[Crash-utility] [PATCH v2 1/3] tree: no need to bail out on tree corruption

[Daniel Vacek]

instead skip the node reporting a proper error and move on

v2: add friendly error messages instead of generic readmem failures
---
 tools.c | 33 +++++++++++++++++++++------------
 1 file changed, 21 insertions(+), 12 deletions(-)

diff --git a/tools.c b/tools.c
index 186b703463a5..7c7f65ac558b 100644
--- a/tools.c
+++ b/tools.c
@@ -4374,8 +4374,8 @@ rbtree_iteration(ulong node_p, struct tree_data *td, char 
*pos)
 {
        int i;
        uint print_radix;
-       ulong struct_p, left_p, right_p;
-       char left_pos[BUFSIZE], right_pos[BUFSIZE];
+       ulong struct_p, new_p, test_p;
+       char new_pos[BUFSIZE];
        static struct req_entry **e;
 
        if (!node_p)
@@ -4430,16 +4430,25 @@ rbtree_iteration(ulong node_p, struct tree_data *td, 
char *pos)
                }
        }
 
-       readmem(node_p+OFFSET(rb_node_rb_left), KVADDR, &left_p,
-               sizeof(void *), "rb_node rb_left", FAULT_ON_ERROR);
-       readmem(node_p+OFFSET(rb_node_rb_right), KVADDR, &right_p,
-               sizeof(void *), "rb_node rb_right", FAULT_ON_ERROR);
-
-       sprintf(left_pos, "%s/l", pos);
-       sprintf(right_pos, "%s/r", pos);
-
-       rbtree_iteration(left_p, td, left_pos);
-       rbtree_iteration(right_p, td, right_pos);               
+       if (       readmem(node_p+OFFSET(rb_node_rb_left), KVADDR, &new_p,
+                       sizeof(void *), "rb_node rb_left", RETURN_ON_ERROR) && 
new_p)
+               if (readmem(new_p+OFFSET(rb_node_rb_left), KVADDR, &test_p,
+                       sizeof(void *), "rb_node rb_left", 
RETURN_ON_ERROR|QUIET)) {
+                       sprintf(new_pos, "%s/l", pos);
+                       rbtree_iteration(new_p, td, new_pos);
+               } else
+                       error(INFO, "rb_node: %lx: corrupted rb_left pointer: 
%lx\n",
+                                       node_p, new_p);
+
+       if (       readmem(node_p+OFFSET(rb_node_rb_right), KVADDR, &new_p,
+                       sizeof(void *), "rb_node rb_right", RETURN_ON_ERROR) && 
new_p)
+               if (readmem(new_p+OFFSET(rb_node_rb_left),  KVADDR, &test_p,
+                       sizeof(void *), "rb_node rb_left",  
RETURN_ON_ERROR|QUIET)) {
+                       sprintf(new_pos, "%s/r", pos);
+                       rbtree_iteration(new_p, td, new_pos);
+               } else
+                       error(INFO, "rb_node: %lx: corrupted rb_right pointer: 
%lx\n",
+                                       node_p, new_p);
 }
 
 void
-- 
2.17.0

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