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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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32bdfac546
We shouldn't hold dpm_list_mtx while executing
[disable|enable]_nonboot_cpus(), because theoretically this may lead
to a deadlock as shown by the following example (provided by Johannes
Berg):
CPU 3 CPU 2 CPU 1
suspend/hibernate
something:
rtnl_lock() device_pm_lock()
-> mutex_lock(&dpm_list_mtx)
mutex_lock(&dpm_list_mtx)
linkwatch_work
-> rtnl_lock()
disable_nonboot_cpus()
-> flush CPU 3 workqueue
Fortunately, device drivers are supposed to stop any activities that
might lead to the registration of new device objects way before
disable_nonboot_cpus() is called, so it shouldn't be necessary to
hold dpm_list_mtx over the entire late part of device suspend and
early part of device resume.
Thus, during the late suspend and the early resume of devices acquire
dpm_list_mtx only when dpm_list is going to be traversed and release
it right after that.
This patch is reported to fix the regressions tracked as
http://bugzilla.kernel.org/show_bug.cgi?id=13245.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Miles Lane <miles.lane@gmail.com>
Tested-by: Ming Lei <tom.leiming@gmail.com>
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|---|---|---|
| .. | ||
| power | ||
| attribute_container.c | ||
| base.h | ||
| bus.c | ||
| class.c | ||
| core.c | ||
| cpu.c | ||
| dd.c | ||
| devres.c | ||
| dma-mapping.c | ||
| driver.c | ||
| firmware_class.c | ||
| firmware.c | ||
| hypervisor.c | ||
| init.c | ||
| iommu.c | ||
| isa.c | ||
| Kconfig | ||
| Makefile | ||
| map.c | ||
| memory.c | ||
| module.c | ||
| node.c | ||
| platform.c | ||
| sys.c | ||
| topology.c | ||
| transport_class.c | ||