Re: [lkp-robot] ee410f15b1 BUG: kernel hang in boot stage

From: Thierry Escande
Date: Tue Jul 03 2018 - 12:26:54 EST

On 03/07/2018 04:51, 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 ee410f15b1418f2f4428e79980674c979081bcb7
Author: Thierry Escande <thierry.escande@xxxxxxxxxx>
AuthorDate: Thu Jun 14 15:28:15 2018 -0700
Commit: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
CommitDate: Fri Jun 15 07:55:25 2018 +0900

lib/test_printf.c: call wait_for_random_bytes() before plain %p tests

This patch is already reverted in Linus tree. It's also been superseded in linux-next by a new version.

Regards,
Thierry

If the test_printf module is loaded before the crng is initialized, the
plain 'p' tests will fail because the printed address will not be hashed
and the buffer will contain '(ptrval)' instead.
This patch adds a call to wait_for_random_bytes() before plain 'p' tests
to make sure the crng is initialized.
Link: http://lkml.kernel.org/r/20180604113708.11554-1-thierry.escande@xxxxxxxxxx
Signed-off-by: Thierry Escande <thierry.escande@xxxxxxxxxx>
Acked-by: Tobin C. Harding <me@xxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: David Miller <davem@xxxxxxxxxxxxx>
Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>

608dbdfb1f hexagon: drop the unused variable zero_page_mask
ee410f15b1 lib/test_printf.c: call wait_for_random_bytes() before plain %p tests
883c9ab9eb Merge branch 'parisc-4.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux
e3c7283c19 Add linux-next specific files for 20180629
+-------------------------------+------------+------------+------------+---------------+
| | 608dbdfb1f | ee410f15b1 | 883c9ab9eb | next-20180629 |
+-------------------------------+------------+------------+------------+---------------+
| boot_successes | 35 | 0 | 19 | 13 |
| boot_failures | 0 | 15 | | |
| BUG:kernel_hang_in_boot_stage | 0 | 15 | | |
+-------------------------------+------------+------------+------------+---------------+

[ 9.488584] -------------
[ 9.491008] Testing concurrent rhashtable access from 10 threads
[ 21.577749] test 3125 add/delete pairs into rhlist
[ 21.734553] test 3125 random rhlist add/delete operations
[ 21.813107] Started 10 threads, 0 failed, rhltable test returns 0
BUG: kernel hang in boot stage


# HH:MM RESULT GOOD BAD GOOD_BUT_DIRTY DIRTY_NOT_BAD
git bisect start 7daf201d7fe8334e2d2364d4e8ed3394ec9af819 v4.17 --
git bisect good a16afaf7928b74c30a4727cdcaa67bd10675a55d # 08:00 G 11 0 0 0 Merge tag 'for-v4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-power-supply
git bisect good dc594c39f7a9dcdfd5dbb1a446ac6d06182e2472 # 08:13 G 11 0 0 0 Merge tag 'ceph-for-4.18-rc1' of git://github.com/ceph/ceph-client
git bisect bad 81e97f01371f4e1701feeafe484665112cd9ddc2 # 08:33 B 0 1 15 0 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid
git bisect bad 35773c93817c5f2df264d013978e7551056a063a # 08:55 B 0 1 15 0 Merge branch 'afs-proc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
git bisect bad 8949170cf48e91da7e4e69a59e2842d81d9a5885 # 09:26 B 0 1 15 0 Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
git bisect bad becfc5e97cbab00b25a592aabc36838ec7217d1f # 09:49 B 0 10 24 0 Merge tag 'drm-next-2018-06-15' of git://anongit.freedesktop.org/drm/drm
git bisect good 7a932516f55cdf430c7cce78df2010ff7db6b874 # 10:21 G 11 0 0 0 Merge tag 'vfs-timespec64' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground
git bisect bad b5d903c2d656e9bc54bc76554a477d796a63120d # 10:44 B 0 1 15 0 Merge branch 'akpm' (patches from Andrew)
git bisect good 3fb3894b84c2e0f83cb1e4f4e960243742e6b3a6 # 11:06 G 10 0 0 0 kernel/relay.c: change return type to vm_fault_t
git bisect good 14f28f5776927be30717986f86b765d49eec392c # 11:20 G 10 0 0 0 ipc: use new return type vm_fault_t
git bisect good fe6bdfc8e1e131720abbe77a2eb990c94c9024cb # 11:44 G 10 0 0 0 mm: fix oom_kill event handling
git bisect good 608dbdfb1f0299f4500e56d62b0d84c44dcfa3be # 11:56 G 11 0 0 0 hexagon: drop the unused variable zero_page_mask
git bisect bad ee410f15b1418f2f4428e79980674c979081bcb7 # 12:16 B 0 1 15 0 lib/test_printf.c: call wait_for_random_bytes() before plain %p tests
# first bad commit: [ee410f15b1418f2f4428e79980674c979081bcb7] lib/test_printf.c: call wait_for_random_bytes() before plain %p tests
git bisect good 608dbdfb1f0299f4500e56d62b0d84c44dcfa3be # 12:42 G 30 0 0 0 hexagon: drop the unused variable zero_page_mask
# extra tests with debug options
git bisect bad ee410f15b1418f2f4428e79980674c979081bcb7 # 13:00 B 0 11 25 0 lib/test_printf.c: call wait_for_random_bytes() before plain %p tests
# extra tests on HEAD of linux-devel/devel-catchup-201807010645
git bisect bad 52e245677317cd2f35888d20fbdf8f72f1b62841 # 13:00 B 0 33 50 0 0day head guard for 'devel-catchup-201807010645'
# extra tests on tree/branch linus/master
git bisect good 883c9ab9eb595f8542d01e55d29a346c8d96862e # 13:12 G 11 0 0 0 Merge branch 'parisc-4.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux
# extra tests on tree/branch linux-next/master
git bisect good e3c7283c19cd9ba999794f38007389ac83408a78 # 13:42 G 11 0 0 0 Add linux-next specific files for 20180629

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