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[ Upstream commit6d206b1ea9] The cooling levels array is supposed to prevent the system fans from being configured below a 20% duty cycle as otherwise some of them get stuck at 0 RPM. Due to an off-by-one error, the last element in the array was not initialized, causing it to be set to zero, which in turn lead to fans being configured with a 0% duty cycle in maximum cooling state. Since commit332fdf951d("mlxsw: thermal: Fix out-of-bounds memory accesses") the contents of the array are static. Therefore, instead of fixing the initialization of the array, simply remove it and adjust thermal_cooling_device_ops::set_cur_state() so that the configured duty cycle is never set below 20%. Before: # cat /sys/class/thermal/thermal_zone0/cdev0/type mlxsw_fan # echo 10 > /sys/class/thermal/thermal_zone0/cdev0/cur_state # cat /sys/class/hwmon/hwmon0/name mlxsw # cat /sys/class/hwmon/hwmon0/pwm1 0 After: # cat /sys/class/thermal/thermal_zone0/cdev0/type mlxsw_fan # echo 10 > /sys/class/thermal/thermal_zone0/cdev0/cur_state # cat /sys/class/hwmon/hwmon0/name mlxsw # cat /sys/class/hwmon/hwmon0/pwm1 255 This bug was uncovered when the thermal subsystem repeatedly tried to configure the cooling devices to their maximum state due to another issue [1]. This resulted in the fans being stuck at 0 RPM, which eventually lead to the system undergoing thermal shutdown. [1] https://lore.kernel.org/netdev/ZA3CFNhU4AbtsP4G@shredder/ Fixes:a421ce088a("mlxsw: core: Extend cooling device with cooling levels") Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: Vadim Pasternak <vadimp@nvidia.com> Signed-off-by: Petr Machata <petrm@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
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.