src: simplify memory management using `node::Malloc()` and friends #8482

addaleax · 2016-09-10T16:47:39Z

Checklist

make -j4 test (UNIX), or vcbuild test nosign (Windows) passes
commit message follows commit guidelines

Affected core subsystem(s)

src

Description of change

Add an optional size param to node::Malloc() and node::Realloc() in calloc(3)-style and use proper overflow detection.
Make the allocation methods templates so that they directly give the correct return type, removing a number of static_casts to the desired pointer types.
Add shortcuts for the node::Malloc() + CHECK_NE(·, nullptr) combinations that often occur together in the codebase.
Call v8::Isolate::GetCurrent()->LowMemoryNotification() when an allocation fails to give V8 a chance to clean up and return memory before retrying (and possibly giving up).

Any of the changes here can be left out but I believe that they all pretty much make sense to have.

~~CI: https://ci.nodejs.org/job/node-test-commit/4994/~~
~~CI: https://ci.nodejs.org/job/node-test-commit/4995/~~
~~CI: https://ci.nodejs.org/job/node-test-commit/4996/~~
~~CI: https://ci.nodejs.org/job/node-test-commit/4997/~~
~~CI: https://ci.nodejs.org/job/node-test-commit/5008/~~
~~CI: https://ci.nodejs.org/job/node-test-commit/5013/~~
CI: https://ci.nodejs.org/job/node-test-commit/5025/

addaleax · 2016-09-10T18:54:20Z

Woooo, internal compiler error on Windows: https://ci.nodejs.org/job/node-compile-windows/4115/label=win-vs2015/console

Edit for future reference: This happened with HEAD = f04c5ed4bc1ae3dcb639da469605ae1ea47ca612

One can probably eliminate that by playing with the code a bit, but maybe this is interesting for someone from @nodejs/platform-windows ?

addaleax · 2016-09-10T21:32:53Z

Also – @joshgav do you want to/should you be added to the platform-windows team?

bnoordhuis · 2016-09-11T08:16:40Z

src/cares_wrap.cc

@@ -142,8 +142,7 @@ static void ares_poll_close_cb(uv_handle_t* watcher) {

 /* Allocates and returns a new node_ares_task */
 static node_ares_task* ares_task_create(Environment* env, ares_socket_t sock) {
-  node_ares_task* task =
-    static_cast<node_ares_task*>(node::Malloc(sizeof(*task)));
+  node_ares_task* task = node::Malloc<node_ares_task>(1);


You're welcome to write this as auto task = ... while you're here.

bnoordhuis · 2016-09-11T08:38:00Z

Woooo, internal compiler error on Windows: https://ci.nodejs.org/job/node-compile-windows/4115/label=win-vs2015/console

Interesting. For all its faults I've never gotten VS to ICE.

seishun · 2016-09-11T12:21:21Z

I'm not getting an ICE locally. Maybe try updating VS on CI?

addaleax · 2016-09-11T14:54:54Z

Trying to run a new CI at https://ci.nodejs.org/job/node-test-pull-request/4012/ but it seems to be stuck reading data from Github?

Edit: https://ci.nodejs.org/job/node-test-commit/5008/

bnoordhuis · 2016-09-12T08:05:36Z

src/stream_wrap.cc

@@ -204,7 +198,7 @@ void StreamWrap::OnReadImpl(ssize_t nread,
    return;
  }

-  char* base = static_cast<char*>(node::Realloc(buf->base, nread));
+  char* base = node::UncheckedRealloc(buf->base, nread);


I'd make this a checked realloc. It can't really fail because it shrinks but I doubt the extra check hurts.

addaleax · 2016-09-12T09:09:58Z

New CI: https://ci.nodejs.org/job/node-test-commit/5013/

bnoordhuis · 2016-09-12T10:45:09Z

src/util-inl.h

+T MultiplyWithOverflowCheck(T a, T b) {
+  T ret = a * b;
+  if (a != 0)
+    CHECK_EQ(b, ret / a);


EDIT: No, I got that wrong. The branch is always taken because a == sizeof(T) and therefore never zero.

bnoordhuis · 2016-09-12T10:48:27Z

LGTM

seishun · 2016-09-12T11:10:36Z

src/util-inl.h

@@ -229,30 +229,74 @@ bool StringEqualNoCaseN(const char* a, const char* b, size_t length) {
  return true;
 }

+template <typename T>
+T MultiplyWithOverflowCheck(T a, T b) {


I don't think making this a template is a good idea. It can't be used with signed types since signed overflow is UB, so the check could be optimized out.

@seishun How strongly do you feel about this? I don’t really care but it might be nice to have a generic utility if one is ever needed again. I can add a static_assert to check for unsignedness, if you want.

Also, I’m surprised, but your worries are not only theoretical; clang actually would optimize the check away for signed integers… oO

I can add a static_assert to check for unsignedness, if you want.

That works, but I would personally prefer to have a function that works just with size_t. That way you can see that it doesn't work with signed values from the signature. Your call, though.

@seishun ¯_(ツ)_/¯ updated with size_t :)

jasnell

LGTM

Adds an optional second parameter to `node::Malloc()` and an optional third parameter to `node::Realloc()` giving the size/number of items to be allocated, in the style of `calloc(3)`. Use a proper overflow check using division; the previous `CHECK_GE(n * size, n);` would not detect all cases of overflow (e.g. `size == SIZE_MAX / 2 && n == 3`). PR-URL: #8482 Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com> Reviewed-By: Ilkka Myller <ilkka.myller@nodefield.com>

Pass the desired return type directly to the allocation functions, so that the resulting `static_cast` from `void*` becomes unneccessary and the return type can be use as a reasonable default value for the `size` parameter. PR-URL: #8482 Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com> Reviewed-By: Ilkka Myller <ilkka.myller@nodefield.com>

Provide shortcut `node::CheckedMalloc()` and friends that replace `node::Malloc()` + `CHECK_NE(·, nullptr);` combinations in a few places. PR-URL: #8482 Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com> Reviewed-By: Ilkka Myller <ilkka.myller@nodefield.com>

Call `v8::Isolate::GetCurrent()->LowMemoryNotification()` when an allocation fails to give V8 a chance to clean up and return memory before retrying (and possibly giving up). PR-URL: #8482 Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com> Reviewed-By: Ilkka Myller <ilkka.myller@nodefield.com>

MylesBorins · 2016-10-06T23:44:40Z

@addaleax I've set this as do not land... please feel free to change if it should be backported

Fishrock123 · 2016-10-10T16:42:40Z

depends on #7082

Make cctest valgrind-clean again by freeing heap-allocated memory. Overlooked in commit ea94086 ("src: provide allocation + nullptr check shortcuts.") PR-URL: nodejs#9667 Refs: nodejs#8482 Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>

Make cctest valgrind-clean again by freeing heap-allocated memory. Overlooked in commit ea94086 ("src: provide allocation + nullptr check shortcuts.") PR-URL: #9667 Refs: #8482 Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>

Adds an optional second parameter to `node::Malloc()` and an optional third parameter to `node::Realloc()` giving the size/number of items to be allocated, in the style of `calloc(3)`. Use a proper overflow check using division; the previous `CHECK_GE(n * size, n);` would not detect all cases of overflow (e.g. `size == SIZE_MAX / 2 && n == 3`). PR-URL: nodejs#8482 Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com> Reviewed-By: Ilkka Myller <ilkka.myller@nodefield.com>

Pass the desired return type directly to the allocation functions, so that the resulting `static_cast` from `void*` becomes unneccessary and the return type can be use as a reasonable default value for the `size` parameter. PR-URL: nodejs#8482 Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com> Reviewed-By: Ilkka Myller <ilkka.myller@nodefield.com>

Provide shortcut `node::CheckedMalloc()` and friends that replace `node::Malloc()` + `CHECK_NE(·, nullptr);` combinations in a few places. PR-URL: nodejs#8482 Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com> Reviewed-By: Ilkka Myller <ilkka.myller@nodefield.com>

Call `v8::Isolate::GetCurrent()->LowMemoryNotification()` when an allocation fails to give V8 a chance to clean up and return memory before retrying (and possibly giving up). PR-URL: nodejs#8482 Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com> Reviewed-By: Ilkka Myller <ilkka.myller@nodefield.com>

bnoordhuis · 2017-10-29T12:17:09Z

v6.x: #16587

Removed the dont-land-on-v6.x label.

Adds an optional second parameter to `node::Malloc()` and an optional third parameter to `node::Realloc()` giving the size/number of items to be allocated, in the style of `calloc(3)`. Use a proper overflow check using division; the previous `CHECK_GE(n * size, n);` would not detect all cases of overflow (e.g. `size == SIZE_MAX / 2 && n == 3`). Backport-PR-URL: #16587 PR-URL: #8482 Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com> Reviewed-By: Ilkka Myller <ilkka.myller@nodefield.com>

Pass the desired return type directly to the allocation functions, so that the resulting `static_cast` from `void*` becomes unneccessary and the return type can be use as a reasonable default value for the `size` parameter. Backport-PR-URL: #16587 PR-URL: #8482 Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com> Reviewed-By: Ilkka Myller <ilkka.myller@nodefield.com>

Provide shortcut `node::CheckedMalloc()` and friends that replace `node::Malloc()` + `CHECK_NE(·, nullptr);` combinations in a few places. Backport-PR-URL: #16587 PR-URL: #8482 Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com> Reviewed-By: Ilkka Myller <ilkka.myller@nodefield.com>

Call `v8::Isolate::GetCurrent()->LowMemoryNotification()` when an allocation fails to give V8 a chance to clean up and return memory before retrying (and possibly giving up). Backport-PR-URL: #16587 PR-URL: #8482 Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com> Reviewed-By: Ilkka Myller <ilkka.myller@nodefield.com>

nodejs-github-bot added the c++ Issues and PRs that require attention from people who are familiar with C++. label Sep 10, 2016

addaleax added the lib / src Issues and PRs related to general changes in the lib or src directory. label Sep 10, 2016

addaleax force-pushed the allocation-rework branch 3 times, most recently from 9e3309c to f04c5ed Compare September 10, 2016 18:03

bnoordhuis reviewed Sep 11, 2016
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addaleax force-pushed the allocation-rework branch 2 times, most recently from 4b39181 to 1491d99 Compare September 11, 2016 14:48

bnoordhuis reviewed Sep 12, 2016
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addaleax force-pushed the allocation-rework branch from 1491d99 to f46329c Compare September 12, 2016 09:07

bnoordhuis reviewed Sep 12, 2016
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seishun reviewed Sep 12, 2016
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addaleax force-pushed the allocation-rework branch from f46329c to d03ff03 Compare September 13, 2016 08:49

jasnell approved these changes Sep 15, 2016

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addaleax added the blocked PRs that are blocked by other issues or PRs. label Sep 17, 2016

addaleax mentioned this pull request Sep 17, 2016

src: Malloc/Calloc size 0 returns non-null pointer #8572

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addaleax deleted the allocation-rework branch September 30, 2016 15:12

MylesBorins added the dont-land-on-v4.x label Oct 6, 2016

addaleax mentioned this pull request Oct 7, 2016

core: normalize malloc, realloc #7564

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2 tasks

Fishrock123 added the dont-land-on-v6.x label Oct 10, 2016

gibfahn mentioned this pull request Jun 15, 2017

Auditing for 6.11.1 nodejs/Release#230

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XadillaX mentioned this pull request Jun 21, 2017

(v6.x backport) dns: fix crash while using dns.setServers after dns.resolve4 #13724

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bnoordhuis mentioned this pull request Oct 29, 2017

[v6.x backport] src: simplify memory management using node::Malloc() and friends #16587

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bnoordhuis removed the dont-land-on-v6.x label Oct 29, 2017

MylesBorins added the backported-to-v6.x label Nov 14, 2017

MylesBorins mentioned this pull request Nov 21, 2017

v6.12.1 proposal #17180

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src: simplify memory management using `node::Malloc()` and friends #8482

src: simplify memory management using `node::Malloc()` and friends #8482

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src: simplify memory management using node::Malloc() and friends #8482

src: simplify memory management using node::Malloc() and friends #8482

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Checklist

Affected core subsystem(s)

Description of change

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src: simplify memory management using `node::Malloc()` and friends #8482

src: simplify memory management using `node::Malloc()` and friends #8482

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