[PATCH] thunderbolt: Fix a double put in tb_cfg_read_raw

From: Lv Yunlong
Date: Mon Mar 22 2021 - 23:16:21 EST

In tb_cfg_read_raw, req is allocated by tb_cfg_request_alloc()
with an initial reference. Before calling tb_cfg_request_sync(),
there is no refcount inc operation. tb_cfg_request_sync()
calls tb_cfg_request(..,req,..) and if the callee failed,
the initial reference of req is dropped and req is freed.

Later in tb_cfg_read_raw before the err check,
tb_cfg_request_put(req) is called again. It may cause error
in race.

My patch puts tb_cfg_request_put(req) after the err check
finished to avoid unexpected result.

Signed-off-by: Lv Yunlong <lyl2019@xxxxxxxxxxxxxxxx>
drivers/thunderbolt/ctl.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/thunderbolt/ctl.c b/drivers/thunderbolt/ctl.c
index f1aeaff9f368..bb60269c89ab 100644
--- a/drivers/thunderbolt/ctl.c
+++ b/drivers/thunderbolt/ctl.c
@@ -890,11 +890,11 @@ struct tb_cfg_result tb_cfg_read_raw(struct tb_ctl *ctl, void *buffer,

res = tb_cfg_request_sync(ctl, req, timeout_msec);

- tb_cfg_request_put(req);
if (res.err != -ETIMEDOUT)

+ tb_cfg_request_put(req);
/* Wait a bit (arbitrary time) until we send a retry */
usleep_range(10, 100);