From: David Howells <dhowells@xxxxxxxxxx>
commit bc212465326e8587325f520a052346f0b57360e6 upstream.
In rxrpc_open_socket(), it sets up the socket and then sets up the I/O
thread that will handle it. This is a problem, however, as there's a gap
between the two phases in which a packet may come into rxrpc_encap_rcv()
from the UDP packet but we oops when trying to wake the not-yet created I/O
thread.
As a quick fix, just make rxrpc_encap_rcv() discard the packet if there's
no I/O thread yet.
A better, but more intrusive fix would perhaps be to rearrange things such
that the socket creation is done by the I/O thread.
Fixes: a275da62e8c1 ("rxrpc: Create a per-local endpoint receive queue and I/O thread")
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: yuxuanzhe@xxxxxxxxxxx
cc: Marc Dionne <marc.dionne@xxxxxxxxxxxx>
cc: Simon Horman <horms@xxxxxxxxxx>
cc: linux-afs@xxxxxxxxxxxxxxxxxxx
Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Link: https://patch.msgid.link/20241001132702.3122709-2-dhowells@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/rxrpc/ar-internal.h | 2 +-
net/rxrpc/io_thread.c | 10 ++++++++--
net/rxrpc/local_object.c | 2 +-
3 files changed, 10 insertions(+), 4 deletions(-)
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -1066,7 +1066,7 @@ bool rxrpc_direct_abort(struct sk_buff *
int rxrpc_io_thread(void *data);
static inline void rxrpc_wake_up_io_thread(struct rxrpc_local *local)
{
- wake_up_process(local->io_thread);
+ wake_up_process(READ_ONCE(local->io_thread));
}
static inline bool rxrpc_protocol_error(struct sk_buff *skb, enum rxrpc_abort_reason why)
--- a/net/rxrpc/io_thread.c
+++ b/net/rxrpc/io_thread.c
@@ -27,11 +27,17 @@ int rxrpc_encap_rcv(struct sock *udp_sk,
{
struct sk_buff_head *rx_queue;
struct rxrpc_local *local = rcu_dereference_sk_user_data(udp_sk);
+ struct task_struct *io_thread;
if (unlikely(!local)) {
kfree_skb(skb);
return 0;
}
+ io_thread = READ_ONCE(local->io_thread);
+ if (!io_thread) {
+ kfree_skb(skb);
+ return 0;
+ }
if (skb->tstamp == 0)
skb->tstamp = ktime_get_real();
@@ -47,7 +53,7 @@ int rxrpc_encap_rcv(struct sock *udp_sk,
#endif
skb_queue_tail(rx_queue, skb);
- rxrpc_wake_up_io_thread(local);
+ wake_up_process(io_thread);
return 0;
}
@@ -554,7 +560,7 @@ int rxrpc_io_thread(void *data)
__set_current_state(TASK_RUNNING);
rxrpc_see_local(local, rxrpc_local_stop);
rxrpc_destroy_local(local);
- local->io_thread = NULL;
+ WRITE_ONCE(local->io_thread, NULL);
rxrpc_see_local(local, rxrpc_local_stopped);
return 0;
}
--- a/net/rxrpc/local_object.c
+++ b/net/rxrpc/local_object.c
@@ -232,7 +232,7 @@ static int rxrpc_open_socket(struct rxrp
}
wait_for_completion(&local->io_thread_ready);
- local->io_thread = io_thread;
+ WRITE_ONCE(local->io_thread, io_thread);
_leave(" = 0");
return 0;
Patches currently in stable-queue which might be from dhowells@xxxxxxxxxx are
queue-6.6/rxrpc-fix-a-race-between-socket-set-up-and-i-o-thread-creation.patch
queue-6.6/cachefiles-fix-dentry-leak-in-cachefiles_open_file.patch
