d8c7f015d1
commit c749bb2d554825e007cbc43b791f54e124dadfce upstream. The current max_pfn equals to zero. In this case, I found it caused users cannot get some page information through /proc such as kpagecount in v5.6 kernel because of new sanity checks. The following message is displayed by stress-ng test suite with the command "stress-ng --verbose --physpage 1 -t 1" on HiFive unleashed board. # stress-ng --verbose --physpage 1 -t 1 stress-ng: debug: [109] 4 processors online, 4 processors configured stress-ng: info: [109] dispatching hogs: 1 physpage stress-ng: debug: [109] cache allocate: reducing cache level from L3 (too high) to L0 stress-ng: debug: [109] get_cpu_cache: invalid cache_level: 0 stress-ng: info: [109] cache allocate: using built-in defaults as no suitable cache found stress-ng: debug: [109] cache allocate: default cache size: 2048K stress-ng: debug: [109] starting stressors stress-ng: debug: [109] 1 stressor spawned stress-ng: debug: [110] stress-ng-physpage: started [110] (instance 0) stress-ng: error: [110] stress-ng-physpage: cannot read page count for address 0x3fd34de000 in /proc/kpagecount, errno=0 (Success) stress-ng: error: [110] stress-ng-physpage: cannot read page count for address 0x3fd32db078 in /proc/kpagecount, errno=0 (Success) ... stress-ng: error: [110] stress-ng-physpage: cannot read page count for address 0x3fd32db078 in /proc/kpagecount, errno=0 (Success) stress-ng: debug: [110] stress-ng-physpage: exited [110] (instance 0) stress-ng: debug: [109] process [110] terminated stress-ng: info: [109] successful run completed in 1.00s # After applying this patch, the kernel can pass the test. # stress-ng --verbose --physpage 1 -t 1 stress-ng: debug: [104] 4 processors online, 4 processors configured stress-ng: info: [104] dispatching hogs: 1 physpage stress-ng: info: [104] cache allocate: using defaults, can't determine cache details from sysfs stress-ng: debug: [104] cache allocate: default cache size: 2048K stress-ng: debug: [104] starting stressors stress-ng: debug: [104] 1 stressor spawned stress-ng: debug: [105] stress-ng-physpage: started [105] (instance 0) stress-ng: debug: [105] stress-ng-physpage: exited [105] (instance 0) stress-ng: debug: [104] process [105] terminated stress-ng: info: [104] successful run completed in 1.01s # Cc: stable@vger.kernel.org Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Reviewed-by: Anup Patel <anup@brainfault.org> Reviewed-by: Yash Shah <yash.shah@sifive.com> Tested-by: Yash Shah <yash.shah@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.