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Bug 1429050
Summary: | Gnome core dumps on startup with llvmpipe crash due to llvm failing to clear high 16bits of correct register. | ||||||
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Product: | [Fedora] Fedora | Reporter: | Jeremy Linton <jeremy.linton> | ||||
Component: | llvm | Assignee: | Adam Jackson <ajax> | ||||
Status: | CLOSED ERRATA | QA Contact: | Fedora Extras Quality Assurance <extras-qa> | ||||
Severity: | unspecified | Docs Contact: | |||||
Priority: | unspecified | ||||||
Version: | rawhide | CC: | ajax, awilliam, bos, davejohansen, dmalcolm, esteban.xandri, fschwarz, gmarr, ignatenko, jistone, nalimilan, pbrobinson, petersen, scottt.tw, tstellar | ||||
Target Milestone: | --- | ||||||
Target Release: | --- | ||||||
Hardware: | aarch64 | ||||||
OS: | Unspecified | ||||||
Whiteboard: | AcceptedFreezeException | ||||||
Fixed In Version: | Doc Type: | If docs needed, set a value | |||||
Doc Text: |
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Story Points: | --- | ||||
Clone Of: | |||||||
: | 1461815 1461818 (view as bug list) | Environment: | |||||
Last Closed: | 2017-03-29 05:04:52 UTC | Type: | Bug | ||||
Regression: | --- | Mount Type: | --- | ||||
Documentation: | --- | CRM: | |||||
Verified Versions: | Category: | --- | |||||
oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||
Cloudforms Team: | --- | Target Upstream Version: | |||||
Embargoed: | |||||||
Bug Depends On: | |||||||
Bug Blocks: | 245418, 1349185, 1394837 | ||||||
Attachments: |
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Description
Jeremy Linton
2017-03-03 23:02:39 UTC
Ok, found a fun pile of unit test failures in llvm too (starting with the fact that ARM64 can't DC against a page without write permissions). The bottom line is that there is a LLVMPipe code generation problem. Its trying to load the constant 2.44331568e-05 into s7 (in this example) and its loading the address of that constant 16 bits at a time into x13 with movk's, but it fails to load the top 16 bits, leaving whatever happens to be in that register stale. Interrestingly it seems that it has code which is trying to clear the top 16 bits as well, but the target register (zxr in this case!) seems to be incorrect. The code in question is in lp_build_sin_or_cos(). and looks like: LLVMValueRef coscof_p0 = lp_build_const_vec(gallivm, bld->type, 2.443315711809948E-005); setting GALLIVM_DEBUG="nopt" fixes the problem! Possible upstream fix here: https://reviews.llvm.org/D27609 Changing component to llvm. Created attachment 1261680 [details]
Fix aarch64 relocation
To be clear the patch is against LLVM 3.9.1 in F26 & rawhide. mesa-17.0.1-2.fc26 has been submitted as an update to Fedora 26. https://bodhi.fedoraproject.org/updates/FEDORA-2017-701f4d0d08 mesa-17.0.1-2.fc26 has been pushed to the Fedora 26 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2017-701f4d0d08 For reference there was a similar problem seen with "root" package building that was fixed by this too. Reference: https://pagure.io/releng/issue/6653 I updated my hikey to the latest rawhide last night and VNC/gnome-shell/firefox were working. I will run a clean F26 install in the next couple days on seattle/juno. Proposed as a Freeze Exception for 26-alpha by Fedora user pbrobinson using the blocker tracking app because: This causes issues with the gnome desktop crashing on aarch64 when using the llvmpipe driver which is used for a number of usecases on aarch64. mesa-17.0.2-1.fc26 has been submitted as an update to Fedora 26. https://bodhi.fedoraproject.org/updates/FEDORA-2017-741d36d0b1 +1 FE Would this affect llvmpipe usage on x86_64 as well? (In reply to Adam Williamson from comment #13) > Would this affect llvmpipe usage on x86_64 as well? No, it was an issue with aarch64 with llvm that was explicitly aarch64 codepaths Discussed during the 2017-03-27 blocker review meeting: [1] The decision was made to classify this bug as an AcceptedFreezeException was made as it would be nice to have this fixed in Alpha release. [1] https://meetbot.fedoraproject.org/fedora-blocker-review/2017-03-27/f26-blocker-review.2017-03-27-16.01.txt mesa-17.0.1-2.fc26 has been pushed to the Fedora 26 stable repository. If problems still persist, please make note of it in this bug report. mesa-17.0.2-1.fc26 has been pushed to the Fedora 26 stable repository. If problems still persist, please make note of it in this bug report. Not directly a 48-bit VA problem, but definitely irritated by it. |