Userfaultfd feature UFFD_FEATURE_SIGBUS was merged recently and
should be available in the Linux 4.14 release. This patch is for
the man page changes documenting this API.
Documents the following commit:
commit 2d6d6f5a09a96cc1fec7ed992b825e05f64cb50e
Author: Prakash Sangappa <prakash.sangappa@oracle.com>
Date: Wed Sep 6 16:23:39 2017 -0700
mm: userfaultfd: add feature to request for a signal delivery
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Prakash Sangappa <prakash.sangappa@oracle.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
When referring to the architecture, consistently use "x86-64",
not "x86_64". Hitherto, there was a mixture of usages, with
"x86-64" predominant.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Combine two redundant paragraphs (one of which I recently
added) describing child_stack==NULL for the raw system call.
Also, make sure this text is in a more obvious place than
its previous location.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
The statement "conferring permitted or effective capabilities"
to the process is somewhat redundant. Binaries with capabilities
confer capabilities only to those process capability sets, so it's
simpler to just say"confers capabilities to the process".
Reported-by: Yubin Ruan <ablacktshirt@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
At the current man page for shmat(2)[1], there is no mentioning
whether the returned memory address of shmat(2) will be page size
aligned or not. As that is quite important to many applications(e.g.,
those that use locks heavily and would like to avoid some locks by
some atomic guarantees provided by the CPU), it would be great to
specify that for Linux.
I walked down the current implementation of shmat(2) in the latest
kernel src and found that shmat(2) does return a page size aligned
memory address:
SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
-> do_shmat(...)
-> do_mmap_pgoff(...)
-> do_mmap(...)
-> get_unmapped_area(...)
-> get_area(...) -> offset_in_page(addr)
there is a `offset_in_page(addr)' assertion at the end and if that is
true a -EINVAL would be returned, by which we can be sure that
shmat(2) will return a page size aligned memory address on success[2].
[1]: http://man7.org/linux/man-pages/man2/shmat.2.html
[2]: there is also a `offset_in_page(2)' in get_unmapped_area(...),
but that doesn't lead to -EINVAL...I am not sure whether the logic of
that code is right.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Expand and rework the text a little, in particular adding
a reference to sigreturn(2) as a source of further
information about the ucontext argument.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Remove reference to non-standard "tlpi_hdr.h" and replace calls to
functions that were declared in this header.
Signed-off-by: Jakub Wilk <jwilk@jwilk.net>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Prakash Sangappa