All autopkgtests for the newly accepted linux-gcp-5.3 (5.3.0-1008.9~18.04.1) for bionic have finished running. The following regressions have been reported in tests triggered by the package:
linux-gcp-5.3/unknown (amd64) Please visit the excuses page listed below and investigate the failures, proceeding afterwards as per the StableReleaseUpdates policy regarding autopkgtest regressions [1]. https://people.canonical.com/~ubuntu-archive/proposed- migration/bionic/update_excuses.html#linux-gcp-5.3 [1] https://wiki.ubuntu.com/StableReleaseUpdates#Autopkgtest_Regressions Thank you! -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1847118 Title: PM / hibernate: fix potential memory corruption Status in linux package in Ubuntu: Fix Committed Status in linux source package in Xenial: Fix Committed Status in linux source package in Bionic: Fix Committed Status in linux source package in Disco: Fix Committed Status in linux source package in Eoan: Fix Committed Bug description: [Impact] A caching bug in the hibernation code can lead to potential memory corruptions on resume. The hibernation code is representing all the allocated pages in memory (pfn) using a list of extents, inside each extent it uses a radix tree and each node in the tree contains a bitmap. This structure is used to save the memory image to disk. To speed up lookups in this structure the kernel is caching the position of the previous lookup in the form (current_extent, current_node). However, if two consecutive lookups are distant enough from each other, the extent can change, but the kernel can still use the cached node (current_node), accessing the wrong bitmap and ending up saving to disk the wrong pfn's. [Test Case] Bug has been reproduced in Xenial and Bionic trying to hibernate a large instance with a lot of RAM (100GB+). But we also wrote a custom kernel module to better isolate the code that triggers the problem: https://code.launchpad.net/~arighi/+git/mybitmap This module has exactly the same code as the hibernation code, but it can be used as a fast test case to reproduce the problem without actually triggering a real hibernation/resume cycle. [Fix] This bug can be fixed by properly invalidating the cached pair (extent, node) when the next lookup falls in a different extent or a different node. [Regression Potential] The fix has been sent to the LKML for review/feedback (https://lkml.org/lkml/2019/9/25/393), we have not received any feedback so far, but the bug is pretty clear and well tested on the affected platforms. Moreover, the code is isolated to the hibernation area, so the overall regression potential is minimal. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1847118/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
