7b6c6c7773
Use ®s->sp instead of regs for getting the top of stack in kernel mode. (on x86-64, regs->sp always points the top of stack) [ Impact: Oprofile decodes only stack for backtracing on i386 ] Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> [ v2: rename the API to kernel_stack_pointer(), move variable inside ] Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: systemtap@sources.redhat.com Cc: Harvey Harrison <harvey.harrison@gmail.com> Cc: Jan Blunck <jblunck@suse.de> Cc: Christoph Hellwig <hch@infradead.org> LKML-Reference: <20090511210300.17332.67549.stgit@localhost.localdomain> Signed-off-by: Ingo Molnar <mingo@elte.hu>
91 lines
1.9 KiB
C
91 lines
1.9 KiB
C
/**
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* @file backtrace.c
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*
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* @remark Copyright 2002 OProfile authors
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* @remark Read the file COPYING
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*
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* @author John Levon
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* @author David Smith
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*/
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#include <linux/oprofile.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <asm/ptrace.h>
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#include <asm/uaccess.h>
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#include <asm/stacktrace.h>
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static void backtrace_warning_symbol(void *data, char *msg,
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unsigned long symbol)
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{
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/* Ignore warnings */
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}
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static void backtrace_warning(void *data, char *msg)
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{
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/* Ignore warnings */
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}
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static int backtrace_stack(void *data, char *name)
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{
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/* Yes, we want all stacks */
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return 0;
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}
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static void backtrace_address(void *data, unsigned long addr, int reliable)
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{
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unsigned int *depth = data;
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if ((*depth)--)
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oprofile_add_trace(addr);
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}
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static struct stacktrace_ops backtrace_ops = {
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.warning = backtrace_warning,
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.warning_symbol = backtrace_warning_symbol,
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.stack = backtrace_stack,
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.address = backtrace_address,
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};
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struct frame_head {
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struct frame_head *bp;
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unsigned long ret;
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} __attribute__((packed));
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static struct frame_head *dump_user_backtrace(struct frame_head *head)
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{
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struct frame_head bufhead[2];
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/* Also check accessibility of one struct frame_head beyond */
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if (!access_ok(VERIFY_READ, head, sizeof(bufhead)))
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return NULL;
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if (__copy_from_user_inatomic(bufhead, head, sizeof(bufhead)))
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return NULL;
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oprofile_add_trace(bufhead[0].ret);
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/* frame pointers should strictly progress back up the stack
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* (towards higher addresses) */
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if (head >= bufhead[0].bp)
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return NULL;
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return bufhead[0].bp;
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}
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void
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x86_backtrace(struct pt_regs * const regs, unsigned int depth)
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{
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struct frame_head *head = (struct frame_head *)frame_pointer(regs);
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if (!user_mode_vm(regs)) {
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unsigned long stack = kernel_stack_pointer(regs);
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if (depth)
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dump_trace(NULL, regs, (unsigned long *)stack, 0,
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&backtrace_ops, &depth);
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return;
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}
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while (depth-- && head)
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head = dump_user_backtrace(head);
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}
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