[PATCH AUTOSEL 4.9 36/42] scripts/kallsyms: fix definitely-lost memory leak

[Sasha Levin]

From: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>

[ Upstream commit 21915eca088dc271c970e8351290e83d938114ac ]

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@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 scripts/kallsyms.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 2c8b8c662da59..6402b0d362914 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -498,6 +498,8 @@ 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;
-- 
2.20.1