[PATCH] Fix recursion loop in mod_count_all_dependencies()

[matwey . kornilov]

>From 48d4d7ba1acbb5c0955f75c6bdda9cf0935240fd Mon Sep 17 00:00:00 2001
From: "Matwey V. Kornilov" <matwey.korni...@gmail.com>
Date: Fri, 11 Apr 2014 19:43:18 +0400
Subject: [PATCH] Fix recursion loop in mod_count_all_dependencies() when
 subgraph has a cycle.

When cycle is detected in mod_count_all_dependencies, use total count of
modules as an upper bound of needed memory. Correct number of nodes is 
determined by
subsequent call of mod_fill_all_unique_dependencies().
---
 tools/depmod.c | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/tools/depmod.c b/tools/depmod.c
index 1aedaaf..c83dee1 100644
--- a/tools/depmod.c
+++ b/tools/depmod.c
@@ -1682,12 +1682,20 @@ static int depmod_load(struct depmod *depmod)
        return 0;
 }
 
-static size_t mod_count_all_dependencies(const struct mod *mod)
+static size_t mod_count_all_dependencies(const struct mod *mod, size_t 
upper_bound)
 {
        size_t i, count = 0;
+       /* cycle is detected */
+       if (mod->dep_loop)
+               return upper_bound;
+
        for (i = 0; i < mod->deps.count; i++) {
                const struct mod *d = mod->deps.array[i];
-               count += 1 + mod_count_all_dependencies(d);
+               const size_t child = mod_count_all_dependencies(d, upper_bound);
+               if(child == upper_bound)
+                       return child;
+
+               count += 1 + child;
        }
        return count;
 }
@@ -1722,12 +1730,12 @@ static int mod_fill_all_unique_dependencies(const 
struct mod *mod, const struct
        return err;
 }
 
-static const struct mod **mod_get_all_sorted_dependencies(const struct mod 
*mod, size_t *n_deps)
+static const struct mod **mod_get_all_sorted_dependencies(const struct mod 
*mod, size_t *n_deps, size_t count)
 {
        const struct mod **deps;
        size_t last = 0;
 
-       *n_deps = mod_count_all_dependencies(mod);
+       *n_deps = mod_count_all_dependencies(mod, count);
        if (*n_deps == 0)
                return NULL;
 
@@ -1771,7 +1779,7 @@ static int output_deps(struct depmod *depmod, FILE *out)
                if (mod->deps.count == 0)
                        goto end;
 
-               deps = mod_get_all_sorted_dependencies(mod, &n_deps);
+               deps = mod_get_all_sorted_dependencies(mod, &n_deps, 
depmod->modules.count);
                if (deps == NULL) {
                        ERR("could not get all sorted dependencies of %s\n", p);
                        goto end;
@@ -1819,7 +1827,7 @@ static int output_deps_bin(struct depmod *depmod, FILE 
*out)
                        continue;
                }
 
-               deps = mod_get_all_sorted_dependencies(mod, &n_deps);
+               deps = mod_get_all_sorted_dependencies(mod, &n_deps, 
depmod->modules.count);
                if (deps == NULL && n_deps > 0) {
                        ERR("could not get all sorted dependencies of %s\n", p);
                        continue;
-- 
1.8.1.4

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