rxrpc: Fix timeout of a call that hasn't yet been granted a channel

afs_make_call() calls rxrpc_kernel_begin_call() to begin a call (which may
get stalled in the background waiting for a connection to become
available); it then calls rxrpc_kernel_set_max_life() to set the timeouts -
but that starts the call timer so the call timer might then expire before
we get a connection assigned - leading to the following oops if the call
stalled:

	BUG: kernel NULL pointer dereference, address: 0000000000000000
	...
	CPU: 1 PID: 5111 Comm: krxrpcio/0 Not tainted 6.3.0-rc7-build3+ #701
	RIP: 0010:rxrpc_alloc_txbuf+0xc0/0x157
	...
	Call Trace:
	 <TASK>
	 rxrpc_send_ACK+0x50/0x13b
	 rxrpc_input_call_event+0x16a/0x67d
	 rxrpc_io_thread+0x1b6/0x45f
	 ? _raw_spin_unlock_irqrestore+0x1f/0x35
	 ? rxrpc_input_packet+0x519/0x519
	 kthread+0xe7/0xef
	 ? kthread_complete_and_exit+0x1b/0x1b
	 ret_from_fork+0x22/0x30

Fix this by noting the timeouts in struct rxrpc_call when the call is
created.  The timer will be started when the first packet is transmitted.

It shouldn't be possible to trigger this directly from userspace through
AF_RXRPC as sendmsg() will return EBUSY if the call is in the
waiting-for-conn state if it dropped out of the wait due to a signal.

Fixes: 9d35d880e0e4 ("rxrpc: Move client call connection to the I/O thread")
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: linux-afs@lists.infradead.org
cc: netdev@vger.kernel.org
cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 6 insertions, 8 deletions

diff --git a/fs/afs/afs.h b/fs/afs/afs.h
index 432cb4b23961..81815724db6c 100644
--- a/fs/afs/afs.h
+++ b/fs/afs/afs.h
@@ -19,8 +19,8 @@
 #define AFSPATHMAX		1024	/* Maximum length of a pathname plus NUL */
 #define AFSOPAQUEMAX		1024	/* Maximum length of an opaque field */
 
-#define AFS_VL_MAX_LIFESPAN	(120 * HZ)
-#define AFS_PROBE_MAX_LIFESPAN	(30 * HZ)
+#define AFS_VL_MAX_LIFESPAN	120
+#define AFS_PROBE_MAX_LIFESPAN	30
 
 typedef u64			afs_volid_t;
 typedef u64			afs_vnodeid_t;
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index ad8523d0d038..68ae91d21b57 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -128,7 +128,7 @@ struct afs_call {
 	spinlock_t		state_lock;
 	int			error;		/* error code */
 	u32			abort_code;	/* Remote abort ID or 0 */
-	unsigned int		max_lifespan;	/* Maximum lifespan to set if not 0 */
+	unsigned int		max_lifespan;	/* Maximum lifespan in secs to set if not 0 */
 	unsigned		request_size;	/* size of request data */
 	unsigned		reply_max;	/* maximum size of reply */
 	unsigned		count2;		/* count used in unmarshalling */
diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c
index e08b850c3e6d..ed1644e7683f 100644
--- a/fs/afs/rxrpc.c
+++ b/fs/afs/rxrpc.c
@@ -335,7 +335,9 @@ void afs_make_call(struct afs_addr_cursor *ac, struct afs_call *call, gfp_t gfp)
 	/* create a call */
 	rxcall = rxrpc_kernel_begin_call(call->net->socket, srx, call->key,
 					 (unsigned long)call,
-					 tx_total_len, gfp,
+					 tx_total_len,
+					 call->max_lifespan,
+					 gfp,
 					 (call->async ?
 					  afs_wake_up_async_call :
 					  afs_wake_up_call_waiter),
@@ -350,10 +352,6 @@ void afs_make_call(struct afs_addr_cursor *ac, struct afs_call *call, gfp_t gfp)
 	}
 
 	call->rxcall = rxcall;
-
-	if (call->max_lifespan)
-		rxrpc_kernel_set_max_life(call->net->socket, rxcall,
-					  call->max_lifespan);
 	call->issue_time = ktime_get_real();
 
 	/* send the request */