181781 2018-01-17 20:42:07 -0800 iOS 11.2.2 and 11.2.5b6 WebAssembly regression (error or hang) 2018-03-26 21:05:46 -0700 1 1 1 Unclassified WebKit WebAssembly Safari 11 iPhone / iPad iOS 11 RESOLVED FIXED InRadar P2 Normal --- 1 bvibber webkit-unassigned ashley fpizlo hello jfbastien keith_miller mark.lam msaboff rmorisset saam shader.yang webkit-bug-importer oldest_to_newest 1390383 0 bvibber 2018-01-17 20:42:07 -0800 At Wikipedia we use an emscripten-based decoder in Safari for some video and audio formats, and are looking at deploying a WebAssembly build for both desktop and mobile. In iOS 11.2.2 there's a major regression in wasm which breaks things with "out of bounds memory access" errors, which I believe is rdar:://problem/36236004 and supposed to be fixed; however the latest version I can test is iOS 11.2.5beta 6, where instead of emitting an error the entire web content process hangs without emitting any console messages. Sample using asm.js build: * https://brionv.com/misc/ogv.js/demo/#player=js ^ works Sample using wasm build: * https://brionv.com/misc/ogv.js/demo/#player=wasm ^ errors out on 11.2.2, hangs on 11.2.5b6 The hang comes during initialization or early execution, making it tricky to connect with the Safari remote debugger. Downstream issues: * https://phabricator.wikimedia.org/T179108 * https://github.com/brion/ogv.js/issues/485 * https://github.com/kripken/emscripten/issues/6042 1390644 1 webkit-bug-importer 2018-01-18 13:17:44 -0800 <rdar://problem/36631309> 1391959 2 bvibber 2018-01-22 20:16:48 -0800 11.2.5 beta 7 on iPad Pro 9.7" no longer seems to hang the web content process; I get the original out of bounds memory access error, now caught by surrounding code and logged internally as opposed to outputting direct to console: [Log] [3395ms] i/o error: Error: Out of bounds memory access (evaluating 'Module["asm"]["_ogv_demuxer_receive_input"].apply(null,arguments)') (ogv.js, line 1005) 1392445 3 bvibber 2018-01-23 22:54:28 -0800 I've identified a smaller test case which I've posted at https://github.com/brion/min-wasm-fail Does an i32.store of a value at index 4 and reads it back -- on iOS I get 0 instead of the expected value. (At index 0, we get the expected value back.) The actual out of bounds exception in emscripten'd code seems to be a side effect of failing to load/store correctly, so pointers get screwed up and something ends up trying to access outside of mem. 1392833 4 bvibber 2018-01-24 16:30:47 -0800 Confirmed resolved in iOS 11.3 beta 1. 1394107 5 jfbastien 2018-01-29 08:53:21 -0800 *** Bug 181598 has been marked as a duplicate of this bug. *** 1394108 6 ashley 2018-01-29 08:59:03 -0800 For those of us who can't see rdar links, is there any news on this? 1394110 7 bvibber 2018-01-29 09:16:15 -0800 (In reply to Ashley Gullen from comment #6) > For those of us who can't see rdar links, is there any news on this? Bug is resolved in iOS 11.3 betas; presumably the fix won't reach the public until 11.3 is complete, so for now people will need to detect the bug and either throw a user-visible error or switch to an asm.js build. I've created a small test case at https://github.com/brion/min-wasm-fail/blob/master/min-wasm-fail.js which can be used to check at runtime whether the bug is present, which I've integrated into my project. Please feel free to copy that test case. 1394124 8 ashley 2018-01-29 09:54:26 -0800 OK, thanks. Is there any indication when 11.3 is due out? We can hack in a workaround but it won't fix all the content that's already been deployed with our software. I can't believe that a key web technology is completely broken and it's being left like that! 1394129 9 bvibber 2018-01-29 10:02:14 -0800 I'm sure the Apple folks can't comment on that, but what indications I have seen in public are "spring" which could mean anywhere from March to May of this year. I would love an earlier fix on the 11.2.x branch too, but I know engineering scheduling is a hard problem... 1394130 10 ashley 2018-01-29 10:05:28 -0800 Wow. Okay. Seriously, it would have been better to simply turn off WebAssembly, so existing fallbacks to asm.js are activated. 1400721 11 ashley 2018-02-20 04:38:38 -0800 WebAssembly is still enabled, and non-functional, on iOS 11.2.6. 1409474 12 shader.yang 2018-03-26 21:05:46 -0700 I think there is no fundamental improvement for this issue, because I have tested it on all kinds of iOS version from 11.0.1 to 11.3 b6, only 11.2.1 can work well so far, I have submitted related issues but the issues' status all are "NEW". Please refer to: https://bugs.webkit.org/show_bug.cgi?id=181723 https://bugs.webkit.org/show_bug.cgi?id=183101 https://github.com/kripken/emscripten/issues/6042 https://forum.unity.com/threads/webgl-builds-crash-issue-on-ios-browsers-unity3d.518240/ I think apple/webkit should face this issue seriously and fix it ASAP, this issue should be reopened. Thanks!