This is a note to let you know that I've just added the patch titled
tipc: fix spinlock recursion bug for failed subscriptions
to the 3.13-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tipc-fix-spinlock-recursion-bug-for-failed-subscriptions.patch
and it can be found in the queue-3.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From foo@baz Thu Apr 10 22:03:04 PDT 2014
From: Erik Hugne <[email protected]>
Date: Mon, 24 Mar 2014 16:56:38 +0100
Subject: tipc: fix spinlock recursion bug for failed subscriptions
From: Erik Hugne <[email protected]>
[ Upstream commit a5d0e7c037119484a7006b883618bfa87996cb41 ]
If a topology event subscription fails for any reason, such as out
of memory, max number reached or because we received an invalid
request the correct behavior is to terminate the subscribers
connection to the topology server. This is currently broken and
produces the following oops:
[27.953662] tipc: Subscription rejected, illegal request
[27.955329] BUG: spinlock recursion on CPU#1, kworker/u4:0/6
[27.957066] lock: 0xffff88003c67f408, .magic: dead4ead, .owner:
kworker/u4:0/6, .owner_cpu: 1
[27.958054] CPU: 1 PID: 6 Comm: kworker/u4:0 Not tainted 3.14.0-rc6+ #5
[27.960230] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[27.960874] Workqueue: tipc_rcv tipc_recv_work [tipc]
[27.961430] ffff88003c67f408 ffff88003de27c18 ffffffff815c0207 ffff88003de1c050
[27.962292] ffff88003de27c38 ffffffff815beec5 ffff88003c67f408 ffffffff817f0a8a
[27.963152] ffff88003de27c58 ffffffff815beeeb ffff88003c67f408 ffffffffa0013520
[27.964023] Call Trace:
[27.964292] [<ffffffff815c0207>] dump_stack+0x45/0x56
[27.964874] [<ffffffff815beec5>] spin_dump+0x8c/0x91
[27.965420] [<ffffffff815beeeb>] spin_bug+0x21/0x26
[27.965995] [<ffffffff81083df6>] do_raw_spin_lock+0x116/0x140
[27.966631] [<ffffffff815c6215>] _raw_spin_lock_bh+0x15/0x20
[27.967256] [<ffffffffa0008540>] subscr_conn_shutdown_event+0x20/0xa0 [tipc]
[27.968051] [<ffffffffa000fde4>] tipc_close_conn+0xa4/0xb0 [tipc]
[27.968722] [<ffffffffa00101ba>] tipc_conn_terminate+0x1a/0x30 [tipc]
[27.969436] [<ffffffffa00089a2>] subscr_conn_msg_event+0x1f2/0x2f0 [tipc]
[27.970209] [<ffffffffa0010000>] tipc_receive_from_sock+0x90/0xf0 [tipc]
[27.970972] [<ffffffffa000fa79>] tipc_recv_work+0x29/0x50 [tipc]
[27.971633] [<ffffffff8105dbf5>] process_one_work+0x165/0x3e0
[27.972267] [<ffffffff8105e869>] worker_thread+0x119/0x3a0
[27.972896] [<ffffffff8105e750>] ? manage_workers.isra.25+0x2a0/0x2a0
[27.973622] [<ffffffff810648af>] kthread+0xdf/0x100
[27.974168] [<ffffffff810647d0>] ? kthread_create_on_node+0x1a0/0x1a0
[27.974893] [<ffffffff815ce13c>] ret_from_fork+0x7c/0xb0
[27.975466] [<ffffffff810647d0>] ? kthread_create_on_node+0x1a0/0x1a0
The recursion occurs when subscr_terminate tries to grab the
subscriber lock, which is already taken by subscr_conn_msg_event.
We fix this by checking if the request to establish a new
subscription was successful, and if not we initiate termination of
the subscriber after we have released the subscriber lock.
Signed-off-by: Erik Hugne <[email protected]>
Reviewed-by: Jon Maloy <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
net/tipc/subscr.c | 29 +++++++++++++++--------------
1 file changed, 15 insertions(+), 14 deletions(-)
--- a/net/tipc/subscr.c
+++ b/net/tipc/subscr.c
@@ -263,9 +263,9 @@ static void subscr_cancel(struct tipc_su
*
* Called with subscriber lock held.
*/
-static struct tipc_subscription *subscr_subscribe(struct tipc_subscr *s,
- struct tipc_subscriber *subscriber)
-{
+static int subscr_subscribe(struct tipc_subscr *s,
+ struct tipc_subscriber *subscriber,
+ struct tipc_subscription **sub_p) {
struct tipc_subscription *sub;
int swap;
@@ -276,23 +276,21 @@ static struct tipc_subscription *subscr_
if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
subscr_cancel(s, subscriber);
- return NULL;
+ return 0;
}
/* Refuse subscription if global limit exceeded */
if (atomic_read(&subscription_count) >= TIPC_MAX_SUBSCRIPTIONS) {
pr_warn("Subscription rejected, limit reached (%u)\n",
TIPC_MAX_SUBSCRIPTIONS);
- subscr_terminate(subscriber);
- return NULL;
+ return -EINVAL;
}
/* Allocate subscription object */
sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
if (!sub) {
pr_warn("Subscription rejected, no memory\n");
- subscr_terminate(subscriber);
- return NULL;
+ return -ENOMEM;
}
/* Initialize subscription object */
@@ -306,8 +304,7 @@ static struct tipc_subscription *subscr_
(sub->seq.lower > sub->seq.upper)) {
pr_warn("Subscription rejected, illegal request\n");
kfree(sub);
- subscr_terminate(subscriber);
- return NULL;
+ return -EINVAL;
}
INIT_LIST_HEAD(&sub->nameseq_list);
list_add(&sub->subscription_list, &subscriber->subscription_list);
@@ -320,8 +317,8 @@ static struct tipc_subscription *subscr_
(Handler)subscr_timeout, (unsigned long)sub);
k_start_timer(&sub->timer, sub->timeout);
}
-
- return sub;
+ *sub_p = sub;
+ return 0;
}
/* Handle one termination request for the subscriber */
@@ -335,10 +332,14 @@ static void subscr_conn_msg_event(int co
void *usr_data, void *buf, size_t len)
{
struct tipc_subscriber *subscriber = usr_data;
- struct tipc_subscription *sub;
+ struct tipc_subscription *sub = NULL;
spin_lock_bh(&subscriber->lock);
- sub = subscr_subscribe((struct tipc_subscr *)buf, subscriber);
+ if (subscr_subscribe((struct tipc_subscr *)buf, subscriber, &sub) < 0) {
+ spin_unlock_bh(&subscriber->lock);
+ subscr_terminate(subscriber);
+ return;
+ }
if (sub)
tipc_nametbl_subscribe(sub);
spin_unlock_bh(&subscriber->lock);
Patches currently in stable-queue which might be from [email protected]
are
queue-3.13/tipc-fix-connection-refcount-leak.patch
queue-3.13/tipc-drop-subscriber-connection-id-invalidation.patch
queue-3.13/tipc-allow-connection-shutdown-callback-to-be-invoked.patch
queue-3.13/tipc-fix-spinlock-recursion-bug-for-failed-subscriptions.patch
queue-3.13/tipc-fix-memory-leak-during-module-removal.patch
queue-3.13/tipc-don-t-log-disabled-tasklet-handler-errors.patch
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