Restore sensible "sess_accept" counter tracking
authorBenjamin Kaduk <bkaduk@akamai.com>
Mon, 22 Oct 2018 16:54:20 +0000 (11:54 -0500)
committerBenjamin Kaduk <kaduk@mit.edu>
Sun, 4 Nov 2018 04:27:12 +0000 (23:27 -0500)
commit33a37a6179bcef6917a28edf7c90a65dcd89ff4a
treea8315e218dffc0369c4ef5246586c0b0168923a7
parenta649b52f86a2aa039a15d9c8c0de5b6786bac0fc
Restore sensible "sess_accept" counter tracking

Commit 9ef9088c1585e13b9727796f15f77da64dbbe623 switched the SSL/SSL_CTX
statistics counters to using Thread-Sanitizer-friendly primitives.
However, it erroneously converted an addition of -1
(for s->session_ctx->stats.sess_accept) to an addition of +1, since that
is the only counter API provided by the internal tsan_assist.h header
until the previous commit.  This means that for each accepted (initial)
connection, the session_ctx's counter would get doubly incremented, and the
(switched) ctx's counter would also get incremented.

Restore the counter decrement so that each accepted connection increments
exactly one counter exactly once (in net effect).

Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/7464)

(cherry picked from commit 2aaa0b146b967397a6e61fa8df969e7847f82086)
ssl/statem/extensions.c