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src: add check against non-weak BaseObjects at process exit - #35490
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addaleax wants to merge 2 commits into
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src: add check against non-weak BaseObjects at process exit#35490addaleax wants to merge 2 commits into
addaleax wants to merge 2 commits into
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When a process exits cleanly, i.e. because the event loop ends up without things to wait for, the Node.js objects that are left on the heap should be: 1. weak, i.e. ready for garbage collection once no longer referenced, or 2. detached, i.e. scheduled for destruction once no longer referenced, or 3. an unrefed libuv handle, i.e. does not keep the event loop alive, or 4. an inactive libuv handle (essentially the same here) There are a few exceptions to this rule, but generally, if there are C++-backed Node.js objects on the heap that do not fall into the above categories, we may be looking at a potential memory leak. Most likely, the cause is a missing `MakeWeak()` call on the corresponding object. In order to avoid this kind of problem, we check the list of BaseObjects for these criteria. In this commit, we only do so when explicitly instructed to or when in debug mode (where --verify-base-objects is always-on). In particular, this avoids the kinds of memory leak issues that were fixed in the PRs referenced below. Refs: nodejs#35488 Refs: nodejs#35487 Refs: nodejs#35481
nodejs-github-bot
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Oct 3, 2020
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Review requested:
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addaleax
commented
Oct 3, 2020
| // XXX: The garbage collection rules for ModuleWrap are *super* unclear. | ||
| // Do these objects ever get GC'd? Are we just okay with leaking them? | ||
| return true; | ||
| } |
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I know the bot already pinged the team, but I’d be curious to know if @nodejs/modules knows more about this … especially for ModuleWraps created by the vm module, creating non-GC-able objects can’t be ideal, right…?
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I thought they were all weak at one point?
jasnell
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Oct 4, 2020
Trott
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Oct 4, 2020
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Trott
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Oct 4, 2020
joyeecheung
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Oct 4, 2020
benjamingr
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Oct 4, 2020
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nodejs-github-bot
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Oct 6, 2020
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addaleax
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Oct 7, 2020
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Landed in 40364b1 |
addaleax added a commit
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Oct 7, 2020
When a process exits cleanly, i.e. because the event loop ends up without things to wait for, the Node.js objects that are left on the heap should be: 1. weak, i.e. ready for garbage collection once no longer referenced, or 2. detached, i.e. scheduled for destruction once no longer referenced, or 3. an unrefed libuv handle, i.e. does not keep the event loop alive, or 4. an inactive libuv handle (essentially the same here) There are a few exceptions to this rule, but generally, if there are C++-backed Node.js objects on the heap that do not fall into the above categories, we may be looking at a potential memory leak. Most likely, the cause is a missing `MakeWeak()` call on the corresponding object. In order to avoid this kind of problem, we check the list of BaseObjects for these criteria. In this commit, we only do so when explicitly instructed to or when in debug mode (where --verify-base-objects is always-on). In particular, this avoids the kinds of memory leak issues that were fixed in the PRs referenced below. Refs: #35488 Refs: #35487 Refs: #35481 PR-URL: #35490 Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Matteo Collina <matteo.collina@gmail.com> Reviewed-By: Rich Trott <rtrott@gmail.com> Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com> Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
gengjiawen
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Oct 8, 2020
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@addaleax This looks caused macOS build failed in github action ../src/env.cc:1227:22: error: lambda capture 'this' is not used [-Werror,-Wunused-lambda-capture] ForEachBaseObject([this](BaseObject* obj) { ^~~~1 error generated. |
addaleax
commented
Oct 8, 2020
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@gengjiawen See #35547 :) |
BethGriggs
commented
Oct 13, 2020
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This didn't land cleanly on v14.x, please raise a backport PR if this should land |
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joesepi pushed a commit
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Jan 8, 2021
When a process exits cleanly, i.e. because the event loop ends up without things to wait for, the Node.js objects that are left on the heap should be: 1. weak, i.e. ready for garbage collection once no longer referenced, or 2. detached, i.e. scheduled for destruction once no longer referenced, or 3. an unrefed libuv handle, i.e. does not keep the event loop alive, or 4. an inactive libuv handle (essentially the same here) There are a few exceptions to this rule, but generally, if there are C++-backed Node.js objects on the heap that do not fall into the above categories, we may be looking at a potential memory leak. Most likely, the cause is a missing `MakeWeak()` call on the corresponding object. In order to avoid this kind of problem, we check the list of BaseObjects for these criteria. In this commit, we only do so when explicitly instructed to or when in debug mode (where --verify-base-objects is always-on). In particular, this avoids the kinds of memory leak issues that were fixed in the PRs referenced below. Refs: nodejs#35488 Refs: nodejs#35487 Refs: nodejs#35481 PR-URL: nodejs#35490 Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Matteo Collina <matteo.collina@gmail.com> Reviewed-By: Rich Trott <rtrott@gmail.com> Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com> Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
addaleax added a commit
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May 23, 2021
When a process exits cleanly, i.e. because the event loop ends up without things to wait for, the Node.js objects that are left on the heap should be: 1. weak, i.e. ready for garbage collection once no longer referenced, or 2. detached, i.e. scheduled for destruction once no longer referenced, or 3. an unrefed libuv handle, i.e. does not keep the event loop alive, or 4. an inactive libuv handle (essentially the same here) There are a few exceptions to this rule, but generally, if there are C++-backed Node.js objects on the heap that do not fall into the above categories, we may be looking at a potential memory leak. Most likely, the cause is a missing `MakeWeak()` call on the corresponding object. In order to avoid this kind of problem, we check the list of BaseObjects for these criteria. In this commit, we only do so when explicitly instructed to or when in debug mode (where --verify-base-objects is always-on). In particular, this avoids the kinds of memory leak issues that were fixed in the PRs referenced below. Refs: nodejs#35488 Refs: nodejs#35487 Refs: nodejs#35481 PR-URL: nodejs#35490 Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Matteo Collina <matteo.collina@gmail.com> Reviewed-By: Rich Trott <rtrott@gmail.com> Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com> Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
targos pushed a commit
that referenced
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May 25, 2021
When a process exits cleanly, i.e. because the event loop ends up without things to wait for, the Node.js objects that are left on the heap should be: 1. weak, i.e. ready for garbage collection once no longer referenced, or 2. detached, i.e. scheduled for destruction once no longer referenced, or 3. an unrefed libuv handle, i.e. does not keep the event loop alive, or 4. an inactive libuv handle (essentially the same here) There are a few exceptions to this rule, but generally, if there are C++-backed Node.js objects on the heap that do not fall into the above categories, we may be looking at a potential memory leak. Most likely, the cause is a missing `MakeWeak()` call on the corresponding object. In order to avoid this kind of problem, we check the list of BaseObjects for these criteria. In this commit, we only do so when explicitly instructed to or when in debug mode (where --verify-base-objects is always-on). In particular, this avoids the kinds of memory leak issues that were fixed in the PRs referenced below. Refs: #35488 Refs: #35487 Refs: #35481 PR-URL: #35490 Backport-PR-URL: #38786 Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Matteo Collina <matteo.collina@gmail.com> Reviewed-By: Rich Trott <rtrott@gmail.com> Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com> Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
targos pushed a commit
that referenced
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Jun 11, 2021
When a process exits cleanly, i.e. because the event loop ends up without things to wait for, the Node.js objects that are left on the heap should be: 1. weak, i.e. ready for garbage collection once no longer referenced, or 2. detached, i.e. scheduled for destruction once no longer referenced, or 3. an unrefed libuv handle, i.e. does not keep the event loop alive, or 4. an inactive libuv handle (essentially the same here) There are a few exceptions to this rule, but generally, if there are C++-backed Node.js objects on the heap that do not fall into the above categories, we may be looking at a potential memory leak. Most likely, the cause is a missing `MakeWeak()` call on the corresponding object. In order to avoid this kind of problem, we check the list of BaseObjects for these criteria. In this commit, we only do so when explicitly instructed to or when in debug mode (where --verify-base-objects is always-on). In particular, this avoids the kinds of memory leak issues that were fixed in the PRs referenced below. Refs: #35488 Refs: #35487 Refs: #35481 PR-URL: #35490 Backport-PR-URL: #38786 Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Matteo Collina <matteo.collina@gmail.com> Reviewed-By: Rich Trott <rtrott@gmail.com> Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com> Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
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When a process exits cleanly, i.e. because the event loop ends up without things to wait for, the Node.js objects that are left on the heap should be:
There are a few exceptions to this rule, but generally, if there are C++-backed Node.js objects on the heap that do not fall into the above categories, we may be looking at a potential memory leak. Most likely, the cause is a missing
MakeWeak()call on the corresponding object.In order to avoid this kind of problem, we check the list of BaseObjects for these criteria. In this commit, we only do so when explicitly instructed to or when in debug mode (where
--verify-base-objectsis always-on).In particular, this avoids the kinds of memory leak issues that were fixed in the PRs referenced below (hence the
blockedlabel).Refs: #35488
Refs: #35487
Refs: #35481
Checklist
make -j4 test(UNIX), orvcbuild test(Windows) passes