From 9efcc4a129363187c9bf15338692f107c5c9b6f0 Mon Sep 17 00:00:00 2001
From: David Howells <dhowells@redhat.com>
Date: Thu, 26 Mar 2020 15:24:07 +0000
Subject: [PATCH] afs: Fix unpinned address list during probing
When it's probing all of a fileserver's interfaces to find which one is
best to use, afs_do_probe_fileserver() takes a lock on the server record
and notes the pointer to the address list.
It doesn't, however, pin the address list, so as soon as it drops the
lock, there's nothing to stop the address list from being freed under
us.
Fix this by taking a ref on the address list inside the locked section
and dropping it at the end of the function.
Fixes: 3bf0fb6f33dd ("afs: Probe multiple fileservers simultaneously")
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
fs/afs/fs_probe.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/afs/fs_probe.c b/fs/afs/fs_probe.c
index cfe62b154f68d..e1b9ed679045d 100644
--- a/fs/afs/fs_probe.c
+++ b/fs/afs/fs_probe.c
@@ -145,6 +145,7 @@ static int afs_do_probe_fileserver(struct afs_net *net,
read_lock(&server->fs_lock);
ac.alist = rcu_dereference_protected(server->addresses,
lockdep_is_held(&server->fs_lock));
+ afs_get_addrlist(ac.alist);
read_unlock(&server->fs_lock);
atomic_set(&server->probe_outstanding, ac.alist->nr_addrs);
@@ -163,6 +164,7 @@ static int afs_do_probe_fileserver(struct afs_net *net,
if (!in_progress)
afs_fs_probe_done(server);
+ afs_put_addrlist(ac.alist);
return in_progress;
}
--
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