[PATCH] thunderbolt: Fix double free of drom buffer

[Andreas Noever <andreas.noever@gmail.com>]

If tb_drom_read fails sw->drom is freed but not set to NULL. sw->drom
is then freed again in the error path of sw_switch_alloc.

The bug can be triggered by unplugging a thunderbolt device shortly
after it is detected by the thunderbolt driver.

Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
Cc: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org
---
 drivers/thunderbolt/eeprom.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/thunderbolt/eeprom.c b/drivers/thunderbolt/eeprom.c
index 0dde34e..545c60c 100644
--- a/drivers/thunderbolt/eeprom.c
+++ b/drivers/thunderbolt/eeprom.c
@@ -444,6 +444,7 @@ int tb_drom_read(struct tb_switch *sw)
 	return tb_drom_parse_entries(sw);
 err:
 	kfree(sw->drom);
+	sw->drom = NULL;
 	return -EIO;
 
 }
-- 
2.8.0