This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:
apport-collect 1835349 and then change the status of the bug to 'Confirmed'. If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'. This change has been made by an automated script, maintained by the Ubuntu Kernel Team. ** Changed in: linux (Ubuntu) Status: New => Incomplete ** Tags added: eoan -- 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/1835349 Title: Fix devm_memremap_pages shutdown handling Status in intel: New Status in linux package in Ubuntu: Incomplete Bug description: Description: > 1) Some p2pdma user calls pci_alloc_p2pmem() to get some memory to DMA > to taking a reference to the pgmap. > 2) Another process unbinds the underlying p2pdma driver and the devm > chain starts to unwind. > 3) devm_memremap_pages_release() is called and it kills the reference > and drop's it's last reference. Oh! Yes, nice find. We need to wait for the percpu-ref to be dead and all outstanding references dropped before we can proceed to arch_remove_memory(), and I think this problem has been there since day one because the final exit was always after devm_memremap_pages() release which means arch_remove_memory() was always racing any final put_page(). I'll take a look, it seems the arch_remove_pages() call needs to be moved out-of-line to its own context and wait for the final exit of the percpu-ref. Target Release: 19.10 Target Kernel: 5.3 To manage notifications about this bug go to: https://bugs.launchpad.net/intel/+bug/1835349/+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