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Peter Zijlstra 5111102360 idle: Prevent late-arriving interrupts from disrupting offline 
[ Upstream commit e78a7614f3 ]

Scheduling-clock interrupts can arrive late in the CPU-offline process,
after idle entry and the subsequent call to cpuhp_report_idle_dead().
Once execution passes the call to rcu_report_dead(), RCU is ignoring
the CPU, which results in lockdep complaints when the interrupt handler
uses RCU:

------------------------------------------------------------------------

=============================
WARNING: suspicious RCU usage
5.2.0-rc1+ #681 Not tainted
-----------------------------
kernel/sched/fair.c:9542 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

RCU used illegally from offline CPU!
rcu_scheduler_active = 2, debug_locks = 1
no locks held by swapper/5/0.

stack backtrace:
CPU: 5 PID: 0 Comm: swapper/5 Not tainted 5.2.0-rc1+ #681
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS Bochs 01/01/2011
Call Trace:
 <IRQ>
 dump_stack+0x5e/0x8b
 trigger_load_balance+0xa8/0x390
 ? tick_sched_do_timer+0x60/0x60
 update_process_times+0x3b/0x50
 tick_sched_handle+0x2f/0x40
 tick_sched_timer+0x32/0x70
 __hrtimer_run_queues+0xd3/0x3b0
 hrtimer_interrupt+0x11d/0x270
 ? sched_clock_local+0xc/0x74
 smp_apic_timer_interrupt+0x79/0x200
 apic_timer_interrupt+0xf/0x20
 </IRQ>
RIP: 0010:delay_tsc+0x22/0x50
Code: ff 0f 1f 80 00 00 00 00 65 44 8b 05 18 a7 11 48 0f ae e8 0f 31 48 89 d6 48 c1 e6 20 48 09 c6 eb 0e f3 90 65 8b 05 fe a6 11 48 <41> 39 c0 75 18 0f ae e8 0f 31 48 c1 e2 20 48 09 c2 48 89 d0 48 29
RSP: 0000:ffff8f92c0157ed0 EFLAGS: 00000212 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000005 RBX: ffff8c861f356400 RCX: ffff8f92c0157e64
RDX: 000000321214c8cc RSI: 00000032120daa7f RDI: 0000000000260f15
RBP: 0000000000000005 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: ffff8c861ee18000 R15: ffff8c861ee18000
 cpuhp_report_idle_dead+0x31/0x60
 do_idle+0x1d5/0x200
 ? _raw_spin_unlock_irqrestore+0x2d/0x40
 cpu_startup_entry+0x14/0x20
 start_secondary+0x151/0x170
 secondary_startup_64+0xa4/0xb0

------------------------------------------------------------------------

This happens rarely, but can be forced by happen more often by
placing delays in cpuhp_report_idle_dead() following the call to
rcu_report_dead().  With this in place, the following rcutorture
scenario reproduces the problem within a few minutes:

tools/testing/selftests/rcutorture/bin/kvm.sh --cpus 8 --duration 5 --kconfig "CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y" --configs "TREE04"

This commit uses the crude but effective expedient of moving the disabling
of interrupts within the idle loop to precede the cpu_is_offline()
check.  It also invokes tick_nohz_idle_stop_tick() instead of
tick_nohz_idle_stop_tick_protected() to shut off the scheduling-clock
interrupt.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
[ paulmck: Revert tick_nohz_idle_stop_tick_protected() removal, new callers. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-10-05 13:09:40 +02:00
arch arm64/prefetch: fix a -Wtype-limits warning 2019-10-05 13:09:38 +02:00
block blk-mq: move cancel of requeue_work to the front of blk_exit_queue 2019-10-01 08:26:10 +02:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: chacha20poly1305 - fix atomic sleep when using async algorithm 2019-07-26 09:14:19 +02:00
Documentation ovl: fix regression caused by overlapping layers detection 2019-09-21 07:17:14 +02:00
drivers firmware: arm_scmi: Check if platform has released shmem before using 2019-10-05 13:09:39 +02:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs f2fs: use generic EFSBADCRC/EFSCORRUPTED 2019-10-01 08:26:13 +02:00
include IB/core: Add an unbound WQ type to the new CQ API 2019-10-01 08:26:00 +02:00
init initramfs: don't free a non-existent initrd 2019-10-01 08:26:09 +02:00
ipc ipc/mqueue.c: only perform resource calculation if user valid 2019-08-06 19:06:52 +02:00
kernel idle: Prevent late-arriving interrupts from disrupting offline 2019-10-05 13:09:40 +02:00
lib lib: logic_pio: Add logic_pio_unregister_range() 2019-09-06 10:22:19 +02:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm mm/migrate.c: initialize pud_entry in migrate_vma() 2019-09-16 08:22:22 +02:00
net nfc: enforce CAP_NET_RAW for raw sockets 2019-10-05 13:09:32 +02:00
samples samples, bpf: suppress compiler warning 2019-07-14 08:11:04 +02:00
scripts scripts/decode_stacktrace: match basepath using shell prefix operator, not regex 2019-09-16 08:21:44 +02:00
security keys: Fix missing null pointer check in request_key_auth_describe() 2019-09-21 07:17:13 +02:00
sound ASoC: rsnd: don't call clk_get_rate() under atomic context 2019-10-05 13:09:38 +02:00
tools bpf: libbpf: retry loading program on EAGAIN 2019-10-01 08:26:08 +02:00
usr initramfs: move gen_initramfs_list.sh from scripts/ to usr/ 2018-08-22 23:21:44 +09:00
virt KVM: coalesced_mmio: add bounds checking 2019-09-21 07:16:44 +02:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS platform/x86: Add Intel AtomISP2 dummy / power-management driver 2019-04-20 09:16:02 +02:00
Makefile Linux 4.19.76 2019-10-01 08:26:13 +02:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

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.