It used to be true that the command line arguments were
not accessible when the process had been swapped out.
In ancient kernels (circa 2.0.*) the problem was that the
kernel relied on get_phys_addr to access the user space buffer,
which stopped working as soon as the process was swapped out.
Recent kernels use get_user_pages for the same purpose and thus
they should not have that limitation.
"/proc/filesystems" of proc.5:
- clarify filesystems listing: not only FS compiled
into the kernel, also FS kernel modules currently loaded
- add a reference to fs(5)
- add an explanation for FS marked with "nodev"
- s/mount(1)/mount(8)/, also corrected in section "SEE ALSO"
- clarify usage by mount: the current wording may lead to
think /proc/filesystems is always used by mount when no FS
is specified. So, usage of "may" which IMHO is more
appropriate + additionnal explanations
In mount(8) we can see:
If no -t option is given, or if the auto type is
specified, mount will try to guess the desired type.
If mount was compiled with the blkid library, the
guessing is done by this library. Otherwise, mount
guesses itself by probing the superblock; if that
does not turn up anything that looks familiar,
mount will try to read the file /etc/filesystems,
or, if that does not exist, /proc/filesystems.
All of the filesystem types listed there will be
tried, except for those that are labeled "nodev"
(e.g., devpts, proc and nfs). If /etc/filesystems
ends in a line with a single * only, mount will
read /proc/filesystems afterwards.