LKML Summary Podcast

Audio: http://media.libsyn.com/media/jcm/linux_kernel_podcast_20090706.mp3

I’m traveling in Tokyo, Japan, this week and surviving on a few hours sleep here and there so apologies that we’re still not quite up to date.

For Mon, July 6th 2009, I’m Jon Masters with a summary of today’s LKML traffic.

In today’s issue: DRBD, file truncations, modules, and pipes.

DRBD. Philipp Reisner posted a series of 16 patches implementing the latest iteration of his ‘drbd’ block device for High Availability clustering. He says “as the first bit of the DRBD patch already got upstream [...] it is time to get more of DRBD towards mainline”. Others, of course, may or may not agree.

File truncations. Amerigo Wang pointed out that, when the suid bit is set on a file, and a non-owner user having write permission attempts to truncate (and not append) the file, they get an EPERM error rather than the correct access to the file. Amerigo has a trivial patch that fixes this behavior to allow the truncation in this situation.

Modules. Sorry I missed this one before. Jan Beulich and Michal Marek discussed the recent patches to cleanup module CRC handling on 64-bit arches. Since they actually only need to generate 32-bit quantities, the use of 64-bit slots to store those quantities is corrected, and this now apparently breaks the dump-modversions feature of modprobe. Jan expressed some concern that userspace was reliant upon this not changing, but Rusty (and myself too) believe that this is a reasonable situation. I’ll post a fix when they figure out how they want to proceed with the CRC patches to the kernel.

Pipes. Ongoing discussion of extending pipe() to support NULL arguments is continuing with debate over position handling in open pipes. Changli Gao pointed out that pipe doesn’t refer to the “pos” when reading or writing, and directs those interested in discussing his patchset to look at the implementation of pipe_read() and pipe_write() first. Separately, Nick Piggin posted a new iteration of his patches for truncate operations, which adds a new ftruncate operation for inodes. Also in other news, Linda Walsh wondered aloud why 2GB read()s didn’t work on pipes, which Eric Dumazet followed up with a pointer to the fixed 2GB per-read limit. This exists even on x86_64 systems and might be a candidate for being dynamic.

In today’s miscellaneous items: A series of SPARC asm-generic conversion patches (Fujta Tomonori), bootmem kmemleak tracking (Catalin Marinas, which should help reduce the false positive warnings even further), a vote for making .governor() always be called with rwsem held in the cpufreq cleanups (Thomas Renninger), some Microblaze architectural cleanups from Michal Simek, some PCI fixes (Jesse Barnes, who says there’s “nothing too exiciting here”), and version 9 of the iosignalfd patch series (Gregory Haskins).

Finally today: We’re still seeing a few extraneous lockdep warnings (although one of those might go away thanks to a SLAB lockdep annotation fix posted from Pekka J Enberg) and crash reports on 2.6.31-rc2 (including one case of Xorg giving a blank screen in rc2, and instability in the tty layer, which Alan Cox is helping correct), so it’s worth putting in some testing, if you can.

In today’s announcements: Rafael J. Wysocki obliged everyone with another round of reported regression summaries for kernels 2.6.31-rc2. A total of 21 unresolved regressions are currently listed, and each has been accompanied with a separate email pinging the owner of the bug in kernel.org bugzilla.

The latest kernel release is: 2.6.31-rc2, which was released by Linus on the 4th of July.

Stephen Rothwell posted a linux-next tree for July 6th. Since Friday, the bkl-removal tree has been removed (since it has served its purpose), the sfi tree is still being dropped dur to build problems, the tree continues to fail to build in an allyesconfig build configuration on powerpc, and several other net gains in conflicts were recorded. With the removal of the bkl bits, the linux-next tree composition is down to 131 trees in today’s compose.

That’s a summary of today’s LKML traffic. For further information visit kernel.org. I’m Jon Masters.