Update libbacktrace #50955
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Update libbacktrace #50955
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Can I question why this includes |
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A number of other patches was applied to our version of libbacktrace after #30908 if you look at git history, Mach-O support in particular. |
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@petrochenkov thanks, good call. I figured there may be more; I hadn't fully checked into it yet. I'll go take a look now that it did build successfully. |
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I've reapplied some patches, and disregarded some others. A double check here would be great. Spelling fixes, that I've disregarded so that we closer track upstream: Backports that should be included with the update: e8121b3 added support for apple platforms, but then 8581b59 disabled it, so I've just not bothered. The original patch was sent upstream, but was ignored and eventually closed. For aa6bd11, the file was completely deleted upstream, and so I don't think applies anymore. |
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(I'd prefer us to transition to a gimli-based library eventually so I'm 👎 to merging this huge PR.) 8581b59 (#45866) only disabled mmap support for macOS, not the entire functionality. The upstream patch ianlancetaylor/libbacktrace#2 was closed because the maintainer simply ignored the PR without any further communication. It doesn't mean the patch is not working. BTW is it possible we just turn libbacktrace into a submodule? +18846/-8114 isn't a fun thing to deal with. |
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A submodule seems like a good idea. |
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I believe at the time that this was originally added the repo didn't exist or I couldn't find it, but I definitely agree that we should use a submodule now. If anything it'll help us track how we diverge! To that end I've now created https://github.com/rust-lang-nursery/libbacktrace Ok and to make sure we don't lose anything, let's take a look at the current history of the "submodule". The commits we're dealing with are:
And I believe that's it. 5f57121, the next element in the history, is where we reset to a revision of upstream gcc, so it's sync'd with the original source. I agree with @steveklabnik to leave out typos, which leaves us with:
and I believe that's everything? The stack of commits is the tip of the @kennytm I agree that eventually we want to move away from libbacktrace, but unfortunately that's a much larger change so for the time being I think an incremental update moving us towards the submodule should probably be sufficient @steveklabnik do you want to update this PR to add a submodule to the repo I've created? |
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@steveklabnik also while you're at it, can you update the backtrace and backtrace-sys crates? |
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@alexcrichton I can do it tomorrow; if you want to just get it done, feel free to close this and do it yourself :)
… On May 22, 2018, at 3:59 PM, Alex Crichton ***@***.***> wrote:
@steveklabnik also while you're at it, can you update the backtrace and backtrace-sys crates?
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@bors: r+ No worries! I've pushed the changes here and let's see what bors thinks of this. |
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📌 Commit 6691dae has been approved by |
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The job Click to expand the log.I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
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@bors: r- |
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@bors: r+ |
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📌 Commit b3ee81e has been approved by |
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Ugh, pinged @alexcrichton on chat about this; I didn't see that he updated the PR, so just did it and force pushed my version. Oops. Hopefully he can restore soon. |
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📌 Commit 7c14a54 has been approved by |
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@bors p=162 |
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May 30, 2018
Update libbacktrace We haven't updated libbacktrace in two years. This is just blindly updating to the latest HEAD; I'd like to see what travis says. It at least builds on my machine, running some tests... This perpetuates the patches from #30908
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☀️ Test successful - status-appveyor, status-travis |
This was referenced May 30, 2018
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Since this commit I'm getting 150 ui test failures (also compile-fail, anything involving failures really). Some of them are segfaults (sample backtrace: https://gist.github.com/nikic/0b752e8aecf12930e488bbfc9bfbd7f1). Most are "panicked while panicking", with the partial trace looking something like In both cases the trace contains a weird low-address function (0x1 for the segfault, 0x3 for the panic). |
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@nikic Could you file a new issue about this? |
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This commit is a proof-of-concept for switching the standard library's backtrace symbolication mechanism on most platforms from libbacktrace to gimli. The standard library's support for `RUST_BACKTRACE=1` requires in-process parsing of object files and DWARF debug information to interpret it and print the filename/line number of stack frames as part of a backtrace. Historically this support in the standard library has come from a library called "libbacktrace". The libbacktrace library seems to have been extracted from gcc at some point and is written in C. We've had a lot of issues with libbacktrace over time, unfortunately, though. The library does not appear to be actively maintained since we've had patches sit for months-to-years without comments. We have discovered a good number of soundness issues with the library itself, both when parsing valid DWARF as well as invalid DWARF. This is enough of an issue that the libs team has previously decided that we cannot feed untrusted inputs to libbacktrace. This also doesn't take into account the portability of libbacktrace which has been difficult to manage and maintain over time. While possible there are lots of exceptions and it's the main C dependency of the standard library right now. For years it's been the desire to switch over to a Rust-based solution for symbolicating backtraces. It's been assumed that we'll be using the Gimli family of crates for this purpose, which are targeted at safely and efficiently parsing DWARF debug information. I've been working recently to shore up the Gimli support in the `backtrace` crate. As of a few weeks ago the `backtrace` crate, by default, uses Gimli when loaded from crates.io. This transition has gone well enough that I figured it was time to start talking seriously about this change to the standard library. This commit is a preview of what's probably the best way to integrate the `backtrace` crate into the standard library with the Gimli feature turned on. While today it's used as a crates.io dependency, this commit switches the `backtrace` crate to a submodule of this repository which will need to be updated manually. This is not done lightly, but is thought to be the best solution. The primary reason for this is that the `backtrace` crate needs to do some pretty nontrivial filesystem interactions to locate debug information. Working without `std::fs` is not an option, and while it might be possible to do some sort of trait-based solution when prototyped it was found to be too unergonomic. Using a submodule allows the `backtrace` crate to build as a submodule of the `std` crate itself, enabling it to use `std::fs` and such. Otherwise this adds new dependencies to the standard library. This step requires extra attention because this means that these crates are now going to be included with all Rust programs by default. It's important to note, however, that we're already shipping libbacktrace with all Rust programs by default and it has a bunch of C code implementing all of this internally anyway, so we're basically already switching already-shipping functionality to Rust from C. * `object` - this crate is used to parse object file headers and contents. Very low-level support is used from this crate and almost all of it is disabled. Largely we're just using struct definitions as well as convenience methods internally to read bytes and such. * `addr2line` - this is the main meat of the implementation for symbolication. This crate depends on `gimli` for DWARF parsing and then provides interfaces needed by the `backtrace` crate to turn an address into a filename / line number. This crate is actually pretty small (fits in a single file almost!) and mirrors most of what `dwarf.c` does for libbacktrace. * `miniz_oxide` - the libbacktrace crate transparently handles compressed debug information which is compressed with zlib. This crate is used to decompress compressed debug sections. * `gimli` - not actually used directly, but a dependency of `addr2line`. * `adler32`- not used directly either, but a dependency of `miniz_oxide`. The goal of this change is to improve the safety of backtrace symbolication in the standard library, especially in the face of possibly malformed DWARF debug information. Even to this day we're still seeing segfaults in libbacktrace which could possibly become security vulnerabilities. This change should almost entirely eliminate this possibility whilc also paving the way forward to adding more features like split debug information. Some references for those interested are: * Original addition of libbacktrace - rust-lang#12602 * OOM with libbacktrace - rust-lang#24231 * Backtrace failure due to use of uninitialized value - rust-lang#28447 * Possibility to feed untrusted data to libbacktrace - rust-lang#21889 * Soundness fix for libbacktrace - rust-lang#33729 * Crash in libbacktrace - rust-lang#39468 * Support for macOS, never merged - ianlancetaylor/libbacktrace#2 * Performance issues with libbacktrace - rust-lang#29293, rust-lang#37477 * Update procedure is quite complicated due to how many patches we need to carry - rust-lang#50955 * Libbacktrace doesn't work on MinGW with dynamic libs - rust-lang#71060 * Segfault in libbacktrace on macOS - rust-lang#71397 Switching to Rust will not make us immune to all of these issues. The crashes are expected to go away, but correctness and performance may still have bugs arise. The gimli and `backtrace` crates, however, are actively maintained unlike libbacktrace, so this should enable us to at least efficiently apply fixes as situations come up.
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Jul 18, 2020
…Simulacrum std: Switch from libbacktrace to gimli This commit is a proof-of-concept for switching the standard library's backtrace symbolication mechanism on most platforms from libbacktrace to gimli. The standard library's support for `RUST_BACKTRACE=1` requires in-process parsing of object files and DWARF debug information to interpret it and print the filename/line number of stack frames as part of a backtrace. Historically this support in the standard library has come from a library called "libbacktrace". The libbacktrace library seems to have been extracted from gcc at some point and is written in C. We've had a lot of issues with libbacktrace over time, unfortunately, though. The library does not appear to be actively maintained since we've had patches sit for months-to-years without comments. We have discovered a good number of soundness issues with the library itself, both when parsing valid DWARF as well as invalid DWARF. This is enough of an issue that the libs team has previously decided that we cannot feed untrusted inputs to libbacktrace. This also doesn't take into account the portability of libbacktrace which has been difficult to manage and maintain over time. While possible there are lots of exceptions and it's the main C dependency of the standard library right now. For years it's been the desire to switch over to a Rust-based solution for symbolicating backtraces. It's been assumed that we'll be using the Gimli family of crates for this purpose, which are targeted at safely and efficiently parsing DWARF debug information. I've been working recently to shore up the Gimli support in the `backtrace` crate. As of a few weeks ago the `backtrace` crate, by default, uses Gimli when loaded from crates.io. This transition has gone well enough that I figured it was time to start talking seriously about this change to the standard library. This commit is a preview of what's probably the best way to integrate the `backtrace` crate into the standard library with the Gimli feature turned on. While today it's used as a crates.io dependency, this commit switches the `backtrace` crate to a submodule of this repository which will need to be updated manually. This is not done lightly, but is thought to be the best solution. The primary reason for this is that the `backtrace` crate needs to do some pretty nontrivial filesystem interactions to locate debug information. Working without `std::fs` is not an option, and while it might be possible to do some sort of trait-based solution when prototyped it was found to be too unergonomic. Using a submodule allows the `backtrace` crate to build as a submodule of the `std` crate itself, enabling it to use `std::fs` and such. Otherwise this adds new dependencies to the standard library. This step requires extra attention because this means that these crates are now going to be included with all Rust programs by default. It's important to note, however, that we're already shipping libbacktrace with all Rust programs by default and it has a bunch of C code implementing all of this internally anyway, so we're basically already switching already-shipping functionality to Rust from C. * `object` - this crate is used to parse object file headers and contents. Very low-level support is used from this crate and almost all of it is disabled. Largely we're just using struct definitions as well as convenience methods internally to read bytes and such. * `addr2line` - this is the main meat of the implementation for symbolication. This crate depends on `gimli` for DWARF parsing and then provides interfaces needed by the `backtrace` crate to turn an address into a filename / line number. This crate is actually pretty small (fits in a single file almost!) and mirrors most of what `dwarf.c` does for libbacktrace. * `miniz_oxide` - the libbacktrace crate transparently handles compressed debug information which is compressed with zlib. This crate is used to decompress compressed debug sections. * `gimli` - not actually used directly, but a dependency of `addr2line`. * `adler32`- not used directly either, but a dependency of `miniz_oxide`. The goal of this change is to improve the safety of backtrace symbolication in the standard library, especially in the face of possibly malformed DWARF debug information. Even to this day we're still seeing segfaults in libbacktrace which could possibly become security vulnerabilities. This change should almost entirely eliminate this possibility whilc also paving the way forward to adding more features like split debug information. Some references for those interested are: * Original addition of libbacktrace - rust-lang#12602 * OOM with libbacktrace - rust-lang#24231 * Backtrace failure due to use of uninitialized value - rust-lang#28447 * Possibility to feed untrusted data to libbacktrace - rust-lang#21889 * Soundness fix for libbacktrace - rust-lang#33729 * Crash in libbacktrace - rust-lang#39468 * Support for macOS, never merged - ianlancetaylor/libbacktrace#2 * Performance issues with libbacktrace - rust-lang#29293, rust-lang#37477 * Update procedure is quite complicated due to how many patches we need to carry - rust-lang#50955 * Libbacktrace doesn't work on MinGW with dynamic libs - rust-lang#71060 * Segfault in libbacktrace on macOS - rust-lang#71397 Switching to Rust will not make us immune to all of these issues. The crashes are expected to go away, but correctness and performance may still have bugs arise. The gimli and `backtrace` crates, however, are actively maintained unlike libbacktrace, so this should enable us to at least efficiently apply fixes as situations come up. --- I want to note that my purpose for creating a PR here is to start a conversation about this. I think that all the various pieces are in place that this is compelling enough that I think this transition should be talked about seriously. There are a number of items which still need to be addressed before actually merging this PR, however: * [ ] `gimli` needs to be published to crates.io * [ ] `addr2line` needs a publish * [ ] `miniz_oxide` needs a publish * [ ] Tests probably shouldn't recommend the `gimli` crate's traits for implementing * [ ] The `backtrace` crate's branch changes need to be merged to the master branch (rust-lang/backtrace-rs#349) * [ ] The support for `libbacktrace` on some platforms needs to be audited to see if we should support more strategies in the gimli implementation - rust-lang/backtrace-rs#325, rust-lang/backtrace-rs#326, rust-lang/backtrace-rs#350, rust-lang/backtrace-rs#351 Most of the merging/publishing I'm not actively pushing on right now. It's a bit wonky for crates to support libstd so I'm holding off on pulling the trigger everywhere until there's a bit more discussion about how to go through with this. Namely rust-lang/backtrace-rs#349 I'm going to hold off merging until we decide to go through with the submodule strategy. In any case this is a pretty major change, so I suspect that the compiler team is likely going to be interested in this. I don't mean to force changes by dumping a bunch of code by any means. Integration of external crates into the standard library is so difficult I wanted to have a proof-of-concept to review while talking about whether to do this at all (hence the PR), but I'm more than happy to follow any processes needed to merge this. I must admit though that I'm not entirely sure myself at this time what the process would be to decide to merge this, so I'm hoping others can help me figure that out!
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Jul 28, 2020
This commit is a proof-of-concept for switching the standard library's backtrace symbolication mechanism on most platforms from libbacktrace to gimli. The standard library's support for `RUST_BACKTRACE=1` requires in-process parsing of object files and DWARF debug information to interpret it and print the filename/line number of stack frames as part of a backtrace. Historically this support in the standard library has come from a library called "libbacktrace". The libbacktrace library seems to have been extracted from gcc at some point and is written in C. We've had a lot of issues with libbacktrace over time, unfortunately, though. The library does not appear to be actively maintained since we've had patches sit for months-to-years without comments. We have discovered a good number of soundness issues with the library itself, both when parsing valid DWARF as well as invalid DWARF. This is enough of an issue that the libs team has previously decided that we cannot feed untrusted inputs to libbacktrace. This also doesn't take into account the portability of libbacktrace which has been difficult to manage and maintain over time. While possible there are lots of exceptions and it's the main C dependency of the standard library right now. For years it's been the desire to switch over to a Rust-based solution for symbolicating backtraces. It's been assumed that we'll be using the Gimli family of crates for this purpose, which are targeted at safely and efficiently parsing DWARF debug information. I've been working recently to shore up the Gimli support in the `backtrace` crate. As of a few weeks ago the `backtrace` crate, by default, uses Gimli when loaded from crates.io. This transition has gone well enough that I figured it was time to start talking seriously about this change to the standard library. This commit is a preview of what's probably the best way to integrate the `backtrace` crate into the standard library with the Gimli feature turned on. While today it's used as a crates.io dependency, this commit switches the `backtrace` crate to a submodule of this repository which will need to be updated manually. This is not done lightly, but is thought to be the best solution. The primary reason for this is that the `backtrace` crate needs to do some pretty nontrivial filesystem interactions to locate debug information. Working without `std::fs` is not an option, and while it might be possible to do some sort of trait-based solution when prototyped it was found to be too unergonomic. Using a submodule allows the `backtrace` crate to build as a submodule of the `std` crate itself, enabling it to use `std::fs` and such. Otherwise this adds new dependencies to the standard library. This step requires extra attention because this means that these crates are now going to be included with all Rust programs by default. It's important to note, however, that we're already shipping libbacktrace with all Rust programs by default and it has a bunch of C code implementing all of this internally anyway, so we're basically already switching already-shipping functionality to Rust from C. * `object` - this crate is used to parse object file headers and contents. Very low-level support is used from this crate and almost all of it is disabled. Largely we're just using struct definitions as well as convenience methods internally to read bytes and such. * `addr2line` - this is the main meat of the implementation for symbolication. This crate depends on `gimli` for DWARF parsing and then provides interfaces needed by the `backtrace` crate to turn an address into a filename / line number. This crate is actually pretty small (fits in a single file almost!) and mirrors most of what `dwarf.c` does for libbacktrace. * `miniz_oxide` - the libbacktrace crate transparently handles compressed debug information which is compressed with zlib. This crate is used to decompress compressed debug sections. * `gimli` - not actually used directly, but a dependency of `addr2line`. * `adler32`- not used directly either, but a dependency of `miniz_oxide`. The goal of this change is to improve the safety of backtrace symbolication in the standard library, especially in the face of possibly malformed DWARF debug information. Even to this day we're still seeing segfaults in libbacktrace which could possibly become security vulnerabilities. This change should almost entirely eliminate this possibility whilc also paving the way forward to adding more features like split debug information. Some references for those interested are: * Original addition of libbacktrace - rust-lang#12602 * OOM with libbacktrace - rust-lang#24231 * Backtrace failure due to use of uninitialized value - rust-lang#28447 * Possibility to feed untrusted data to libbacktrace - rust-lang#21889 * Soundness fix for libbacktrace - rust-lang#33729 * Crash in libbacktrace - rust-lang#39468 * Support for macOS, never merged - ianlancetaylor/libbacktrace#2 * Performance issues with libbacktrace - rust-lang#29293, rust-lang#37477 * Update procedure is quite complicated due to how many patches we need to carry - rust-lang#50955 * Libbacktrace doesn't work on MinGW with dynamic libs - rust-lang#71060 * Segfault in libbacktrace on macOS - rust-lang#71397 Switching to Rust will not make us immune to all of these issues. The crashes are expected to go away, but correctness and performance may still have bugs arise. The gimli and `backtrace` crates, however, are actively maintained unlike libbacktrace, so this should enable us to at least efficiently apply fixes as situations come up.
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We haven't updated libbacktrace in two years. This is just blindly updating to the latest HEAD; I'd like to see what travis says. It at least builds on my machine, running some tests...
This perpetuates the patches from #30908