PR for llvm/llvm-project#53612 #11
Open
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
Adds libunwind support for SPARCv9 (aka sparc64). This is a rebase of @kettenis' patch D32450, which I created (with his permission) because the original review has become inactive. The changes are of a cosmetic nature to make it fit better with the new code style, and to reuse the existing SPARCv8 code, whenever possible. Please let me know if I posted this on the wrong place. Also, the summary of the original review is reproduced below: > This adds unwinder support for 64-bit SPARC (aka SPARCv9). The implementation was done on OpenBSD/sparc64, so it takes StackGhost into account: > > https://www.usenix.org/legacy/publications/library/proceedings/sec01/full_papers/frantzen/frantzen_html/index.html > > Since StackGhost xor's return addresses with a random cookie before storing them on the stack, the unwinder has to do some extra work to recover those. This is done by introducing a new kRegisterInCFADecrypt "location" type that is used to implement the DW_CFA_GNU_window_save opcode. That implementation is SPARC-specific, but should work for 32-bit SPARC as well. DW_CFA_GNU_window_save is only ever generated on SPARC as far as I know. Co-authored-by: Mark Kettenis Reviewed By: #libunwind, thesamesam, MaskRay, Arfrever Differential Revision: https://reviews.llvm.org/D116857 (cherry picked from commit 2b9554b)
llvmbot
pushed a commit
that referenced
this pull request
Feb 10, 2022
We experienced some deadlocks when we used multiple threads for logging using `scan-builds` intercept-build tool when we used multiple threads by e.g. logging `make -j16` ``` (gdb) bt #0 0x00007f2bb3aff110 in __lll_lock_wait () from /lib/x86_64-linux-gnu/libpthread.so.0 #1 0x00007f2bb3af70a3 in pthread_mutex_lock () from /lib/x86_64-linux-gnu/libpthread.so.0 #2 0x00007f2bb3d152e4 in ?? () #3 0x00007ffcc5f0cc80 in ?? () #4 0x00007f2bb3d2bf5b in ?? () from /lib64/ld-linux-x86-64.so.2 #5 0x00007f2bb3b5da27 in ?? () from /lib/x86_64-linux-gnu/libc.so.6 #6 0x00007f2bb3b5dbe0 in exit () from /lib/x86_64-linux-gnu/libc.so.6 #7 0x00007f2bb3d144ee in ?? () #8 0x746e692f706d742f in ?? () #9 0x692d747065637265 in ?? () #10 0x2f653631326b3034 in ?? () #11 0x646d632e35353532 in ?? () #12 0x0000000000000000 in ?? () ``` I think the gcc's exit call caused the injected `libear.so` to be unloaded by the `ld`, which in turn called the `void on_unload() __attribute__((destructor))`. That tried to acquire an already locked mutex which was left locked in the `bear_report_call()` call, that probably encountered some error and returned early when it forgot to unlock the mutex. All of these are speculation since from the backtrace I could not verify if frames 2 and 3 are in fact corresponding to the `libear.so` module. But I think it's a fairly safe bet. So, hereby I'm releasing the held mutex on *all paths*, even if some failure happens. PS: I would use lock_guards, but it's C. Reviewed-by: NoQ Differential Revision: https://reviews.llvm.org/D118439 (cherry picked from commit d919d02)
tstellar
pushed a commit
that referenced
this pull request
Feb 14, 2022
We experienced some deadlocks when we used multiple threads for logging using `scan-builds` intercept-build tool when we used multiple threads by e.g. logging `make -j16` ``` (gdb) bt #0 0x00007f2bb3aff110 in __lll_lock_wait () from /lib/x86_64-linux-gnu/libpthread.so.0 #1 0x00007f2bb3af70a3 in pthread_mutex_lock () from /lib/x86_64-linux-gnu/libpthread.so.0 #2 0x00007f2bb3d152e4 in ?? () #3 0x00007ffcc5f0cc80 in ?? () #4 0x00007f2bb3d2bf5b in ?? () from /lib64/ld-linux-x86-64.so.2 #5 0x00007f2bb3b5da27 in ?? () from /lib/x86_64-linux-gnu/libc.so.6 #6 0x00007f2bb3b5dbe0 in exit () from /lib/x86_64-linux-gnu/libc.so.6 #7 0x00007f2bb3d144ee in ?? () #8 0x746e692f706d742f in ?? () #9 0x692d747065637265 in ?? () #10 0x2f653631326b3034 in ?? () #11 0x646d632e35353532 in ?? () #12 0x0000000000000000 in ?? () ``` I think the gcc's exit call caused the injected `libear.so` to be unloaded by the `ld`, which in turn called the `void on_unload() __attribute__((destructor))`. That tried to acquire an already locked mutex which was left locked in the `bear_report_call()` call, that probably encountered some error and returned early when it forgot to unlock the mutex. All of these are speculation since from the backtrace I could not verify if frames 2 and 3 are in fact corresponding to the `libear.so` module. But I think it's a fairly safe bet. So, hereby I'm releasing the held mutex on *all paths*, even if some failure happens. PS: I would use lock_guards, but it's C. Reviewed-by: NoQ Differential Revision: https://reviews.llvm.org/D118439 (cherry picked from commit d919d02)
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.
resolves llvm#53612