xffff, SIGSEGV);
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print_modules();
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show_regs(regs);
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bust_spinlocks(0);
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add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
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spin_unlock_irq(&die_lock);
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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: panic_on_oops");
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oops_exit();
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make_task_dead(SIGSEGV);
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}
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