linux-stable.git/fs, branch v4.14.4

lockd: lost rollback of set_grace_period() in lockd_down_net()

2017-12-05T10:26:30+00:00

commit 3a2b19d1ee5633f76ae8a88da7bc039a5d1732aa upstream.

Commit efda760fe95ea ("lockd: fix lockd shutdown race") is incorrect,
it removes lockd_manager and disarm grace_period_end for init_net only.

If nfsd was started from another net namespace lockd_up_net() calls
set_grace_period() that adds lockd_manager into per-netns list
and queues grace_period_end delayed work.

These action should be reverted in lockd_down_net().
Otherwise it can lead to double list_add on after restart nfsd in netns,
and to use-after-free if non-disarmed delayed work will be executed after netns destroy.

Fixes: efda760fe95e ("lockd: fix lockd shutdown race")
Signed-off-by: Vasily Averin 
Signed-off-by: J. Bruce Fields 
Signed-off-by: Greg Kroah-Hartman

nfsd: fix panic in posix_unblock_lock called from nfs4_laundromat

2017-12-05T10:26:30+00:00

commit 64ebe12494fd5d193f014ce38e1fd83cc57883c8 upstream.

From kernel 4.9, my two nfsv4 servers sometimes suffer from
    "panic: unable to handle kernel page request"
in posix_unblock_lock() called from nfs4_laundromat().

These panics diseappear if we revert the commit "nfsd: add a LRU list
for blocked locks".

The cause appears to be a typo in nfs4_laundromat(), which is also
present in nfs4_state_shutdown_net().

Fixes: 7919d0a27f1e "nfsd: add a LRU list for blocked locks"
Cc: jlayton@redhat.com
Reveiwed-by: Jeff Layton 
Signed-off-by: J. Bruce Fields 
Signed-off-by: Greg Kroah-Hartman

nfsd: Fix another OPEN stateid race

2017-12-05T10:26:30+00:00

commit d8a1a000555ecd1b824ac1ed6df8fe364dfbbbb0 upstream.

If nfsd4_process_open2() is initialising a new stateid, and yet the
call to nfs4_get_vfs_file() fails for some reason, then we must
declare the stateid closed, and unhash it before dropping the mutex.

Right now, we unhash the stateid after dropping the mutex, and without
changing the stateid type, meaning that another OPEN could theoretically
look it up and attempt to use it.

Reported-by: Andrew W Elble 
Signed-off-by: Trond Myklebust 
Signed-off-by: J. Bruce Fields 
Signed-off-by: Greg Kroah-Hartman

nfsd: Fix stateid races between OPEN and CLOSE

2017-12-05T10:26:30+00:00

commit 15ca08d3299682dc49bad73251677b2c5017ef08 upstream.

Open file stateids can linger on the nfs4_file list of stateids even
after they have been closed. In order to avoid reusing such a
stateid, and confusing the client, we need to recheck the
nfs4_stid's type after taking the mutex.
Otherwise, we risk reusing an old stateid that was already closed,
which will confuse clients that expect new stateids to conform to
RFC7530 Sections 9.1.4.2 and 16.2.5 or RFC5661 Sections 8.2.2 and 18.2.4.

Signed-off-by: Trond Myklebust 
Signed-off-by: J. Bruce Fields 
Signed-off-by: Greg Kroah-Hartman

btrfs: clear space cache inode generation always

2017-12-05T10:26:30+00:00

commit 8e138e0d92c6c9d3d481674fb14e3439b495be37 upstream.

We discovered a box that had double allocations, and suspected the space
cache may be to blame.  While auditing the write out path I noticed that
if we've already setup the space cache we will just carry on.  This
means that any error we hit after cache_save_setup before we go to
actually write the cache out we won't reset the inode generation, so
whatever was already written will be considered correct, except it'll be
stale.  Fix this by _always_ resetting the generation on the block group
inode, this way we only ever have valid or invalid cache.

With this patch I was no longer able to reproduce cache corruption with
dm-log-writes and my bpf error injection tool.

Signed-off-by: Josef Bacik 
Signed-off-by: David Sterba 
Signed-off-by: Greg Kroah-Hartman

autofs: revert "autofs: fix AT_NO_AUTOMOUNT not being honored"

2017-12-05T10:26:29+00:00

commit 5d38f049cee1e1c4a7ac55aa79d37d01ddcc3860 upstream.

Commit 42f461482178 ("autofs: fix AT_NO_AUTOMOUNT not being honored")
allowed the fstatat(2) system call to properly honor the AT_NO_AUTOMOUNT
flag but introduced a semantic change.

In order to honor AT_NO_AUTOMOUNT a semantic change was made to the
negative dentry case for stat family system calls in follow_automount().

This changed the unconditional triggering of an automount in this case
to no longer be done and an error returned instead.

This has caused more problems than I expected so reverting the change is
needed.

In a discussion with Neil Brown it was concluded that the automount(8)
daemon can implement this change without kernel modifications.  So that
will be done instead and the autofs module documentation updated with a
description of the problem and what needs to be done by module users for
this specific case.

Link: http://lkml.kernel.org/r/151174730120.6162.3848002191530283984.stgit@pluto.themaw.net
Fixes: 42f4614821 ("autofs: fix AT_NO_AUTOMOUNT not being honored")
Signed-off-by: Ian Kent 
Cc: Neil Brown 
Cc: Al Viro 
Cc: David Howells 
Cc: Colin Walters 
Cc: Ondrej Holy 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

autofs: revert "autofs: take more care to not update last_used on path walk"

2017-12-05T10:26:29+00:00

commit 43694d4bf843ddd34519e8e9de983deefeada699 upstream.

While commit 092a53452bb7 ("autofs: take more care to not update
last_used on path walk") helped (partially) resolve a problem where
automounts were not expiring due to aggressive accesses from user space
it has a side effect for very large environments.

This change helps with the expire problem by making the expire more
aggressive but, for very large environments, that means more mount
requests from clients.  When there are a lot of clients that can mean
fairly significant server load increases.

It turns out I put the last_used in this position to solve this very
problem and failed to update my own thinking of the autofs expire
policy.  So the patch being reverted introduces a regression which
should be fixed.

Link: http://lkml.kernel.org/r/151174729420.6162.1832622523537052460.stgit@pluto.themaw.net
Fixes: 092a53452b ("autofs: take more care to not update last_used on path walk")
Signed-off-by: Ian Kent 
Reviewed-by: NeilBrown 
Cc: Al Viro 
Cc: Colin Walters 
Cc: David Howells 
Cc: Ondrej Holy 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

fs/fat/inode.c: fix sb_rdonly() change

2017-12-05T10:26:29+00:00

commit b6e8e12c0aeb5fbf1bf46c84d58cc93aedede385 upstream.

Commit bc98a42c1f7d ("VFS: Convert sb->s_flags & MS_RDONLY to
sb_rdonly(sb)") converted fat_remount():new_rdonly from a bool to an
int.

However fat_remount() depends upon the compiler's conversion of a
non-zero integer into boolean `true'.

Fix it by switching `new_rdonly' back into a bool.

Link: http://lkml.kernel.org/r/87mv3d5x51.fsf@mail.parknet.co.jp
Fixes: bc98a42c1f7d0f8 ("VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb)")
Signed-off-by: OGAWA Hirofumi 
Cc: Joe Perches 
Cc: David Howells 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

exec: avoid RLIMIT_STACK races with prlimit()

2017-12-05T10:26:29+00:00

commit 04e35f4495dd560db30c25efca4eecae8ec8c375 upstream.

While the defense-in-depth RLIMIT_STACK limit on setuid processes was
protected against races from other threads calling setrlimit(), I missed
protecting it against races from external processes calling prlimit().
This adds locking around the change and makes sure that rlim_max is set
too.

Link: http://lkml.kernel.org/r/20171127193457.GA11348@beast
Fixes: 64701dee4178e ("exec: Use sane stack rlimit under secureexec")
Signed-off-by: Kees Cook 
Reported-by: Ben Hutchings 
Reported-by: Brad Spengler 
Acked-by: Serge Hallyn 
Cc: James Morris 
Cc: Andy Lutomirski 
Cc: Oleg Nesterov 
Cc: Jiri Slaby 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

dax: fix PMD faults on zero-length files

2017-11-30T08:40:53+00:00

commit 957ac8c421ad8b5eef9b17fe98e146d8311a541e upstream.

PMD faults on a zero length file on a file system mounted with -o dax
will not generate SIGBUS as expected.

	fd = open(...O_TRUNC);
	addr = mmap(NULL, 2*1024*1024, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
	*addr = 'a';
        

The problem is this code in dax_iomap_pmd_fault:

	max_pgoff = (i_size_read(inode) - 1) >> PAGE_SHIFT;

If the inode size is zero, we end up with a max_pgoff that is way larger
than 0.  :)  Fix it by using DIV_ROUND_UP, as is done elsewhere in the
kernel.

I tested this with some simple test code that ensured that SIGBUS was
received where expected.

Fixes: 642261ac995e ("dax: add struct iomap based DAX PMD support")
Signed-off-by: Jeff Moyer 
Signed-off-by: Dan Williams 
Signed-off-by: Greg Kroah-Hartman