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afs: Fix client call Rx-phase signal handling

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Fix the handling of signals in client rxrpc calls made by the afs
filesystem.  Ignore signals completely, leaving call abandonment or
connection loss to be detected by timeouts inside AF_RXRPC.

Allowing a filesystem call to be interrupted after the entire request has
been transmitted and an abort sent means that the server may or may not
have done the action - and we don't know.  It may even be worse than that
for older servers.

Fixes: bc5e3a546d ("rxrpc: Use MSG_WAITALL to tell sendmsg() to temporarily ignore signals")
Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
David Howells 2020-03-12 21:40:06 +00:00
parent dde9f09558
commit 7d7587db0d
5 changed files with 6 additions and 67 deletions
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34
fs/afs/rxrpc.c
View File

@ -604,11 +604,7 @@ static void afs_deliver_to_call(struct afs_call *call)
long afs_wait_for_call_to_complete(struct afs_call *call,
struct afs_addr_cursor *ac)
{
signed long rtt2, timeout;
long ret;
bool stalled = false;
u64 rtt;
u32 life, last_life;
bool rxrpc_complete = false;
DECLARE_WAITQUEUE(myself, current);
@ -619,14 +615,6 @@ long afs_wait_for_call_to_complete(struct afs_call *call,
if (ret < 0)
goto out;
rtt = rxrpc_kernel_get_rtt(call->net->socket, call->rxcall);
rtt2 = nsecs_to_jiffies64(rtt) * 2;
if (rtt2 < 2)
rtt2 = 2;
timeout = rtt2;
rxrpc_kernel_check_life(call->net->socket, call->rxcall, &last_life);
add_wait_queue(&call->waitq, &myself);
for (;;) {
set_current_state(TASK_UNINTERRUPTIBLE);
@ -637,37 +625,19 @@ long afs_wait_for_call_to_complete(struct afs_call *call,
call->need_attention = false;
__set_current_state(TASK_RUNNING);
afs_deliver_to_call(call);
timeout = rtt2;
continue;
}
if (afs_check_call_state(call, AFS_CALL_COMPLETE))
break;
if (!rxrpc_kernel_check_life(call->net->socket, call->rxcall, &life)) {
if (!rxrpc_kernel_check_life(call->net->socket, call->rxcall)) {
/* rxrpc terminated the call. */
rxrpc_complete = true;
break;
}
if (call->intr && timeout == 0 &&
life == last_life && signal_pending(current)) {
if (stalled)
break;
__set_current_state(TASK_RUNNING);
rxrpc_kernel_probe_life(call->net->socket, call->rxcall);
timeout = rtt2;
stalled = true;
continue;
}
if (life != last_life) {
timeout = rtt2;
last_life = life;
stalled = false;
}
timeout = schedule_timeout(timeout);
schedule();
}
remove_wait_queue(&call->waitq, &myself);

4
include/net/af_rxrpc.h
View File

@ -64,9 +64,7 @@ int rxrpc_kernel_charge_accept(struct socket *, rxrpc_notify_rx_t,
rxrpc_user_attach_call_t, unsigned long, gfp_t,
unsigned int);
void rxrpc_kernel_set_tx_length(struct socket *, struct rxrpc_call *, s64);
bool rxrpc_kernel_check_life(const struct socket *, const struct rxrpc_call *,
u32 *);
void rxrpc_kernel_probe_life(struct socket *, struct rxrpc_call *);
bool rxrpc_kernel_check_life(const struct socket *, const struct rxrpc_call *);
u32 rxrpc_kernel_get_epoch(struct socket *, struct rxrpc_call *);
bool rxrpc_kernel_get_reply_time(struct socket *, struct rxrpc_call *,
ktime_t *);

33
net/rxrpc/af_rxrpc.c
View File

@ -371,44 +371,17 @@ EXPORT_SYMBOL(rxrpc_kernel_end_call);
* rxrpc_kernel_check_life - Check to see whether a call is still alive
* @sock: The socket the call is on
* @call: The call to check
* @_life: Where to store the life value
*
* Allow a kernel service to find out whether a call is still alive - ie. we're
* getting ACKs from the server. Passes back in *_life a number representing
* the life state which can be compared to that returned by a previous call and
* return true if the call is still alive.
*
* If the life state stalls, rxrpc_kernel_probe_life() should be called and
* then 2RTT waited.
* Allow a kernel service to find out whether a call is still alive -
* ie. whether it has completed.
*/
bool rxrpc_kernel_check_life(const struct socket *sock,
const struct rxrpc_call *call,
u32 *_life)
const struct rxrpc_call *call)
{
*_life = call->acks_latest;
return call->state != RXRPC_CALL_COMPLETE;
}
EXPORT_SYMBOL(rxrpc_kernel_check_life);
/**
* rxrpc_kernel_probe_life - Poke the peer to see if it's still alive
* @sock: The socket the call is on
* @call: The call to check
*
* In conjunction with rxrpc_kernel_check_life(), allow a kernel service to
* find out whether a call is still alive by pinging it. This should cause the
* life state to be bumped in about 2*RTT.
*
* The must be called in TASK_RUNNING state on pain of might_sleep() objecting.
*/
void rxrpc_kernel_probe_life(struct socket *sock, struct rxrpc_call *call)
{
rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, true, false,
rxrpc_propose_ack_ping_for_check_life);
rxrpc_send_ack_packet(call, true, NULL);
}
EXPORT_SYMBOL(rxrpc_kernel_probe_life);
/**
* rxrpc_kernel_get_epoch - Retrieve the epoch value from a call.
* @sock: The socket the call is on

1
net/rxrpc/ar-internal.h
View File

@ -675,7 +675,6 @@ struct rxrpc_call {
/* transmission-phase ACK management */
ktime_t acks_latest_ts; /* Timestamp of latest ACK received */
rxrpc_serial_t acks_latest; /* serial number of latest ACK received */
rxrpc_seq_t acks_lowest_nak; /* Lowest NACK in the buffer (or ==tx_hard_ack) */
rxrpc_seq_t acks_lost_top; /* tx_top at the time lost-ack ping sent */
rxrpc_serial_t acks_lost_ping; /* Serial number of probe ACK */

1
net/rxrpc/input.c
View File

@ -882,7 +882,6 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
before(prev_pkt, call->ackr_prev_seq))
goto out;
call->acks_latest_ts = skb->tstamp;
call->acks_latest = sp->hdr.serial;
call->ackr_first_seq = first_soft_ack;
call->ackr_prev_seq = prev_pkt;