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rxrpc: Fix trace-after-put looking at the put call record 

rxrpc_put_call() calls trace_rxrpc_call() after it has done the decrement
of the refcount - which looks at the debug_id in the call record.  But
unless the refcount was reduced to zero, we no longer have the right to
look in the record and, indeed, it may be deleted by some other thread.

Fix this by getting the debug_id out before decrementing the refcount and
then passing that into the tracepoint.

Fixes: e34d4234b0 ("rxrpc: Trace rxrpc_call usage")
Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
David Howells 2019-10-07 10:58:29 +01:00
parent 4c1295dccc
commit 48c9e0ec7c
3 changed files with 21 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
include/trace/events/rxrpc.h
View File

@ -606,10 +606,10 @@ TRACE_EVENT(rxrpc_client,
);
TRACE_EVENT(rxrpc_call,
TP_PROTO(struct rxrpc_call *call, enum rxrpc_call_trace op,
TP_PROTO(unsigned int call_debug_id, enum rxrpc_call_trace op,
int usage, const void *where, const void *aux),
TP_ARGS(call, op, usage, where, aux),
TP_ARGS(call_debug_id, op, usage, where, aux),
TP_STRUCT__entry(
__field(unsigned int, call )
@ -620,7 +620,7 @@ TRACE_EVENT(rxrpc_call,
),
TP_fast_assign(
__entry->call = call->debug_id;
__entry->call = call_debug_id;
__entry->op = op;
__entry->usage = usage;
__entry->where = where;

2
net/rxrpc/call_accept.c
View File

@ -97,7 +97,7 @@ static int rxrpc_service_prealloc_one(struct rxrpc_sock *rx,
call->flags |= (1 << RXRPC_CALL_IS_SERVICE);
call->state = RXRPC_CALL_SERVER_PREALLOC;
trace_rxrpc_call(call, rxrpc_call_new_service,
trace_rxrpc_call(call->debug_id, rxrpc_call_new_service,
atomic_read(&call->usage),
here, (const void *)user_call_ID);

28
net/rxrpc/call_object.c
View File

@ -240,7 +240,8 @@ struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx,
if (p->intr)
__set_bit(RXRPC_CALL_IS_INTR, &call->flags);
call->tx_total_len = p->tx_total_len;
trace_rxrpc_call(call, rxrpc_call_new_client, atomic_read(&call->usage),
trace_rxrpc_call(call->debug_id, rxrpc_call_new_client,
atomic_read(&call->usage),
here, (const void *)p->user_call_ID);
/* We need to protect a partially set up call against the user as we
@ -290,8 +291,8 @@ struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx,
if (ret < 0)
goto error;
trace_rxrpc_call(call, rxrpc_call_connected, atomic_read(&call->usage),
here, NULL);
trace_rxrpc_call(call->debug_id, rxrpc_call_connected,
atomic_read(&call->usage), here, NULL);
rxrpc_start_call_timer(call);
@ -313,8 +314,8 @@ error_dup_user_ID:
error:
__rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR,
RX_CALL_DEAD, ret);
trace_rxrpc_call(call, rxrpc_call_error, atomic_read(&call->usage),
here, ERR_PTR(ret));
trace_rxrpc_call(call->debug_id, rxrpc_call_error,
atomic_read(&call->usage), here, ERR_PTR(ret));
rxrpc_release_call(rx, call);
mutex_unlock(&call->user_mutex);
rxrpc_put_call(call, rxrpc_call_put);
@ -376,7 +377,8 @@ bool rxrpc_queue_call(struct rxrpc_call *call)
if (n == 0)
return false;
if (rxrpc_queue_work(&call->processor))
trace_rxrpc_call(call, rxrpc_call_queued, n + 1, here, NULL);
trace_rxrpc_call(call->debug_id, rxrpc_call_queued, n + 1,
here, NULL);
else
rxrpc_put_call(call, rxrpc_call_put_noqueue);
return true;
@ -391,7 +393,8 @@ bool __rxrpc_queue_call(struct rxrpc_call *call)
int n = atomic_read(&call->usage);
ASSERTCMP(n, >=, 1);
if (rxrpc_queue_work(&call->processor))
trace_rxrpc_call(call, rxrpc_call_queued_ref, n, here, NULL);
trace_rxrpc_call(call->debug_id, rxrpc_call_queued_ref, n,
here, NULL);
else
rxrpc_put_call(call, rxrpc_call_put_noqueue);
return true;
@ -406,7 +409,8 @@ void rxrpc_see_call(struct rxrpc_call *call)
if (call) {
int n = atomic_read(&call->usage);
trace_rxrpc_call(call, rxrpc_call_seen, n, here, NULL);
trace_rxrpc_call(call->debug_id, rxrpc_call_seen, n,
here, NULL);
}
}
@ -418,7 +422,7 @@ void rxrpc_get_call(struct rxrpc_call *call, enum rxrpc_call_trace op)
const void *here = __builtin_return_address(0);
int n = atomic_inc_return(&call->usage);
trace_rxrpc_call(call, op, n, here, NULL);
trace_rxrpc_call(call->debug_id, op, n, here, NULL);
}
/*
@ -445,7 +449,8 @@ void rxrpc_release_call(struct rxrpc_sock *rx, struct rxrpc_call *call)
_enter("{%d,%d}", call->debug_id, atomic_read(&call->usage));
trace_rxrpc_call(call, rxrpc_call_release, atomic_read(&call->usage),
trace_rxrpc_call(call->debug_id, rxrpc_call_release,
atomic_read(&call->usage),
here, (const void *)call->flags);
ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE);
@ -534,12 +539,13 @@ void rxrpc_put_call(struct rxrpc_call *call, enum rxrpc_call_trace op)
{
struct rxrpc_net *rxnet = call->rxnet;
const void *here = __builtin_return_address(0);
unsigned int debug_id = call->debug_id;
int n;
ASSERT(call != NULL);
n = atomic_dec_return(&call->usage);
trace_rxrpc_call(call, op, n, here, NULL);
trace_rxrpc_call(debug_id, op, n, here, NULL);
ASSERTCMP(n, >=, 0);
if (n == 0) {
_debug("call %d dead", call->debug_id);