David Howells 5481fc6eb8 afs: Fix hang on rmmod due to outstanding timer ... The fileserver probe timer, net->fs_probe_timer, isn't cancelled when the kafs module is being removed and so the count it holds on net->servers_outstanding doesn't get dropped.. This causes rmmod to wait forever. The hung process shows a stack like: afs_purge_servers+0x1b5/0x23c [kafs] afs_net_exit+0x44/0x6e [kafs] ops_exit_list+0x72/0x93 unregister_pernet_operations+0x14c/0x1ba unregister_pernet_subsys+0x1d/0x2a afs_exit+0x29/0x6f [kafs] __do_sys_delete_module.isra.0+0x1a2/0x24b do_syscall_64+0x51/0x95 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fix this by: (1) Attempting to cancel the probe timer and, if successful, drop the count that the timer was holding. (2) Make the timer function just drop the count and not schedule the prober if the afs portion of net namespace is being destroyed. Also, whilst we're at it, make the following changes: (3) Initialise net->servers_outstanding to 1 and decrement it before waiting on it so that it doesn't generate wake up events by being decremented to 0 until we're cleaning up. (4) Switch the atomic_dec() on ->servers_outstanding for ->fs_timer in afs_purge_servers() to use the helper function for that. Fixes: f6cbb368bc ("afs: Actively poll fileservers to maintain NAT or firewall openings") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2020-06-20 12:01:58 -07:00
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addr_list.c
afs_cm.h
afs_fs.h
afs_vl.h
afs.h
cache.c
callback.c
cell.c
cmservice.c
dir_edit.c
dir_silly.c
dir.c
dynroot.c
file.c
flock.c
fs_operation.c
fs_probe.c
fsclient.c
inode.c
internal.h
Kconfig
main.c
Makefile
misc.c
mntpt.c
proc.c
protocol_uae.h
protocol_yfs.h
rotate.c
rxrpc.c
security.c
server_list.c
server.c
super.c
vl_alias.c
vl_list.c
vl_probe.c
vl_rotate.c
vlclient.c
volume.c
write.c
xattr.c
xdr_fs.h
yfsclient.c