]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
tty: fix up atime/mtime mess, take four
authorJiri Slaby <jslaby@suse.cz>
Fri, 27 Feb 2015 17:40:31 +0000 (18:40 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 7 Mar 2015 02:06:51 +0000 (03:06 +0100)
commitf0bf0bd07943bfde8f5ac39a32664810a379c7d3
treebd55289965c449cadab342b0e57fe549dc9cb3eb
parentdfd37668ea6d5029fb5d8a66ea5e202d0655fad7
tty: fix up atime/mtime mess, take four

This problem was taken care of three times already in
b0de59b5733d18b0d1974a060860a8b5c1b36a2e (TTY: do not update
  atime/mtime on read/write),
37b7f3c76595e23257f61bd80b223de8658617ee (TTY: fix atime/mtime
  regression), and
b0b885657b6c8ef63a46bc9299b2a7715d19acde (tty: fix up atime/mtime
  mess, take three)

But it still misses one point. As John Paul correctly points out, we
do not care about setting date. If somebody ever changes wall
time backwards (by mistake for example), tty timestamps are never
updated until the original wall time passes.

So check the absolute difference of times and if it large than "8
seconds or so", always update the time. That means we will update
immediatelly when changing time. Ergo, CAP_SYS_TIME can foul the
check, but it was always that way.

Thanks John for serving me this so nicely debugged.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: John Paul Perry <john_paul.perry@alcatel-lucent.com>
Cc: <stable@vger.kernel.org> # all, as b0b885657 was backported
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/tty/tty_io.c