git checkout 259d51a40fe48cf12038fb8b5a417d1d21d2732e Previous HEAD position was 83b324c... add a refcount check in dput() HEAD is now at 259d51a... video: mmpdisp: add spi port in display controller 2013-02-06-17:16:03 259d51a40fe48cf12038fb8b5a417d1d21d2732e compiling /home/wfg/linux 2013-02-06-17:17:11 detecting boot state 3.8.0-rc6-bisect-00040-g259d51a #79 7.......................................................... 8 SUCCESS bisect: good commit 259d51a40fe48cf12038fb8b5a417d1d21d2732e git bisect start 83b324c5ff5cca85bbeb2ba913d465f108afe472 259d51a40fe48cf12038fb8b5a417d1d21d2732e -- Previous HEAD position was 259d51a... video: mmpdisp: add spi port in display controller HEAD is now at 1e51120... userns: Convert 9p's uid/gid handling Bisecting: 249 revisions left to test after this (roughly 8 steps) [f8df01c1d7833ff2dfb45ccd0017c38c7e803872] memcg: debugging facility to access dangling memcgs git bisect run /c/kernel-tests/bisect-test-boot-failure.sh obj-bisect-i386 running /c/kernel-tests/bisect-test-boot-failure.sh obj-bisect-i386 2013-02-06-17:48:11 f8df01c1d7833ff2dfb45ccd0017c38c7e803872 compiling chown: changing group of `/tmp/bisect-bad-kvm_bisect': Operation not permitted chown: changing group of `/tmp/bisect-build-skip-kvm_bisect': Operation not permitted chown: changing group of `/tmp/bisect-good-kvm_bisect': Operation not permitted chown: changing group of `/tmp/bisect-log-kvm_bisect': Operation not permitted chown: changing group of `/tmp/bisect-skip-kvm_bisect': Operation not permitted /home/wfg/linux 2013-02-06-17:49:22 detecting boot state 3.8.0-rc6-mm1-bisect-00289-gf8df01c #80 ....................................................... 1 10.......................................................... 11 SUCCESS Bisecting: 124 revisions left to test after this (roughly 7 steps) [4538bd3e5b6543108230b034cccd8011ba968496] Documentation/cgroups/blkio-controller.txt: fix typo running /c/kernel-tests/bisect-test-boot-failure.sh obj-bisect-i386 2013-02-06-18:47:57 4538bd3e5b6543108230b034cccd8011ba968496 compiling rm: cannot remove `/tmp/bisect-build-skip-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-skip-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-good-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-bad-kvm_bisect': Operation not permitted /home/wfg/linux 2013-02-06-18:49:08 detecting boot state 3.8.0-rc6-mm1-bisect-00414-g4538bd3 #81 ........................................................ 1 TEST FAILURE Bisecting: 62 revisions left to test after this (roughly 6 steps) [a612644e542ef0212d668d2ecee308e8d57cd2e4] drivers/video/backlight/ld9040.c: use devm_regulator_bulk_get() API running /c/kernel-tests/bisect-test-boot-failure.sh obj-bisect-i386 2013-02-06-19:18:11 a612644e542ef0212d668d2ecee308e8d57cd2e4 compiling rm: cannot remove `/tmp/bisect-build-skip-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-skip-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-good-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-bad-kvm_bisect': Operation not permitted /home/wfg/linux 2013-02-06-19:19:06 detecting boot state 3.8.0-rc6-mm1-bisect-00351-ga612644 #82 TEST FAILURE Bisecting: 30 revisions left to test after this (roughly 5 steps) [c48d189f2ef81158f786a84975ad8db05278f6dd] backlight: s6e63m0: remove unnecessary NULL deference check running /c/kernel-tests/bisect-test-boot-failure.sh obj-bisect-i386 2013-02-06-19:19:37 c48d189f2ef81158f786a84975ad8db05278f6dd compiling rm: cannot remove `/tmp/bisect-build-skip-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-skip-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-good-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-bad-kvm_bisect': Operation not permitted /home/wfg/linux 2013-02-06-19:20:15 detecting boot state 3.8.0-rc6-mm1-bisect-00320-gc48d189 #83 TEST FAILURE Bisecting: 15 revisions left to test after this (roughly 4 steps) [d78fb70a902de2247e9e44fcf7b8e73b96a4a7b3] kernel/smp.c: cleanups running /c/kernel-tests/bisect-test-boot-failure.sh obj-bisect-i386 2013-02-06-19:20:46 d78fb70a902de2247e9e44fcf7b8e73b96a4a7b3 compiling rm: cannot remove `/tmp/bisect-build-skip-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-skip-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-good-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-bad-kvm_bisect': Operation not permitted /home/wfg/linux 2013-02-06-19:21:28 detecting boot state 3.8.0-rc6-mm1-bisect-00304-gd78fb70 #84 3.......................................................... 8 SUCCESS Bisecting: 7 revisions left to test after this (roughly 3 steps) [10fdc3252f827e3ab9652870773349e099e2f4d6] backlight-add-lms501kf03-lcd-driver-fix-fix running /c/kernel-tests/bisect-test-boot-failure.sh obj-bisect-i386 2013-02-06-19:52:01 10fdc3252f827e3ab9652870773349e099e2f4d6 compiling rm: cannot remove `/tmp/bisect-build-skip-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-skip-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-good-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-bad-kvm_bisect': Operation not permitted /home/wfg/linux 2013-02-06-19:53:10 detecting boot state 3.8.0-rc6-mm1-bisect-00312-g10fdc32 #85 ........................................................ 5 TEST FAILURE Bisecting: 3 revisions left to test after this (roughly 2 steps) [6c35e4b5601ad676682232beed50d558bef11331] get_maintainer.pl: find maintainers for removed files running /c/kernel-tests/bisect-test-boot-failure.sh obj-bisect-i386 2013-02-06-20:22:13 6c35e4b5601ad676682232beed50d558bef11331 compiling rm: cannot remove `/tmp/bisect-build-skip-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-skip-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-good-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-bad-kvm_bisect': Operation not permitted /home/wfg/linux 2013-02-06-20:23:01 detecting boot state 3.8.0-rc6-mm1-bisect-00308-g6c35e4b #86 TEST FAILURE Bisecting: 1 revision left to test after this (roughly 1 step) [c6a6e37da505d1cd79d8dfa7ac68ef953d2bf6dd] printk: Avoid softlockups in console_unlock() running /c/kernel-tests/bisect-test-boot-failure.sh obj-bisect-i386 2013-02-06-20:23:32 c6a6e37da505d1cd79d8dfa7ac68ef953d2bf6dd compiling rm: cannot remove `/tmp/bisect-build-skip-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-skip-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-good-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-bad-kvm_bisect': Operation not permitted /home/wfg/linux 2013-02-06-20:24:12 detecting boot state 3.8.0-rc6-mm1-bisect-00306-gc6a6e37 #87 TEST FAILURE Bisecting: 0 revisions left to test after this (roughly 0 steps) [8e798f4e517d1f32fe9794e75802d4e864a916b7] lib/vsprintf.c: add %pa format specifier for phys_addr_t types running /c/kernel-tests/bisect-test-boot-failure.sh obj-bisect-i386 2013-02-06-20:24:43 8e798f4e517d1f32fe9794e75802d4e864a916b7 compiling rm: cannot remove `/tmp/bisect-build-skip-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-skip-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-good-kvm_bisect': Operation not permitted rm: cannot remove `/tmp/bisect-bad-kvm_bisect': Operation not permitted /home/wfg/linux 2013-02-06-20:25:27 detecting boot state 3.8.0-rc6-mm1-bisect-00305-g8e798f4 #88 5.......................................................... 7 SUCCESS /c/kernel-tests/common.sh: line 2784: printf: `p': invalid format character c6a6e37da505d1cd79d8dfa7ac68ef953d2bf6dd is the first bad commit commit c6a6e37da505d1cd79d8dfa7ac68ef953d2bf6dd Author: Jan Kara Date: Wed Feb 6 02:04:42 2013 +0000 printk: Avoid softlockups in console_unlock() A CPU can be caught in console_unlock() for a long time (tens of seconds are reported by our customers) when other CPUs are using printk heavily and serial console makes printing slow. Despite serial console drivers are calling touch_nmi_watchdog() this triggers softlockup warnings because interrupts are disabled for the whole time console_unlock() runs (e.g. vprintk() calls console_unlock() with interrupts disabled). Thus IPIs cannot be processed and other CPUs get stuck spinning in calls like smp_call_function_many(). Also RCU eventually starts reporting lockups. In my artificial testing I also managed to trigger a situation when disk disappeared from the system apparently because commands to / from it could not be delivered for long enough. This is why just silencing watchdogs isn't a reliable solution to the problem and we simply have to avoid spending too long in console_unlock(). We fix the issue by limiting the time we spend in console_unlock() to watchdog_thresh() / 4 (unless we are in an early boot stage or oops is happening). The rest of the buffer will be printed either by further callers to printk() or by a queued work. Signed-off-by: Jan Kara Cc: Frederic Weisbecker Cc: Steven Rostedt Cc: Ingo Molnar Signed-off-by: Andrew Morton :040000 040000 5690af7205389aa554d8ff37c392d3714223d706 7cbc219bc23af72e87baa4dcc766a62d79f6e1ee M include :040000 040000 cb55853596127ceeda90b184626e80bb4674a245 fa0ec34e2de821679f51aa97d3cb5a43bb285b28 M kernel bisect run success 2013-02-06-20:56:00 8e798f4e517d1f32fe9794e75802d4e864a916b7 compiling /home/wfg/linux 2013-02-06-20:56:21 detecting boot state 3.8.0-rc6-mm1-bisect-00305-g8e798f4 #88 .......................................................... 6 10.......................................................... 15 20.......................................................... 24 SUCCESS ========= linux-next ========= 2013-02-06-22:26:38 1587f71ebbf5aedf754062baa11fcc9e9b49ecf0 compiling /home/wfg/linux 2013-02-06-22:28:11 detecting boot state 3.8.0-rc4-bisect-next-20130125 #89 ....................................................... 5 10.......................................................... 12 20........................................................... 30........................................................... 37 SUCCESS