linux-kernel - [PATCH v2 02/16] scripts/kallsyms: fix definitely-lost memory leak

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Date:   Sun, 24 Nov 2019 01:04:30 +0900
From:   Masahiro Yamada <yamada.masahiro@...ionext.com>
To:     linux-kbuild@...r.kernel.org
Cc:     Masahiro Yamada <yamada.masahiro@...ionext.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2 02/16] scripts/kallsyms: fix definitely-lost memory leak

build_initial_tok_table() overwrites unused sym_entry to shrink the
table size. Before the entry is overwritten, table[i].sym must be freed
since it is malloc'ed data.

This fixes the 'definitely lost' report from valgrind. I ran valgrind
against x86_64_defconfig of v5.4-rc8 kernel, and here is the summary:

[Before the fix]

  LEAK SUMMARY:
     definitely lost: 53,184 bytes in 2,874 blocks

[After the fix]

  LEAK SUMMARY:
     definitely lost: 0 bytes in 0 blocks

Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
---

Changes in v2: None

 scripts/kallsyms.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 918c2ba071b5..79641874d860 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -487,6 +487,8 @@ static void build_initial_tok_table(void)
 				table[pos] = table[i];
 			learn_symbol(table[pos].sym, table[pos].len);
 			pos++;
+		} else {
+			free(table[i].sym);
 		}
 	}
 	table_cnt = pos;
-- 
2.17.1