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Sergey Senozhatsky ad241cb1cf wq: handle VM suspension in stall detection
[ Upstream commit 940d71c6462e8151c78f28e4919aa8882ff2054e ]

If VCPU is suspended (VM suspend) in wq_watchdog_timer_fn() then
once this VCPU resumes it will see the new jiffies value, while it
may take a while before IRQ detects PVCLOCK_GUEST_STOPPED on this
VCPU and updates all the watchdogs via pvclock_touch_watchdogs().
There is a small chance of misreported WQ stalls in the meantime,
because new jiffies is time_after() old 'ts + thresh'.

wq_watchdog_timer_fn()
{
	for_each_pool(pool, pi) {
		if (time_after(jiffies, ts + thresh)) {
			pr_emerg("BUG: workqueue lockup - pool");
		}
	}
}

Save jiffies at the beginning of this function and use that value
for stall detection. If VM gets suspended then we continue using
"old" jiffies value and old WQ touch timestamps. If IRQ at some
point restarts the stall detection cycle (pvclock_touch_watchdogs())
then old jiffies will always be before new 'ts + thresh'.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-06-16 12:01:36 +02:00
arch x86/kvm: Disable all PV features on crash 2021-06-10 13:39:29 +02:00
block blk-mq: Swap two calls in blk_mq_exit_queue() 2021-05-19 10:13:14 +02:00
certs certs: Fix blacklist flag type confusion 2021-03-04 11:37:59 +01:00
crypto async_xor: increase src_offs when dropping destination page 2021-05-14 09:49:59 +02:00
Documentation Documentation: seccomp: Fix user notification documentation 2021-06-03 09:00:31 +02:00
drivers net: mdiobus: get rid of a BUG_ON() 2021-06-16 12:01:36 +02:00
fs proc: Track /proc/$pid/attr/ opener mm_struct 2021-06-16 12:01:34 +02:00
include net: caif: add proper error handling 2021-06-10 13:39:24 +02:00
init pid: take a reference when initializing cad_pid 2021-06-10 13:39:26 +02:00
ipc ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry 2021-05-26 12:06:54 +02:00
kernel wq: handle VM suspension in stall detection 2021-06-16 12:01:36 +02:00
lib lib/lz4: explicitly support in-place decompression 2021-06-10 13:39:29 +02:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm mm, hugetlb: fix simple resv_huge_pages underflow on UFFDIO_COPY 2021-06-10 13:39:28 +02:00
net netlink: disable IRQs for netlink_lock_table() 2021-06-16 12:01:36 +02:00
samples samples: vfio-mdev: fix error handing in mdpy_fb_probe() 2021-06-10 13:39:15 +02:00
scripts scripts/clang-tools: switch explicitly to Python 3 2021-06-03 09:00:52 +02:00
security KEYS: trusted: Fix memory leak on object td 2021-05-19 10:12:50 +02:00
sound ASoC: sti-sas: add missing MODULE_DEVICE_TABLE 2021-06-16 12:01:35 +02:00
tools wireguard: selftests: make sure rp_filter is disabled on vethc 2021-06-10 13:39:24 +02:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt Revert "irqbypass: do not start cons/prod when failed connect" 2021-06-03 09:00:34 +02:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore kbuild: generate Module.symvers only when vmlinux exists 2021-05-19 10:12:59 +02:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS f2fs: move ioctl interface definitions to separated file 2021-05-19 10:13:00 +02:00
Makefile Linux 5.10.43 2021-06-10 13:39:29 +02:00
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.

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.