Bjørn Mork <[email protected]> writes: > "Paul E. McKenney" <[email protected]> writes: > >> Other than wondering whether powertop has issues similar to the bug >> Steven Rostedt located, I must confess myself clueless. Here are some >> diagnostics I can suggest: >> >> 1. Run in 32-bit mode. This disables some of the new adaptive-ticks >> functionality, so might give a probabilistic indication of where >> the bug lies. >> >> 2. The standard fallback of bisection. >> >> Would you be willing to do either of these? > > Willing, yes. But it will take some time before I am able to do either > unless I can recreate the problem in a virtual machine. I assume that > you by " 32-bit mode" mean a 32bit kernel? I'm not exactly set up to > run that on my laptop. Bisection will be less work. > > To be honest, I don't even know how old this thing is. It could be > totally unrelated to your recent changes for all I know. Running > powertop is something I do once every 6 kernel releases or something > like that... > > I'll see what I can come up with. Thanks for your attention.
I was unable to recreate the problem in a virtual machine, which is slightly suspicious. And bisecting it ended up pointing to a merge commit: commit ab86e974f04b1cd827a9c7c35273834ebcd9ab38 Merge: 8700c95 6f7a05d Author: Linus Torvalds <[email protected]> Date: Tue Apr 30 08:15:40 2013 -0700 Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip .. which I don't think makes much sense at all. The bisect log leading to this was: bjorn@canardo:/usr/local/src/build-tmp/linux$ git bisect log # bad: [f722406faae2d073cc1d01063d1123c35425939e] Linux 3.10-rc1 # good: [c1be5a5b1b355d40e6cf79cc979eb66dafa24ad1] Linux 3.9 git bisect start 'v3.10-rc1' 'v3.9' # bad: [73287a43cc79ca06629a88d1a199cd283f42456a] Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next git bisect bad 73287a43cc79ca06629a88d1a199cd283f42456a # bad: [5d434fcb255dec99189f1c58a06e4f56e12bf77d] Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial git bisect bad 5d434fcb255dec99189f1c58a06e4f56e12bf77d # good: [507ffe4f3840ac24890a8123c702cf1b7fe4d33c] Merge tag 'tty-3.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty git bisect good 507ffe4f3840ac24890a8123c702cf1b7fe4d33c # good: [4a7b4d2360175f67ab2c58effeeb8362a3057c25] x86: pageattr-test: remove srandom32 call git bisect good 4a7b4d2360175f67ab2c58effeeb8362a3057c25 # good: [46d9be3e5eb01f71fc02653755d970247174b400] Merge branch 'for-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq git bisect good 46d9be3e5eb01f71fc02653755d970247174b400 # good: [e0972916e8fe943f342b0dd1c9d43dbf5bc261c2] Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip git bisect good e0972916e8fe943f342b0dd1c9d43dbf5bc261c2 # bad: [ab86e974f04b1cd827a9c7c35273834ebcd9ab38] Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip git bisect bad ab86e974f04b1cd827a9c7c35273834ebcd9ab38 # good: [8700c95adb033843fc163d112b9d21d4fda78018] Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip git bisect good 8700c95adb033843fc163d112b9d21d4fda78018 # good: [0ed2aef9b3bffe598045b62a31a50d912eee92d8] Merge branch 'fortglx/3.10/time' of git://git.linaro.org/people/jstultz/linux into timers/core git bisect good 0ed2aef9b3bffe598045b62a31a50d912eee92d8 # good: [8f294b5a139ee4b75e890ad5b443c93d1e558a8b] hrtimer: Add expiry time overflow check in hrtimer_interrupt git bisect good 8f294b5a139ee4b75e890ad5b443c93d1e558a8b # good: [60cf7ea849e77c8782dee147cfb8c38d1984236e] timer_list: Split timer_list_show_tickdevices git bisect good 60cf7ea849e77c8782dee147cfb8c38d1984236e # good: [d2054b2c11682495fca41e9d4092e654df63b517] posix-timers: Remove unused variable git bisect good d2054b2c11682495fca41e9d4092e654df63b517 # good: [6402c7dc2a19c19bd8cdc7d80878b850da418942] Merge branch 'linus' into timers/core Reason: Get upstream fixes before adding conflicting code. git bisect good 6402c7dc2a19c19bd8cdc7d80878b850da418942 # good: [6f7a05d7018de222e40ca003721037a530979974] clockevents: Set dummy handler on CPU_DEAD shutdown git bisect good 6f7a05d7018de222e40ca003721037a530979974 So there it stands. I have no clue and I don't think I'm able to provide any clue for anyone else either. Given that the problem seems to be very consistently reproducible on my laptop, I am a bit puzzled as to how the bisect would fail like that. Bjørn -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
