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RalfJung opened this issue Jul 5, 2019 · 16 comments · Fixed by #67507
Closed
4 of 6 tasks

Get rid of uses of mem::uninitialized #62397

RalfJung opened this issue Jul 5, 2019 · 16 comments · Fixed by #67507
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T-libs-api Relevant to the library API team, which will review and decide on the PR/issue.

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@RalfJung
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RalfJung commented Jul 5, 2019 •
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007d87f added a bunch of allow(deprecated) because there are still a few places where we use mem::uninitialized. These should all be fixed, to remove the allow (and hopefully prevent other deprecated methods from being used there).

  • SGX
  • libterm
  • librustc_codegen_llvm
  • std::io::util
  • CloudAbi layout tests (src/libstd/sys/cloudabi/abi/cloudabi.rs)
  • rustc tests

Cc @EdSchouten for CloudAbi, @jethrogb for SGX.
@RalfJung RalfJung added E-mentor Call for participation: This issue has a mentor. Use #t-compiler/help on Zulip for discussion. E-medium Call for participation: Medium difficulty. Experience needed to fix: Intermediate. labels Jul 5, 2019
@jethrogb jethrogb mentioned this issue Jul 5, 2019
Merged
Centril added a commit to Centril/rust that referenced this issue Jul 5, 2019
@Centril
Rollup merge of rust-lang#62414 - jethrogb:jb/sgx-uninit, r=Mark-Simu…
7ed1b8c 
…lacrum

Remove last use of mem::uninitialized in SGX

See rust-lang#62397
Centril added a commit to Centril/rust that referenced this issue Jul 5, 2019
@Centril
Rollup merge of rust-lang#62414 - jethrogb:jb/sgx-uninit, r=Mark-Simu…
e89bd8c 
…lacrum

Remove last use of mem::uninitialized in SGX

See rust-lang#62397
@tesuji tesuji mentioned this issue Jul 5, 2019
Merged
Centril added a commit to Centril/rust that referenced this issue Jul 6, 2019
@Centril
Rollup merge of rust-lang#62422 - lzutao:remove-some-mem-uinit, r=ale…
63a8f36 
…xcrichton

Remove some uses of mem::uninitialized

cc rust-lang#62397
r? @RalfJung
Centril added a commit to Centril/rust that referenced this issue Jul 6, 2019
@Centril
Rollup merge of rust-lang#62422 - lzutao:remove-some-mem-uinit, r=ale…
1864ea4 
…xcrichton

Remove some uses of mem::uninitialized

cc rust-lang#62397
r? @RalfJung
Centril added a commit to Centril/rust that referenced this issue Jul 6, 2019
@Centril
Rollup merge of rust-lang#62422 - lzutao:remove-some-mem-uinit, r=ale…
9d80f05 
…xcrichton

Remove some uses of mem::uninitialized

cc rust-lang#62397
r? @RalfJung
Centril added a commit to Centril/rust that referenced this issue Jul 6, 2019
@Centril
Rollup merge of rust-lang#62422 - lzutao:remove-some-mem-uinit, r=ale…
30e4a87 
…xcrichton

Remove some uses of mem::uninitialized

cc rust-lang#62397
r? @RalfJung
@JulianGindi
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JulianGindi commented Jul 11, 2019 •
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Going to take a stab at addressing this issue if that's all right.

@JulianGindi
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Actually looks like some of this was already handled.

@RalfJung
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The SGX and libterm and codegen ones have been handled. CloudAbi and std::io::util remain open as far as I can see.

@JulianGindi
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CloudAbi and std::io::util remain open as far as I can see.

Ah, gotcha. Will take a crack at it. Thanks!

@jethrogb
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And what about all the tests?

@JulianGindi
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JulianGindi commented Jul 12, 2019 •
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And what about all the tests?

Good question. I'm a bit less confident with figuring out how to handle those tests. I removed mem::uninitialized from CloudAbi and std::io::util and tests still pass. I can submit a PR with just that change, but I want to remove it from the tests as well if that's appropriate.

My progress can be viewed here for reference/guidance.

@RalfJung
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I'm less worried about the tests TBH. The affected ones fairly deliberately cause UB. They can probably be fixed by replacing it with MaybeUninit::uninit().assume_init() and adding a comment that we cause UB here but for some reason we still want to test this.

@JulianGindi IMO it anyway makes sense to separate the test changes from the others as they are unrelated, so why don't you make a PR with what you got?

@JulianGindi JulianGindi mentioned this issue Jul 13, 2019
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@JulianGindi
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Sounds good @RalfJung. I have that test code as well for later if we want to move forwards with it. I have submitted the PR and it's linked above.

@RalfJung
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The remaining open boxes in this issue are up for grabs again. To properly fix this, you should have some experience with unsafe code.

Maybe I should mark this "hard" instead of "medium"? I don't know how to figure out which label is more appropriate. It's not a lot of work to do this, but it requires rewriting some subtle unsafe code that deals with uninitialized memory.

This was referenced Jul 16, 2019
Merged
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@RalfJung RalfJung mentioned this issue Jul 17, 2019
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Mark-Simulacrum added a commit to Mark-Simulacrum/rust that referenced this issue Jul 18, 2019
@Mark-Simulacrum
Rollup merge of rust-lang#62732 - nathanwhit:fix_mem_uninit, r=Amanieu
5d4681f 
Remove last use of mem::uninitialized from std::io::util

Addresses rust-lang#62397 for std::io::util
@RalfJung
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@nathanwhit please make you to mention in an issue when you are (partially) addressing it. Now we both did the same work but in different ways.

@nathanwhit
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I'm sorry, that's totally my mistake. These are my first few contributions, so I'm still in the process of learning the ropes. I'll make sure to do so in the future.

@RalfJung
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No hard feelings, just letting you know. :)

@Diggsey
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Diggsey commented Jul 19, 2019

Seems like under the new UB guidelines, those tests should be testing unspecified rather than uninitialised values. (I believe they're being called "frozen" values?)

Centril added a commit to Centril/rust that referenced this issue Jul 21, 2019
@Centril
Rollup merge of rust-lang#62746 - RalfJung:deprecated, r=KodrAus
9182b70 
 do not use assume_init in std::io

Cc rust-lang#62397
@nathanwhit
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I've done work on addressing this for CloudAbi (excluding the tests), the PR with my work so far is #62738, feedback is much appreciated!

Centril added a commit to Centril/rust that referenced this issue Jul 22, 2019
@Centril
Rollup merge of rust-lang#62746 - RalfJung:deprecated, r=KodrAus
1d7faaf 
 do not use assume_init in std::io

Cc rust-lang#62397
Centril added a commit to Centril/rust that referenced this issue Jul 23, 2019
@Centril
Rollup merge of rust-lang#62738 - nathanwhit:fix_mem_uninit_cloudabi,…
3f786a8 
… r=RalfJung

Remove uses of mem::uninitialized from std::sys::cloudabi

Addresses rust-lang#62397 for std::sys::cloudabi, excluding the tests within cloudabi, which will be a separate PR
Centril added a commit to Centril/rust that referenced this issue Jul 24, 2019
@Centril
Rollup merge of rust-lang#62738 - nathanwhit:fix_mem_uninit_cloudabi,…
9258ed6 
… r=RalfJung

Remove uses of mem::uninitialized from std::sys::cloudabi

Addresses rust-lang#62397 for std::sys::cloudabi, excluding the tests within cloudabi, which will be a separate PR
Centril added a commit to Centril/rust that referenced this issue Jul 24, 2019
@Centril
Rollup merge of rust-lang#62738 - nathanwhit:fix_mem_uninit_cloudabi,…
efdcce1 
… r=RalfJung

Remove uses of mem::uninitialized from std::sys::cloudabi

Addresses rust-lang#62397 for std::sys::cloudabi, excluding the tests within cloudabi, which will be a separate PR
@tesuji tesuji mentioned this issue Aug 14, 2019
Merged
Centril added a commit to Centril/rust that referenced this issue Aug 15, 2019
@Centril
Rollup merge of rust-lang#63546 - lzutao:clouldabi-maybeuninit, r=Ral…
87e3393 
…fJung

Remove uses of `mem::uninitialized()` from cloudabi

This PR removes uses of `mem::uninitialized` from `cloudabi` module,
excluding the layout test in `src/libstd/sys/cloudabi/abi/cloudabi.rs`.

r? @RalfJung
cc @EdSchouten
cc rust-lang#62397
Centril added a commit to Centril/rust that referenced this issue Aug 15, 2019
@Centril
Rollup merge of rust-lang#63546 - lzutao:clouldabi-maybeuninit, r=Ral…
e452738 
…fJung

Remove uses of `mem::uninitialized()` from cloudabi

This PR removes uses of `mem::uninitialized` from `cloudabi` module,
excluding the layout test in `src/libstd/sys/cloudabi/abi/cloudabi.rs`.

r? @RalfJung
cc @EdSchouten
cc rust-lang#62397
@RalfJung RalfJung added T-libs-api Relevant to the library API team, which will review and decide on the PR/issue. and removed E-medium Call for participation: Medium difficulty. Experience needed to fix: Intermediate. E-mentor Call for participation: This issue has a mentor. Use #t-compiler/help on Zulip for discussion. labels Aug 25, 2019
@Mark-Simulacrum
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Remaining (removable) cases in our test cases are removed in #67507. I also filed NuxiNL/cloudabi#18 upstream to suggest fixing the CloudABI piece; I don't think we should keep this open once #67507 lands as the CloudABI issue must be fixed upstream (the file says "don't edit").

@m-ou-se
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m-ou-se commented Dec 22, 2019

I've updated the upstream cloudabi.rs to fix this problem, and also include the other changes that were made in the rust repository (#[non_exhaustive], and using *mut instead of &mut for output parameters).

@Mark-Simulacrum Mark-Simulacrum mentioned this issue Dec 22, 2019
Merged
@bors bors closed this as completed in 67c0f4e Dec 23, 2019
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@RalfJung @Diggsey @JulianGindi @m-ou-se @jethrogb @Mark-Simulacrum @nathanwhit