man-pages-4.11 is released

From: Michael Kerrisk (man-pages)
Date: Wed May 03 2017 - 16:39:01 EST

The Linux man-pages maintainer proudly announces:

man-pages-4.11 - man pages for Linux

This release resulted from patches, bug reports, reviews, and comments
from over 30 contributors. The release sees a large number of changes:
over 300 commits changing more than 100 pages. The changes include the
addition of 5 pages, significant rewriting of 1 page, and enhancements
to many other pages.

Tarball download:
Git repository:
Online changelog:

A short summary of the release is blogged at:

The current version of the pages is browsable at:

A selection of changes in this release that may be of interest
to readers on LKML is shown below.



==================== Changes in man-pages-4.11 ====================

Released: 2017-05-03, Baden, Switzerland

New and rewritten pages

Michael Kerrisk, Mike Rapoport
New page describing ioctl(2) operations for userfaultfd

David Howells, Michael Kerrisk [Andreas Dilger]
New page describing statx(2) system call added in Linux 4.11

Mike Rapoport, Michael Kerrisk [Andrea Arcangeli]
New page describing userfaultfd(2) system call.

Michael Kerrisk
New page describing pthread_atfork(3)

Michael Kerrisk
Rewrite to try to bring the content close to current reality
There's still gaps to fill in, but the existing page
was in any case hugely out of date.

Michael Kerrisk
New page with information about inodes
David Howells provided a statx(2) page that duplicated much of
the information from stat(2). Avoid such duplication
by moving the common information in stat(2) and statx(2)
to a new page.

Newly documented interfaces in existing pages

Michael Kerrisk
Document the NS_GET_NSTYPE operation added in Linux 4.11
Michael Kerrisk
Document the NS_GET_OWNER_UID operation added in Linux 4.11

Michael Kerrisk
Document /proc/sys/kernel/sched_child_runs_first

Michael Kerrisk
Document the /proc/sys/user/* files added in Linux 4.9

Francois Saint-Jacques, Michael Kerrisk

Changes to individual pages

Michael Kerrisk
Exceeding one of the limits in /proc/sys/user/* can cause ENOSPC
Michael Kerrisk
CLONE_NEWPID yields ENOSPC if nesting limit of PID namespaces is reached
Michael Kerrisk
Exceeding the maximum nested user namespace limit now gives ENOSPC
Formerly, if the limit of 32 nested user namespaces was exceeded,
the error EUSERS resulted. Starting with Linux 4.9, the error

Michael Kerrisk
Defer to poll(2) for an explanation of EPOLLIN
Michael Kerrisk [Nicolas Biscos]
EPOLLERR is also set on write end of a pipe when the read end is closed
Michael Kerrisk [Nicolas Biscos]
Give the reader a clue that the 'events' field can be zero
'events' specified as zero still allows EPOLLHUP and
EPOLLERR to be reported.

Michael Kerrisk
On exit, child processes may be inherited by a "subreaper"
It is no longer necessarily true that orphaned processes
are inherited by PID 1.
Michael Kerrisk
Only the least significant byte of exit status is passed to the parent

Michael Kerrisk
Mention memfd_create() in the discussion of file seals
Give the reader a clue about what kinds of objects can
be employed with file seals.
Michael Kerrisk
File seals are not generally applicable to tmpfs(5) files
As far as I can see, file seals can be applied only to
memfd_create(2) file descriptors. This was checked by experiment
and by reading mm/shmem.c::shmem_get_inode((), where one finds
the following line that applies to all new shmem files:

info->seals = F_SEAL_SEAL;

Only in the code of the memfd_create() system call is this
setting reversed (in mm/shmem.c::memfd_create):

if (flags & MFD_ALLOW_SEALING)
info->seals &= ~F_SEAL_SEAL;
Michael Kerrisk
Expand discussion of POLLPRI
Michael Kerrisk [Nicolas Biscos]
POLLERR is also set on write end of a pipe when the read end is closed

Mike Frysinger
PR_SET_MM: Document new PR_SET_MM_MAP{,_SIZE} helpers
Michael Kerrisk
Explain rationale for use of subreaper processes
Michael Kerrisk
Note semantics of child_subreaper setting on fork() and exec()
Michael Kerrisk
Improve description of PR_SET_CHILD_SUBREAPER

Michael Kerrisk [Matthew Wilcox, Carlos O'Donell]
Linux select() is buggy wrt POSIX in its check for EBADF errors
Michael Kerrisk
Show correspondence between select() and poll() readiness notifications
Michael Kerrisk
Give a hint that sets must be reinitialized if using select() in a loop

Michael Kerrisk
SIGKILL and SIGSTOP are silently ignored in 'mask'

Michael Kerrisk
sigwaitinfo() can't be used to accept synchronous signals

Michael Kerrisk
Orphaned children may be adopted by a "subreaper", rather by than PD 1

Michael Kerrisk
Tell a more nuanced story about what grantpt() does or does not do

Michael Kerrisk
Clarify that POSIX shared memory uses tmpfs(5)

Michael Kerrisk
The maximum nesting depth for PID namespaces is 32
Michael Kerrisk
Expand description of /etc/

Michael Kerrisk
Linux man-pages maintainer;
Linux/UNIX System Programming Training: