Fix: don't dereference NULL pointers

[lttng-ust.git] / libringbuffer / ring_buffer_frontend.c

diff --git a/libringbuffer/ring_buffer_frontend.c b/libringbuffer/ring_buffer_frontend.c
index aeb7f7d94a10a9c4b63d098df1191ba4cdcef47e..77019e9c3fce8e65159a4e7e7e73076b40719177 100644 (file)
--- a/libringbuffer/ring_buffer_frontend.c
+++ b/libringbuffer/ring_buffer_frontend.c
@@ -159,10 +159,14 @@ static struct timer_signal_data timer_signal = {
 void lib_ring_buffer_reset(struct lttng_ust_lib_ring_buffer *buf,
                           struct lttng_ust_shm_handle *handle)
 {
-       struct channel *chan = shmp(handle, buf->backend.chan);
-       const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
+       struct channel *chan;
+       const struct lttng_ust_lib_ring_buffer_config *config;
        unsigned int i;
 
+       chan = shmp(handle, buf->backend.chan);
+       if (!chan)
+               abort();
+       config = &chan->backend.config;
        /*
         * Reset iterator first. It will put the subbuffer if it currently holds
         * it.
@@ -302,6 +306,9 @@ void lib_ring_buffer_channel_switch_timer(int sig, siginfo_t *si, void *uc)
                for_each_possible_cpu(cpu) {
                        struct lttng_ust_lib_ring_buffer *buf =
                                shmp(handle, chan->backend.buf[cpu].shmp);
+
+                       if (!buf)
+                               abort();
                        if (uatomic_read(&buf->active_readers))
                                lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE,
                                        chan->handle);
@@ -310,6 +317,8 @@ void lib_ring_buffer_channel_switch_timer(int sig, siginfo_t *si, void *uc)
                struct lttng_ust_lib_ring_buffer *buf =
                        shmp(handle, chan->backend.buf[0].shmp);
 
+               if (!buf)
+                       abort();
                if (uatomic_read(&buf->active_readers))
                        lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE,
                                chan->handle);
@@ -337,6 +346,8 @@ void lib_ring_buffer_channel_do_read(struct channel *chan)
                        struct lttng_ust_lib_ring_buffer *buf =
                                shmp(handle, chan->backend.buf[cpu].shmp);
 
+                       if (!buf)
+                               abort();
                        if (uatomic_read(&buf->active_readers)
                            && lib_ring_buffer_poll_deliver(config, buf,
                                        chan, handle)) {
@@ -347,6 +358,8 @@ void lib_ring_buffer_channel_do_read(struct channel *chan)
                struct lttng_ust_lib_ring_buffer *buf =
                        shmp(handle, chan->backend.buf[0].shmp);
 
+               if (!buf)
+                       abort();
                if (uatomic_read(&buf->active_readers)
                    && lib_ring_buffer_poll_deliver(config, buf,
                                chan, handle)) {