Recently we have been seeing kernel panic in cifs_reconnect function while accessing tgt_list. Looks like tgt_list is not initialized correctly. There are fixes already present in 5.10 and later trees. Backporting them to 5.4
CIFS VFS: \172.30.1.14 cifs_reconnect: no target servers for DFS failover BUG: unable to handle page fault for address: fffffffffffffff8 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 260e067 P4D 260e067 PUD 2610067 PMD 0 Oops: 0000 [#1] SMP PTI RIP: 0010:cifs_reconnect+0x51d/0xef0 [cifs] RSP: 0018:ffffc90000693da0 EFLAGS: 00010282 RAX: fffffffffffffff8 RBX: ffff8887fa63b800 RCX: fffffffffffffff8 Call Trace: cifs_handle_standard+0x18d/0x1b0 [cifs] cifs_demultiplex_thread+0xa5c/0xc90 [cifs] kthread+0x113/0x130
Paulo Alcantara (2): cifs: get rid of unused parameter in reconn_setup_dfs_targets() cifs: handle empty list of targets in cifs_reconnect()
fs/cifs/connect.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-)