** Description changed: [Impact] "UBUNTU: SAUCE: cachefiles: Page leaking in cachefiles_read_backing_file while vmscan is active" has been applied to fix a page leaking issue. However a slightly different fix has been applied upstream: 9a24ce5b66f9c8190d63b15f4473600db4935f1f cachefiles: Fix page leak in cachefiles_read_backing_file while vmscan is active Basically we are fixing the same issue in two different ways at the same time, but even worse our patch an introduce a potential NULL pointer dereference: we do a put_page(newpage) and set newpage = NULL in the main for() loop and then we may do additional put_page(newpage) after the main for loop if ret == -EEXIST, that would trigger the NULL pointer dereference. [Test case] No test case or reproducer is available at the moment, this issue has been found simply by reviewing the code. [Fix] Drop the SAUCE patch and rely on the upstream fix. [Regression potential] - If the analysis is not correct we may re-introduce a page leak in + If the analysis is not correct we may re-introduce a page leak in cachefiles (NFS for example), but it seems unlikely to happen, since the upstream fix is addressing the page leaking already. - I think we should really drop this SAUCE patch from all the kernels that are applying the upstream fix already (9a24ce5b66f9c8190d63b15f4473600db4935f1f).
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1947709 Title: Drop "UBUNTU: SAUCE: cachefiles: Page leaking in cachefiles_read_backing_file while vmscan is active" To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1947709/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
