[5.4,0/2] Backport few dfs related fixes to cifs

Message

Rishabh Bhatnagar June 1, 2023, 8:58 p.m. UTC

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(-)