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32cdba1e05
This was always racy, but 268720903f
"uprobes: Rework register_for_each_vma() to make it O(n)" should be
blamed anyway, it made everything worse and I didn't notice.
register/unregister call build_map_info() and then do install/remove
breakpoint for every mm which mmaps inode/offset. This can obviously
race with fork()->dup_mmap() in between and we can miss the child.
uprobe_register() could be easily fixed but unregister is much worse,
the new mm inherits "int3" from parent and there is no way to detect
this if uprobe goes away.
So this patch simply adds percpu_down_read/up_read around dup_mmap(),
and percpu_down_write/up_write into register_for_each_vma().
This adds 2 new hooks into dup_mmap() but we can kill uprobe_dup_mmap()
and fold it into uprobe_end_dup_mmap().
Reported-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
164 lines
4.8 KiB
C
164 lines
4.8 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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struct vm_area_struct;
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struct mm_struct;
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struct inode;
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#ifdef CONFIG_ARCH_SUPPORTS_UPROBES
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# include <asm/uprobes.h>
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#endif
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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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/*
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* filter is optional; If a filter exists, handler is run
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* if and only if filter returns true.
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*/
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bool (*filter)(struct uprobe_consumer *self, struct task_struct *task);
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struct uprobe_consumer *next;
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};
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#ifdef CONFIG_UPROBES
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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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struct arch_uprobe_task autask;
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struct uprobe *active_uprobe;
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unsigned long xol_vaddr;
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unsigned long vaddr;
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};
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/*
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* On a breakpoint hit, thread contests for a slot. It frees the
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* slot after singlestep. Currently a fixed number of slots are
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* allocated.
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*/
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struct xol_area {
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wait_queue_head_t wq; /* if all slots are busy */
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atomic_t slot_count; /* number of in-use slots */
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unsigned long *bitmap; /* 0 = free slot */
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struct page *page;
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/*
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* We keep the vma's vm_start rather than a pointer to the vma
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* itself. The probed process or a naughty kernel module could make
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* the vma go away, and we must handle that reasonably gracefully.
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*/
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unsigned long vaddr; /* Page(s) of instruction slots */
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};
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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 __weak set_swbp(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr);
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extern int __weak set_orig_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr);
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extern bool __weak is_swbp_insn(uprobe_opcode_t *insn);
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extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
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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);
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extern unsigned long __weak uprobe_get_swbp_addr(struct pt_regs *regs);
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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 __weak 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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#else /* !CONFIG_UPROBES */
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struct uprobes_state {
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};
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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 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 unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
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{
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return 0;
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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)
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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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