[PATCH 5.4 149/168] RDMA/iwcm: Fix iwcm work deallocation

Greg Kroah-Hartman
2020-03-10T13:27:26Z

From: Bernard Metzler <bmt@zurich.ibm.com>

commit 810dbc69087b08fd53e1cdd6c709f385bc2921ad upstream.

The dealloc_work_entries() function must update the work_free_list pointer
while freeing its entries, since potentially called again on same list. A
second iteration of the work list caused system crash. This happens, if
work allocation fails during cma_iw_listen() and free_cm_id() tries to
free the list again during cleanup.

Fixes: 922a8e9fb2e0 ("RDMA: iWARP Connection Manager.")
Link: https://lore.kernel.org/r/20200302181614.17042-1-bmt@zurich.ibm.com
Reported-by: syzbot+cb0c054eabfba4342146@syzkaller.appspotmail.com
Signed-off-by: Bernard Metzler <bmt@zurich.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/infiniband/core/iwcm.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/infiniband/core/iwcm.c
+++ b/drivers/infiniband/core/iwcm.c
@@ -159,8 +159,10 @@ static void dealloc_work_entries(struct
{
struct list_head *e, *tmp;

- list_for_each_safe(e, tmp, &cm_id_priv->work_free_list)
+ list_for_each_safe(e, tmp, &cm_id_priv->work_free_list) {
+ list_del(e);
kfree(list_entry(e, struct iwcm_work, free_list));
+ }
}

static int alloc_work_entries(struct iwcm_id_private *cm_id_priv, int count)