<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
<html lang="en" style='--code-editor-font: var(--default-mono-font, "Menlo"), DejaVu Sans Mono, Liberation Mono, Consolas, Ubuntu Mono, Courier New, andale mono, lucida console, monospace;'>
<head>
<meta content="text/html; charset=US-ASCII" http-equiv="Content-Type">
<title>
GitLab
</title>
<style data-premailer="ignore" type="text/css">
a { color: #1068bf; }
</style>
<style>img {
max-width: 100%; height: auto;
}
body {
font-size: 0.875rem;
}
body {
-webkit-text-shadow: rgba(255,255,255,0.01) 0 0 1px;
}
body {
font-family: var(--default-regular-font, -apple-system),BlinkMacSystemFont,"Segoe UI",Roboto,"Noto Sans",Ubuntu,Cantarell,"Helvetica Neue",sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol","Noto Color Emoji"; font-size: inherit;
}
</style>
</head>
<body style='font-size: inherit; -webkit-text-shadow: rgba(255,255,255,0.01) 0 0 1px; font-family: var(--default-regular-font, -apple-system),BlinkMacSystemFont,"Segoe UI",Roboto,"Noto Sans",Ubuntu,Cantarell,"Helvetica Neue",sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol","Noto Color Emoji";'>
<div class="content">
<h3 style="margin-top: 20px; margin-bottom: 10px;">
Ben Gamari pushed to branch wip/tsan/fixes-2 at <a href="https://gitlab.haskell.org/ghc/ghc">Glasgow Haskell Compiler / GHC</a>
</h3>
<h4 style="margin-top: 10px; margin-bottom: 10px;">
Commits:
</h4>
<ul>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/8d96dbd06e192b8d9cb720b548c267d8abb2e784">8d96dbd0</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-20T08:46:03-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "Menlo"),"DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>rts: Fix data race in CHECK_GC
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/fa2d7eceee57b9440e243d87e80c2e1ce51b96b5">fa2d7ece</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-20T08:46:03-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "Menlo"),"DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>base: use atomic write when updating timer manager
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/8f61117e07805fcf6ff06f103f6c71211a823d3c">8f61117e</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-20T08:46:03-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "Menlo"),"DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Use relaxed atomics to manipulate TSO status fields
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/b94b1578bc99d7d8aa72701f58f341e90f59f43d">b94b1578</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-20T08:46:03-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "Menlo"),"DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>rts: Add necessary barriers when manipulating TSO owner
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/9b6e128fdd56415d1b124ed12af65b86696a10c2">9b6e128f</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-20T08:46:03-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "Menlo"),"DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>rts: Fix synchronization on thread blocking state
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/cc4c72c696c2619dd07a87f766f7944b0c54bfb2">cc4c72c6</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-20T08:46:03-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "Menlo"),"DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>rts: Relaxed load MutVar info table
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/d8aaca20ac972e3a316986c8d4841c8e3b78272f">d8aaca20</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-20T08:46:03-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "Menlo"),"DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>hadrian: More debug information
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/4d433891681223201adbb32938a66c1d4b4f0c1f">4d433891</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-20T08:46:03-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "Menlo"),"DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>hadrian: More selective TSAN instrumentation
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/2581141542b07a42dec1ed69a533fd8fe2fb45e3">25811415</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-20T08:46:03-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "Menlo"),"DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>codeGen/tsan: Rework handling of spilling
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/117cdf4a29536a2b8e4649721dc3820ddd62446b">117cdf4a</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-20T08:46:03-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "Menlo"),"DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>codeGen: Ensure that TSAN is aware of writeArray# write barriers
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/c4e038ab1147191127e9951e25306febb1b7d241">c4e038ab</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-20T08:46:04-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "Menlo"),"DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>codeGen: Ensure that array reads have necessary barriers
This was the cause of #23541.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/eada1f19a1797674f0f6c00bd955964fe7cafefc">eada1f19</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-20T08:46:04-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "Menlo"),"DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Wordsmith TSAN Note
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/13f259b95466c625a5bafbf0cee0d1d0e5574b29">13f259b9</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-20T08:46:04-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "Menlo"),"DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>codeGen: Use relaxed accesses in ticky bumping
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/dd9364aad2f2a49dfa0f0b3f54c30d6a49627f0b">dd9364aa</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-20T08:46:04-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "Menlo"),"DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>codeGen: Use relaxed-read in closureInfoPtr
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/b7aecf4d1eb1ca75f53ddaf588098317afa72bf6">b7aecf4d</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-20T08:46:04-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "Menlo"),"DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Fix thunk update ordering
Previously we attempted to ensure soundness of concurrent thunk update
by synchronizing on the access of the thunk's info table pointer field.
This was believed to be sufficient since the indirectee (which may
expose a closure allocated by another core) would not be examined
until the info table pointer update is complete.
However, it turns out that this can result in data races in the presence
of multiple threads racing a update a single thunk. For instance,
consider this interleaving under the old scheme:
Thread A Thread B
--------- ---------
t=0 Enter t
1 Push update frame
2 Begin evaluation
4 Pause thread
5 t.indirectee=tso
6 Release t.info=BLACKHOLE
7 ... (e.g. GC)
8 Resume thread
9 Finish evaluation
10 Relaxed t.indirectee=x
11 Load t.info
12 Acquire fence
13 Inspect t.indirectee
14 Release t.info=BLACKHOLE
Here Thread A enters thunk `t` but is soon paused, resulting in `t`
being lazily blackholed at t=6. Then, at t=10 Thread A finishes
evaluation and updates `t.indirectee` with a relaxed store.
Meanwhile, Thread B enters the blackhole. Under the old scheme this
would introduce an acquire-fence but this would only synchronize with
Thread A at t=6. Consequently, the result of the evaluation, `x`, is not
visible to Thread B, introducing a data race.
We fix this by treating the `indirectee` field as we do all other
mutable fields. This means we must always access this field with
acquire-loads and release-stores.
See #23185.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/cb8ee074814645bd4c34f80e158e9d2f73d6947c">cb8ee074</a></strong>
<div>
<span> by Ben Gamari </span> <i> at 2023-06-20T08:46:04-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "Menlo"),"DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>STM: Use acquire loads when possible
Full sequential consistency is not needed here.
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/5e9184512cb04b00b01000141a048a9e11362242">5e918451</a></strong>
<div>
<span> by Ubuntu </span> <i> at 2023-06-20T08:46:04-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "Menlo"),"DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>ghc-prim: Use C11 atomics
</pre>
</li>
<li>
<strong style="font-weight: bold;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/a382b0bf1073f01799a5d482dca0ca81404e61da">a382b0bf</a></strong>
<div>
<span> by Ubuntu </span> <i> at 2023-06-20T08:46:04-04:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 0.875rem; color: #333238; position: relative; font-family: var(--default-mono-font, "Menlo"),"DejaVu Sans Mono","Liberation Mono","Consolas","Ubuntu Mono","Courier New","andale mono","lucida console",monospace; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Run script
</pre>
</li>
</ul>
<h4 style="margin-top: 10px; margin-bottom: 10px;">
30 changed files:
</h4>
<ul>
<li class="file-stats">
<a href="#47cba74ae8965f1665cd11bf2b023760ea27594e">
compiler/GHC/Cmm/Info.hs
</a>
</li>
<li class="file-stats">
<a href="#194e2602b82bb08fd31c3028aace1da113aae36f">
compiler/GHC/Cmm/ThreadSanitizer.hs
</a>
</li>
<li class="file-stats">
<a href="#2f341f858154eb8e1900d5bd92a156b13ddd06f3">
compiler/GHC/StgToCmm/Bind.hs
</a>
</li>
<li class="file-stats">
<a href="#d12a108e34fe83acc9c99357ae841e22a0af0a23">
compiler/GHC/StgToCmm/Prim.hs
</a>
</li>
<li class="file-stats">
<a href="#b62375d0938c2cf6d00a6bec9649e795e57a9683">
compiler/GHC/StgToCmm/Ticky.hs
</a>
</li>
<li class="file-stats">
<a href="#13bc6c694b9a1fa78aeab1e992926d759374ecb2">
compiler/GHC/StgToCmm/Utils.hs
</a>
</li>
<li class="file-stats">
<a href="#1655041cfd1add79e4c335c656405ee3eb3bd0dd">
hadrian/src/Flavour.hs
</a>
</li>
<li class="file-stats">
<a href="#85027f4b37c07925334b1e4215f1cd73816e69c4">
libraries/base/GHC/Event/Thread.hs
</a>
</li>
<li class="file-stats">
<a href="#786d2d970e91533a64e0123b52368c3ec897ed39">
libraries/ghc-prim/cbits/atomic.c
</a>
</li>
<li class="file-stats">
<a href="#c6ca7d2b8bb94ab0a0ee349206e12a4a65925cec">
rts/Apply.cmm
</a>
</li>
<li class="file-stats">
<a href="#850b7a6f6f95faed03d3f83b3039ec0a562dfe86">
rts/Compact.cmm
</a>
</li>
<li class="file-stats">
<a href="#deed6a3bec2843fc56bafbd3ae930f535197b3a6">
rts/Exception.cmm
</a>
</li>
<li class="file-stats">
<a href="#7cd911ebab0f9f45be4a3d53fd5b4cb6cf96de6b">
rts/Heap.c
</a>
</li>
<li class="file-stats">
<a href="#c295ca8b90dc6b200fb3e0cbd3dfdc5df307bbc7">
rts/HeapStackCheck.cmm
</a>
</li>
<li class="file-stats">
<a href="#539d43389593f2626a387f2c904f03c215c7c802">
rts/Interpreter.c
</a>
</li>
<li class="file-stats">
<a href="#63bb2dcb45bf7982130b0b95ecf366bf1a617e82">
rts/Messages.c
</a>
</li>
<li class="file-stats">
<a href="#6db965f97cbab901f493506a385bcf1283009921">
rts/PrimOps.cmm
</a>
</li>
<li class="file-stats">
<a href="#515f190a948b1d6c490c96f75a3f909580e927b0">
rts/RaiseAsync.c
</a>
</li>
<li class="file-stats">
<a href="#e137645f8a9be9fa32cc764e19cea2b492e33d9c">
rts/STM.c
</a>
</li>
<li class="file-stats">
<a href="#7d6961cb073b9fe3df3a81f0ad5cf36eed293c42">
rts/Schedule.c
</a>
</li>
<li class="file-stats">
<a href="#2f69bf0632a148614b9aceae17e7e627784cf567">
rts/StableName.c
</a>
</li>
<li class="file-stats">
<a href="#6ca006a5d6dfdfdb97d0dd72db322e3f6eaa6214">
rts/StgMiscClosures.cmm
</a>
</li>
<li class="file-stats">
<a href="#bc72b4a3b6d14a4bef59af382d2283682543f512">
rts/StgStartup.cmm
</a>
</li>
<li class="file-stats">
<a href="#4b22b3f666af23f7c8097b32282abfd52fb6c342">
rts/ThreadPaused.c
</a>
</li>
<li class="file-stats">
<a href="#a5d219117032120cc7bde9f13451d9627cff5614">
rts/Threads.c
</a>
</li>
<li class="file-stats">
<a href="#bc180b2947a591ed637c69fdae89b63d91cdf3bf">
rts/TraverseHeap.c
</a>
</li>
<li class="file-stats">
<a href="#e75f2499559f277537fa125a01e84e75d66fbd62">
rts/Updates.cmm
</a>
</li>
<li class="file-stats">
<a href="#2ffbdc61d9d0e36978f07f62c00c08f33149e335">
rts/Updates.h
</a>
</li>
<li class="file-stats">
<a href="#1ce50078fc531487782432592488ae95c6156df4">
rts/include/Cmm.h
</a>
</li>
<li class="file-stats">
<a href="#61977c39ce09c06bef2408df54ae269f828dd56f">
rts/include/rts/storage/ClosureMacros.h
</a>
</li>
</ul>
<h5 style="margin-top: 10px; margin-bottom: 10px; font-size: 0.875rem;">
The diff was not included because it is too large.
</h5>
</div>
<div class="footer" style="margin-top: 10px;">
<p style="font-size: small; color: #737278;">
—
<br>
<a href="https://gitlab.haskell.org/ghc/ghc/-/compare/e485e238e2ae4a9e9a9b6124613d1d43ad523725...a382b0bf1073f01799a5d482dca0ca81404e61da">View it on GitLab</a>.
<br>
You're receiving this email because of your account on <a target="_blank" rel="noopener noreferrer" href="https://gitlab.haskell.org">gitlab.haskell.org</a>. <a href="https://gitlab.haskell.org/-/profile/notifications" target="_blank" rel="noopener noreferrer" class="mng-notif-link">Manage all notifications</a> · <a href="https://gitlab.haskell.org/help" target="_blank" rel="noopener noreferrer" class="help-link">Help</a>
</p>
</div>
</body>
</html>