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uprobes: Do not delete uprobe if uprobe_unregister() fails
delete_uprobe() must not be called if register_for_each_vma(false) fails to remove all breakpoints, __uprobe_unregister() is correct. The problem is that register_for_each_vma(false) always returns 0 and thus this logic does not work. 1. Change verify_opcode() to return 0 rather than -EINVAL when unregister detects the !is_swbp insn, we can treat this case as success and currently unregister paths ignore the error code anyway. 2. Change remove_breakpoint() to propagate the error code from write_opcode(). 3. Change register_for_each_vma(is_register => false) to remove as much breakpoints as possible but return non-zero if remove_breakpoint() fails at least once. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
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@ -203,7 +203,7 @@ static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t
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return 0;
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} else {
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if (!is_swbp) /* unregister: was it changed by us? */
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return -EINVAL;
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return 0;
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}
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return 1;
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@ -616,15 +616,15 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
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return ret;
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}
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static void
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static int
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remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, unsigned long vaddr)
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{
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/* can happen if uprobe_register() fails */
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if (!test_bit(MMF_HAS_UPROBES, &mm->flags))
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return;
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return 0;
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set_bit(MMF_RECALC_UPROBES, &mm->flags);
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set_orig_insn(&uprobe->arch, mm, vaddr);
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return set_orig_insn(&uprobe->arch, mm, vaddr);
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}
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/*
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@ -740,7 +740,7 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
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struct mm_struct *mm = info->mm;
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struct vm_area_struct *vma;
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if (err)
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if (err && is_register)
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goto free;
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down_write(&mm->mmap_sem);
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@ -756,7 +756,7 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
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if (is_register)
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err = install_breakpoint(uprobe, mm, vma, info->vaddr);
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else
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remove_breakpoint(uprobe, mm, info->vaddr);
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err |= remove_breakpoint(uprobe, mm, info->vaddr);
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unlock:
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up_write(&mm->mmap_sem);
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