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Diffstat (limited to 'results/classifier/deepseek-2-tmp/output/device/1661758')
| -rw-r--r-- | results/classifier/deepseek-2-tmp/output/device/1661758 | 118 |
1 files changed, 0 insertions, 118 deletions
diff --git a/results/classifier/deepseek-2-tmp/output/device/1661758 b/results/classifier/deepseek-2-tmp/output/device/1661758 deleted file mode 100644 index 194baf3b..00000000 --- a/results/classifier/deepseek-2-tmp/output/device/1661758 +++ /dev/null @@ -1,118 +0,0 @@ - -qemu-nbd causes data corruption in VDI-format disk images - -Hi, - -This is a duplicate of #1422307. I can't figure out a way to re-open -it--the status of "Fix Released" is changeable only by a project -maintainer or bug supervisor--so I'm opening a new bug to make sure -this gets looked at again. - -qemu-nbd will sometimes corrupt VDI disk images. The bug was thought -to be fixed in commit f0ab6f109630940146cbaf47d0cd99993ddba824, but -I'm able to reproduce it in both that commit and in the latest commit -(a951316b8a5c3c63254f20a826afeed940dd4cba). I just needed to run more -iterations of the test. It's possible that it was partially fixed, or -that the added serialization made it harder to catch this -non-deterministic bug, but the same symptoms persist: data corruption -of VDI-format disk images. - -This affects at least qemu-nbd. I haven't tried reproducing the issue -with qemu proper or qemu-img, but the original bug report suggests -that the bug in the common VDI backend may corrupt data written by -those programs. - -Please let me know if I can provide any further information or help -with testing. Thank you very much for looking into this! - -Test procedure -************** - -The procedure used is the one given by Max Reitz (xanclic) in the -original bug report, comment 3 -(https://bugs.launchpad.net/qemu/+bug/1422307/comments/3), in the -section "VDI and NBD over /dev/nbd0", but with up to 1000 iterations -instead of 10: - - $ cd ~/qemu-origfix-f0ab6f1/bin - $ dd if=/dev/urandom of=blob.raw bs=1M count=64 - 64+0 records in - 64+0 records out - 67108864 bytes (67 MB) copied, 4.36475 s, 15.4 MB/s - $ sudo sh -c 'for i in $(seq 0 999); do ./qemu-img create -f vdi test.vdi 64M > /dev/null; ./qemu-nbd -c /dev/nbd0 test.vdi; sleep 1; ./qemu-img convert -n blob.raw /dev/nbd0; ./qemu-img convert /dev/nbd0 test1.raw; sync; echo 1 > /proc/sys/vm/drop_caches; ./qemu-img convert /dev/nbd0 test2.raw; ./qemu-nbd -d /dev/nbd0 > /dev/null; if ! ./qemu-img compare -q test1.raw test2.raw; then md5sum test1.raw test2.raw; echo "$i failed"; break; fi; done; echo "done"' -27a66c3a8ac2cf06f2c925968ea9e964 test1.raw -2da9bf169041a7c2bd144c4ab3a29aea test2.raw -64 failed -done - -I've run this process a handful of times, and I've seen it take as -little as 10 iterations and as many as 161 (taking 32 minutes in the -latter case). Please be patient. Putting the images on tmpfs will -probably help it go faster, and I have successfully reproduced the -issue on tmpfs in addition to ext4. - -Nothing different was needed to reproduce the issue in a directory -containing a build of the latest commit. It still takes somewhere -around 1-200 iterations to find, in my testing. - -Build procedure -*************** - - $ git clone git://git.qemu-project.org/qemu.git - [omitted] - $ git clone qemu qemu-origfix-f0ab6f1 - Cloning into 'qemu-origfix-f0ab6f1'... - done. - $ cd qemu-origfix-f0ab6f1 - $ git checkout f0ab6f109630940146cbaf47d0cd99993ddba824 - Note: checking out 'f0ab6f109630940146cbaf47d0cd99993ddba824'. - - You are in 'detached HEAD' state. You can look around, make experimental - changes and commit them, and you can discard any commits you make in this - state without impacting any branches by performing another checkout. - - If you want to create a new branch to retain commits you create, you may - do so (now or later) by using -b with the checkout command again. Example: - - git checkout -b new_branch_name - - HEAD is now at f0ab6f1... block/vdi: Add locking for parallel requests - $ mkdir bin - $ cd bin - $ script -c'time (../configure --enable-debug --target-list=x86_64-softmmu && make -j6; echo "result: $?")' - Script started, file is typescript - [omitted; the build typescript is attached separately] - LINK x86_64-softmmu/qemu-system-x86_64 - result: 0 - - real 1m5.733s - user 2m3.904s - sys 0m13.828s - Script done, file is typescript - -Nothing different was done when building the latest commit (besides -cloning to a different directory, and not running `git checkout`). - -Environment -*********** - - * Machine: x86_64 - - * Hypervisor: Xen 4.4 (Debian package xen-hypervisor-4.4-amd64, - version 4.4.1-9+deb8u8) - - * A Xen domU (guest) for building QEMU and reproducing the issue. - All testing was done within the virtual machine for convenience - and access to better hardware than what I have for my development - machine (I expected the build to take much longer than it really - does). - - - x86_64 architecture with six VCPUs and 1.2 GiB RAM allocated, - operating in HVM (fully virtualized) mode. - - - Distribution: Debian 8.7 Jessie amd64 - - - Kernel: Linux 3.16.0 x86_64 (Debian package - linux-image-3.16.0-4-amd64, version 3.16.39-1) - - - Compiler: GCC 4.9.2 (Debian package gcc-4.9, version 4.9.2-10) \ No newline at end of file |