diff options
| author | Andy Polyakov <appro@openssl.org> | 2018-08-17 12:30:36 +0200 |
|---|---|---|
| committer | Andy Polyakov <appro@openssl.org> | 2018-08-26 17:47:49 +0200 |
| commit | 7d38ca3f8bca58bf7b69e78c1f1ab69e5f429dff (patch) | |
| tree | 4b95e6c1dd4f10bc9a7c649e2856579d7e5db5ab /crypto/x509v3 | |
| parent | internal/tsan_assist.h: add tsan_ld_acq and tsan_st_rel. (diff) | |
| download | openssl-7d38ca3f8bca58bf7b69e78c1f1ab69e5f429dff.tar.xz openssl-7d38ca3f8bca58bf7b69e78c1f1ab69e5f429dff.zip | |
x509v3/v3_purp.c: refine lock-free check in x509v3_cache_extensions.
Reviewed-by: Kurt Roeckx <kurt@roeckx.be>
(Merged from https://github.com/openssl/openssl/pull/6996)
Diffstat (limited to 'crypto/x509v3')
| -rw-r--r-- | crypto/x509v3/v3_purp.c | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/crypto/x509v3/v3_purp.c b/crypto/x509v3/v3_purp.c index 5a535e2ade..70b0397d97 100644 --- a/crypto/x509v3/v3_purp.c +++ b/crypto/x509v3/v3_purp.c @@ -354,9 +354,11 @@ static void x509v3_cache_extensions(X509 *x) X509_EXTENSION *ex; int i; +#ifdef tsan_ld_acq /* fast lock-free check, see end of the function for details. */ - if (tsan_load((TSAN_QUALIFIER int *)&x->ex_cached)) + if (tsan_ld_acq((TSAN_QUALIFIER int *)&x->ex_cached)) return; +#endif CRYPTO_THREAD_write_lock(x->lock); if (x->ex_flags & EXFLAG_SET) { @@ -498,13 +500,15 @@ static void x509v3_cache_extensions(X509 *x) } x509_init_sig_info(x); x->ex_flags |= EXFLAG_SET; - CRYPTO_THREAD_unlock(x->lock); +#ifdef tsan_st_rel + tsan_st_rel((TSAN_QUALIFIER int *)&x->ex_cached, 1); /* - * It has to be placed after memory barrier, which is implied by unlock. - * Worst thing that can happen is that another thread proceeds to lock - * and checks x->ex_flags & EXFLAGS_SET. See beginning of the function. + * Above store triggers fast lock-free check in the beginning of the + * function. But one has to ensure that the structure is "stable", i.e. + * all stores are visible on all processors. Hence the release fence. */ - tsan_store((TSAN_QUALIFIER int *)&x->ex_cached, 1); +#endif + CRYPTO_THREAD_unlock(x->lock); } /*- |