840d719604
Daniel Casini got this warn while running a DL task here at RetisLab:
[ 461.137582] ------------[ cut here ]------------
[ 461.137583] rq->clock_update_flags < RQCF_ACT_SKIP
[ 461.137599] WARNING: CPU: 4 PID: 2354 at kernel/sched/sched.h:967 assert_clock_updated.isra.32.part.33+0x17/0x20
[a ton of modules]
[ 461.137646] CPU: 4 PID: 2354 Comm: label_image Not tainted 4.18.0-rc4+ #3
[ 461.137647] Hardware name: ASUS All Series/Z87-K, BIOS 0801 09/02/2013
[ 461.137649] RIP: 0010:assert_clock_updated.isra.32.part.33+0x17/0x20
[ 461.137649] Code: ff 48 89 83 08 09 00 00 eb c6 66 0f 1f 84 00 00 00 00 00 55 48 c7 c7 98 7a 6c a5 c6 05 bc 0d 54 01 01 48 89 e5 e8 a9 84 fb ff <0f> 0b 5d c3 0f 1f 44 00 00 0f 1f 44 00 00 83 7e 60 01 74 0a 48 3b
[ 461.137673] RSP: 0018:ffffa77e08cafc68 EFLAGS: 00010082
[ 461.137674] RAX: 0000000000000000 RBX: ffff8b3fc1702d80 RCX: 0000000000000006
[ 461.137674] RDX: 0000000000000007 RSI: 0000000000000096 RDI: ffff8b3fded164b0
[ 461.137675] RBP: ffffa77e08cafc68 R08: 0000000000000026 R09: 0000000000000339
[ 461.137676] R10: ffff8b3fd060d410 R11: 0000000000000026 R12: ffffffffa4e14e20
[ 461.137677] R13: ffff8b3fdec22940 R14: ffff8b3fc1702da0 R15: ffff8b3fdec22940
[ 461.137678] FS: 00007efe43ee5700(0000) GS:ffff8b3fded00000(0000) knlGS:0000000000000000
[ 461.137679] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 461.137680] CR2: 00007efe30000010 CR3: 0000000301744003 CR4: 00000000001606e0
[ 461.137680] Call Trace:
[ 461.137684] push_dl_task.part.46+0x3bc/0x460
[ 461.137686] task_woken_dl+0x60/0x80
[ 461.137689] ttwu_do_wakeup+0x4f/0x150
[ 461.137690] ttwu_do_activate+0x77/0x80
[ 461.137692] try_to_wake_up+0x1d6/0x4c0
[ 461.137693] wake_up_q+0x32/0x70
[ 461.137696] do_futex+0x7e7/0xb50
[ 461.137698] __x64_sys_futex+0x8b/0x180
[ 461.137701] do_syscall_64+0x5a/0x110
[ 461.137703] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 461.137705] RIP: 0033:0x7efe4918ca26
[ 461.137705] Code: 00 00 00 74 17 49 8b 48 20 44 8b 59 10 41 83 e3 30 41 83 fb 20 74 1e be 85 00 00 00 41 ba 01 00 00 00 41 b9 01 00 00 04 0f 05 <48> 3d 01 f0 ff ff 73 1f 31 c0 c3 be 8c 00 00 00 49 89 c8 4d 31 d2
[ 461.137738] RSP: 002b:00007efe43ee4928 EFLAGS: 00000283 ORIG_RAX: 00000000000000ca
[ 461.137739] RAX: ffffffffffffffda RBX: 0000000005094df0 RCX: 00007efe4918ca26
[ 461.137740] RDX: 0000000000000001 RSI: 0000000000000085 RDI: 0000000005094e24
[ 461.137741] RBP: 00007efe43ee49c0 R08: 0000000005094e20 R09: 0000000004000001
[ 461.137741] R10: 0000000000000001 R11: 0000000000000283 R12: 0000000000000000
[ 461.137742] R13: 0000000005094df8 R14: 0000000000000001 R15: 0000000000448a10
[ 461.137743] ---[ end trace 187df4cad2bf7649 ]---
This warning happened in the push_dl_task(), because
__add_running_bw()->cpufreq_update_util() is getting the rq_clock of
the later_rq before its update, which takes place at activate_task().
The fix then is to update the rq_clock before calling add_running_bw().
To avoid double rq_clock_update() call, we set ENQUEUE_NOCLOCK flag to
activate_task().
Reported-by: Daniel Casini <daniel.casini@santannapisa.it>
Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@santannapisa.it>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tommaso Cucinotta <tommaso.cucinotta@santannapisa.it>
Fixes:
|
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.