Clarify probe registration documentation/errors

[lttng-ust.git] / doc / man / lttng-ust.3

diff --git a/doc/man/lttng-ust.3 b/doc/man/lttng-ust.3
index 88025c0e702727da568f9a99b7dbb70bd248cc2c..0de6b6a1e9e1d1bccee7bce37e964cb25d15e62a 100644 (file)
--- a/doc/man/lttng-ust.3
+++ b/doc/man/lttng-ust.3
@@ -148,6 +148,11 @@ TRACEPOINT_EVENT(
                ctf_float(double, doublefield, doublearg)
        )
 )
+
+There can be an arbitrary number of tracepoint providers within an
+application, but they must each have their own provider name. Duplicate
+provider names are not allowed.
+
 .fi
 
 .SH "ASSIGNING LOGLEVEL TO EVENTS"
@@ -257,7 +262,7 @@ carefully:
     - If building the provider directly into the application,
       link the application with "\-llttng-ust".
     - If building a static library for the provider, link the static
-      library with "\-lllttng-ust".
+      library with "\-llttng-ust".
     - Include the tracepoint provider header into all C files using
       the provider.
     - Example:
@@ -326,10 +331,23 @@ startup time.
 .PP
 lttng-gen-tp(1), lttng(1), babeltrace(1), lttng-sessiond(8)
 .PP
+
+.SH "COMPATIBILITY"
+
+.PP
+Older lttng-ust libraries reject more recent, and incompatible, probe
+providers. Newer lttng-ust librairies accept older probe providers, even
+though some newer features might not be available with those providers.
+.PP
+
 .SH "BUGS"
 
 .PP
-No knows bugs at this point.
+LTTng-UST 2.0 and 2.1 lttng-ust libraries do not check for probe
+provider version compatibility. This can lead to out-of-bound accesses
+when using a more recent probe provider with an older lttng-ust library.
+These error only trigger when tracing is active. This issue has been
+fixed in LTTng-UST 2.2.
 
 If you encounter any issues or usability problem, please report it on
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