<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/fs/ext4, branch v3.4.86</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>ext4: atomically set inode-&gt;i_flags in ext4_set_inode_flags()</title>
<updated>2014-04-03T18:58:46+00:00</updated>
<author>
<name>Theodore Ts'o</name>
<email>tytso@mit.edu</email>
</author>
<published>2014-03-30T14:20:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=ff624a813eef9f51a8d4f3dd8e4f12db9286433d'/>
<id>ff624a813eef9f51a8d4f3dd8e4f12db9286433d</id>
<content type='text'>
commit 00a1a053ebe5febcfc2ec498bd894f035ad2aa06 upstream.

Use cmpxchg() to atomically set i_flags instead of clearing out the
S_IMMUTABLE, S_APPEND, etc. flags and then setting them from the
EXT4_IMMUTABLE_FL, EXT4_APPEND_FL flags, since this opens up a race
where an immutable file has the immutable flag cleared for a brief
window of time.

Reported-by: John Sullivan &lt;jsrhbz@kanargh.force9.co.uk&gt;
Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 00a1a053ebe5febcfc2ec498bd894f035ad2aa06 upstream.

Use cmpxchg() to atomically set i_flags instead of clearing out the
S_IMMUTABLE, S_APPEND, etc. flags and then setting them from the
EXT4_IMMUTABLE_FL, EXT4_APPEND_FL flags, since this opens up a race
where an immutable file has the immutable flag cleared for a brief
window of time.

Reported-by: John Sullivan &lt;jsrhbz@kanargh.force9.co.uk&gt;
Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ext4: return ENOMEM if sb_getblk() fails</title>
<updated>2014-03-11T23:10:06+00:00</updated>
<author>
<name>Theodore Ts'o</name>
<email>tytso@mit.edu</email>
</author>
<published>2013-01-12T21:19:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=c28414d3497a0db41a9fb08650131ee15989ee9c'/>
<id>c28414d3497a0db41a9fb08650131ee15989ee9c</id>
<content type='text'>
commit 860d21e2c585f7ee8a4ecc06f474fdc33c9474f4 upstream.

The only reason for sb_getblk() failing is if it can't allocate the
buffer_head.  So ENOMEM is more appropriate than EIO.  In addition,
make sure that the file system is marked as being inconsistent if
sb_getblk() fails.

Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
[xr: Backported to 3.4:
 - Drop change to inline.c
 - Call to ext4_ext_check() from ext4_ext_find_extent() is conditional]
Signed-off-by: Rui Xiang &lt;rui.xiang@huawei.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 860d21e2c585f7ee8a4ecc06f474fdc33c9474f4 upstream.

The only reason for sb_getblk() failing is if it can't allocate the
buffer_head.  So ENOMEM is more appropriate than EIO.  In addition,
make sure that the file system is marked as being inconsistent if
sb_getblk() fails.

Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
[xr: Backported to 3.4:
 - Drop change to inline.c
 - Call to ext4_ext_check() from ext4_ext_find_extent() is conditional]
Signed-off-by: Rui Xiang &lt;rui.xiang@huawei.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ext4: fix possible use-after-free with AIO</title>
<updated>2014-03-11T23:10:05+00:00</updated>
<author>
<name>Jan Kara</name>
<email>jack@suse.cz</email>
</author>
<published>2013-01-30T03:48:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=b54e3acc375bf344c2273662c61ce0265969b5fd'/>
<id>b54e3acc375bf344c2273662c61ce0265969b5fd</id>
<content type='text'>
commit 091e26dfc156aeb3b73bc5c5f277e433ad39331c upstream.

Running AIO is pinning inode in memory using file reference. Once AIO
is completed using aio_complete(), file reference is put and inode can
be freed from memory. So we have to be sure that calling aio_complete()
is the last thing we do with the inode.

Reviewed-by: Carlos Maiolino &lt;cmaiolino@redhat.com&gt;
Acked-by: Jeff Moyer &lt;jmoyer@redhat.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: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Cc: Rui Xiang &lt;rui.xiang@huawei.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 091e26dfc156aeb3b73bc5c5f277e433ad39331c upstream.

Running AIO is pinning inode in memory using file reference. Once AIO
is completed using aio_complete(), file reference is put and inode can
be freed from memory. So we have to be sure that calling aio_complete()
is the last thing we do with the inode.

Reviewed-by: Carlos Maiolino &lt;cmaiolino@redhat.com&gt;
Acked-by: Jeff Moyer &lt;jmoyer@redhat.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: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Cc: Rui Xiang &lt;rui.xiang@huawei.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ext4/jbd2: don't wait (forever) for stale tid caused by wraparound</title>
<updated>2014-03-11T23:10:05+00:00</updated>
<author>
<name>Theodore Ts'o</name>
<email>tytso@mit.edu</email>
</author>
<published>2013-04-04T02:02:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=ebdc12a0b5ed501c23b52b1ab5d28aea681badcd'/>
<id>ebdc12a0b5ed501c23b52b1ab5d28aea681badcd</id>
<content type='text'>
commit d76a3a77113db020d9bb1e894822869410450bd9 upstream.

In the case where an inode has a very stale transaction id (tid) in
i_datasync_tid or i_sync_tid, it's possible that after a very large
(2**31) number of transactions, that the tid number space might wrap,
causing tid_geq()'s calculations to fail.

Commit deeeaf13 "jbd2: fix fsync() tid wraparound bug", later modified
by commit e7b04ac0 "jbd2: don't wake kjournald unnecessarily",
attempted to fix this problem, but it only avoided kjournald spinning
forever by fixing the logic in jbd2_log_start_commit().

Unfortunately, in the codepaths in fs/ext4/fsync.c and fs/ext4/inode.c
that might call jbd2_log_start_commit() with a stale tid, those
functions will subsequently call jbd2_log_wait_commit() with the same
stale tid, and then wait for a very long time.  To fix this, we
replace the calls to jbd2_log_start_commit() and
jbd2_log_wait_commit() with a call to a new function,
jbd2_complete_transaction(), which will correctly handle stale tid's.

As a bonus, jbd2_complete_transaction() will avoid locking
j_state_lock for writing unless a commit needs to be started.  This
should have a small (but probably not measurable) improvement for
ext4's scalability.

Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Reported-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Reported-by: George Barnett &lt;gbarnett@atlassian.com&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Cc: Rui Xiang &lt;rui.xiang@huawei.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit d76a3a77113db020d9bb1e894822869410450bd9 upstream.

In the case where an inode has a very stale transaction id (tid) in
i_datasync_tid or i_sync_tid, it's possible that after a very large
(2**31) number of transactions, that the tid number space might wrap,
causing tid_geq()'s calculations to fail.

Commit deeeaf13 "jbd2: fix fsync() tid wraparound bug", later modified
by commit e7b04ac0 "jbd2: don't wake kjournald unnecessarily",
attempted to fix this problem, but it only avoided kjournald spinning
forever by fixing the logic in jbd2_log_start_commit().

Unfortunately, in the codepaths in fs/ext4/fsync.c and fs/ext4/inode.c
that might call jbd2_log_start_commit() with a stale tid, those
functions will subsequently call jbd2_log_wait_commit() with the same
stale tid, and then wait for a very long time.  To fix this, we
replace the calls to jbd2_log_start_commit() and
jbd2_log_wait_commit() with a call to a new function,
jbd2_complete_transaction(), which will correctly handle stale tid's.

As a bonus, jbd2_complete_transaction() will avoid locking
j_state_lock for writing unless a commit needs to be started.  This
should have a small (but probably not measurable) improvement for
ext4's scalability.

Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Reported-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Reported-by: George Barnett &lt;gbarnett@atlassian.com&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Cc: Rui Xiang &lt;rui.xiang@huawei.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ext4: don't leave i_crtime.tv_sec uninitialized</title>
<updated>2014-03-11T23:09:56+00:00</updated>
<author>
<name>Theodore Ts'o</name>
<email>tytso@mit.edu</email>
</author>
<published>2014-02-17T00:29:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=6c3515f0ec08a1aa21007f3b261d2c3445adaae7'/>
<id>6c3515f0ec08a1aa21007f3b261d2c3445adaae7</id>
<content type='text'>
commit 19ea80603715d473600cd993b9987bc97d042e02 upstream.

If the i_crtime field is not present in the inode, don't leave the
field uninitialized.

Fixes: ef7f38359 ("ext4: Add nanosecond timestamps")
Reported-by: Vegard Nossum &lt;vegard.nossum@oracle.com&gt;
Tested-by: Vegard Nossum &lt;vegard.nossum@oracle.com&gt;
Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 19ea80603715d473600cd993b9987bc97d042e02 upstream.

If the i_crtime field is not present in the inode, don't leave the
field uninitialized.

Fixes: ef7f38359 ("ext4: Add nanosecond timestamps")
Reported-by: Vegard Nossum &lt;vegard.nossum@oracle.com&gt;
Tested-by: Vegard Nossum &lt;vegard.nossum@oracle.com&gt;
Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ext4: fix online resize with a non-standard blocks per group setting</title>
<updated>2014-03-11T23:09:56+00:00</updated>
<author>
<name>Theodore Ts'o</name>
<email>tytso@mit.edu</email>
</author>
<published>2014-02-16T03:42:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=080368aadcb269a5949f331e6f2594720866eb83'/>
<id>080368aadcb269a5949f331e6f2594720866eb83</id>
<content type='text'>
commit 3d2660d0c9c2f296837078c189b68a47f6b2e3b5 upstream.

The set_flexbg_block_bitmap() function assumed that the number of
blocks in a blockgroup was sb-&gt;blocksize * 8, which is normally true,
but not always!  Use EXT4_BLOCKS_PER_GROUP(sb) instead, to fix block
bitmap corruption after:

mke2fs -t ext4 -g 3072 -i 4096 /dev/vdd 1G
mount -t ext4 /dev/vdd /vdd
resize2fs /dev/vdd 8G

Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Reported-by: Jon Bernard &lt;jbernard@tuxion.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 3d2660d0c9c2f296837078c189b68a47f6b2e3b5 upstream.

The set_flexbg_block_bitmap() function assumed that the number of
blocks in a blockgroup was sb-&gt;blocksize * 8, which is normally true,
but not always!  Use EXT4_BLOCKS_PER_GROUP(sb) instead, to fix block
bitmap corruption after:

mke2fs -t ext4 -g 3072 -i 4096 /dev/vdd 1G
mount -t ext4 /dev/vdd /vdd
resize2fs /dev/vdd 8G

Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Reported-by: Jon Bernard &lt;jbernard@tuxion.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ext4: don't try to modify s_flags if the the file system is read-only</title>
<updated>2014-03-11T23:09:56+00:00</updated>
<author>
<name>Theodore Ts'o</name>
<email>tytso@mit.edu</email>
</author>
<published>2014-02-12T17:16:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=a8909f1fc06b034f0d790f48c8babf9bc6b2341f'/>
<id>a8909f1fc06b034f0d790f48c8babf9bc6b2341f</id>
<content type='text'>
commit 23301410972330c0ae9a8afc379ba2005e249cc6 upstream.

If an ext4 file system is created by some tool other than mke2fs
(perhaps by someone who has a pathalogical fear of the GPL) that
doesn't set one or the other of the EXT2_FLAGS_{UN}SIGNED_HASH flags,
and that file system is then mounted read-only, don't try to modify
the s_flags field.  Otherwise, if dm_verity is in use, the superblock
will change, causing an dm_verity failure.

Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 23301410972330c0ae9a8afc379ba2005e249cc6 upstream.

If an ext4 file system is created by some tool other than mke2fs
(perhaps by someone who has a pathalogical fear of the GPL) that
doesn't set one or the other of the EXT2_FLAGS_{UN}SIGNED_HASH flags,
and that file system is then mounted read-only, don't try to modify
the s_flags field.  Otherwise, if dm_verity is in use, the superblock
will change, causing an dm_verity failure.

Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ext4: protect group inode free counting with group lock</title>
<updated>2014-02-20T18:45:32+00:00</updated>
<author>
<name>Tao Ma</name>
<email>boyu.mt@taobao.com</email>
</author>
<published>2012-05-28T22:20:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=4e0bc3f3cd9028d4a2bc2f21c6d371b2f671823b'/>
<id>4e0bc3f3cd9028d4a2bc2f21c6d371b2f671823b</id>
<content type='text'>
commit 6f2e9f0e7d795214b9cf5a47724a273b705fd113 upstream.

Now when we set the group inode free count, we don't have a proper
group lock so that multiple threads may decrease the inode free
count at the same time. And e2fsck will complain something like:

Free inodes count wrong for group #1 (1, counted=0).
Fix? no

Free inodes count wrong for group #2 (3, counted=0).
Fix? no

Directories count wrong for group #2 (780, counted=779).
Fix? no

Free inodes count wrong for group #3 (2272, counted=2273).
Fix? no

So this patch try to protect it with the ext4_lock_group.

btw, it is found by xfstests test case 269 and the volume is
mkfsed with the parameter
"-O ^resize_inode,^uninit_bg,extent,meta_bg,flex_bg,ext_attr"
and I have run it 100 times and the error in e2fsck doesn't
show up again.

Signed-off-by: Tao Ma &lt;boyu.mt@taobao.com&gt;
Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Signed-off-by: Benjamin LaHaise &lt;bcrl@kvack.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;


</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 6f2e9f0e7d795214b9cf5a47724a273b705fd113 upstream.

Now when we set the group inode free count, we don't have a proper
group lock so that multiple threads may decrease the inode free
count at the same time. And e2fsck will complain something like:

Free inodes count wrong for group #1 (1, counted=0).
Fix? no

Free inodes count wrong for group #2 (3, counted=0).
Fix? no

Directories count wrong for group #2 (780, counted=779).
Fix? no

Free inodes count wrong for group #3 (2272, counted=2273).
Fix? no

So this patch try to protect it with the ext4_lock_group.

btw, it is found by xfstests test case 269 and the volume is
mkfsed with the parameter
"-O ^resize_inode,^uninit_bg,extent,meta_bg,flex_bg,ext_attr"
and I have run it 100 times and the error in e2fsck doesn't
show up again.

Signed-off-by: Tao Ma &lt;boyu.mt@taobao.com&gt;
Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Signed-off-by: Benjamin LaHaise &lt;bcrl@kvack.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;


</pre>
</div>
</content>
</entry>
<entry>
<title>ext4: check for overlapping extents in ext4_valid_extent_entries()</title>
<updated>2014-01-08T17:42:11+00:00</updated>
<author>
<name>Eryu Guan</name>
<email>guaneryu@gmail.com</email>
</author>
<published>2013-12-04T02:22:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=a1192c0e5d037def6763f3873d3340615c241fe7'/>
<id>a1192c0e5d037def6763f3873d3340615c241fe7</id>
<content type='text'>
commit 5946d089379a35dda0e531710b48fca05446a196 upstream.

A corrupted ext4 may have out of order leaf extents, i.e.

extent: lblk 0--1023, len 1024, pblk 9217, flags: LEAF UNINIT
extent: lblk 1000--2047, len 1024, pblk 10241, flags: LEAF UNINIT
             ^^^^ overlap with previous extent

Reading such extent could hit BUG_ON() in ext4_es_cache_extent().

	BUG_ON(end &lt; lblk);

The problem is that __read_extent_tree_block() tries to cache holes as
well but assumes 'lblk' is greater than 'prev' and passes underflowed
length to ext4_es_cache_extent(). Fix it by checking for overlapping
extents in ext4_valid_extent_entries().

I hit this when fuzz testing ext4, and am able to reproduce it by
modifying the on-disk extent by hand.

Also add the check for (ee_block + len - 1) in ext4_valid_extent() to
make sure the value is not overflow.

Ran xfstests on patched ext4 and no regression.

Cc: Lukáš Czerner &lt;lczerner@redhat.com&gt;
Signed-off-by: Eryu Guan &lt;guaneryu@gmail.com&gt;
Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 5946d089379a35dda0e531710b48fca05446a196 upstream.

A corrupted ext4 may have out of order leaf extents, i.e.

extent: lblk 0--1023, len 1024, pblk 9217, flags: LEAF UNINIT
extent: lblk 1000--2047, len 1024, pblk 10241, flags: LEAF UNINIT
             ^^^^ overlap with previous extent

Reading such extent could hit BUG_ON() in ext4_es_cache_extent().

	BUG_ON(end &lt; lblk);

The problem is that __read_extent_tree_block() tries to cache holes as
well but assumes 'lblk' is greater than 'prev' and passes underflowed
length to ext4_es_cache_extent(). Fix it by checking for overlapping
extents in ext4_valid_extent_entries().

I hit this when fuzz testing ext4, and am able to reproduce it by
modifying the on-disk extent by hand.

Also add the check for (ee_block + len - 1) in ext4_valid_extent() to
make sure the value is not overflow.

Ran xfstests on patched ext4 and no regression.

Cc: Lukáš Czerner &lt;lczerner@redhat.com&gt;
Signed-off-by: Eryu Guan &lt;guaneryu@gmail.com&gt;
Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ext4: fix use-after-free in ext4_mb_new_blocks</title>
<updated>2014-01-08T17:42:11+00:00</updated>
<author>
<name>Junho Ryu</name>
<email>jayr@google.com</email>
</author>
<published>2013-12-03T23:10:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=510e024d1e74bb0f574d14ee19436a56ed4fc476'/>
<id>510e024d1e74bb0f574d14ee19436a56ed4fc476</id>
<content type='text'>
commit 4e8d2139802ce4f41936a687f06c560b12115247 upstream.

ext4_mb_put_pa should hold pa-&gt;pa_lock before accessing pa-&gt;pa_count.
While ext4_mb_use_preallocated checks pa-&gt;pa_deleted first and then
increments pa-&gt;count later, ext4_mb_put_pa decrements pa-&gt;pa_count
before holding pa-&gt;pa_lock and then sets pa-&gt;pa_deleted.

* Free sequence
ext4_mb_put_pa (1):		atomic_dec_and_test pa-&gt;pa_count
ext4_mb_put_pa (2):		lock pa-&gt;pa_lock
ext4_mb_put_pa (3):			check pa-&gt;pa_deleted
ext4_mb_put_pa (4):			set pa-&gt;pa_deleted=1
ext4_mb_put_pa (5):		unlock pa-&gt;pa_lock
ext4_mb_put_pa (6):		remove pa from a list
ext4_mb_pa_callback:		free pa

* Use sequence
ext4_mb_use_preallocated (1):	iterate over preallocation
ext4_mb_use_preallocated (2):	lock pa-&gt;pa_lock
ext4_mb_use_preallocated (3):		check pa-&gt;pa_deleted
ext4_mb_use_preallocated (4):		increase pa-&gt;pa_count
ext4_mb_use_preallocated (5):	unlock pa-&gt;pa_lock
ext4_mb_release_context:	access pa

* Use-after-free sequence
[initial status]		&lt;pa-&gt;pa_deleted = 0, pa_count = 1&gt;
ext4_mb_use_preallocated (1):	iterate over preallocation
ext4_mb_use_preallocated (2):	lock pa-&gt;pa_lock
ext4_mb_use_preallocated (3):		check pa-&gt;pa_deleted
ext4_mb_put_pa (1):		atomic_dec_and_test pa-&gt;pa_count
[pa_count decremented]		&lt;pa-&gt;pa_deleted = 0, pa_count = 0&gt;
ext4_mb_use_preallocated (4):		increase pa-&gt;pa_count
[pa_count incremented]		&lt;pa-&gt;pa_deleted = 0, pa_count = 1&gt;
ext4_mb_use_preallocated (5):	unlock pa-&gt;pa_lock
ext4_mb_put_pa (2):		lock pa-&gt;pa_lock
ext4_mb_put_pa (3):			check pa-&gt;pa_deleted
ext4_mb_put_pa (4):			set pa-&gt;pa_deleted=1
[race condition!]		&lt;pa-&gt;pa_deleted = 1, pa_count = 1&gt;
ext4_mb_put_pa (5):		unlock pa-&gt;pa_lock
ext4_mb_put_pa (6):		remove pa from a list
ext4_mb_pa_callback:		free pa
ext4_mb_release_context:	access pa

AddressSanitizer has detected use-after-free in ext4_mb_new_blocks
Bug report: http://goo.gl/rG1On3

Signed-off-by: Junho Ryu &lt;jayr@google.com&gt;
Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 4e8d2139802ce4f41936a687f06c560b12115247 upstream.

ext4_mb_put_pa should hold pa-&gt;pa_lock before accessing pa-&gt;pa_count.
While ext4_mb_use_preallocated checks pa-&gt;pa_deleted first and then
increments pa-&gt;count later, ext4_mb_put_pa decrements pa-&gt;pa_count
before holding pa-&gt;pa_lock and then sets pa-&gt;pa_deleted.

* Free sequence
ext4_mb_put_pa (1):		atomic_dec_and_test pa-&gt;pa_count
ext4_mb_put_pa (2):		lock pa-&gt;pa_lock
ext4_mb_put_pa (3):			check pa-&gt;pa_deleted
ext4_mb_put_pa (4):			set pa-&gt;pa_deleted=1
ext4_mb_put_pa (5):		unlock pa-&gt;pa_lock
ext4_mb_put_pa (6):		remove pa from a list
ext4_mb_pa_callback:		free pa

* Use sequence
ext4_mb_use_preallocated (1):	iterate over preallocation
ext4_mb_use_preallocated (2):	lock pa-&gt;pa_lock
ext4_mb_use_preallocated (3):		check pa-&gt;pa_deleted
ext4_mb_use_preallocated (4):		increase pa-&gt;pa_count
ext4_mb_use_preallocated (5):	unlock pa-&gt;pa_lock
ext4_mb_release_context:	access pa

* Use-after-free sequence
[initial status]		&lt;pa-&gt;pa_deleted = 0, pa_count = 1&gt;
ext4_mb_use_preallocated (1):	iterate over preallocation
ext4_mb_use_preallocated (2):	lock pa-&gt;pa_lock
ext4_mb_use_preallocated (3):		check pa-&gt;pa_deleted
ext4_mb_put_pa (1):		atomic_dec_and_test pa-&gt;pa_count
[pa_count decremented]		&lt;pa-&gt;pa_deleted = 0, pa_count = 0&gt;
ext4_mb_use_preallocated (4):		increase pa-&gt;pa_count
[pa_count incremented]		&lt;pa-&gt;pa_deleted = 0, pa_count = 1&gt;
ext4_mb_use_preallocated (5):	unlock pa-&gt;pa_lock
ext4_mb_put_pa (2):		lock pa-&gt;pa_lock
ext4_mb_put_pa (3):			check pa-&gt;pa_deleted
ext4_mb_put_pa (4):			set pa-&gt;pa_deleted=1
[race condition!]		&lt;pa-&gt;pa_deleted = 1, pa_count = 1&gt;
ext4_mb_put_pa (5):		unlock pa-&gt;pa_lock
ext4_mb_put_pa (6):		remove pa from a list
ext4_mb_pa_callback:		free pa
ext4_mb_release_context:	access pa

AddressSanitizer has detected use-after-free in ext4_mb_new_blocks
Bug report: http://goo.gl/rG1On3

Signed-off-by: Junho Ryu &lt;jayr@google.com&gt;
Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
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</entry>
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