16326 2026-06-18 16:31:47 +0000 [scarthgap] x86_64 qemu-arm fails to emulate F_SETLK64 (EINVAL), breaking SQLite and file-locking on 32‑bit ARM userlands 2026-10-12 16:08:50 +0000 1 1 7 Build System, Metadata & Runtime OE-Core oe-core other unspecified x86 arm IN PROGRESS REVIEW Medium major 5.0.22 1 daniel.slater bbnpreetsingh daniel.slater randy.macleod ross.burton tim.orling yoann.congal --- --- Don't know oldest_to_newest 105949 0 5231 daniel.slater 2026-06-18 16:31:47 +0000 Created attachment 5231 locktest.c is a simple test program to demonstrate the issue. Problem: The x86_64 build of qemu-arm incorrectly returns EINVAL for the syscall fcntl64(F_SETLK64). This causes SQLite and any ARM binaries that rely on POSIX advisory file locking to fail with a "disk I/O error". The same binaries run correctly under the i386 build of qemu-arm and on real ARM hardware. This appears to be a syscall translation issue in QEMU’s 64-bit user-mode implementation of struct flock64. Expected behavior: The fcntl64(F_SETLK64) call should succeed, matching the behavior of real ARM hardware, the i386 qemu-arm build, and the Linux kernel’s expected handling of 32-bit file locks. Actual behavior: When running under x86_64 qemu-arm, the following output is observed: fcntl64(F_SETLK64) failed: errno=22 (Invalid argument) When running the same binary under i386 qemu-arm, the call succeeds. When running on actual ARM hardware, the call also succeeds. Minimal reproducer: The attached ARM test program demonstrates the issue. It opens a file and attempts to acquire a write lock using F_SETLK64. When run under x86_64 qemu-arm, the lock attempt fails with EINVAL. When run under i386 qemu-arm or on real ARM hardware, the lock succeeds. How to reproduce: Build the test program using the Yocto SDK compiler. Run the resulting ARM binary under x86_64 qemu-arm. The lock attempt fails with EINVAL. Run the same binary under i386 qemu-arm. The lock attempt succeeds. Run the same binary on actual ARM hardware. The lock attempt succeeds. Impact: This issue prevents many ARM binaries from running correctly under the Yocto SDK’s qemu-arm, including SQLite, LMDB, Berkeley DB, and any application that relies on POSIX file locking. This makes the x86_64 qemu-arm unsuitable for testing or running 32-bit ARM userlands that depend on file locking. Suggested fix: Provide a 32-bit (i386) build of qemu-arm in addition to the x86_64 build, or document that the i386 build is required for correct emulation of 32-bit ARM file-locking behavior. 106008 1 tim.orling 2026-06-25 14:38:47 +0000 This is probably worth filing a bug upstream with qemu. Can you do that? 106025 2 daniel.slater 2026-06-25 18:47:04 +0000 Before filing an upstream bug with qemu, I downloaded and built the latest qemu release (11.0.1). qemu-arm 11.0.1 successfully runs the attached test program. qemu-arm that ships with my version of Yocto (Scarthgap) is version 8.2.1 and it fails to successfully run the test program. It looks like qemu has addressed this issue sometime between version 8 and 11. 106079 3 tim.orling 2026-07-02 15:25:56 +0000 Could you see if you can figure out a patch for qemu 8 that we could apply for Scarthgap? 106333 4 daniel.slater 2026-07-24 17:39:38 +0000 I am not familiar with qemu source code at all. I'm not able to create a patch to backport the fix. 106389 5 randy.macleod 2026-07-30 15:17:00 +0000 Thanks Daniel. We don't have anyone to work on this issue unfortunately. 107046 6 yoann.congal 2026-10-12 09:23:39 +0000 Patch sent on ML: https://patchwork.yoctoproject.org/project/oe-core/patch/20261001233250.7-1-bbnpreetsingh@gmail.com/ 107047 7 yoann.congal 2026-10-12 09:26:14 +0000 (In reply to Yoann Congal from comment #6) > Patch sent on ML: > https://patchwork.yoctoproject.org/project/oe-core/patch/20261001233250.7-1- > bbnpreetsingh@gmail.com/ @Daniel, can you help test/review it? 107053 8 daniel.slater 2026-10-12 15:47:53 +0000 (In reply to Yoann Congal from comment #7) > (In reply to Yoann Congal from comment #6) > > Patch sent on ML: > > https://patchwork.yoctoproject.org/project/oe-core/patch/20261001233250.7-1- > > bbnpreetsingh@gmail.com/ > > @Daniel, can you help test/review it? I applied the patch to my Scarthgap build, rebuilt the toolchain, and now qemu-arm successfully runs the locktest test program: The original version: ``` [dslat@feynman-wsl:~] Σ /opt/thermo-imx-fb/5.0/sysroots/x86_64-pokysdk-linux/usr/bin/qemu-arm -L /opt/thermo-imx-fb/5.0/sysroots/cortexa7t2hf-neon-poky-linux-gnueabi ./locktest fcntl64(F_SETLK64) failed: errno=22 (Invalid argument) ``` and the patched version: ``` [dslat@feynman-wsl:~] Σ /opt/thermo-imx-fb/5.0-qemu-patched/sysroots/x86_64-pokysdk-linux/usr/bin/qemu-arm -L /opt/thermo-imx-fb/5.0-qemu-patched/sysroots/cortexa7t2hf-neon-poky-linux-gnueabi ./locktest fcntl64(F_SETLK64) succeeded ``` 107054 9 yoann.congal 2026-10-12 15:55:35 +0000 (In reply to Daniel R. Slater from comment #8) > (In reply to Yoann Congal from comment #7) > > (In reply to Yoann Congal from comment #6) > > > Patch sent on ML: > > > https://patchwork.yoctoproject.org/project/oe-core/patch/20261001233250.7-1- > > > bbnpreetsingh@gmail.com/ > > > > @Daniel, can you help test/review it? > > I applied the patch to my Scarthgap build, rebuilt the toolchain, and now > qemu-arm successfully runs the locktest test program: Excellent, thanks! If you want to be credited for this work you can reply on list with (either/both): Reviewed-by: ... Tested-by: ... ... and I'll add this to the merged commit. 107055 10 daniel.slater 2026-10-12 16:08:50 +0000 Reviewed-by: Daniel R. Slater <daniel.slater@thermofisher.com> Tested-by: Daniel R. Slater <daniel.slater@thermofisher.com> Reviewed the patch, applied it to my Scarthgap build, and verified the fix. 5231 2026-06-18 16:31:47 +0000 2026-06-18 16:31:47 +0000 locktest.c is a simple test program to demonstrate the issue. locktest.c text/plain 733 daniel.slater I2RlZmluZSBfR05VX1NPVVJDRQojZGVmaW5lIF9MQVJHRUZJTEU2NF9TT1VSQ0UKCiNpbmNsdWRl IDxzdGRpby5oPgojaW5jbHVkZSA8dW5pc3RkLmg+CiNpbmNsdWRlIDxmY250bC5oPgojaW5jbHVk ZSA8c3RyaW5nLmg+CiNpbmNsdWRlIDxlcnJuby5oPgoKaW50IG1haW4odm9pZCkgewogICAgY29u c3QgY2hhciAqcGF0aCA9ICJsb2NrdGVzdC5kYiI7CiAgICBpbnQgZmQgPSBvcGVuKHBhdGgsIE9f UkRXUiB8IE9fQ1JFQVQsIDA2NDQpOwogICAgaWYgKGZkIDwgMCkgewogICAgICAgIHBlcnJvcigi b3BlbiIpOwogICAgICAgIHJldHVybiAxOwogICAgfQoKICAgIHN0cnVjdCBmbG9jazY0IGZsOwog ICAgbWVtc2V0KCZmbCwgMCwgc2l6ZW9mKGZsKSk7CiAgICBmbC5sX3R5cGUgPSBGX1dSTENLOwog ICAgZmwubF93aGVuY2UgPSBTRUVLX1NFVDsKICAgIGZsLmxfc3RhcnQgPSAwOwogICAgZmwubF9s ZW4gPSAwOyAgIC8vIGxvY2sgZW50aXJlIGZpbGUKCiAgICBpbnQgcmMgPSBmY250bChmZCwgRl9T RVRMSzY0LCAmZmwpOwogICAgaWYgKHJjIDwgMCkgewogICAgICAgIHByaW50ZigiZmNudGw2NChG X1NFVExLNjQpIGZhaWxlZDogZXJybm89JWQgKCVzKVxuIiwKICAgICAgICAgICAgICAgZXJybm8s IHN0cmVycm9yKGVycm5vKSk7CiAgICAgICAgcmV0dXJuIDE7CiAgICB9CgogICAgcHJpbnRmKCJm Y250bDY0KEZfU0VUTEs2NCkgc3VjY2VlZGVkXG4iKTsKICAgIHJldHVybiAwOwp9Cg==