[Bug runtime/27881] failed to extend vma mapped entry when the address is adjacent

["zhuizhuhaomeng at gmail dot com" <sourceware-bugzilla@sourceware.org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=27881

--- Comment #2 from lijunlong <zhuizhuhaomeng at gmail dot com> ---
The patch is here. Added an attachment also.

diff --git a/runtime/task_finder_vma.c b/runtime/task_finder_vma.c
index 17aaec386..fc388aaf2 100644
--- a/runtime/task_finder_vma.c
+++ b/runtime/task_finder_vma.c
@@ -54,7 +54,7 @@ struct __stp_tf_vma_entry {
        struct task_struct *tsk;
        unsigned long vm_start;
        unsigned long vm_end;
-       unsigned long offset;
+       unsigned long offset;  //offset from base addr of the module
        char path[TASK_FINDER_VMA_ENTRY_PATHLEN]; /* mmpath name, if known */

        // User data (possibly stp_module)
@@ -243,7 +243,7 @@ stap_add_vma_map_info(struct task_struct *tsk, unsigned
long vm_start,
        }

        stp_spin_lock_irqsave(&bucket->lock, flags);
-       hlist_add_head_rcu(&entry->hlist, &bucket->head);
+       hlist_add_tail_rcu(&entry->hlist, &bucket->head);
        stp_spin_unlock_irqrestore(&bucket->lock, flags);
        return 0;
 }
@@ -303,7 +303,7 @@ stap_find_vma_map_info(struct task_struct *tsk, unsigned
long addr,

        bucket = __stp_tf_get_vma_bucket(tsk);
        entry = __stp_tf_get_vma_map(bucket, tsk, 1, addr >= entry->vm_start &&
-                                    addr < entry->vm_end);
+                                    addr <= entry->vm_end);
        if (!entry)
                return -ESRCH;

diff --git a/runtime/vma.c b/runtime/vma.c
index 2bf1b0a9c..78623fda3 100644
--- a/runtime/vma.c
+++ b/runtime/vma.c
@@ -185,14 +185,15 @@ static int _stp_vma_mmap_cb(struct
stap_task_finder_target *tgt,
                                                            module,
                                                            &vm_start, &vm_end,
                                                            NULL);
-                         if (res == -ESRCH || vm_start + offset == addr)
+                         if (res == -ESRCH)
                            res = stap_add_vma_map_info(tsk->group_leader,
-                                                       addr, addr + length,
-                                                       offset, path, module);
-                         else if (res == 0 && vm_end + 1 == addr)
-                           res = stap_extend_vma_map_info(tsk->group_leader,
-                                                          vm_start,
-                                                          addr + length);
+                                                       addr, addr + length,
+                                                       0, path, module);
+                         else
+                           res = stap_add_vma_map_info(tsk->group_leader,
+                                                       addr, addr + length,
+                                                       addr - vm_start, path,
module);
+
                          /* VMA entries are allocated dynamically, this is
fine,
                           * since we are in a task_finder callback, which is
in
                           * user context. */

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