summaryrefslogtreecommitdiff
path: root/net/rxrpc/call_object.c
diff options
context:
space:
mode:
authorDavid Howells <dhowells@redhat.com>2019-04-30 08:34:08 +0100
committerDavid S. Miller <davem@davemloft.net>2019-04-30 10:50:50 -0400
commitb13023421b5179413421333f602850914f6a7ad8 (patch)
tree83cf6ecb7938b0b73b5d76a960a943a17737d805 /net/rxrpc/call_object.c
parentb145745fc8d15cf9d45a5c7a8f5dbc4862e17cf2 (diff)
downloadlinux-sh-b13023421b5179413421333f602850914f6a7ad8.tar.gz
rxrpc: Fix net namespace cleanup
In rxrpc_destroy_all_calls(), there are two phases: (1) make sure the ->calls list is empty, emitting error messages if not, and (2) wait for the RCU cleanup to happen on outstanding calls (ie. ->nr_calls becomes 0). To avoid taking the call_lock, the function prechecks ->calls and if empty, it returns to avoid taking the lock - this is wrong, however: it still needs to go and do the second phase and wait for ->nr_calls to become 0. Without this, the rxrpc_net struct may get deallocated before we get to the RCU cleanup for the last calls. This can lead to: Slab corruption (Not tainted): kmalloc-16k start=ffff88802b178000, len=16384 050: 6b 6b 6b 6b 6b 6b 6b 6b 61 6b 6b 6b 6b 6b 6b 6b kkkkkkkkakkkkkkk Note the "61" at offset 0x58. This corresponds to the ->nr_calls member of struct rxrpc_net (which is >9k in size, and thus allocated out of the 16k slab). Fix this by flipping the condition on the if-statement, putting the locked section inside the if-body and dropping the return from there. The function will then always go on to wait for the RCU cleanup on outstanding calls. Fixes: 2baec2c3f854 ("rxrpc: Support network namespacing") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/rxrpc/call_object.c')
-rw-r--r--net/rxrpc/call_object.c32
1 files changed, 16 insertions, 16 deletions
diff --git a/net/rxrpc/call_object.c b/net/rxrpc/call_object.c
index 8aa2937b069f..fe96881a334d 100644
--- a/net/rxrpc/call_object.c
+++ b/net/rxrpc/call_object.c
@@ -604,30 +604,30 @@ void rxrpc_destroy_all_calls(struct rxrpc_net *rxnet)
_enter("");
- if (list_empty(&rxnet->calls))
- return;
+ if (!list_empty(&rxnet->calls)) {
+ write_lock(&rxnet->call_lock);
- write_lock(&rxnet->call_lock);
+ while (!list_empty(&rxnet->calls)) {
+ call = list_entry(rxnet->calls.next,
+ struct rxrpc_call, link);
+ _debug("Zapping call %p", call);
- while (!list_empty(&rxnet->calls)) {
- call = list_entry(rxnet->calls.next, struct rxrpc_call, link);
- _debug("Zapping call %p", call);
+ rxrpc_see_call(call);
+ list_del_init(&call->link);
- rxrpc_see_call(call);
- list_del_init(&call->link);
+ pr_err("Call %p still in use (%d,%s,%lx,%lx)!\n",
+ call, atomic_read(&call->usage),
+ rxrpc_call_states[call->state],
+ call->flags, call->events);
- pr_err("Call %p still in use (%d,%s,%lx,%lx)!\n",
- call, atomic_read(&call->usage),
- rxrpc_call_states[call->state],
- call->flags, call->events);
+ write_unlock(&rxnet->call_lock);
+ cond_resched();
+ write_lock(&rxnet->call_lock);
+ }
write_unlock(&rxnet->call_lock);
- cond_resched();
- write_lock(&rxnet->call_lock);
}
- write_unlock(&rxnet->call_lock);
-
atomic_dec(&rxnet->nr_calls);
wait_var_event(&rxnet->nr_calls, !atomic_read(&rxnet->nr_calls));
}