Re: 67bb8e999e ("x86/mm: Disable various instrumentations of .."): BUG: -1 unexpected failures (out of 262) - debugging disabled! |

From: Tom Lendacky
Date: Tue Oct 31 2017 - 11:10:01 EST


On 10/29/2017 8:39 PM, kernel test robot wrote:
Greetings,

0day kernel testing robot got the below dmesg and the first bad commit is

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

commit 67bb8e999e0aeac285d22f0e53c856b9df5282c6
Author: Tom Lendacky <thomas.lendacky@xxxxxxx>
AuthorDate: Tue Oct 10 14:45:04 2017 -0500
Commit: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed Oct 11 17:22:59 2017 +0200


So this patch just allows the boot to continue where it previously was not
able to continue. The config has KCOV and FUNCTION_TRACER/STACK_TRACER
enabled which causes issues with the early boot code in mm/mem_encrypt.c.

If there is an issue that is being hidden by these config options, then
performing a bisect without those settings may help identify the real
issue.

Thanks,
Tom

x86/mm: Disable various instrumentations of mm/mem_encrypt.c and mm/tlb.c
Some routines in mem_encrypt.c are called very early in the boot process,
e.g. sme_enable(). When CONFIG_KCOV=y is defined the resulting code added
to sme_enable() (and others) for KCOV instrumentation results in a kernel
crash. Disable the KCOV instrumentation for mem_encrypt.c by adding
KCOV_INSTRUMENT_mem_encrypt.o := n to arch/x86/mm/Makefile.
In order to avoid other possible early boot issues, model mem_encrypt.c
after head64.c in regards to tools. In addition to disabling KCOV as
stated above and a previous patch that disables branch profiling, also
remove the "-pg" CFLAG if CONFIG_FUNCTION_TRACER is enabled and set
KASAN_SANITIZE to "n", each of which are done on a file basis.
Reported-by: kernel test robot <lkp@xxxxxx>
Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20171010194504.18887.38053.stgit@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>

ab7ff471aa x86/hyperv: Fix hypercalls with extended CPU ranges for TLB flushing
67bb8e999e x86/mm: Disable various instrumentations of mm/mem_encrypt.c and mm/tlb.c
19e12196da Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
36ef71cae3 Add linux-next specific files for 20171018
+--------------------------------------------------------------------------------------+------------+------------+------------+---------------+
| | ab7ff471aa | 67bb8e999e | 19e12196da | next-20171018 |
+--------------------------------------------------------------------------------------+------------+------------+------------+---------------+
| boot_successes | 3 | 0 | 2 | 10 |
| boot_failures | 761 | 42 | 201 | 77 |
| BUG:kernel_reboot-without-warning_in_early-boot_stage,last_printk:Booting_the_kernel | 760 | | | |
| BUG:kernel_reboot-without-warning_in_test_stage | 1 | | | |
| BUG:-#unexpected_failures(out_of#)-debugging_disabled!| | 0 | 42 | | |
| BUG:kernel_hang_in_test_stage | 0 | 42 | 200 | 77 |
| WARNING:at_kernel/events/core.c:#perf_swevent_add | 0 | 1 | 10 | 1 |
+--------------------------------------------------------------------------------------+------------+------------+------------+---------------+

[ 0.003333] context:failed| ok | ok |
[ 0.003333] try:failed| ok |failed|
[ 0.003333] block:failed| ok |failed|
[ 0.003333] spinlock:failed| ok |failed|
[ 0.003333] -----------------------------------------------------------------
[ 0.003333] BUG: -1 unexpected failures (out of 262) - debugging disabled! |
[ 0.003333] -----------------------------------------------------------------
[ 0.003333] ODEBUG: selftest passed
[ 0.003333] clocksource: hpet: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604467 ns
[ 0.003333] hpet clockevent registered
[ 0.003345] tsc: Detected 2926.328 MHz processor

# HH:MM RESULT GOOD BAD GOOD_BUT_DIRTY DIRTY_NOT_BAD
git bisect start bb176f67090ca54869fc1262c913aa69d2ede070 v4.13 --
git bisect good 820bf5c419e4b85298e5c3001bd1b5be46d60765 # 21:42 G 38 0 6 6 Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
git bisect good 9c0c1adab6024ab7222333ead95c57ca60f39f6f # 21:53 G 38 0 38 40 Merge tag 'drm-fixes-for-v4.14-rc4' of git://people.freedesktop.org/~airlied/linux
git bisect good 9aa0d2dde6ebd14e9d16e28081a24721d5b41cc8 # 22:29 G 38 0 38 38 Merge tag 'drm-fixes-for-v4.14-rc5' of git://people.freedesktop.org/~airlied/linux
git bisect bad 27fdb35fe99011d86bcc54f62fe84712c53f4d05 # 23:11 B 6 3 6 7 doc: Fix various RCU docbook comment-header problems
git bisect bad 33d930e59a98fa10a0db9f56c7fa2f21a4aef9b9 # 23:12 B 0 1 15 1 Linux 4.14-rc5
git bisect good 7b764cedcb1a04e795795dd0fa38570467583be3 # 23:33 G 35 0 33 33 Merge branch 'ras-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
git bisect bad 7a23c5abb930cefcef85df6dc0c8fb3e8961980c # 00:08 B 8 5 8 8 Merge tag 'dmaengine-fix-4.14-rc5' of git://git.infradead.org/users/vkoul/slave-dma
git bisect good a339b351304d5e6b02c7cf8eed895d181e64bce0 # 00:31 G 38 0 10 13 Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
git bisect bad e7a36a6ec9cf1b60273e48ee980b8920f333bd4d # 01:06 B 8 5 8 9 Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
git bisect good d4a2d031dd42f9594107d317e2a9a0c6d73ad46b # 01:30 G 36 0 26 28 x86/unwind: Disable unwinder warnings on 32-bit
git bisect bad 67bb8e999e0aeac285d22f0e53c856b9df5282c6 # 02:05 B 12 1 12 12 x86/mm: Disable various instrumentations of mm/mem_encrypt.c and mm/tlb.c
git bisect good 60d73a7c96601434dfdb56d5b9167ff3b850d8d7 # 03:04 G 195 0 195 195 x86/hyperv: Don't use percpu areas for pcpu_flush/pcpu_flush_ex structures
git bisect good ab7ff471aa5db670197070760f022622793da7e5 # 03:23 G 188 0 188 190 x86/hyperv: Fix hypercalls with extended CPU ranges for TLB flushing
# first bad commit: [67bb8e999e0aeac285d22f0e53c856b9df5282c6] x86/mm: Disable various instrumentations of mm/mem_encrypt.c and mm/tlb.c
git bisect good ab7ff471aa5db670197070760f022622793da7e5 # 03:55 G 561 0 560 750 x86/hyperv: Fix hypercalls with extended CPU ranges for TLB flushing
# extra tests with CONFIG_DEBUG_INFO_REDUCED
git bisect bad 67bb8e999e0aeac285d22f0e53c856b9df5282c6 # 04:40 B 26 19 26 26 x86/mm: Disable various instrumentations of mm/mem_encrypt.c and mm/tlb.c
# extra tests on HEAD of linux-devel/devel-hourly-2017102915
git bisect bad 75c176ba09dee0b693e5f63442b2c96315799cc1 # 04:40 B 0 2 28 10 0day head guard for 'devel-hourly-2017102915'
# extra tests on tree/branch linus/master
git bisect bad 19e12196da601f7b80b5639adbcecf60fae13389 # 06:25 B 10 1 10 16 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
# extra tests with first bad commit reverted
git bisect good 191d249fb18624fb43bf27b4105b081db434d721 # 08:20 G 187 0 187 187 Revert "x86/mm: Disable various instrumentations of mm/mem_encrypt.c and mm/tlb.c"
# extra tests on tree/branch linux-next/master
git bisect bad 36ef71cae353f88fd6e095e2aaa3e5953af1685d # 09:27 B 28 1 28 28 Add linux-next specific files for 20171018

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