cannot access `./proc/6535/task/6535/fd/4

[lina <lina.lastname@gmail.com>]

du: cannot access `./proc/6535/task/6535/fd/4': No such file or directory
du: cannot access `./proc/6535/task/6535/fdinfo/4': No such file or directory
du: cannot access `./proc/6535/fd/4': No such file or directory
du: cannot access `./proc/6535/fdinfo/4': No such file or directory
End

Just want to know is it dangerous?

Today, I checked the df -h
it showed used 100%, actually there were still 7M left.

so I remove one old kernel, so now is
/dev/sda5       666M  547M   86M  87% /

I remember once Camaleón suggested to check the

cd /

du -sh | grep [0-9]M | sort -nr

find out the largest ones,

but when I used, I met above problem,

Something wrong?

and it's bad no warning about the / nearly reach full.

Thanks with best regards,