diff options
| -rw-r--r-- | kernel/events/uprobes.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index f69ecd39b1a8..2d1457eee965 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -453,7 +453,7 @@ static int update_ref_ctr(struct uprobe *uprobe, struct mm_struct *mm, * @vaddr: the virtual address to store the opcode. * @opcode: opcode to be written at @vaddr. * - * Called with mm->mmap_lock held for write. + * Called with mm->mmap_lock held for read or write. * Return 0 (success) or a negative errno. */ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, @@ -1046,7 +1046,13 @@ register_for_each_vma(struct uprobe *uprobe, struct uprobe_consumer *new) if (err && is_register) goto free; - + /* + * We take mmap_lock for writing to avoid the race with + * find_active_uprobe() which takes mmap_lock for reading. + * Thus this install_breakpoint() can not make + * is_trap_at_addr() true right after find_uprobe() + * returns NULL in find_active_uprobe(). + */ mmap_write_lock(mm); vma = find_vma(mm, info->vaddr); if (!vma || !valid_vma(vma, is_register) || |