IB/core: Fix potential NULL pointer dereference in pkey cache
The IB core pkey cache is populated by procedure ib_cache_update(). Initially, the pkey cache pointer is NULL. ib_cache_update allocates a buffer and populates it with the device's pkeys, via repeated calls to procedure ib_query_pkey(). If there is a failure in populating the pkey buffer via ib_query_pkey(), ib_cache_update does not replace the old pkey buffer cache with the updated one -- it leaves the old cache as is. Since initially the pkey buffer cache is NULL, when calling ib_cache_update the first time, a failure in ib_query_pkey() will cause the pkey buffer cache pointer to remain NULL. In this situation, any calls subsequent to ib_get_cached_pkey(), ib_find_cached_pkey(), or ib_find_cached_pkey_exact() will try to dereference the NULL pkey cache pointer, causing a kernel panic. Fix this by checking the ib_cache_update() return value. Fixes: 8faea9fd ("RDMA/cache: Move the cache per-port data into the main ib_port_data") Fixes: 1da177e4 ("Linux-2.6.12-rc2") Link: https://lore.kernel.org/r/20200507071012.100594-1-leon@kernel.org Signed-off-by:Jack Morgenstein <jackm@dev.mellanox.co.il> Signed-off-by: