Dynamically size sigaltstk in rustc #113528
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
(rustbot has picked a reviewer for you, use r? to override) |
rustbot
added
S-waiting-on-review
|
This is more-or-less a twin of #113525 but since the code winds up moduled-off from the rest of the world in either case and the two have different contexts, I figured I'd submit it separately. |
workingjubilee
force-pushed
the
use-at-minsigstksz-in-rustc-signal-handler
branch
from
9577722
to
1e8d24d
Compare
workingjubilee
commented
Jul 10, 2023
| unsafe { | ||
| const ALT_STACK_SIZE: usize = libc::MINSIGSTKSZ + 64 * 1024; | ||
| let alt_stack_size: usize = min_sigstack_size() + 64 * 1024; |
There was a problem hiding this comment.
It might seem like 64KiB is greater than the largest number I mentioned, 16KiB.
...but it's up to 16KiB per vector register, and it has way more than one. 🫠
workingjubilee
commented
Jul 10, 2023
| @@ -1469,6 +1470,23 @@ mod signal_handler { | |||
| libc::sigaction(libc::SIGSEGV, &sa, std::ptr::null_mut()); | |||
| } | |||
| } | |||
|
|
|||
| /// Modern kernels on modern hardware can have dynamic signal stack sizes. | |||
| #[cfg(any(target_os = "linux", target_os = "android"))] | |||
There was a problem hiding this comment.
Yes, I have spoken to people who run rustc on Android.
jyn514
reviewed
Jul 10, 2023
| #[cfg(any(target_os = "linux", target_os = "android"))] | ||
| fn min_sigstack_size() -> usize { | ||
| const AT_MINSIGSTKSZ: core::ffi::c_ulong = 51; | ||
| let dynamic_sigstksz = unsafe { libc::getauxval(AT_MINSIGSTKSZ) }; |
There was a problem hiding this comment.
doesn't need to block this PR, but does it make sense to upstream AT_MINSIGSTKSZ to the libc crate so we don't need to hardcode it here?
There was a problem hiding this comment.
you mean would it be good for rust-lang/libc#3125 to be reviewed and accepted? yes, I think so.
WaffleLapkin
approved these changes
Jul 10, 2023
WaffleLapkin
added
S-waiting-on-author
rustc installs a signal stack that assumes that MINSIGSTKSZ is a constant, unchanging value. Newer hardware undermines that assumption greatly, with register files larger than MINSIGSTKZ. Properly handle this so that it is correct on all supported Linux versions with all CPUs.
workingjubilee
force-pushed
the
use-at-minsigstksz-in-rustc-signal-handler
branch
from
1e8d24d
to
094cb1a
Compare
|
@bors r=WaffleLapkin |
bors
added
S-waiting-on-bors
matthiaskrgr
added a commit
to matthiaskrgr/rust
that referenced
this pull request
Jul 10, 2023
…in-rustc-signal-handler, r=WaffleLapkin Dynamically size sigaltstk in rustc rustc installs a signal stack that assumes that MINSIGSTKSZ is a constant, unchanging value. Newer hardware undermines that assumption greatly, with register files larger than glibc's traditional static MINSIGSTKZ. Properly handle this so that it is correct on all supported Linux versions with all CPUs.
matthiaskrgr
added a commit
to matthiaskrgr/rust
that referenced
this pull request
Jul 10, 2023
…in-rustc-signal-handler, r=WaffleLapkin Dynamically size sigaltstk in rustc rustc installs a signal stack that assumes that MINSIGSTKSZ is a constant, unchanging value. Newer hardware undermines that assumption greatly, with register files larger than glibc's traditional static MINSIGSTKZ. Properly handle this so that it is correct on all supported Linux versions with all CPUs.
bors
added a commit
to rust-lang-ci/rust
that referenced
this pull request
Jul 11, 2023
…iaskrgr Rollup of 7 pull requests Successful merges: - rust-lang#113386 (style-guide: Expand example of combinable expressions to include arrays) - rust-lang#113523 (Reuse LLVMConstInBoundsGEP2) - rust-lang#113528 (Dynamically size sigaltstk in rustc) - rust-lang#113543 (Remove `rustc_llvm` from llvm-stamp nags) - rust-lang#113548 (Update books) - rust-lang#113551 (bootstrap: Don't print "Skipping" twice) - rust-lang#113556 (Don't use serde-derive in the rls shim) r? `@ghost` `@rustbot` modify labels: rollup
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
rustc installs a signal stack that assumes that MINSIGSTKSZ is a constant, unchanging value. Newer hardware undermines that assumption greatly, with register files larger than glibc's traditional static MINSIGSTKZ. Properly handle this so that it is correct on all supported Linux versions with all CPUs.