mainline inclusion
from mainline-v5.0-rc4-142-g1fde6f21
commit 1fde6f21
category: bugfix
bugzilla: 7439
CVE: NA

-------------------------------------------------

/proc entries under /proc/net/* can't be cached into dcache because
setns(2) can change current net namespace.

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: avoid vim miscolorization]
[adobriyan@gmail.com: write test, add dummy ->d_revalidate hook: necessary if /proc/net/* is pinned at setns time]
  Link: http://lkml.kernel.org/r/20190108192350.GA12034@avx2
Link: http://lkml.kernel.org/r/20190107162336.GA9239@avx2
Fixes: 1da4d377 ("proc: revalidate misc dentries")
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Reported-by: NMateusz Stępień <mateusz.stepien@netrounds.com>
Reported-by: NAhmad Fatoum <a.fatoum@pengutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NMao Wenan <maowenan@huawei.com>
Reviewed-by: NWei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>