Don Zickus b13b3b706a kernel/watchdog: prevent false hardlockup on overloaded system ... [ Upstream commit b94f51183b ] On an overloaded system, it is possible that a change in the watchdog threshold can be delayed long enough to trigger a false positive. This can easily be achieved by having a cpu spinning indefinitely on a task, while another cpu updates watchdog threshold. What happens is while trying to park the watchdog threads, the hrtimers on the other cpus trigger and reprogram themselves with the new slower watchdog threshold. Meanwhile, the nmi watchdog is still programmed with the old faster threshold. Because the one cpu is blocked, it prevents the thread parking on the other cpus from completing, which is needed to shutdown the nmi watchdog and reprogram it correctly. As a result, a false positive from the nmi watchdog is reported. Fix this by setting a park_in_progress flag to block all lockups until the parking is complete. Fix provided by Ulrich Obergfell. [akpm@linux-foundation.org: s/park_in_progress/watchdog_park_in_progress/] Link: http://lkml.kernel.org/r/1481041033-192236-1-git-send-email-dzickus@redhat.com Signed-off-by: Don Zickus <dzickus@redhat.com> Reviewed-by: Aaron Tomlin <atomlin@redhat.com> Cc: Ulrich Obergfell <uobergfe@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2017-06-17 06:41:57 +02:00
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acpi	ACPICA: Linuxize: Restore and fix Intel compiler build	2017-02-26 11:10:52 +01:00
asm-generic	asm-prototypes: Clear any CPP defines before declaring the functions	2017-01-12 11:39:07 +01:00
clocksource
crypto	crypto: ahash - Fix EINPROGRESS notification callback	2017-04-21 09:31:23 +02:00
drm	drm: Don't race connector registration	2017-06-17 06:41:53 +02:00
dt-bindings	ARM: dts: r8a7794: remove Z clock	2017-01-26 08:24:36 +01:00
keys
kvm
linux	kernel/watchdog: prevent false hardlockup on overloaded system	2017-06-17 06:41:57 +02:00
math-emu
media
memory
misc
net	ipv6: fix flow labels when the traffic class is non-0	2017-06-17 06:41:52 +02:00
pcmcia
ras
rdma	RDMA/core: Fix incorrect structure packing for booleans	2017-03-12 06:41:50 +01:00
rxrpc
scsi	scsi: libiscsi: add lock around task lists to fix list corruption regression	2017-03-26 13:05:58 +02:00
soc	ARM: at91: define LPDDR types	2017-03-12 06:41:41 +01:00
sound	ASoC: hdmi-codec: use unsigned type to structure members with bit-field	2017-01-19 20:18:02 +01:00
target	target: Avoid mappedlun symlink creation during lun shutdown	2017-04-21 09:31:21 +02:00
trace	tracing: Add #undef to fix compile error	2017-03-18 19:14:29 +08:00
uapi	net: ipv6: RTF_PCPU should not be settable from userspace	2017-05-03 08:36:36 -07:00
video	fbdev changes for 4.9	2016-10-12 11:01:37 -07:00
xen	xen: Revert commits da72ff5bfc and 72a9b18629	2017-05-14 14:00:22 +02:00
Kbuild