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db087ef69a
The previous change documents that cleanup_return_instances() can't always detect the dead frames, the stack can grow. But there is one special case which imho worth fixing: arch_uretprobe_is_alive() can return true when the stack didn't actually grow, but the next "call" insn uses the already invalidated frame. Test-case: #include <stdio.h> #include <setjmp.h> jmp_buf jmp; int nr = 1024; void func_2(void) { if (--nr == 0) return; longjmp(jmp, 1); } void func_1(void) { setjmp(jmp); func_2(); } int main(void) { func_1(); return 0; } If you ret-probe func_1() and func_2() prepare_uretprobe() hits the MAX_URETPROBE_DEPTH limit and "return" from func_2() is not reported. When we know that the new call is not chained, we can do the more strict check. In this case "sp" points to the new ret-addr, so every frame which uses the same "sp" must be dead. The only complication is that arch_uretprobe_is_alive() needs to know was it chained or not, so we add the new RP_CHECK_CHAIN_CALL enum and change prepare_uretprobe() to pass RP_CHECK_CALL only if !chained. Note: arch_uretprobe_is_alive() could also re-read *sp and check if this word is still trampoline_vaddr. This could obviously improve the logic, but I would like to avoid another copy_from_user() especially in the case when we can't avoid the false "alive == T" positives. Tested-by: Pratyush Anand <panand@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Anton Arapov <arapov@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150721134028.GA4786@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
207 lines
6.3 KiB
C
207 lines
6.3 KiB
C
#ifndef _LINUX_UPROBES_H
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#define _LINUX_UPROBES_H
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/*
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* User-space Probes (UProbes)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* Copyright (C) IBM Corporation, 2008-2012
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* Authors:
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* Srikar Dronamraju
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* Jim Keniston
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* Copyright (C) 2011-2012 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
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*/
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#include <linux/errno.h>
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#include <linux/rbtree.h>
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#include <linux/types.h>
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struct vm_area_struct;
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struct mm_struct;
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struct inode;
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struct notifier_block;
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struct page;
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#define UPROBE_HANDLER_REMOVE 1
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#define UPROBE_HANDLER_MASK 1
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#define MAX_URETPROBE_DEPTH 64
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enum uprobe_filter_ctx {
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UPROBE_FILTER_REGISTER,
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UPROBE_FILTER_UNREGISTER,
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UPROBE_FILTER_MMAP,
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};
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struct uprobe_consumer {
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int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs);
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int (*ret_handler)(struct uprobe_consumer *self,
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unsigned long func,
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struct pt_regs *regs);
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bool (*filter)(struct uprobe_consumer *self,
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enum uprobe_filter_ctx ctx,
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struct mm_struct *mm);
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struct uprobe_consumer *next;
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};
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#ifdef CONFIG_UPROBES
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#include <asm/uprobes.h>
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enum uprobe_task_state {
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UTASK_RUNNING,
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UTASK_SSTEP,
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UTASK_SSTEP_ACK,
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UTASK_SSTEP_TRAPPED,
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};
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/*
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* uprobe_task: Metadata of a task while it singlesteps.
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*/
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struct uprobe_task {
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enum uprobe_task_state state;
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union {
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struct {
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struct arch_uprobe_task autask;
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unsigned long vaddr;
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};
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struct {
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struct callback_head dup_xol_work;
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unsigned long dup_xol_addr;
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};
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};
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struct uprobe *active_uprobe;
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unsigned long xol_vaddr;
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struct return_instance *return_instances;
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unsigned int depth;
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};
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struct return_instance {
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struct uprobe *uprobe;
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unsigned long func;
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unsigned long stack; /* stack pointer */
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unsigned long orig_ret_vaddr; /* original return address */
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bool chained; /* true, if instance is nested */
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struct return_instance *next; /* keep as stack */
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};
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enum rp_check {
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RP_CHECK_CALL,
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RP_CHECK_CHAIN_CALL,
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RP_CHECK_RET,
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};
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struct xol_area;
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struct uprobes_state {
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struct xol_area *xol_area;
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};
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extern int set_swbp(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr);
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extern int set_orig_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr);
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extern bool is_swbp_insn(uprobe_opcode_t *insn);
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extern bool is_trap_insn(uprobe_opcode_t *insn);
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extern unsigned long uprobe_get_swbp_addr(struct pt_regs *regs);
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extern unsigned long uprobe_get_trap_addr(struct pt_regs *regs);
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extern int uprobe_write_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t);
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extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
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extern int uprobe_apply(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, bool);
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extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
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extern int uprobe_mmap(struct vm_area_struct *vma);
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extern void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end);
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extern void uprobe_start_dup_mmap(void);
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extern void uprobe_end_dup_mmap(void);
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extern void uprobe_dup_mmap(struct mm_struct *oldmm, struct mm_struct *newmm);
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extern void uprobe_free_utask(struct task_struct *t);
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extern void uprobe_copy_process(struct task_struct *t, unsigned long flags);
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extern int uprobe_post_sstep_notifier(struct pt_regs *regs);
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extern int uprobe_pre_sstep_notifier(struct pt_regs *regs);
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extern void uprobe_notify_resume(struct pt_regs *regs);
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extern bool uprobe_deny_signal(void);
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extern bool arch_uprobe_skip_sstep(struct arch_uprobe *aup, struct pt_regs *regs);
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extern void uprobe_clear_state(struct mm_struct *mm);
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extern int arch_uprobe_analyze_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long addr);
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extern int arch_uprobe_pre_xol(struct arch_uprobe *aup, struct pt_regs *regs);
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extern int arch_uprobe_post_xol(struct arch_uprobe *aup, struct pt_regs *regs);
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extern bool arch_uprobe_xol_was_trapped(struct task_struct *tsk);
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extern int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, void *data);
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extern void arch_uprobe_abort_xol(struct arch_uprobe *aup, struct pt_regs *regs);
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extern unsigned long arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs *regs);
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extern bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx, struct pt_regs *regs);
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extern bool arch_uprobe_ignore(struct arch_uprobe *aup, struct pt_regs *regs);
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extern void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
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void *src, unsigned long len);
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#else /* !CONFIG_UPROBES */
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struct uprobes_state {
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};
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#define uprobe_get_trap_addr(regs) instruction_pointer(regs)
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static inline int
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uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
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{
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return -ENOSYS;
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}
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static inline int
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uprobe_apply(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, bool add)
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{
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return -ENOSYS;
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}
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static inline void
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uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
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{
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}
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static inline int uprobe_mmap(struct vm_area_struct *vma)
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{
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return 0;
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}
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static inline void
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uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end)
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{
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}
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static inline void uprobe_start_dup_mmap(void)
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{
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}
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static inline void uprobe_end_dup_mmap(void)
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{
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}
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static inline void
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uprobe_dup_mmap(struct mm_struct *oldmm, struct mm_struct *newmm)
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{
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}
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static inline void uprobe_notify_resume(struct pt_regs *regs)
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{
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}
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static inline bool uprobe_deny_signal(void)
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{
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return false;
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}
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static inline void uprobe_free_utask(struct task_struct *t)
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{
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}
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static inline void uprobe_copy_process(struct task_struct *t, unsigned long flags)
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{
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}
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static inline void uprobe_clear_state(struct mm_struct *mm)
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{
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}
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#endif /* !CONFIG_UPROBES */
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#endif /* _LINUX_UPROBES_H */
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