| Message ID | 20240512061136.726299-1-andrea.righi@canonical.com |
|---|---|
| Headers | show |
| Series | fix autopkgtest-virt-qemu regression with 6.8 | expand |
On 5/12/24 08:09, Andrea Righi wrote: > BugLink: https://bugs.launchpad.net/bugs/2056461 > > [Impact] > > It seems that kernel 6.8 introduced a regression in the 9pfs related to > caching and netfslib, that can cause some user-space apps to read > content from files that is not up-to-date (when they are used in a > producer/consumer fashion). > > It seems that the offending commit is this one: > > 80105ed2fd27 ("9p: Use netfslib read/write_iter") > > Reverting the commit seems to fix the problem. However the actual bug > might be in netfslib or how netfslib is used in the 9p context. > > The regression has been reported upstream and we are still investigating > (https://lore.kernel.org/lkml/Zj0ErxVBE3DYT2Ea@gpd/). > > In the meantime it probably makes sense to temporarily revert the commit > as a SAUCE patch. Then we will drop the SAUCE patch once we'll have a > proper fix upstream. > > [Test case] > > The following test should complete correctly without any timeout: > > pull-lp-source -d hello > autopkgtest-buildvm-ubuntu-cloud -r noble > autopkgtest -U hello*.dsc -- qemu ./autopkgtest-noble-amd64.img > > [Fix] > > Revert the following commit (until we have a proper fix upstream): > > 80105ed2fd27 ("9p: Use netfslib read/write_iter") > > [Regression potential] > > We may experience other regressions related to 9pfs with this change, > however it's quite unlikely to happen since we are reverting a commit, > restoring the previous behavior. > Acked-by: Tim Gardner <tim.gardner@canonical.com>
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 On Sun, May 12 2024, Andrea Righi wrote: > BugLink: https://bugs.launchpad.net/bugs/2056461 > > [Impact] > > It seems that kernel 6.8 introduced a regression in the 9pfs related to > caching and netfslib, that can cause some user-space apps to read > content from files that is not up-to-date (when they are used in a > producer/consumer fashion). > > It seems that the offending commit is this one: > > 80105ed2fd27 ("9p: Use netfslib read/write_iter") > > Reverting the commit seems to fix the problem. However the actual bug > might be in netfslib or how netfslib is used in the 9p context. > > The regression has been reported upstream and we are still investigating > (https://lore.kernel.org/lkml/Zj0ErxVBE3DYT2Ea@gpd/). > > In the meantime it probably makes sense to temporarily revert the commit > as a SAUCE patch. Then we will drop the SAUCE patch once we'll have a > proper fix upstream. > > [Test case] > > The following test should complete correctly without any timeout: > > pull-lp-source -d hello > autopkgtest-buildvm-ubuntu-cloud -r noble > autopkgtest -U hello*.dsc -- qemu ./autopkgtest-noble-amd64.img > > [Fix] > > Revert the following commit (until we have a proper fix upstream): > > 80105ed2fd27 ("9p: Use netfslib read/write_iter") > > [Regression potential] > > We may experience other regressions related to 9pfs with this change, > however it's quite unlikely to happen since we are reverting a commit, > restoring the previous behavior. Acked-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com> - -- Regards, Marcelo -----BEGIN PGP SIGNATURE----- iQHQBAEBCgA6FiEExJjLjAfVL0XbfEr56e82LoessAkFAmZPJ8AcHG1hcmNlbG8u Y2VycmlAY2Fub25pY2FsLmNvbQAKCRDp7zYuh6ywCS5xC/4sPqGVimwzKH7o7qRs dTlHbhDNPYbLNvdmKZe1Q4DQpNera1/v7+I0u2NZqTs5D41wpn1/4tHxEy2YNI1P kNiE4OsX9L4ZdDoFquFTf4Ii1EbPZaDFK1JPWTehqv7eDKZ9OMYST+mIJvFwk6d9 hyMnMzb+/ZGrl8r8wo4STSjuucsnBw4uy8orCEDdp+AcFWhRhQWoE1/T5OLRQVrg Wv7pU1OeIJ2DFDt+I4p2e4irPGDefSmjQvVe7bd/FxxXX6bXuW0kGNrGc7gn3eIl FktfwioxYwHNRiDqJfJZ44byKkpoLQML6l2LniRPGmdizrj2F/I/GzqAu4hFBec/ gk7JsU8wrcf10UQhpIs7joZdpY5GIj4eJQcQV9iGmm/4Cyk4DBCaNefxr9KOQkoR JTGqKX0Zv4tnh1gtzBER9WLqOInSUHMisAvF+VthA/0B3M8tLbwrX2l2Vkn5QV8G b9l2qhP/5h4Gdly8VaITLpk7mOy6zH9UlhlNMJOwfyqGpkY= =+qfu -----END PGP SIGNATURE-----
BugLink: https://bugs.launchpad.net/bugs/2056461 [Impact] It seems that kernel 6.8 introduced a regression in the 9pfs related to caching and netfslib, that can cause some user-space apps to read content from files that is not up-to-date (when they are used in a producer/consumer fashion). It seems that the offending commit is this one: 80105ed2fd27 ("9p: Use netfslib read/write_iter") Reverting the commit seems to fix the problem. However the actual bug might be in netfslib or how netfslib is used in the 9p context. The regression has been reported upstream and we are still investigating (https://lore.kernel.org/lkml/Zj0ErxVBE3DYT2Ea@gpd/). In the meantime it probably makes sense to temporarily revert the commit as a SAUCE patch. Then we will drop the SAUCE patch once we'll have a proper fix upstream. [Test case] The following test should complete correctly without any timeout: pull-lp-source -d hello autopkgtest-buildvm-ubuntu-cloud -r noble autopkgtest -U hello*.dsc -- qemu ./autopkgtest-noble-amd64.img [Fix] Revert the following commit (until we have a proper fix upstream): 80105ed2fd27 ("9p: Use netfslib read/write_iter") [Regression potential] We may experience other regressions related to 9pfs with this change, however it's quite unlikely to happen since we are reverting a commit, restoring the previous behavior.