LKML Summary Podcast

Audio: http://media.libsyn.com/media/jcm/linux_kernel_podcast_20090809.mp3

For the weekend of August 9th 2009, I’m Jon Masters with a summary of today’s LKML traffic.

In today’s issue: clone_with_pids(), HTC Dream, Nested SVM, and Performance Counters.

clone_with_pids(). Sukadev Bhattiprolu posted version 4 of a 7 part patch series implementing a new clone_with_pids() system call for use with checkpoint application restarting support. The idea is to request that the kernel give a newly created task or tasks a specific set of process IDs so that code being resumed from a checkpoint will have a consistent process ID. Sukadev is interested in feedback on the proposed system call interface and offers two alternatives for consideration.

HTC Dream. Pavel Machek posted yet more patches for the HTC Dream. At this point he has done a large amount of work at pushing this support into the staging tree. The latest effort included support for input devices connected to GPIO pins, and a number of other fixes. Separately, Jiri Slaby posted a buffer overflow fix for the Dream, which he is unable to even build test as he doesn’t have an ARM toolchain (this suggests he doesn’t have hardware either).

Nested SVM. Joerg Roedel posted version 2 of a series of nested SVM cleanups. The patchset has been tested with the use case of KVM within KVM and has shown apparently no regressions (with the first-level guest using nested and shadow paging). The latest version of the patch enables nested SVM support by default, although the user must still invoke qemu with -enable-nesting.

Performance counters. There were a number of small patches to performance counters over the weekend, from a number of people, suggesting that many are starting to play with these now. Of the patches, there was support for displaying per-thread event counters from Brice Goglin, and a fix to avoid oopsing on PowerPC CPUs without performance counter hardware support from Paul Mackerras.

In today’s miscellaneous items: some reposted patches implementing asm-generic and dma-mapping-common for SPARC from Tujita Tomonori, a futex bugfix from Darrent Hart, a series of fsnotify patches from Eric Paris, a series of patches converting parts of the kernel over to using printk_once from Marcin Slusarz, version 2 of a patch fixing an oops in identify_cpu() on CPUs without the CPUID instruction on x86 from Ondrej Zary, some timer, tracing, core, and x86 fixes from Ingo Molnar, some critical KVM updates for 2.6.31-rc6 from Avi Kivity (including a guest-initiated DoS fix), a winbond IR driver from David Hardeman, a possible regression in XFS in 2.6.30.4 raised by Justin Piszcz, a number of updates to the staging tree and some USB fixes (including addressing some EHCI warnings folks are seeing – Greg included – and a number of other fairly minor fixes) from Greg Kroah-Hartman, some RT fixes for ARM from Uwe Kleine-Konig, some fixes for SDHCI (high speed and 4-bit SD cards) from Anton Vorontsov, a few “relatively small” bug fixes for btrfs from Chris Mason, a pull request for some wireless updates from John Linville, version 5 of a patch adding trace events to the page allocator from Mel Gormon, version 4 (apparently “for the upstream community, this is revision 3″ – worth fixing that to adopt one numbering scheme soon) of support for the Intel RAR Register from Mark Allyn, a lockdep warning in 2.6.31-rc5-rt1.1 from Clark Williams, an update to CPU topology detection for AMD Magny-Cours from Andreas Herrmann, a fix to a memory leak in the ring_buffer free code from Eric Dumazet (which was immediately released as a pull request from Steven Rostedt), version 3 of a patch allowing file truncations on files with suid and write permissions set, which previously incorrectly failed with EPERM, from Amerigo Wang, a patch changing superblock s_maxbytes for an loff_t type from Jeff Layton, and yet another round of DRM fixes for 2.6.31-rc6 from Dave Airlie.

Finally today, Robert P. J. Day inquired as to whether any official standard existed for determining when/if tools should be moved into the top level directory of the same name. As an example, he cited Documentation/fs/slabinfo.c as a candidate.

In today’s security items: A read buffer overflow fix for FAT from Roel Kluin, and the aforementioned KVM guest DoS fixes from Avi Kivity.

The latest kernel release is 2.6.31-rc5, which was released over a week ago.

Hugh Dickens wonders if CONFIG_PREEMPT_RCU is supposed to be working in next/mmotm at the moment, because he suspects it is failing on his PowerPC G5 system, as evidenced by a parallel kernel compilation test the fails in what appears to be a manner consistent with RCU failing to reap the “filp” SLAB. Separately, Martin Schwidefsky wondered whether there was a race in the case of RCU and NOHZ being defined at kernel build time. Martin posted an example interaction showing how this might happen and requested input from Paul E. McKenney, who is the inventor and implementor of RCU support.

Rafael J. Wysocki posted a list of regressions between 2.6.29 and 2.6.30 and also between 2.6.30 and 2.6.31-rc5-git5. The former list of regressions appears to be leveling off for the older kernel (a total of 37 unresolved bugs are cited from the upstream kernel.org bugzilla), however the more recent regressions have increased, with a total of 24 unresolved regressions. Of course, these are just regressions for which there is a tracking bug.

Stephen Rothwell posted a linux-next tree for August 7th. Since Thursday, the following trees gained conflicts and/or build failures: net, security-testing, tip. The following trees lost conflicts and/or build failures: rr, agp. The total sub-tree count remains steady at 138 trees.

That’s a summary of today’s Linux Kernel Mailing List traffic, for further information visit www.kernel.org. I’m Jon Masters.