When performing a library base address statedump, the UST threads can
grab the RCU read-side lock, which touch a TLS. We should "pre-fault"
this TLS in the constructor to eliminate a deadlock involving libc
dynamic loader lock.
When an application traced with per-UID buffers vanishes between its
reserve and commit ring buffer operations (e.g. segfault), it may cause
the consumer daemon to enter an endless loop, awaiting for the
application to complete its commit.
Fix this situation by bounding the number of retry using an adaptative
approach: try actively for a few times, and then try a few more times
with a 10ms delay between attempts.
This issue affects only architectures without efficient unaligned
accesses, only when a context field with larger alignment follows a
context field with smaller alignment. It generates unreadable traces
when such context fields are enabled in this configuration.
std=c99 without #define __USE_BSD does not work for tracepoint header,
due to missing endianness macros. Force their definition in the
ust-endian.h wrapper if they are missing.
