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rxrpc: Fix missing locking causing hanging calls

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If a call gets aborted (e.g. because kafs saw a signal) between it being
queued for connection and the I/O thread picking up the call, the abort
will be prioritised over the connection and it will be removed from
local->new_client_calls by rxrpc_disconnect_client_call() without a lock
being held.  This may cause other calls on the list to disappear if a race
occurs.

Fix this by taking the client_call_lock when removing a call from whatever
list its ->wait_link happens to be on.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-afs@lists.infradead.org
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Fixes: 9d35d880e0 ("rxrpc: Move client call connection to the I/O thread")
Link: https://patch.msgid.link/726660.1730898202@warthog.procyon.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
David Howells 2024-11-06 13:03:22 +00:00 committed by Jakub Kicinski
parent de88df0179
commit fc9de52de3
2 changed files with 5 additions and 0 deletions
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1
include/trace/events/rxrpc.h
View File

@ -287,6 +287,7 @@
EM(rxrpc_call_see_input, "SEE input ") \
EM(rxrpc_call_see_release, "SEE release ") \
EM(rxrpc_call_see_userid_exists, "SEE u-exists") \
EM(rxrpc_call_see_waiting_call, "SEE q-conn ") \
E_(rxrpc_call_see_zap, "SEE zap ")
#define rxrpc_txqueue_traces \

4
net/rxrpc/conn_client.c
View File

@ -516,6 +516,7 @@ void rxrpc_connect_client_calls(struct rxrpc_local *local)
spin_lock(&local->client_call_lock);
list_move_tail(&call->wait_link, &bundle->waiting_calls);
rxrpc_see_call(call, rxrpc_call_see_waiting_call);
spin_unlock(&local->client_call_lock);
if (rxrpc_bundle_has_space(bundle))
@ -586,7 +587,10 @@ void rxrpc_disconnect_client_call(struct rxrpc_bundle *bundle, struct rxrpc_call
_debug("call is waiting");
ASSERTCMP(call->call_id, ==, 0);
ASSERT(!test_bit(RXRPC_CALL_EXPOSED, &call->flags));
/* May still be on ->new_client_calls. */
spin_lock(&local->client_call_lock);
list_del_init(&call->wait_link);
spin_unlock(&local->client_call_lock);
return;
}