Messages in this thread | | | Date | Sun, 19 Sep 2021 09:52:26 +0200 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH] cpumask: Omit terminating null byte in cpumap_print_{list,bitmask}_to_buf |
| |
On Sun, Sep 19, 2021 at 07:33:52PM +1200, Barry Song wrote: > On Sat, Sep 18, 2021 at 1:27 AM Tobias Klauser <tklauser@distanz.ch> wrote: > > > > On 2021-09-17 at 01:19:04 +0200, Yury Norov <yury.norov@gmail.com> wrote: > > > [CC Greg KH <gregkh@linuxfoundation.org>] > > > > > > On Thu, Sep 16, 2021 at 10:53:39PM +0000, Song Bao Hua (Barry Song) wrote: > > > > > > > > > > > > > -----Original Message----- > > > > > From: Tobias Klauser [mailto:tklauser@distanz.ch] > > > > > Sent: Friday, September 17, 2021 10:27 AM > > > > > To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>; Jonathan Cameron > > > > > <jonathan.cameron@huawei.com>; tiantao (H) <tiantao6@hisilicon.com>; Song Bao > > > > > Hua (Barry Song) <song.bao.hua@hisilicon.com> > > > > > Cc: Andrew Morton <akpm@linux-foundation.org>; Andy Shevchenko > > > > > <andriy.shevchenko@linux.intel.com>; Yury Norov <yury.norov@gmail.com>; Peter > > > > > Zijlstra <peterz@infradead.org>; linux-kernel@vger.kernel.org > > > > > Subject: [PATCH] cpumask: Omit terminating null byte in > > > > > cpumap_print_{list,bitmask}_to_buf > > > > > > > > > > The changes in the patch series [1] introduced a terminating null byte > > > > > when reading from cpulist or cpumap sysfs files, for example: > > > > > > > > > > $ xxd /sys/devices/system/node/node0/cpulist > > > > > 00000000: 302d 310a 00 0-1.. > > > > > > > > > > Before this change, the output looked as follows: > > > > > > > > > > $ xxd /sys/devices/system/node/node0/cpulist > > > > > 00000000: 302d 310a 0-1. > > > > > > > > If we don't use xxd, I don't see any actual harm of this NULL byte > > > > by cat, lscpu, numactl etc. this doesn't break them at all. > > > > > > Barry, Tobias' script that uses xxd is userspace. Linux kernel never breaks > > > userspace. > > > > FWIW, the example using xxd was just to illustrate the issue in a > > concise way for the commit message. This is breaking other userspace > > programs as well. Originally, I discovered this because Kubernetes' > > kubelet was crashing on a bpf-next kernel. See [1] and following > > comments for more information: > > > > [1] https://github.com/cilium/cilium/pull/17394#issuecomment-920902042 > > > > cat, lscpu, numactl tools were tested. the above was not in the test cases. > Anyway, if some apps depend on the last character, this patch makes > sense. we need this one. sorry for missing the test case. > > Acked-by: Barry Song <song.bao.hua@hisilicon.com> > > Greg, can you please help merge this one into 5.15?
Yes, will apply it to my tree soon.
thanks,
greg k-h
| |