linux-toradex.git/fs, branch v3.14.7

mm: add !pte_present() check on existing hugetlb_entry callbacks

2014-06-11T18:54:13+00:00

commit d4c54919ed86302094c0ca7d48a8cbd4ee753e92 upstream.

The age table walker doesn't check non-present hugetlb entry in common
path, so hugetlb_entry() callbacks must check it.  The reason for this
behavior is that some callers want to handle it in its own way.

[ I think that reason is bogus, btw - it should just do what the regular
  code does, which is to call the "pte_hole()" function for such hugetlb
  entries  - Linus]

However, some callers don't check it now, which causes unpredictable
result, for example when we have a race between migrating hugepage and
reading /proc/pid/numa_maps.  This patch fixes it by adding !pte_present
checks on buggy callbacks.

This bug exists for years and got visible by introducing hugepage
migration.

ChangeLog v2:
- fix if condition (check !pte_present() instead of pte_present())

Reported-by: Sasha Levin 
Signed-off-by: Naoya Horiguchi 
Cc: Rik van Riel 
Signed-off-by: Andrew Morton 
[ Backported to 3.15.  Signed-off-by: Josh Boyer  ]
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

sysfs: make sure read buffer is zeroed

2014-06-07T17:28:24+00:00

commit f5c16f29bf5e57ba4051fc7785ba7f035f798c71 upstream.

13c589d5b0ac ("sysfs: use seq_file when reading regular files")
switched sysfs from custom read implementation to seq_file to enable
later transition to kernfs.  After the change, the buffer passed to
->show() is acquired through seq_get_buf(); unfortunately, this
introduces a subtle behavior change.  Before the commit, the buffer
passed to ->show() was always zero as it was allocated using
get_zeroed_page().  Because seq_file doesn't clear buffers on
allocation and neither does seq_get_buf(), after the commit, depending
on the behavior of ->show(), we may end up exposing uninitialized data
to userland thus possibly altering userland visible behavior and
leaking information.

Fix it by explicitly clearing the buffer.

Signed-off-by: Tejun Heo 
Reported-by: Ron 
Fixes: 13c589d5b0ac ("sysfs: use seq_file when reading regular files")
Signed-off-by: Greg Kroah-Hartman

metag: Reduce maximum stack size to 256MB

2014-06-07T17:28:23+00:00

commit d71f290b4e98a39f49f2595a13be3b4d5ce8e1f1 upstream.

Specify the maximum stack size for arches where the stack grows upward
(parisc and metag) in asm/processor.h rather than hard coding in
fs/exec.c so that metag can specify a smaller value of 256MB rather than
1GB.

This fixes a BUG on metag if the RLIMIT_STACK hard limit is increased
beyond a safe value by root. E.g. when starting a process after running
"ulimit -H -s unlimited" it will then attempt to use a stack size of the
maximum 1GB which is far too big for metag's limited user virtual
address space (stack_top is usually 0x3ffff000):

BUG: failure at fs/exec.c:589/shift_arg_pages()!

Signed-off-by: James Hogan 
Cc: Helge Deller 
Cc: "James E.J. Bottomley" 
Cc: linux-parisc@vger.kernel.org
Cc: linux-metag@vger.kernel.org
Cc: John David Anglin 
Signed-off-by: Greg Kroah-Hartman

nfsd4: remove lockowner when removing lock stateid

2014-06-07T17:28:21+00:00

commit a1b8ff4c97b4375d21b6d6c45d75877303f61b3b upstream.

The nfsv4 state code has always assumed a one-to-one correspondance
between lock stateid's and lockowners even if it appears not to in some
places.

We may actually change that, but for now when FREE_STATEID releases a
lock stateid it also needs to release the parent lockowner.

Symptoms were a subsequent LOCK crashing in find_lockowner_str when it
calls same_lockowner_ino on a lockowner that unexpectedly has an empty
so_stateids list.

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

nfsd4: warn on finding lockowner without stateid's

2014-06-07T17:28:21+00:00

commit 27b11428b7de097c42f205beabb1764f4365443b upstream.

The current code assumes a one-to-one lockowner<->lock stateid
correspondance.

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

NFSD: Call ->set_acl with a NULL ACL structure if no entries

2014-06-07T17:28:21+00:00

commit aa07c713ecfc0522916f3cd57ac628ea6127c0ec upstream.

After setting ACL for directory, I got two problems that caused
by the cached zero-length default posix acl.

This patch make sure nfsd4_set_nfs4_acl calls ->set_acl
with a NULL ACL structure if there are no entries.

Thanks for Christoph Hellwig's advice.

First problem:
............ hang ...........

Second problem:
[ 1610.167668] ------------[ cut here ]------------
[ 1610.168320] kernel BUG at /root/nfs/linux/fs/nfsd/nfs4acl.c:239!
[ 1610.168320] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC
[ 1610.168320] Modules linked in: nfsv4(OE) nfs(OE) nfsd(OE)
rpcsec_gss_krb5 fscache ip6t_rpfilter ip6t_REJECT cfg80211 xt_conntrack
rfkill ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables
ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6
ip6table_mangle ip6table_security ip6table_raw ip6table_filter
ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4
nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw
auth_rpcgss nfs_acl snd_intel8x0 ppdev lockd snd_ac97_codec ac97_bus
snd_pcm snd_timer e1000 pcspkr parport_pc snd parport serio_raw joydev
i2c_piix4 sunrpc(OE) microcode soundcore i2c_core ata_generic pata_acpi
[last unloaded: nfsd]
[ 1610.168320] CPU: 0 PID: 27397 Comm: nfsd Tainted: G           OE
3.15.0-rc1+ #15
[ 1610.168320] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS
VirtualBox 12/01/2006
[ 1610.168320] task: ffff88005ab653d0 ti: ffff88005a944000 task.ti:
ffff88005a944000
[ 1610.168320] RIP: 0010:[]  []
_posix_to_nfsv4_one+0x3cd/0x3d0 [nfsd]
[ 1610.168320] RSP: 0018:ffff88005a945b00  EFLAGS: 00010293
[ 1610.168320] RAX: 0000000000000001 RBX: ffff88006700bac0 RCX:
0000000000000000
[ 1610.168320] RDX: 0000000000000000 RSI: ffff880067c83f00 RDI:
ffff880068233300
[ 1610.168320] RBP: ffff88005a945b48 R08: ffffffff81c64830 R09:
0000000000000000
[ 1610.168320] R10: ffff88004ea85be0 R11: 000000000000f475 R12:
ffff880068233300
[ 1610.168320] R13: 0000000000000003 R14: 0000000000000002 R15:
ffff880068233300
[ 1610.168320] FS:  0000000000000000(0000) GS:ffff880077800000(0000)
knlGS:0000000000000000
[ 1610.168320] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 1610.168320] CR2: 00007f5bcbd3b0b9 CR3: 0000000001c0f000 CR4:
00000000000006f0
[ 1610.168320] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
0000000000000000
[ 1610.168320] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
0000000000000400
[ 1610.168320] Stack:
[ 1610.168320]  ffffffff00000000 0000000b67c83500 000000076700bac0
0000000000000000
[ 1610.168320]  ffff88006700bac0 ffff880068233300 ffff88005a945c08
0000000000000002
[ 1610.168320]  0000000000000000 ffff88005a945b88 ffffffffa034e2d5
000000065a945b68
[ 1610.168320] Call Trace:
[ 1610.168320]  [] nfsd4_get_nfs4_acl+0x95/0x150 [nfsd]
[ 1610.168320]  [] nfsd4_encode_fattr+0x646/0x1e70 [nfsd]
[ 1610.168320]  [] ? kmemleak_alloc+0x4e/0xb0
[ 1610.168320]  [] ?
nfsd_setuser_and_check_port+0x52/0x80 [nfsd]
[ 1610.168320]  [] ? selinux_cred_prepare+0x1b/0x30
[ 1610.168320]  [] nfsd4_encode_getattr+0x5a/0x60 [nfsd]
[ 1610.168320]  [] nfsd4_encode_operation+0x67/0x110
[nfsd]
[ 1610.168320]  [] nfsd4_proc_compound+0x21d/0x810 [nfsd]
[ 1610.168320]  [] nfsd_dispatch+0xbb/0x200 [nfsd]
[ 1610.168320]  [] svc_process_common+0x46d/0x6d0 [sunrpc]
[ 1610.168320]  [] svc_process+0x103/0x170 [sunrpc]
[ 1610.168320]  [] nfsd+0xbf/0x130 [nfsd]
[ 1610.168320]  [] ? nfsd_destroy+0x80/0x80 [nfsd]
[ 1610.168320]  [] kthread+0xd2/0xf0
[ 1610.168320]  [] ? insert_kthread_work+0x40/0x40
[ 1610.168320]  [] ret_from_fork+0x7c/0xb0
[ 1610.168320]  [] ? insert_kthread_work+0x40/0x40
[ 1610.168320] Code: 78 02 e9 e7 fc ff ff 31 c0 31 d2 31 c9 66 89 45 ce
41 8b 04 24 66 89 55 d0 66 89 4d d2 48 8d 04 80 49 8d 5c 84 04 e9 37 fd
ff ff <0f> 0b 90 0f 1f 44 00 00 55 8b 56 08 c7 07 00 00 00 00 8b 46 0c
[ 1610.168320] RIP  [] _posix_to_nfsv4_one+0x3cd/0x3d0
[nfsd]
[ 1610.168320]  RSP 
[ 1610.257313] ---[ end trace 838254e3e352285b ]---

Signed-off-by: Kinglong Mee 
Signed-off-by: J. Bruce Fields 
Signed-off-by: Greg Kroah-Hartman

NFSd: call rpc_destroy_wait_queue() from free_client()

2014-06-07T17:28:21+00:00

commit 4cb57e3032d4e4bf5e97780e9907da7282b02b0c upstream.

Mainly to ensure that we don't leave any hanging timers.

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

NFSd: Move default initialisers from create_client() to alloc_client()

2014-06-07T17:28:21+00:00

commit 5694c93e6c4954fa9424c215f75eeb919bddad64 upstream.

Aside from making it clearer what is non-trivial in create_client(), it
also fixes a bug whereby we can call free_client() before idr_init()
has been called.

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

fix races between __d_instantiate() and checks of dentry flags

2014-06-07T17:28:20+00:00

commit 22213318af7ae265bc6cd8aef2febbc2d69a2440 upstream.

in non-lazy walk we need to be careful about dentry switching from
negative to positive - both ->d_flags and ->d_inode are updated,
and in some places we might see only one store.  The cases where
dentry has been obtained by dcache lookup with ->i_mutex held on
parent are safe - ->d_lock and ->i_mutex provide all the barriers
we need.  However, there are several places where we run into
trouble:
	* do_last() fetches ->d_inode, then checks ->d_flags and
assumes that inode won't be NULL unless d_is_negative() is true.
Race with e.g. creat() - we might have fetched the old value of
->d_inode (still NULL) and new value of ->d_flags (already not
DCACHE_MISS_TYPE).  Lin Ming has observed and reported the resulting
oops.
	* a bunch of places checks ->d_inode for being non-NULL,
then checks ->d_flags for "is it a symlink".  Race with symlink(2)
in case if our CPU sees ->d_inode update first - we see non-NULL
there, but ->d_flags still contains DCACHE_MISS_TYPE instead of
DCACHE_SYMLINK_TYPE.  Result: false negative on "should we follow
link here?", with subsequent unpleasantness.

Reported-and-tested-by: Lin Ming 
Signed-off-by: Al Viro 
Signed-off-by: Greg Kroah-Hartman

autofs: fix lockref lookup

2014-06-07T17:28:20+00:00

commit 6b6751f7feba68d8f5c72b72cc69a1c5a625529c upstream.

autofs needs to be able to see private data dentry flags for its dentrys
that are being created but not yet hashed and for its dentrys that have
been rmdir()ed but not yet freed.  It needs to do this so it can block
processes in these states until a status has been returned to indicate
the given operation is complete.

It does this by keeping two lists, active and expring, of dentrys in
this state and uses ->d_release() to keep them stable while it checks
the reference count to determine if they should be used.

But with the recent lockref changes dentrys being freed sometimes don't
transition to a reference count of 0 before being freed so autofs can
occassionally use a dentry that is invalid which can lead to a panic.

Signed-off-by: Ian Kent 
Cc: Al Viro 
Cc: Linus Torvalds 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman