[PATCH] fs: dlm: Fix memory leak of object mh

From: Colin King
Date: Wed May 26 2021 - 10:46:43 EST


From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

There is an error return path that is not kfree'ing mh after
it has been successfully allocates. Fix this by moving the
call to create_rcom to after the check on rc_in->rc_id check
to avoid this.

Thanks to Alexander Ahring Oder Aring for suggesting the
correct way to fix this.

Addresses-Coverity: ("Resource leak")
Fixes: a070a91cf140 ("fs: dlm: add more midcomms hooks")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
V2: don't kfree the object, instead move the check to before
the call to create_rcom
---
fs/dlm/rcom.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/dlm/rcom.c b/fs/dlm/rcom.c
index 085f21966c72..a7727b9e5e83 100644
--- a/fs/dlm/rcom.c
+++ b/fs/dlm/rcom.c
@@ -385,10 +385,6 @@ static void receive_rcom_lookup(struct dlm_ls *ls, struct dlm_rcom *rc_in)
int error, ret_nodeid, nodeid = rc_in->rc_header.h_nodeid;
int len = rc_in->rc_header.h_length - sizeof(struct dlm_rcom);

- error = create_rcom(ls, nodeid, DLM_RCOM_LOOKUP_REPLY, 0, &rc, &mh);
- if (error)
- return;
-
/* Old code would send this special id to trigger a debug dump. */
if (rc_in->rc_id == 0xFFFFFFFF) {
log_error(ls, "receive_rcom_lookup dump from %d", nodeid);
@@ -396,6 +392,10 @@ static void receive_rcom_lookup(struct dlm_ls *ls, struct dlm_rcom *rc_in)
return;
}

+ error = create_rcom(ls, nodeid, DLM_RCOM_LOOKUP_REPLY, 0, &rc, &mh);
+ if (error)
+ return;
+
error = dlm_master_lookup(ls, nodeid, rc_in->rc_buf, len,
DLM_LU_RECOVER_MASTER, &ret_nodeid, NULL);
if (error)
--
2.31.1