196779b9b4
Both dump_stack() and show_stack() are currently implemented by each architecture. show_stack(NULL, NULL) dumps the backtrace for the current task as does dump_stack(). On some archs, dump_stack() prints extra information - pid, utsname and so on - in addition to the backtrace while the two are identical on other archs. The usages in arch-independent code of the two functions indicate show_stack(NULL, NULL) should print out bare backtrace while dump_stack() is used for debugging purposes when something went wrong, so it does make sense to print additional information on the task which triggered dump_stack(). There's no reason to require archs to implement two separate but mostly identical functions. It leads to unnecessary subtle information. This patch expands the dummy fallback dump_stack() implementation in lib/dump_stack.c such that it prints out debug information (taken from x86) and invokes show_stack(NULL, NULL) and drops arch-specific dump_stack() implementations in all archs except blackfin. Blackfin's dump_stack() does something wonky that I don't understand. Debug information can be printed separately by calling dump_stack_print_info() so that arch-specific dump_stack() implementation can still emit the same debug information. This is used in blackfin. This patch brings the following behavior changes. * On some archs, an extra level in backtrace for show_stack() could be printed. This is because the top frame was determined in dump_stack() on those archs while generic dump_stack() can't do that reliably. It can be compensated by inlining dump_stack() but not sure whether that'd be necessary. * Most archs didn't use to print debug info on dump_stack(). They do now. An example WARN dump follows. WARNING: at kernel/workqueue.c:4841 init_workqueues+0x35/0x505() Hardware name: empty Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.9.0-rc1-work+ #9 0000000000000009 ffff88007c861e08 ffffffff81c614dc ffff88007c861e48 ffffffff8108f50f ffffffff82228240 0000000000000040 ffffffff8234a03c 0000000000000000 0000000000000000 0000000000000000 ffff88007c861e58 Call Trace: [<ffffffff81c614dc>] dump_stack+0x19/0x1b [<ffffffff8108f50f>] warn_slowpath_common+0x7f/0xc0 [<ffffffff8108f56a>] warn_slowpath_null+0x1a/0x20 [<ffffffff8234a071>] init_workqueues+0x35/0x505 ... v2: CPU number added to the generic debug info as requested by s390 folks and dropped the s390 specific dump_stack(). This loses %ksp from the debug message which the maintainers think isn't important enough to keep the s390-specific dump_stack() implementation. dump_stack_print_info() is moved to kernel/printk.c from lib/dump_stack.c. Because linkage is per objecct file, dump_stack_print_info() living in the same lib file as generic dump_stack() means that archs which implement custom dump_stack() - at this point, only blackfin - can't use dump_stack_print_info() as that will bring in the generic version of dump_stack() too. v1 The v1 patch broke build on blackfin due to this issue. The build breakage was reported by Fengguang Wu. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Vineet Gupta <vgupta@synopsys.com> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Vineet Gupta <vgupta@synopsys.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> [s390 bits] Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Sam Ravnborg <sam@ravnborg.org> Acked-by: Richard Kuo <rkuo@codeaurora.org> [hexagon bits] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
220 lines
6.3 KiB
C
220 lines
6.3 KiB
C
/*
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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/module.h>
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#include <linux/sched.h>
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#include <asm/processor.h>
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#include <asm/debug.h>
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#include <asm/ipl.h>
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#ifndef CONFIG_64BIT
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#define LONG "%08lx "
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#define FOURLONG "%08lx %08lx %08lx %08lx\n"
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static int kstack_depth_to_print = 12;
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#else /* CONFIG_64BIT */
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#define LONG "%016lx "
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#define FOURLONG "%016lx %016lx %016lx %016lx\n"
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static int kstack_depth_to_print = 20;
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#endif /* CONFIG_64BIT */
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/*
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* For show_trace we have tree different stack to consider:
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* - the panic stack which is used if the kernel stack has overflown
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* - the asynchronous interrupt stack (cpu related)
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* - the synchronous kernel stack (process related)
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* The stack trace can start at any of the three stack and can potentially
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* touch all of them. The order is: panic stack, async stack, sync stack.
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*/
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static unsigned long
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__show_trace(unsigned long sp, unsigned long low, unsigned long high)
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{
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struct stack_frame *sf;
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struct pt_regs *regs;
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while (1) {
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sp = sp & PSW_ADDR_INSN;
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if (sp < low || sp > high - sizeof(*sf))
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return sp;
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sf = (struct stack_frame *) sp;
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printk("([<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
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print_symbol("%s)\n", sf->gprs[8] & PSW_ADDR_INSN);
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/* Follow the backchain. */
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while (1) {
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low = sp;
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sp = sf->back_chain & PSW_ADDR_INSN;
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if (!sp)
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break;
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if (sp <= low || sp > high - sizeof(*sf))
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return sp;
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sf = (struct stack_frame *) sp;
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printk(" [<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
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print_symbol("%s\n", sf->gprs[8] & PSW_ADDR_INSN);
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}
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/* Zero backchain detected, check for interrupt frame. */
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sp = (unsigned long) (sf + 1);
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if (sp <= low || sp > high - sizeof(*regs))
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return sp;
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regs = (struct pt_regs *) sp;
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printk(" [<%016lx>] ", regs->psw.addr & PSW_ADDR_INSN);
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print_symbol("%s\n", regs->psw.addr & PSW_ADDR_INSN);
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low = sp;
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sp = regs->gprs[15];
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}
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}
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static void show_trace(struct task_struct *task, unsigned long *stack)
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{
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register unsigned long __r15 asm ("15");
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unsigned long sp;
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sp = (unsigned long) stack;
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if (!sp)
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sp = task ? task->thread.ksp : __r15;
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printk("Call Trace:\n");
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#ifdef CONFIG_CHECK_STACK
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sp = __show_trace(sp, S390_lowcore.panic_stack - 4096,
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S390_lowcore.panic_stack);
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#endif
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sp = __show_trace(sp, S390_lowcore.async_stack - ASYNC_SIZE,
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S390_lowcore.async_stack);
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if (task)
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__show_trace(sp, (unsigned long) task_stack_page(task),
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(unsigned long) task_stack_page(task) + THREAD_SIZE);
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else
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__show_trace(sp, S390_lowcore.thread_info,
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S390_lowcore.thread_info + THREAD_SIZE);
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if (!task)
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task = current;
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debug_show_held_locks(task);
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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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register unsigned long *__r15 asm ("15");
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unsigned long *stack;
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int i;
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if (!sp)
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stack = task ? (unsigned long *) task->thread.ksp : __r15;
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else
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stack = sp;
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for (i = 0; i < kstack_depth_to_print; i++) {
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if (((addr_t) stack & (THREAD_SIZE-1)) == 0)
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break;
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if ((i * sizeof(long) % 32) == 0)
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printk("%s ", i == 0 ? "" : "\n");
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printk(LONG, *stack++);
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}
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printk("\n");
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show_trace(task, sp);
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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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#ifdef CONFIG_64BIT
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printk("Last Breaking-Event-Address:\n");
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printk(" [<%016lx>] ", regs->args[0] & PSW_ADDR_INSN);
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print_symbol("%s\n", regs->args[0] & PSW_ADDR_INSN);
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#endif
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}
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static inline int mask_bits(struct pt_regs *regs, unsigned long bits)
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{
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return (regs->psw.mask & bits) / ((~bits + 1) & bits);
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}
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void show_registers(struct pt_regs *regs)
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{
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char *mode;
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mode = user_mode(regs) ? "User" : "Krnl";
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printk("%s PSW : %p %p",
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mode, (void *) regs->psw.mask,
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(void *) regs->psw.addr);
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print_symbol(" (%s)\n", regs->psw.addr & PSW_ADDR_INSN);
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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", mask_bits(regs, PSW_MASK_PER),
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mask_bits(regs, PSW_MASK_DAT), mask_bits(regs, PSW_MASK_IO),
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mask_bits(regs, PSW_MASK_EXT), mask_bits(regs, PSW_MASK_KEY),
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mask_bits(regs, PSW_MASK_MCHECK), mask_bits(regs, PSW_MASK_WAIT),
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mask_bits(regs, PSW_MASK_PSTATE), mask_bits(regs, PSW_MASK_ASC),
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mask_bits(regs, PSW_MASK_CC), mask_bits(regs, PSW_MASK_PM));
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#ifdef CONFIG_64BIT
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printk(" EA:%x", mask_bits(regs, PSW_MASK_EA | PSW_MASK_BA));
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#endif
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printk("\n%s GPRS: " FOURLONG, mode,
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regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
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printk(" " FOURLONG,
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regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
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printk(" " FOURLONG,
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regs->gprs[8], regs->gprs[9], regs->gprs[10], regs->gprs[11]);
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printk(" " FOURLONG,
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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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printk("CPU: %d %s %s %.*s\n",
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task_thread_info(current)->cpu, print_tainted(),
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init_utsname()->release,
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(int)strcspn(init_utsname()->version, " "),
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init_utsname()->version);
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printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
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current->comm, current->pid, current,
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(void *) current->thread.ksp);
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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_trace(NULL, (unsigned long *) regs->gprs[15]);
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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 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 [#%d] ", str, regs->int_code & 0xffff, ++die_counter);
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#ifdef CONFIG_PREEMPT
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printk("PREEMPT ");
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#endif
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#ifdef CONFIG_SMP
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printk("SMP ");
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#endif
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#ifdef CONFIG_DEBUG_PAGEALLOC
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printk("DEBUG_PAGEALLOC");
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#endif
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printk("\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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do_exit(SIGSEGV);
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}
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