Ladies and gentlemen,
I have curious problem after booting into 5.3.11. I can't read a stream of
zeroes from /dev/null anymore:
$ dd if=/dev/null of=zero.dat bs=2048 count=1
0+0 records in
0+0 records out
0 bytes copied, 0.00036764 s, 0.0 kB/s
and:
$ file /dev/null
/dev/null: character special (1/3)
$ ls -l /dev/null
crw-rw-rw-. 1 root root 1, 3 Nov 14 20:28 /dev/null
No matter if I try this as a root or as a ordinary user. Results are
exactly same. I did not test this with kernels 5.3.7 and 5.3.8, I jumped to
5.3.11 from 5.3.6 and I think 5.3.6 did provide a stream of zero data. No
strace gives anything special, just ordinary read() after dup2() and read
returns zero length for 2048 requested. Now is this a problem of kernel or
is it within dd and how it opens a /dev/null or how it flags read()
function?
Sincerely,
Juha