<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/fs, branch v3.2.79</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>hpfs: don't truncate the file when delete fails</title>
<updated>2016-04-01T00:54:35+00:00</updated>
<author>
<name>Mikulas Patocka</name>
<email>mikulas@twibright.com</email>
</author>
<published>2016-02-25T17:17:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6a12cf844fe7fdf154bee04b274a4e14c157c3c7'/>
<id>6a12cf844fe7fdf154bee04b274a4e14c157c3c7</id>
<content type='text'>
commit b6853f78e763d42c7a158d8de3549c9827c604ab upstream.

The delete opration can allocate additional space on the HPFS filesystem
due to btree split. The HPFS driver checks in advance if there is
available space, so that it won't corrupt the btree if we run out of space
during splitting.

If there is not enough available space, the HPFS driver attempted to
truncate the file, but this results in a deadlock since the commit
7dd29d8d865efdb00c0542a5d2c87af8c52ea6c7 ("HPFS: Introduce a global mutex
and lock it on every callback from VFS").

This patch removes the code that tries to truncate the file and -ENOSPC is
returned instead. If the user hits -ENOSPC on delete, he should try to
delete other files (that are stored in a leaf btree node), so that the
delete operation will make some space for deleting the file stored in
non-leaf btree node.

Reported-by: Al Viro &lt;viro@ZenIV.linux.org.uk&gt;
Signed-off-by: Mikulas Patocka &lt;mikulas@artax.karlin.mff.cuni.cz&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
[bwh: Backported to 3.2: deleted code is slightly different]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit b6853f78e763d42c7a158d8de3549c9827c604ab upstream.

The delete opration can allocate additional space on the HPFS filesystem
due to btree split. The HPFS driver checks in advance if there is
available space, so that it won't corrupt the btree if we run out of space
during splitting.

If there is not enough available space, the HPFS driver attempted to
truncate the file, but this results in a deadlock since the commit
7dd29d8d865efdb00c0542a5d2c87af8c52ea6c7 ("HPFS: Introduce a global mutex
and lock it on every callback from VFS").

This patch removes the code that tries to truncate the file and -ENOSPC is
returned instead. If the user hits -ENOSPC on delete, he should try to
delete other files (that are stored in a leaf btree node), so that the
delete operation will make some space for deleting the file stored in
non-leaf btree node.

Reported-by: Al Viro &lt;viro@ZenIV.linux.org.uk&gt;
Signed-off-by: Mikulas Patocka &lt;mikulas@artax.karlin.mff.cuni.cz&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
[bwh: Backported to 3.2: deleted code is slightly different]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Fix directory hardlinks from deleted directories</title>
<updated>2016-04-01T00:54:35+00:00</updated>
<author>
<name>David Woodhouse</name>
<email>David.Woodhouse@intel.com</email>
</author>
<published>2016-02-01T14:04:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=bb96b5354a62154d0aca4b2015a5b3eee68a4ac5'/>
<id>bb96b5354a62154d0aca4b2015a5b3eee68a4ac5</id>
<content type='text'>
commit be629c62a603e5935f8177fd8a19e014100a259e upstream.

When a directory is deleted, we don't take too much care about killing off
all the dirents that belong to it — on the basis that on remount, the scan
will conclude that the directory is dead anyway.

This doesn't work though, when the deleted directory contained a child
directory which was moved *out*. In the early stages of the fs build
we can then end up with an apparent hard link, with the child directory
appearing both in its true location, and as a child of the original
directory which are this stage of the mount process we don't *yet* know
is defunct.

To resolve this, take out the early special-casing of the "directories
shall not have hard links" rule in jffs2_build_inode_pass1(), and let the
normal nlink processing happen for directories as well as other inodes.

Then later in the build process we can set ic-&gt;pino_nlink to the parent
inode#, as is required for directories during normal operaton, instead
of the nlink. And complain only *then* about hard links which are still
in evidence even after killing off all the unreachable paths.

Reported-by: Liu Song &lt;liu.song11@zte.com.cn&gt;
Signed-off-by: David Woodhouse &lt;David.Woodhouse@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit be629c62a603e5935f8177fd8a19e014100a259e upstream.

When a directory is deleted, we don't take too much care about killing off
all the dirents that belong to it — on the basis that on remount, the scan
will conclude that the directory is dead anyway.

This doesn't work though, when the deleted directory contained a child
directory which was moved *out*. In the early stages of the fs build
we can then end up with an apparent hard link, with the child directory
appearing both in its true location, and as a child of the original
directory which are this stage of the mount process we don't *yet* know
is defunct.

To resolve this, take out the early special-casing of the "directories
shall not have hard links" rule in jffs2_build_inode_pass1(), and let the
normal nlink processing happen for directories as well as other inodes.

Then later in the build process we can set ic-&gt;pino_nlink to the parent
inode#, as is required for directories during normal operaton, instead
of the nlink. And complain only *then* about hard links which are still
in evidence even after killing off all the unreachable paths.

Reported-by: Liu Song &lt;liu.song11@zte.com.cn&gt;
Signed-off-by: David Woodhouse &lt;David.Woodhouse@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>jffs2: Fix page lock / f-&gt;sem deadlock</title>
<updated>2016-04-01T00:54:35+00:00</updated>
<author>
<name>David Woodhouse</name>
<email>David.Woodhouse@intel.com</email>
</author>
<published>2016-02-01T12:37:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0a2688146b9afcfdc368b81cc0696a19c0cd6c6a'/>
<id>0a2688146b9afcfdc368b81cc0696a19c0cd6c6a</id>
<content type='text'>
commit 49e91e7079febe59a20ca885a87dd1c54240d0f1 upstream.

With this fix, all code paths should now be obtaining the page lock before
f-&gt;sem.

Reported-by: Szabó Tamás &lt;sztomi89@gmail.com&gt;
Tested-by: Thomas Betker &lt;thomas.betker@rohde-schwarz.com&gt;
Signed-off-by: David Woodhouse &lt;David.Woodhouse@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 49e91e7079febe59a20ca885a87dd1c54240d0f1 upstream.

With this fix, all code paths should now be obtaining the page lock before
f-&gt;sem.

Reported-by: Szabó Tamás &lt;sztomi89@gmail.com&gt;
Tested-by: Thomas Betker &lt;thomas.betker@rohde-schwarz.com&gt;
Signed-off-by: David Woodhouse &lt;David.Woodhouse@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "jffs2: Fix lock acquisition order bug in jffs2_write_begin"</title>
<updated>2016-04-01T00:54:35+00:00</updated>
<author>
<name>Thomas Betker</name>
<email>thomas.betker@rohde-schwarz.com</email>
</author>
<published>2015-11-10T21:18:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b7289da851178cdb10e4871547c36947eccd84af'/>
<id>b7289da851178cdb10e4871547c36947eccd84af</id>
<content type='text'>
commit 157078f64b8a9cd7011b6b900b2f2498df850748 upstream.

This reverts commit 5ffd3412ae55
("jffs2: Fix lock acquisition order bug in jffs2_write_begin").

The commit modified jffs2_write_begin() to remove a deadlock with
jffs2_garbage_collect_live(), but this introduced new deadlocks found
by multiple users. page_lock() actually has to be called before
mutex_lock(&amp;c-&gt;alloc_sem) or mutex_lock(&amp;f-&gt;sem) because
jffs2_write_end() and jffs2_readpage() are called with the page locked,
and they acquire c-&gt;alloc_sem and f-&gt;sem, resp.

In other words, the lock order in jffs2_write_begin() was correct, and
it is the jffs2_garbage_collect_live() path that has to be changed.

Revert the commit to get rid of the new deadlocks, and to clear the way
for a better fix of the original deadlock.

Reported-by: Deng Chao &lt;deng.chao1@zte.com.cn&gt;
Reported-by: Ming Liu &lt;liu.ming50@gmail.com&gt;
Reported-by: wangzaiwei &lt;wangzaiwei@top-vision.cn&gt;
Signed-off-by: Thomas Betker &lt;thomas.betker@rohde-schwarz.com&gt;
Signed-off-by: David Woodhouse &lt;David.Woodhouse@intel.com&gt;
[bwh: Backported to 3.2: use D1(printk(KERN_DEBUG ...)) instead of
 jffs2_dbg(1, ...)]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 157078f64b8a9cd7011b6b900b2f2498df850748 upstream.

This reverts commit 5ffd3412ae55
("jffs2: Fix lock acquisition order bug in jffs2_write_begin").

The commit modified jffs2_write_begin() to remove a deadlock with
jffs2_garbage_collect_live(), but this introduced new deadlocks found
by multiple users. page_lock() actually has to be called before
mutex_lock(&amp;c-&gt;alloc_sem) or mutex_lock(&amp;f-&gt;sem) because
jffs2_write_end() and jffs2_readpage() are called with the page locked,
and they acquire c-&gt;alloc_sem and f-&gt;sem, resp.

In other words, the lock order in jffs2_write_begin() was correct, and
it is the jffs2_garbage_collect_live() path that has to be changed.

Revert the commit to get rid of the new deadlocks, and to clear the way
for a better fix of the original deadlock.

Reported-by: Deng Chao &lt;deng.chao1@zte.com.cn&gt;
Reported-by: Ming Liu &lt;liu.ming50@gmail.com&gt;
Reported-by: wangzaiwei &lt;wangzaiwei@top-vision.cn&gt;
Signed-off-by: Thomas Betker &lt;thomas.betker@rohde-schwarz.com&gt;
Signed-off-by: David Woodhouse &lt;David.Woodhouse@intel.com&gt;
[bwh: Backported to 3.2: use D1(printk(KERN_DEBUG ...)) instead of
 jffs2_dbg(1, ...)]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ext4: fix bh-&gt;b_state corruption</title>
<updated>2016-04-01T00:54:34+00:00</updated>
<author>
<name>Jan Kara</name>
<email>jack@suse.com</email>
</author>
<published>2016-02-19T05:18:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=01dda5f90b3e0fd5e65b5d25d347b05fdf08bd27'/>
<id>01dda5f90b3e0fd5e65b5d25d347b05fdf08bd27</id>
<content type='text'>
commit ed8ad83808f009ade97ebbf6519bc3a97fefbc0c upstream.

ext4 can update bh-&gt;b_state non-atomically in _ext4_get_block() and
ext4_da_get_block_prep(). Usually this is fine since bh is just a
temporary storage for mapping information on stack but in some cases it
can be fully living bh attached to a page. In such case non-atomic
update of bh-&gt;b_state can race with an atomic update which then gets
lost. Usually when we are mapping bh and thus updating bh-&gt;b_state
non-atomically, nobody else touches the bh and so things work out fine
but there is one case to especially worry about: ext4_finish_bio() uses
BH_Uptodate_Lock on the first bh in the page to synchronize handling of
PageWriteback state. So when blocksize &lt; pagesize, we can be atomically
modifying bh-&gt;b_state of a buffer that actually isn't under IO and thus
can race e.g. with delalloc trying to map that buffer. The result is
that we can mistakenly set / clear BH_Uptodate_Lock bit resulting in the
corruption of PageWriteback state or missed unlock of BH_Uptodate_Lock.

Fix the problem by always updating bh-&gt;b_state bits atomically.

Reported-by: Nikolay Borisov &lt;kernel@kyup.com&gt;
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
[bwh: Backported to 3.2:
 - s/READ_ONCE/ACCESS_ONCE/
 - Adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit ed8ad83808f009ade97ebbf6519bc3a97fefbc0c upstream.

ext4 can update bh-&gt;b_state non-atomically in _ext4_get_block() and
ext4_da_get_block_prep(). Usually this is fine since bh is just a
temporary storage for mapping information on stack but in some cases it
can be fully living bh attached to a page. In such case non-atomic
update of bh-&gt;b_state can race with an atomic update which then gets
lost. Usually when we are mapping bh and thus updating bh-&gt;b_state
non-atomically, nobody else touches the bh and so things work out fine
but there is one case to especially worry about: ext4_finish_bio() uses
BH_Uptodate_Lock on the first bh in the page to synchronize handling of
PageWriteback state. So when blocksize &lt; pagesize, we can be atomically
modifying bh-&gt;b_state of a buffer that actually isn't under IO and thus
can race e.g. with delalloc trying to map that buffer. The result is
that we can mistakenly set / clear BH_Uptodate_Lock bit resulting in the
corruption of PageWriteback state or missed unlock of BH_Uptodate_Lock.

Fix the problem by always updating bh-&gt;b_state bits atomically.

Reported-by: Nikolay Borisov &lt;kernel@kyup.com&gt;
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Signed-off-by: Theodore Ts'o &lt;tytso@mit.edu&gt;
[bwh: Backported to 3.2:
 - s/READ_ONCE/ACCESS_ONCE/
 - Adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cifs: fix erroneous return value</title>
<updated>2016-04-01T00:54:31+00:00</updated>
<author>
<name>Anton Protopopov</name>
<email>a.s.protopopov@gmail.com</email>
</author>
<published>2016-02-10T17:50:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=751a5cf7c9ab11b54c97fdee372b5d57aba66224'/>
<id>751a5cf7c9ab11b54c97fdee372b5d57aba66224</id>
<content type='text'>
commit 4b550af519854421dfec9f7732cdddeb057134b2 upstream.

The setup_ntlmv2_rsp() function may return positive value ENOMEM instead
of -ENOMEM in case of kmalloc failure.

Signed-off-by: Anton Protopopov &lt;a.s.protopopov@gmail.com&gt;
Signed-off-by: Steve French &lt;smfrench@gmail.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 4b550af519854421dfec9f7732cdddeb057134b2 upstream.

The setup_ntlmv2_rsp() function may return positive value ENOMEM instead
of -ENOMEM in case of kmalloc failure.

Signed-off-by: Anton Protopopov &lt;a.s.protopopov@gmail.com&gt;
Signed-off-by: Steve French &lt;smfrench@gmail.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>pipe: Fix buffer offset after partially failed read</title>
<updated>2016-02-27T14:28:49+00:00</updated>
<author>
<name>Ben Hutchings</name>
<email>ben@decadent.org.uk</email>
</author>
<published>2016-02-13T02:34:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=feae3ca2e5e1a8f44aa6290255d3d9709985d0b2'/>
<id>feae3ca2e5e1a8f44aa6290255d3d9709985d0b2</id>
<content type='text'>
Quoting the RHEL advisory:

&gt; It was found that the fix for CVE-2015-1805 incorrectly kept buffer
&gt; offset and buffer length in sync on a failed atomic read, potentially
&gt; resulting in a pipe buffer state corruption. A local, unprivileged user
&gt; could use this flaw to crash the system or leak kernel memory to user
&gt; space. (CVE-2016-0774, Moderate)

The same flawed fix was applied to stable branches from 2.6.32.y to
3.14.y inclusive, and I was able to reproduce the issue on 3.2.y.
We need to give pipe_iov_copy_to_user() a separate offset variable
and only update the buffer offset if it succeeds.

References: https://rhn.redhat.com/errata/RHSA-2016-0103.html
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Quoting the RHEL advisory:

&gt; It was found that the fix for CVE-2015-1805 incorrectly kept buffer
&gt; offset and buffer length in sync on a failed atomic read, potentially
&gt; resulting in a pipe buffer state corruption. A local, unprivileged user
&gt; could use this flaw to crash the system or leak kernel memory to user
&gt; space. (CVE-2016-0774, Moderate)

The same flawed fix was applied to stable branches from 2.6.32.y to
3.14.y inclusive, and I was able to reproduce the issue on 3.2.y.
We need to give pipe_iov_copy_to_user() a separate offset variable
and only update the buffer offset if it succeeds.

References: https://rhn.redhat.com/errata/RHSA-2016-0103.html
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>pipe: limit the per-user amount of pages allocated in pipes</title>
<updated>2016-02-27T14:28:49+00:00</updated>
<author>
<name>Willy Tarreau</name>
<email>w@1wt.eu</email>
</author>
<published>2016-01-18T15:36:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=92375b85b70395c8180991084c05e8d78e55d066'/>
<id>92375b85b70395c8180991084c05e8d78e55d066</id>
<content type='text'>
commit 759c01142a5d0f364a462346168a56de28a80f52 upstream.

On no-so-small systems, it is possible for a single process to cause an
OOM condition by filling large pipes with data that are never read. A
typical process filling 4000 pipes with 1 MB of data will use 4 GB of
memory. On small systems it may be tricky to set the pipe max size to
prevent this from happening.

This patch makes it possible to enforce a per-user soft limit above
which new pipes will be limited to a single page, effectively limiting
them to 4 kB each, as well as a hard limit above which no new pipes may
be created for this user. This has the effect of protecting the system
against memory abuse without hurting other users, and still allowing
pipes to work correctly though with less data at once.

The limit are controlled by two new sysctls : pipe-user-pages-soft, and
pipe-user-pages-hard. Both may be disabled by setting them to zero. The
default soft limit allows the default number of FDs per process (1024)
to create pipes of the default size (64kB), thus reaching a limit of 64MB
before starting to create only smaller pipes. With 256 processes limited
to 1024 FDs each, this results in 1024*64kB + (256*1024 - 1024) * 4kB =
1084 MB of memory allocated for a user. The hard limit is disabled by
default to avoid breaking existing applications that make intensive use
of pipes (eg: for splicing).

Reported-by: socketpair@gmail.com
Reported-by: Tetsuo Handa &lt;penguin-kernel@I-love.SAKURA.ne.jp&gt;
Mitigates: CVE-2013-4312 (Linux 2.0+)
Suggested-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Willy Tarreau &lt;w@1wt.eu&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 759c01142a5d0f364a462346168a56de28a80f52 upstream.

On no-so-small systems, it is possible for a single process to cause an
OOM condition by filling large pipes with data that are never read. A
typical process filling 4000 pipes with 1 MB of data will use 4 GB of
memory. On small systems it may be tricky to set the pipe max size to
prevent this from happening.

This patch makes it possible to enforce a per-user soft limit above
which new pipes will be limited to a single page, effectively limiting
them to 4 kB each, as well as a hard limit above which no new pipes may
be created for this user. This has the effect of protecting the system
against memory abuse without hurting other users, and still allowing
pipes to work correctly though with less data at once.

The limit are controlled by two new sysctls : pipe-user-pages-soft, and
pipe-user-pages-hard. Both may be disabled by setting them to zero. The
default soft limit allows the default number of FDs per process (1024)
to create pipes of the default size (64kB), thus reaching a limit of 64MB
before starting to create only smaller pipes. With 256 processes limited
to 1024 FDs each, this results in 1024*64kB + (256*1024 - 1024) * 4kB =
1084 MB of memory allocated for a user. The hard limit is disabled by
default to avoid breaking existing applications that make intensive use
of pipes (eg: for splicing).

Reported-by: socketpair@gmail.com
Reported-by: Tetsuo Handa &lt;penguin-kernel@I-love.SAKURA.ne.jp&gt;
Mitigates: CVE-2013-4312 (Linux 2.0+)
Suggested-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Willy Tarreau &lt;w@1wt.eu&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>btrfs: properly set the termination value of ctx-&gt;pos in readdir</title>
<updated>2016-02-27T14:28:48+00:00</updated>
<author>
<name>David Sterba</name>
<email>dsterba@suse.com</email>
</author>
<published>2015-11-13T12:44:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=57ce57616accf5c20822be601a0ddfef08af000b'/>
<id>57ce57616accf5c20822be601a0ddfef08af000b</id>
<content type='text'>
commit bc4ef7592f657ae81b017207a1098817126ad4cb upstream.

The value of ctx-&gt;pos in the last readdir call is supposed to be set to
INT_MAX due to 32bit compatibility, unless 'pos' is intentially set to a
larger value, then it's LLONG_MAX.

There's a report from PaX SIZE_OVERFLOW plugin that "ctx-&gt;pos++"
overflows (https://forums.grsecurity.net/viewtopic.php?f=1&amp;t=4284), on a
64bit arch, where the value is 0x7fffffffffffffff ie. LLONG_MAX before
the increment.

We can get to that situation like that:

* emit all regular readdir entries
* still in the same call to readdir, bump the last pos to INT_MAX
* next call to readdir will not emit any entries, but will reach the
  bump code again, finds pos to be INT_MAX and sets it to LLONG_MAX

Normally this is not a problem, but if we call readdir again, we'll find
'pos' set to LLONG_MAX and the unconditional increment will overflow.

The report from Victor at
(http://thread.gmane.org/gmane.comp.file-systems.btrfs/49500) with debugging
print shows that pattern:

 Overflow: e
 Overflow: 7fffffff
 Overflow: 7fffffffffffffff
 PAX: size overflow detected in function btrfs_real_readdir
   fs/btrfs/inode.c:5760 cicus.935_282 max, count: 9, decl: pos; num: 0;
   context: dir_context;
 CPU: 0 PID: 2630 Comm: polkitd Not tainted 4.2.3-grsec #1
 Hardware name: Gigabyte Technology Co., Ltd. H81ND2H/H81ND2H, BIOS F3 08/11/2015
  ffffffff81901608 0000000000000000 ffffffff819015e6 ffffc90004973d48
  ffffffff81742f0f 0000000000000007 ffffffff81901608 ffffc90004973d78
  ffffffff811cb706 0000000000000000 ffff8800d47359e0 ffffc90004973ed8
 Call Trace:
  [&lt;ffffffff81742f0f&gt;] dump_stack+0x4c/0x7f
  [&lt;ffffffff811cb706&gt;] report_size_overflow+0x36/0x40
  [&lt;ffffffff812ef0bc&gt;] btrfs_real_readdir+0x69c/0x6d0
  [&lt;ffffffff811dafc8&gt;] iterate_dir+0xa8/0x150
  [&lt;ffffffff811e6d8d&gt;] ? __fget_light+0x2d/0x70
  [&lt;ffffffff811dba3a&gt;] SyS_getdents+0xba/0x1c0
 Overflow: 1a
  [&lt;ffffffff811db070&gt;] ? iterate_dir+0x150/0x150
  [&lt;ffffffff81749b69&gt;] entry_SYSCALL_64_fastpath+0x12/0x83

The jump from 7fffffff to 7fffffffffffffff happens when new dir entries
are not yet synced and are processed from the delayed list. Then the code
could go to the bump section again even though it might not emit any new
dir entries from the delayed list.

The fix avoids entering the "bump" section again once we've finished
emitting the entries, both for synced and delayed entries.

References: https://forums.grsecurity.net/viewtopic.php?f=1&amp;t=4284
Reported-by: Victor &lt;services@swwu.com&gt;
Signed-off-by: David Sterba &lt;dsterba@suse.com&gt;
Tested-by: Holger Hoffstätte &lt;holger.hoffstaette@googlemail.com&gt;
Signed-off-by: Chris Mason &lt;clm@fb.com&gt;
[bwh: Backported to 3.2:
 - s/ctx-&gt;pos/filp-&gt;f_pos/
 - Adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit bc4ef7592f657ae81b017207a1098817126ad4cb upstream.

The value of ctx-&gt;pos in the last readdir call is supposed to be set to
INT_MAX due to 32bit compatibility, unless 'pos' is intentially set to a
larger value, then it's LLONG_MAX.

There's a report from PaX SIZE_OVERFLOW plugin that "ctx-&gt;pos++"
overflows (https://forums.grsecurity.net/viewtopic.php?f=1&amp;t=4284), on a
64bit arch, where the value is 0x7fffffffffffffff ie. LLONG_MAX before
the increment.

We can get to that situation like that:

* emit all regular readdir entries
* still in the same call to readdir, bump the last pos to INT_MAX
* next call to readdir will not emit any entries, but will reach the
  bump code again, finds pos to be INT_MAX and sets it to LLONG_MAX

Normally this is not a problem, but if we call readdir again, we'll find
'pos' set to LLONG_MAX and the unconditional increment will overflow.

The report from Victor at
(http://thread.gmane.org/gmane.comp.file-systems.btrfs/49500) with debugging
print shows that pattern:

 Overflow: e
 Overflow: 7fffffff
 Overflow: 7fffffffffffffff
 PAX: size overflow detected in function btrfs_real_readdir
   fs/btrfs/inode.c:5760 cicus.935_282 max, count: 9, decl: pos; num: 0;
   context: dir_context;
 CPU: 0 PID: 2630 Comm: polkitd Not tainted 4.2.3-grsec #1
 Hardware name: Gigabyte Technology Co., Ltd. H81ND2H/H81ND2H, BIOS F3 08/11/2015
  ffffffff81901608 0000000000000000 ffffffff819015e6 ffffc90004973d48
  ffffffff81742f0f 0000000000000007 ffffffff81901608 ffffc90004973d78
  ffffffff811cb706 0000000000000000 ffff8800d47359e0 ffffc90004973ed8
 Call Trace:
  [&lt;ffffffff81742f0f&gt;] dump_stack+0x4c/0x7f
  [&lt;ffffffff811cb706&gt;] report_size_overflow+0x36/0x40
  [&lt;ffffffff812ef0bc&gt;] btrfs_real_readdir+0x69c/0x6d0
  [&lt;ffffffff811dafc8&gt;] iterate_dir+0xa8/0x150
  [&lt;ffffffff811e6d8d&gt;] ? __fget_light+0x2d/0x70
  [&lt;ffffffff811dba3a&gt;] SyS_getdents+0xba/0x1c0
 Overflow: 1a
  [&lt;ffffffff811db070&gt;] ? iterate_dir+0x150/0x150
  [&lt;ffffffff81749b69&gt;] entry_SYSCALL_64_fastpath+0x12/0x83

The jump from 7fffffff to 7fffffffffffffff happens when new dir entries
are not yet synced and are processed from the delayed list. Then the code
could go to the bump section again even though it might not emit any new
dir entries from the delayed list.

The fix avoids entering the "bump" section again once we've finished
emitting the entries, both for synced and delayed entries.

References: https://forums.grsecurity.net/viewtopic.php?f=1&amp;t=4284
Reported-by: Victor &lt;services@swwu.com&gt;
Signed-off-by: David Sterba &lt;dsterba@suse.com&gt;
Tested-by: Holger Hoffstätte &lt;holger.hoffstaette@googlemail.com&gt;
Signed-off-by: Chris Mason &lt;clm@fb.com&gt;
[bwh: Backported to 3.2:
 - s/ctx-&gt;pos/filp-&gt;f_pos/
 - Adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ocfs2/dlm: clear refmap bit of recovery lock while doing local recovery cleanup</title>
<updated>2016-02-27T14:28:47+00:00</updated>
<author>
<name>xuejiufei</name>
<email>xuejiufei@huawei.com</email>
</author>
<published>2016-02-05T23:36:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ee614e584ca63f8abe167c74680065d573266617'/>
<id>ee614e584ca63f8abe167c74680065d573266617</id>
<content type='text'>
commit c95a51807b730e4681e2ecbdfd669ca52601959e upstream.

When recovery master down, dlm_do_local_recovery_cleanup() only remove
the $RECOVERY lock owned by dead node, but do not clear the refmap bit.
Which will make umount thread falling in dead loop migrating $RECOVERY
to the dead node.

Signed-off-by: xuejiufei &lt;xuejiufei@huawei.com&gt;
Reviewed-by: Joseph Qi &lt;joseph.qi@huawei.com&gt;
Cc: Mark Fasheh &lt;mfasheh@suse.de&gt;
Cc: Joel Becker &lt;jlbec@evilplan.org&gt;
Cc: Junxiao Bi &lt;junxiao.bi@oracle.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit c95a51807b730e4681e2ecbdfd669ca52601959e upstream.

When recovery master down, dlm_do_local_recovery_cleanup() only remove
the $RECOVERY lock owned by dead node, but do not clear the refmap bit.
Which will make umount thread falling in dead loop migrating $RECOVERY
to the dead node.

Signed-off-by: xuejiufei &lt;xuejiufei@huawei.com&gt;
Reviewed-by: Joseph Qi &lt;joseph.qi@huawei.com&gt;
Cc: Mark Fasheh &lt;mfasheh@suse.de&gt;
Cc: Joel Becker &lt;jlbec@evilplan.org&gt;
Cc: Junxiao Bi &lt;junxiao.bi@oracle.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
</feed>
