From 076a365b3da99b68c5d58e394714d0611f1fa002 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Sun, 30 Sep 2012 18:54:53 +0200 Subject: [PATCH] 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 Acked-by: Srikar Dronamraju --- kernel/events/uprobes.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 588a557..a1b466d 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -203,7 +203,7 @@ static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t return 0; } else { if (!is_swbp) /* unregister: was it changed by us? */ - return -EINVAL; + return 0; } return 1; @@ -616,15 +616,15 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, return ret; } -static void +static int remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, unsigned long vaddr) { /* can happen if uprobe_register() fails */ if (!test_bit(MMF_HAS_UPROBES, &mm->flags)) - return; + return 0; set_bit(MMF_RECALC_UPROBES, &mm->flags); - set_orig_insn(&uprobe->arch, mm, vaddr); + return set_orig_insn(&uprobe->arch, mm, vaddr); } /* @@ -740,7 +740,7 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register) struct mm_struct *mm = info->mm; struct vm_area_struct *vma; - if (err) + if (err && is_register) goto free; down_write(&mm->mmap_sem); @@ -756,7 +756,7 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register) if (is_register) err = install_breakpoint(uprobe, mm, vma, info->vaddr); else - remove_breakpoint(uprobe, mm, info->vaddr); + err |= remove_breakpoint(uprobe, mm, info->vaddr); unlock: up_write(&mm->mmap_sem); -- 2.7.4