Commits · 10540a6998de5d283e3e471f0d0f4e55e2a6872c · Kirill Smelkov / linux

27 May, 2016 16 commits

MAINTAINERS: add kexec_core.c and kexec_file.c · 10540a69

Minfei Huang authored May 27, 2016

In the below commits kexec.c was split to kexec.c, kexec_file.c and
kexec_core.c.

commit a43cac0d ("kexec: split kexec_file syscall code to kexec_file.c")
commit 2965faa5 ("kexec: split kexec_load syscall from kexec core code")

Both kexec_file.c and kexec_core.c still belong to the kexec component.
In order to get correct mail lists by using the script get_maintainer.pl,
add these files to MAINTAINERS.

Link: http://lkml.kernel.org/r/1464189735-59113-1-git-send-email-mnghuan@gmail.comSigned-off-by: Minfei Huang <mnghuan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

10540a69

mm: oom: do not reap task if there are live threads in threadgroup · edd9f723

Vladimir Davydov authored May 27, 2016

If the current process is exiting, we don't invoke oom killer, instead
we give it access to memory reserves and try to reap its mm in case
nobody is going to use it. There's a mistake in the code performing
this check - we just ignore any process of the same thread group no
matter if it is exiting or not - see try_oom_reaper. Fix it.

Link: http://lkml.kernel.org/r/1464087628-7318-1-git-send-email-vdavydov@virtuozzo.com
Fixes: 3ef22dff ("oom, oom_reaper: try to reap tasks which skip regular OOM killer path")Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

edd9f723

direct-io: fix direct write stale data exposure from concurrent buffered read · 9ecd10b7

Eryu Guan authored May 27, 2016

Currently direct writes inside i_size on a DIO_SKIP_HOLES filesystem are
not allowed to allocate blocks(get_more_blocks() sets 'create' to 0
before calling get_block() callback), if it's a sparse file, direct
writes fall back to buffered writes to avoid stale data exposure from
concurrent buffered read.  But there're two cases that can result in
stale data exposure are not correctly detected.

1. The detection for "writing inside i_size" is not sufficient,
   writes can be treated as "extending writes" wrongly.  For example,
   direct write 1FSB (file system block) to a 1FSB sparse file on
   ext2/3/4, starting from offset 0, in this case it's writing inside
   i_size, but 'create' is non-zero, because 'block_in_file' and
   '(i_size_read(inode) >> blkbits' are both zero.

2. Direct writes starting from or beyong i_size (not inside i_size)
   also could trigger block allocation and expose stale data.  For
   example, consider a sparse file with i_size of 2k, and a write to
   offset 2k or 3k into the file, with a filesystem block size of 4k.
   (Thanks to Jeff Moyer for pointing this case out in his review.)

The first problem can be demostrated by running ltp-aiodio test ADSP045
many times.  When testing on extN filesystems, I see test failures
occasionally, buffered read could read non-zero (stale) data.

ADSP045: dio_sparse -a 4k -w 4k -s 2k -n 1

dio_sparse    0  TINFO  :  Dirtying free blocks
dio_sparse    0  TINFO  :  Starting I/O tests
non zero buffer at buf[0] => 0xffffffaa,ffffffaa,ffffffaa,ffffffaa
non-zero read at offset 0
dio_sparse    0  TINFO  :  Killing childrens(s)
dio_sparse    1  TFAIL  :  dio_sparse.c:191: 1 children(s) exited abnormally

The second problem can also be reproduced easily by a hacked dio_sparse
program, which accepts an option to specify the write offset.

What we should really do is to disable block allocation for writes that
could result in filling holes inside i_size.

Link: http://lkml.kernel.org/r/1463156728-13357-1-git-send-email-guaneryu@gmail.comReviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>