131630 2014-04-14 12:51:58 -0700 monotonicallyIncreasingTime() should only initialize its static timebaseInfo once 2014-04-14 13:33:06 -0700 1 1 1 Unclassified WebKit JavaScriptCore 528+ (Nightly build) Unspecified Unspecified RESOLVED FIXED InRadar P2 Normal --- 1 mark.lam mark.lam benjamin cmarcelo commit-queue fpizlo ggaren mhahnenberg mmirman msaboff oliver simon.fraser oldest_to_newest 1000579 0 mark.lam 2014-04-14 12:51:58 -0700 The current initialization of the static field is not thread safe. 1000580 1 mark.lam 2014-04-14 12:52:54 -0700 <rdar://problem/16413527> 1000583 2 229302 mark.lam 2014-04-14 13:02:53 -0700 Created attachment 229302 the patch 1000584 3 229302 fpizlo 2014-04-14 13:20:28 -0700 Comment on attachment 229302 the patch View in context: https://bugs.webkit.org/attachment.cgi?id=229302&action=review > Source/WTF/wtf/CurrentTime.cpp:278 > // Based on listing #2 from Apple QA 1398. > static mach_timebase_info_data_t timebaseInfo; > - if (!timebaseInfo.denom) { > + static std::once_flag initializeTimerOnceFlag; > + std::call_once(initializeTimerOnceFlag, [] { You should change the comment to say that it fixes the race condition in that listing. Say something like "Based on listing #2 from Apple QA 1398, but modified to be thread-safe". 1000586 4 mark.lam 2014-04-14 13:33:06 -0700 Thanks. Patch has been updated as suggested. Landed in r167263: <http://trac.webkit.org/r167263>. 229302 2014-04-14 13:02:53 -0700 2014-04-14 13:20:28 -0700 the patch bug-131630.patch text/plain 1614 mark.lam SW5kZXg6IFNvdXJjZS9XVEYvQ2hhbmdlTG9nCj09PT09PT09PT09PT09PT09PT09PT09PT09PT09 PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT0KLS0tIFNvdXJjZS9XVEYvQ2hh bmdlTG9nCShyZXZpc2lvbiAxNjcyNjApCisrKyBTb3VyY2UvV1RGL0NoYW5nZUxvZwkod29ya2lu ZyBjb3B5KQpAQCAtMSwzICsxLDE1IEBACisyMDE0LTA0LTE0ICBNYXJrIExhbSAgPG1hcmsubGFt QGFwcGxlLmNvbT4KKworICAgICAgICBtb25vdG9uaWNhbGx5SW5jcmVhc2luZ1RpbWUoKSBzaG91 bGQgb25seSBpbml0aWFsaXplIGl0cyBzdGF0aWMgdGltZWJhc2VJbmZvIG9uY2UuCisgICAgICAg IDxodHRwczovL3dlYmtpdC5vcmcvYi8xMzE2MzA+CisKKyAgICAgICAgUmV2aWV3ZWQgYnkgTk9C T0RZIChPT1BTISkuCisKKyAgICAgICAgVGhlIGN1cnJlbnQgaW5pdGlhbGl6YXRpb24gb2YgdGhl IHN0YXRpYyBmaWVsZCBpcyBub3QgdGhyZWFkIHNhZmUuCisKKyAgICAgICAgKiB3dGYvQ3VycmVu dFRpbWUuY3BwOgorICAgICAgICAoV1RGOjptb25vdG9uaWNhbGx5SW5jcmVhc2luZ1RpbWUpOgor CiAyMDE0LTA0LTE0ICBCZW5qYW1pbiBQb3VsYWluICA8YmVuamFtaW5Ad2Via2l0Lm9yZz4KIAog ICAgICAgICBbSlNDXSBJbXByb3ZlIHRoZSBjYWxsIHNpdGUgb2Ygc3RyaW5nIGNvbXBhcmlzb24g aW4gc29tZSBob3QgcGF0aApJbmRleDogU291cmNlL1dURi93dGYvQ3VycmVudFRpbWUuY3BwCj09 PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09 PT09PT09PT0KLS0tIFNvdXJjZS9XVEYvd3RmL0N1cnJlbnRUaW1lLmNwcAkocmV2aXNpb24gMTY3 MjU0KQorKysgU291cmNlL1dURi93dGYvQ3VycmVudFRpbWUuY3BwCSh3b3JraW5nIGNvcHkpCkBA IC0zNyw2ICszNyw3IEBACiAjaWYgT1MoREFSV0lOKQogI2luY2x1ZGUgPG1hY2gvbWFjaC5oPgog I2luY2x1ZGUgPG1hY2gvbWFjaF90aW1lLmg+CisjaW5jbHVkZSA8bXV0ZXg+CiAjaW5jbHVkZSA8 c3lzL3RpbWUuaD4KICNlbGlmIE9TKFdJTkRPV1MpCiAKQEAgLTI3MywxMCArMjc0LDEzIEBAIGRv dWJsZSBtb25vdG9uaWNhbGx5SW5jcmVhc2luZ1RpbWUoKQogewogICAgIC8vIEJhc2VkIG9uIGxp c3RpbmcgIzIgZnJvbSBBcHBsZSBRQSAxMzk4LgogICAgIHN0YXRpYyBtYWNoX3RpbWViYXNlX2lu Zm9fZGF0YV90IHRpbWViYXNlSW5mbzsKLSAgICBpZiAoIXRpbWViYXNlSW5mby5kZW5vbSkgewor ICAgIHN0YXRpYyBzdGQ6Om9uY2VfZmxhZyBpbml0aWFsaXplVGltZXJPbmNlRmxhZzsKKyAgICBz dGQ6OmNhbGxfb25jZShpbml0aWFsaXplVGltZXJPbmNlRmxhZywgW10gewogICAgICAgICBrZXJu X3JldHVybl90IGtyID0gbWFjaF90aW1lYmFzZV9pbmZvKCZ0aW1lYmFzZUluZm8pOwogICAgICAg ICBBU1NFUlRfVU5VU0VEKGtyLCBrciA9PSBLRVJOX1NVQ0NFU1MpOwotICAgIH0KKyAgICAgICAg QVNTRVJUKHRpbWViYXNlSW5mby5kZW5vbSk7CisgICAgfSk7CisKICAgICByZXR1cm4gKG1hY2hf YWJzb2x1dGVfdGltZSgpICogdGltZWJhc2VJbmZvLm51bWVyKSAvICgxLjBlOSAqIHRpbWViYXNl SW5mby5kZW5vbSk7CiB9CiAK