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| author | David Howells <dhowells@redhat.com> | 2024-10-01 16:26:58 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-10-10 12:58:08 +0300 |
| commit | cdf4bbbdb956d7426f687f38757ebca2a2759a0f (patch) | |
| tree | c850f100a4bc818e3364b22acf23e4074b9d4d42 | |
| parent | b538fefeb1026aad9dcdcbb410c42b56dff8aae9 (diff) | |
| download | linux-cdf4bbbdb956d7426f687f38757ebca2a2759a0f.tar.xz | |
rxrpc: Fix a race between socket set up and I/O thread creation
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@redhat.com>
cc: yuxuanzhe@outlook.com
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Simon Horman <horms@kernel.org>
cc: linux-afs@lists.infradead.org
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20241001132702.3122709-2-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/rxrpc/ar-internal.h | 2 | ||||
| -rw-r--r-- | net/rxrpc/io_thread.c | 10 | ||||
| -rw-r--r-- | net/rxrpc/local_object.c | 2 |
3 files changed, 10 insertions, 4 deletions
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h index d431376bb120..66ad7dc10864 100644 --- a/net/rxrpc/ar-internal.h +++ b/net/rxrpc/ar-internal.h @@ -1066,7 +1066,7 @@ bool rxrpc_direct_abort(struct sk_buff *skb, enum rxrpc_abort_reason why, 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) diff --git a/net/rxrpc/io_thread.c b/net/rxrpc/io_thread.c index 4a3a08a0e2cd..d7e72bae4d2b 100644 --- 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 *skb) { 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, struct sk_buff *skb) #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; } diff --git a/net/rxrpc/local_object.c b/net/rxrpc/local_object.c index 34d307368135..8da6120f6533 100644 --- a/net/rxrpc/local_object.c +++ b/net/rxrpc/local_object.c @@ -232,7 +232,7 @@ static int rxrpc_open_socket(struct rxrpc_local *local, struct net *net) } wait_for_completion(&local->io_thread_ready); - local->io_thread = io_thread; + WRITE_ONCE(local->io_thread, io_thread); _leave(" = 0"); return 0; |