Linux v3.17-rc4-158-ge874a5fe3efa

- Add patch to fix oops on keyring gc (rhbz 1116347)

1 files changed, 95 insertions, 0 deletions

diff --git a/KEYS-Fix-termination-condition-in-assoc-array-garbag.patch b/KEYS-Fix-termination-condition-in-assoc-array-garbag.patch
new file mode 100644
index 000000000..3afe63123
--- /dev/null
+++ b/KEYS-Fix-termination-condition-in-assoc-array-garbag.patch
@@ -0,0 +1,95 @@
+From 11646ff9e6874d205ab92af605db6b90fbe214d1 Mon Sep 17 00:00:00 2001
+From: David Howells <dhowells@redhat.com>
+Date: Tue, 9 Sep 2014 19:12:32 +0100
+Subject: [PATCH] KEYS: Fix termination condition in assoc array garbage
+ collection
+
+It is possible for an associative array to end up with a shortcut node at the
+root of the tree, if there are more than fan-out nodes in the tree, but they
+all crowd into the same slot in the lowest level (ie. they all have the same
+first nibble of their index keys).
+
+When assoc_array_gc() returns back up the tree after scanning some leaves, it
+can fall off of the root and crash because it assumes that the back pointer
+from a shortcut (after label ascend_old_tree) must point to a normal node -
+which isn't true of a shortcut node at the root.
+
+Should we find we're ascending rootwards over a shortcut, we should check to
+see if the backpointer is zero - and if it is, we have completed the scan.
+
+This particular bug cannot occur if the root node is not a shortcut - ie. if
+you have fewer than 17 keys in a keyring or if you have at least two keys that
+sit into separate slots (eg. a keyring and a non keyring).
+
+If we do fall off of the top of the tree, we get the following oops:
+
+  BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
+  IP: [<ffffffff8136cea7>] assoc_array_gc+0x2f7/0x540
+  PGD dae15067 PUD cfc24067 PMD 0
+  Oops: 0000 [#1] SMP
+  Modules linked in: xt_nat xt_mark nf_conntrack_netbios_ns nf_conntrack_broadcast ip6t_rpfilter ip6t_REJECT xt_conntrack ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_ni
+  CPU: 0 PID: 26011 Comm: kworker/0:1 Not tainted 3.14.9-200.fc20.x86_64 #1
+  Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
+  Workqueue: events key_garbage_collector
+  task: ffff8800918bd580 ti: ffff8800aac14000 task.ti: ffff8800aac14000
+  RIP: 0010:[<ffffffff8136cea7>] [<ffffffff8136cea7>] assoc_array_gc+0x2f7/0x540
+  RSP: 0018:ffff8800aac15d40  EFLAGS: 00010206
+  RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff8800aaecacc0
+  RDX: ffff8800daecf440 RSI: 0000000000000001 RDI: ffff8800aadc2bc0
+  RBP: ffff8800aac15da8 R08: 0000000000000001 R09: 0000000000000003
+  R10: ffffffff8136ccc7 R11: 0000000000000000 R12: 0000000000000000
+  R13: 0000000000000000 R14: 0000000000000070 R15: 0000000000000001
+  FS:  0000000000000000(0000) GS:ffff88011fc00000(0000) knlGS:0000000000000000
+  CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
+  CR2: 0000000000000018 CR3: 00000000db10d000 CR4: 00000000000006f0
+  Stack:
+   ffff8800aac15d50 0000000000000011 ffff8800aac15db8 ffffffff812e2a70
+   ffff880091a00600 0000000000000000 ffff8800aadc2bc3 00000000cd42c987
+   ffff88003702df20 ffff88003702dfa0 0000000053b65c09 ffff8800aac15fd8
+  Call Trace:
+   [<ffffffff812e2a70>] ? keyring_detect_cycle_iterator+0x30/0x30
+   [<ffffffff812e3e75>] keyring_gc+0x75/0x80
+   [<ffffffff812e1424>] key_garbage_collector+0x154/0x3c0
+   [<ffffffff810a67b6>] process_one_work+0x176/0x430
+   [<ffffffff810a744b>] worker_thread+0x11b/0x3a0
+   [<ffffffff810a7330>] ? rescuer_thread+0x3b0/0x3b0
+   [<ffffffff810ae1a8>] kthread+0xd8/0xf0
+   [<ffffffff810ae0d0>] ? insert_kthread_work+0x40/0x40
+   [<ffffffff816ffb7c>] ret_from_fork+0x7c/0xb0
+   [<ffffffff810ae0d0>] ? insert_kthread_work+0x40/0x40
+  Code: 08 4c 8b 22 0f 84 bf 00 00 00 41 83 c7 01 49 83 e4 fc 41 83 ff 0f 4c 89 65 c0 0f 8f 5a fe ff ff 48 8b 45 c0 4d 63 cf 49 83 c1 02 <4e> 8b 34 c8 4d 85 f6 0f 84 be 00 00 00 41 f6 c6 01 0f 84 92
+  RIP  [<ffffffff8136cea7>] assoc_array_gc+0x2f7/0x540
+   RSP <ffff8800aac15d40>
+  CR2: 0000000000000018
+  ---[ end trace 1129028a088c0cbd ]---
+
+Bugzilla: 1116347
+Upstream-status: ??
+
+Signed-off-by: David Howells <dhowells@redhat.com>
+---
+ lib/assoc_array.c | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/lib/assoc_array.c b/lib/assoc_array.c
+index ae146f0734eb..2404d03e251a 100644
+--- a/lib/assoc_array.c
++++ b/lib/assoc_array.c
+@@ -1723,11 +1723,13 @@ ascend_old_tree:
+ 		shortcut = assoc_array_ptr_to_shortcut(ptr);
+ 		slot = shortcut->parent_slot;
+ 		cursor = shortcut->back_pointer;
++		if (!cursor)
++			goto gc_complete;
+ 	} else {
+ 		slot = node->parent_slot;
+ 		cursor = ptr;
+ 	}
+-	BUG_ON(!ptr);
++	BUG_ON(!cursor);
+ 	node = assoc_array_ptr_to_node(cursor);
+ 	slot++;
+ 	goto continue_node;
+-- 
+1.9.3
+