linux-toradex.git/include/linux, branch v3.8.2

pstore: Avoid deadlock in panic and emergency-restart path

2013-03-03T22:03:38+00:00

commit 9f244e9cfd70c7c0f82d3c92ce772ab2a92d9f64 upstream.

[Issue]

When pstore is in panic and emergency-restart paths, it may be blocked
in those paths because it simply takes spin_lock.

This is an example scenario which pstore may hang up in a panic path:

 - cpuA grabs psinfo->buf_lock
 - cpuB panics and calls smp_send_stop
 - smp_send_stop sends IRQ to cpuA
 - after 1 second, cpuB gives up on cpuA and sends an NMI instead
 - cpuA is now in an NMI handler while still holding buf_lock
 - cpuB is deadlocked

This case may happen if a firmware has a bug and
cpuA is stuck talking with it more than one second.

Also, this is a similar scenario in an emergency-restart path:

 - cpuA grabs psinfo->buf_lock and stucks in a firmware
 - cpuB kicks emergency-restart via either sysrq-b or hangcheck timer.
   And then, cpuB is deadlocked by taking psinfo->buf_lock again.

[Solution]

This patch avoids the deadlocking issues in both panic and emergency_restart
paths by introducing a function, is_non_blocking_path(), to check if a cpu
can be blocked in current path.

With this patch, pstore is not blocked even if another cpu has
taken a spin_lock, in those paths by changing from spin_lock_irqsave
to spin_trylock_irqsave.

In addition, according to a comment of emergency_restart() in kernel/sys.c,
spin_lock shouldn't be taken in an emergency_restart path to avoid
deadlock. This patch fits the comment below.


/**
 *      emergency_restart - reboot the system
 *
 *      Without shutting down any hardware or taking any locks
 *      reboot the system.  This is called when we know we are in
 *      trouble so this is our best effort to reboot.  This is
 *      safe to call in interrupt context.
 */
void emergency_restart(void)


Signed-off-by: Seiji Aguchi 
Acked-by: Don Zickus 
Signed-off-by: Tony Luck 
Cc: CAI Qian 
Signed-off-by: Greg Kroah-Hartman

xen-blkfront: drop the use of llist_for_each_entry_safe

2013-03-03T22:03:35+00:00

commit f84adf4921ae3115502f44ff467b04bf2f88cf04 upstream.

Replace llist_for_each_entry_safe with a while loop.

llist_for_each_entry_safe can trigger a bug in GCC 4.1, so it's best
to remove it and use a while loop and do the deletion manually.

Specifically this bug can be triggered by hot-unplugging a disk, either
by doing xm block-detach or by save/restore cycle.

BUG: unable to handle kernel paging request at fffffffffffffff0
IP: [] blkif_free+0x63/0x130 [xen_blkfront]
The crash call trace is:
	...
bad_area_nosemaphore+0x13/0x20
do_page_fault+0x25e/0x4b0
page_fault+0x25/0x30
? blkif_free+0x63/0x130 [xen_blkfront]
blkfront_resume+0x46/0xa0 [xen_blkfront]
xenbus_dev_resume+0x6c/0x140
pm_op+0x192/0x1b0
device_resume+0x82/0x1e0
dpm_resume+0xc9/0x1a0
dpm_resume_end+0x15/0x30
do_suspend+0x117/0x1e0

When drilling down to the assembler code, on newer GCC it does
.L29:
        cmpq    $-16, %r12      #, persistent_gnt check
        je      .L30    	#, out of the loop
.L25:
	... code in the loop
        testq   %r13, %r13      # n
        je      .L29    	#, back to the top of the loop
        cmpq    $-16, %r12      #, persistent_gnt check
        movq    16(%r12), %r13  # .node.next, n
        jne     .L25    	#,	back to the top of the loop
.L30:

While on GCC 4.1, it is:
L78:
	... code in the loop
	testq   %r13, %r13      # n
        je      .L78    #,	back to the top of the loop
        movq    16(%rbx), %r13  # .node.next, n
        jmp     .L78    #,	back to the top of the loop

Which basically means that the exit loop condition instead of
being:

	&(pos)->member != NULL;

is:
	;

which makes the loop unbound.

Since xen-blkfront is the only user of the llist_for_each_entry_safe
macro remove it from llist.h.

Orabug: 16263164
Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Greg Kroah-Hartman

quota: autoload the quota_v2 module for QFMT_VFS_V1 quota format

2013-03-03T22:03:32+00:00

commit c3ad83d9efdfe6a86efd44945a781f00c879b7b4 upstream.

Otherwise, ext4 file systems with the quota featured enable will get a
very confusing "No such process" error message if the quota code is
built as a module and the quota_v2 module has not been loaded.

Signed-off-by: "Theodore Ts'o" 
Reviewed-by: Carlos Maiolino 
Acked-by: Jan Kara 
Signed-off-by: Greg Kroah-Hartman

vlan: adjust vlan_set_encap_proto() for its callers

2013-02-28T13:38:41+00:00

[ Upstream commit da8c87241c26aac81a64c7e4d21d438a33018f4e ]

There are two places to call vlan_set_encap_proto():
vlan_untag() and __pop_vlan_tci().

vlan_untag() assumes skb->data points after mac addr, otherwise
the following code

        vhdr = (struct vlan_hdr *) skb->data;
        vlan_tci = ntohs(vhdr->h_vlan_TCI);
        __vlan_hwaccel_put_tag(skb, vlan_tci);

        skb_pull_rcsum(skb, VLAN_HLEN);

won't be correct. But __pop_vlan_tci() assumes points _before_
mac addr.

In vlan_set_encap_proto(), it looks for some magic L2 value
after mac addr:

        rawp = skb->data;
        if (*(unsigned short *) rawp == 0xFFFF)
	...

Therefore __pop_vlan_tci() is obviously wrong.

A quick fix is avoiding using skb->data in vlan_set_encap_proto(),
use 'vhdr+1' is always correct in both cases.

Signed-off-by: Cong Wang 
Cc: David S. Miller 
Cc: Jesse Gross 
Acked-by: Jesse Gross 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

fb: Yet another band-aid for fixing lockdep mess

2013-02-28T13:38:39+00:00

commit e93a9a868792ad71cdd09d75e5a02d8067473c4e upstream.

I've still got lockdep warnings even after Alan's patch, and it seems that
yet more band aids are required to paper over similar paths for
unbind_con_driver() and unregister_con_driver().  After this hack, lockdep
warnings are finally gone.

Signed-off-by: Takashi Iwai 
Cc: Alan Cox 
Cc: Florian Tobias Schandinat 
Cc: Jiri Kosina 
Tested-by: Sedat Dilek 
Signed-off-by: Andrew Morton 
Signed-off-by: Dave Airlie 
Signed-off-by: Greg Kroah-Hartman

fb: rework locking to fix lock ordering on takeover

2013-02-28T13:38:39+00:00

commit 50e244cc793d511b86adea24972f3a7264cae114 upstream.

Adjust the console layer to allow a take over call where the caller
already holds the locks.  Make the fb layer lock in order.

This is partly a band aid, the fb layer is terminally confused about the
locking rules it uses for its notifiers it seems.

[akpm@linux-foundation.org: remove stray non-ascii char, tidy comment]
[akpm@linux-foundation.org: export do_take_over_console()]
[airlied: cleanup another non-ascii char]
Signed-off-by: Alan Cox 
Cc: Florian Tobias Schandinat 
Cc: Stephen Rothwell 
Cc: Jiri Kosina 
Tested-by: Sedat Dilek 
Reviewed-by: Daniel Vetter 
Signed-off-by: Andrew Morton 
Signed-off-by: Dave Airlie 
Signed-off-by: Greg Kroah-Hartman

vgacon/vt: clear buffer attributes when we load a 512 character font (v2)

2013-02-28T13:38:34+00:00

commit 2a2483072393b27f4336ab068a1f48ca19ff1c1e upstream.

When we switch from 256->512 byte font rendering mode, it means the
current contents of the screen is being reinterpreted. The bit that holds
the high bit of the 9-bit font, may have been previously set, and thus
the new font misrenders.

The problem case we see is grub2 writes spaces with the bit set, so it
ends up with data like 0x820, which gets reinterpreted into 0x120 char
which the font translates into G with a circumflex. This flashes up on
screen at boot and is quite ugly.

A current side effect of this patch though is that any rendering on the
screen changes color to a slightly darker color, but at least the screen
no longer corrupts.

v2: as suggested by hpa, always clear the attribute space, whether we
are are going to or from 512 chars.

Signed-off-by: Dave Airlie 
Signed-off-by: Greg Kroah-Hartman

pps: Add pps_lookup_dev() function

2013-02-28T13:38:30+00:00

commit 513b032c98b4b9414aa4e9b4a315cb1bf0380101 upstream.

The PPS serial line discipline wants to attach a PPS device to a tty
without changing the tty code to add a struct pps_device * pointer.

Since the number of PPS devices in a typical system is generally very low
(n=1 is by far the most common), it's practical to search the entire list
of allocated pps devices.  (We capture the timestamp before the lookup,
so the timing isn't affected.)

It is a bit ugly that this function, which is part of the in-kernel
PPS API, has to be in pps.c as opposed to kapi,c, but that's not
something that affects users.

Signed-off-by: George Spelvin 
Acked-by: Rodolfo Giometti 
Signed-off-by: Greg Kroah-Hartman

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2013-02-08T20:55:24+00:00

Pull networking fixes from David Miller:

 1) Revert iwlwifi reclaimed packet tracking, it causes problems for a
    bunch of folks.  From Emmanuel Grumbach.

 2) Work limiting code in brcmsmac wifi driver can clear tx status
    without processing the event.  From Arend van Spriel.

 3) rtlwifi USB driver processes wrong SKB, fix from Larry Finger.

 4) l2tp tunnel delete can race with close, fix from Tom Parkin.

 5) pktgen_add_device() failures are not checked at all, fix from Cong
    Wang.

 6) Fix unintentional removal of carrier off from tun_detach(),
    otherwise we confuse userspace, from Michael S.  Tsirkin.

 7) Don't leak socket reference counts and ubufs in vhost-net driver,
    from Jason Wang.

 8) vmxnet3 driver gets it's initial carrier state wrong, fix from Neil
    Horman.

 9) Protect against USB networking devices which spam the host with 0
    length frames, from Bjørn Mork.

10) Prevent neighbour overflows in ipv6 for locally destined routes,
    from Marcelo Ricardo.  This is the best short-term fix for this, a
    longer term fix has been implemented in net-next.

11) L2TP uses ipv4 datagram routines in it's ipv6 code, whoops.  This
    mistake is largely because the ipv6 functions don't even have some
    kind of prefix in their names to suggest they are ipv6 specific.
    From Tom Parkin.

12) Check SYN packet drops properly in tcp_rcv_fastopen_synack(), from
    Yuchung Cheng.

13) Fix races and TX skb freeing bugs in via-rhine's NAPI support, from
    Francois Romieu and your's truly.

14) Fix infinite loops and divides by zero in TCP congestion window
    handling, from Eric Dumazet, Neal Cardwell, and Ilpo Järvinen.

15) AF_PACKET tx ring handling can leak kernel memory to userspace, fix
    from Phil Sutter.

16) Fix error handling in ipv6 GRE tunnel transmit, from Tommi Rantala.

17) Protect XEN netback driver against hostile frontend putting garbage
    into the rings, don't leak pages in TX GOP checking, and add proper
    resource releasing in error path of xen_netbk_get_requests().  From
    Ian Campbell.

18) SCTP authentication keys should be cleared out and released with
    kzfree(), from Daniel Borkmann.

19) L2TP is a bit too clever trying to maintain skb->truesize, and ends
    up corrupting socket memory accounting to the point where packet
    sending is halted indefinitely.  Just remove the adjustments
    entirely, they aren't really needed.  From Eric Dumazet.

20) ATM Iphase driver uses a data type with the same name as the S390
    headers, rename to fix the build.  From Heiko Carstens.

21) Fix a typo in copying the inner network header offset from one SKB
    to another, from Pravin B Shelar.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (56 commits)
  net: sctp: sctp_endpoint_free: zero out secret key data
  net: sctp: sctp_setsockopt_auth_key: use kzfree instead of kfree
  atm/iphase: rename fregt_t -> ffreg_t
  net: usb: fix regression from FLAG_NOARP code
  l2tp: dont play with skb->truesize
  net: sctp: sctp_auth_key_put: use kzfree instead of kfree
  netback: correct netbk_tx_err to handle wrap around.
  xen/netback: free already allocated memory on failure in xen_netbk_get_requests
  xen/netback: don't leak pages on failure in xen_netbk_tx_check_gop.
  xen/netback: shutdown the ring if it contains garbage.
  net: qmi_wwan: add more Huawei devices, including E320
  net: cdc_ncm: add another Huawei vendor specific device
  ipv6/ip6_gre: fix error case handling in ip6gre_tunnel_xmit()
  tcp: fix for zero packets_in_flight was too broad
  brcmsmac: rework of mac80211 .flush() callback operation
  ssb: unregister gpios before unloading ssb
  bcma: unregister gpios before unloading bcma
  rtlwifi: Fix scheduling while atomic bug
  net: usbnet: fix tx_dropped statistics
  tcp: ipv6: Update MIB counters for drops
  ...

net: usb: fix regression from FLAG_NOARP code

2013-02-08T06:49:49+00:00

In commit 6509141f9c2ba74df6cc72ec35cd1865276ae3a4 ("usbnet: add new
flag FLAG_NOARP for usb net devices"), the newly added flag NOARP was
using an already defined value, which broke drivers using flag
MULTI_PACKET.

Signed-off-by: Lucas Stach 
Signed-off-by: David S. Miller