[PATCH v2 04/53] migration/rdma: Drop fragile wr_id formatting

[Markus Armbruster]

wrid_desc[] uses 4001 pointers to map four integer values to strings.

print_wrid() accesses wrid_desc[] out of bounds when passed a negative
argument.  It returns null for values 2..1999 and 2001..3999.

qemu_rdma_poll() and qemu_rdma_block_for_wrid() print wrid_desc[wr_id]
and passes print_wrid(wr_id) to tracepoints.  Could conceivably crash
trying to format a null string.  I believe access out of bounds is not
possible.

Not worth cleaning up.  Dumb down to show just numeric wr_id.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
---
 migration/rdma.c       | 32 +++++++-------------------------
 migration/trace-events |  8 ++++----
 2 files changed, 11 insertions(+), 29 deletions(-)

diff --git a/migration/rdma.c b/migration/rdma.c
index d448c3e538..fc9eab0ff7 100644
--- a/migration/rdma.c
+++ b/migration/rdma.c
@@ -133,13 +133,6 @@ enum {
     RDMA_WRID_RECV_CONTROL = 4000,
 };
 
-static const char *wrid_desc[] = {
-    [RDMA_WRID_NONE] = "NONE",
-    [RDMA_WRID_RDMA_WRITE] = "WRITE RDMA",
-    [RDMA_WRID_SEND_CONTROL] = "CONTROL SEND",
-    [RDMA_WRID_RECV_CONTROL] = "CONTROL RECV",
-};
-
 /*
  * Work request IDs for IB SEND messages only (not RDMA writes).
  * This is used by the migration protocol to transmit
@@ -535,7 +528,6 @@ static void network_to_result(RDMARegisterResult *result)
     result->host_addr = ntohll(result->host_addr);
 };
 
-const char *print_wrid(int wrid);
 static int qemu_rdma_exchange_send(RDMAContext *rdma, RDMAControlHeader *head,
                                    uint8_t *data, RDMAControlHeader *resp,
                                    int *resp_idx,
@@ -1362,14 +1354,6 @@ static int qemu_rdma_reg_control(RDMAContext *rdma, int 
idx)
     return -1;
 }
 
-const char *print_wrid(int wrid)
-{
-    if (wrid >= RDMA_WRID_RECV_CONTROL) {
-        return wrid_desc[RDMA_WRID_RECV_CONTROL];
-    }
-    return wrid_desc[wrid];
-}
-
 /*
  * Perform a non-optimized memory unregistration after every transfer
  * for demonstration purposes, only if pin-all is not requested.
@@ -1491,15 +1475,15 @@ static int qemu_rdma_poll(RDMAContext *rdma, struct 
ibv_cq *cq,
     if (wc.status != IBV_WC_SUCCESS) {
         fprintf(stderr, "ibv_poll_cq wc.status=%d %s!\n",
                         wc.status, ibv_wc_status_str(wc.status));
-        fprintf(stderr, "ibv_poll_cq wrid=%s!\n", wrid_desc[wr_id]);
+        fprintf(stderr, "ibv_poll_cq wrid=%" PRIu64 "!\n", wr_id);
 
         return -1;
     }
 
     if (rdma->control_ready_expected &&
         (wr_id >= RDMA_WRID_RECV_CONTROL)) {
-        trace_qemu_rdma_poll_recv(wrid_desc[RDMA_WRID_RECV_CONTROL],
-                  wr_id - RDMA_WRID_RECV_CONTROL, wr_id, rdma->nb_sent);
+        trace_qemu_rdma_poll_recv(wr_id - RDMA_WRID_RECV_CONTROL, wr_id,
+                                  rdma->nb_sent);
         rdma->control_ready_expected = 0;
     }
 
@@ -1510,7 +1494,7 @@ static int qemu_rdma_poll(RDMAContext *rdma, struct 
ibv_cq *cq,
             (wc.wr_id & RDMA_WRID_BLOCK_MASK) >> RDMA_WRID_BLOCK_SHIFT;
         RDMALocalBlock *block = &(rdma->local_ram_blocks.block[index]);
 
-        trace_qemu_rdma_poll_write(print_wrid(wr_id), wr_id, rdma->nb_sent,
+        trace_qemu_rdma_poll_write(wr_id, rdma->nb_sent,
                                    index, chunk, block->local_host_addr,
                                    (void *)(uintptr_t)block->remote_host_addr);
 
@@ -1520,7 +1504,7 @@ static int qemu_rdma_poll(RDMAContext *rdma, struct 
ibv_cq *cq,
             rdma->nb_sent--;
         }
     } else {
-        trace_qemu_rdma_poll_other(print_wrid(wr_id), wr_id, rdma->nb_sent);
+        trace_qemu_rdma_poll_other(wr_id, rdma->nb_sent);
     }
 
     *wr_id_out = wc.wr_id;
@@ -1665,8 +1649,7 @@ static int qemu_rdma_block_for_wrid(RDMAContext *rdma, 
int wrid_requested,
             break;
         }
         if (wr_id != wrid_requested) {
-            trace_qemu_rdma_block_for_wrid_miss(print_wrid(wrid_requested),
-                       wrid_requested, print_wrid(wr_id), wr_id);
+            trace_qemu_rdma_block_for_wrid_miss(wrid_requested, wr_id);
         }
     }
 
@@ -1705,8 +1688,7 @@ static int qemu_rdma_block_for_wrid(RDMAContext *rdma, 
int wrid_requested,
                 break;
             }
             if (wr_id != wrid_requested) {
-                trace_qemu_rdma_block_for_wrid_miss(print_wrid(wrid_requested),
-                                   wrid_requested, print_wrid(wr_id), wr_id);
+                trace_qemu_rdma_block_for_wrid_miss(wrid_requested, wr_id);
             }
         }
 
diff --git a/migration/trace-events b/migration/trace-events
index 4666f19325..b78808f28b 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -207,7 +207,7 @@ qemu_rdma_accept_incoming_migration(void) ""
 qemu_rdma_accept_incoming_migration_accepted(void) ""
 qemu_rdma_accept_pin_state(bool pin) "%d"
 qemu_rdma_accept_pin_verbsc(void *verbs) "Verbs context after listen: %p"
-qemu_rdma_block_for_wrid_miss(const char *wcompstr, int wcomp, const char 
*gcompstr, uint64_t req) "A Wanted wrid %s (%d) but got %s (%" PRIu64 ")"
+qemu_rdma_block_for_wrid_miss(int wcomp, uint64_t req) "A Wanted wrid %d but 
got %" PRIu64
 qemu_rdma_cleanup_disconnect(void) ""
 qemu_rdma_close(void) ""
 qemu_rdma_connect_pin_all_requested(void) ""
@@ -221,9 +221,9 @@ qemu_rdma_exchange_send_waiting(const char *desc) "Waiting 
for response %s"
 qemu_rdma_exchange_send_received(const char *desc) "Response %s received."
 qemu_rdma_fill(size_t control_len, size_t size) "RDMA %zd of %zd bytes already 
in buffer"
 qemu_rdma_init_ram_blocks(int blocks) "Allocated %d local ram block structures"
-qemu_rdma_poll_recv(const char *compstr, int64_t comp, int64_t id, int sent) 
"completion %s #%" PRId64 " received (%" PRId64 ") left %d"
-qemu_rdma_poll_write(const char *compstr, int64_t comp, int left, uint64_t 
block, uint64_t chunk, void *local, void *remote) "completions %s (%" PRId64 ") 
left %d, block %" PRIu64 ", chunk: %" PRIu64 " %p %p"
-qemu_rdma_poll_other(const char *compstr, int64_t comp, int left) "other 
completion %s (%" PRId64 ") received left %d"
+qemu_rdma_poll_recv(int64_t comp, int64_t id, int sent) "completion %" PRId64 
" received (%" PRId64 ") left %d"
+qemu_rdma_poll_write(int64_t comp, int left, uint64_t block, uint64_t chunk, 
void *local, void *remote) "completions %" PRId64 " left %d, block %" PRIu64 ", 
chunk: %" PRIu64 " %p %p"
+qemu_rdma_poll_other(int64_t comp, int left) "other completion %" PRId64 " 
received left %d"
 qemu_rdma_post_send_control(const char *desc) "CONTROL: sending %s.."
 qemu_rdma_register_and_get_keys(uint64_t len, void *start) "Registering %" 
PRIu64 " bytes @ %p"
 qemu_rdma_register_odp_mr(const char *name) "Try to register On-Demand Paging 
memory region: %s"
-- 
2.41.0