linux-stable.git/include/linux, branch linux-4.2.y

ext4, jbd2: ensure entering into panic after recording an error in superblock

2015-12-15T05:25:42+00:00

commit 4327ba52afd03fc4b5afa0ee1d774c9c5b0e85c5 upstream.

If a EXT4 filesystem utilizes JBD2 journaling and an error occurs, the
journaling will be aborted first and the error number will be recorded
into JBD2 superblock and, finally, the system will enter into the
panic state in "errors=panic" option.  But, in the rare case, this
sequence is little twisted like the below figure and it will happen
that the system enters into panic state, which means the system reset
in mobile environment, before completion of recording an error in the
journal superblock. In this case, e2fsck cannot recognize that the
filesystem failure occurred in the previous run and the corruption
wouldn't be fixed.

Task A                        Task B
ext4_handle_error()
-> jbd2_journal_abort()
  -> __journal_abort_soft()
    -> __jbd2_journal_abort_hard()
    | -> journal->j_flags |= JBD2_ABORT;
    |
    |                         __ext4_abort()
    |                         -> jbd2_journal_abort()
    |                         | -> __journal_abort_soft()
    |                         |   -> if (journal->j_flags & JBD2_ABORT)
    |                         |           return;
    |                         -> panic()
    |
    -> jbd2_journal_update_sb_errno()

Tested-by: Hobin Woo 
Signed-off-by: Daeho Jeong 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

ipv6: add complete rcu protection around np->opt

2015-12-15T05:25:39+00:00

[ Upstream commit 45f6fad84cc305103b28d73482b344d7f5b76f39 ]

This patch addresses multiple problems :

UDP/RAW sendmsg() need to get a stable struct ipv6_txoptions
while socket is not locked : Other threads can change np->opt
concurrently. Dmitry posted a syzkaller
(http://github.com/google/syzkaller) program desmonstrating
use-after-free.

Starting with TCP/DCCP lockless listeners, tcp_v6_syn_recv_sock()
and dccp_v6_request_recv_sock() also need to use RCU protection
to dereference np->opt once (before calling ipv6_dup_options())

This patch adds full RCU protection to np->opt

Reported-by: Dmitry Vyukov 
Signed-off-by: Eric Dumazet 
Acked-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tty: audit: Fix audit source

2015-12-09T19:31:25+00:00

commit 6b2a3d628aa752f0ab825fc6d4d07b09e274d1c1 upstream.

The data to audit/record is in the 'from' buffer (ie., the input
read buffer).

Fixes: 72586c6061ab ("n_tty: Fix auditing support for cannonical mode")
Cc: Miloslav Trmač 
Signed-off-by: Peter Hurley 
Acked-by: Laura Abbott 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

KVM: Provide function for VCPU lookup by id

2015-12-09T19:31:20+00:00

commit db27a7a37aa0b1f8b373f8b0fb72a2ccaafb85b7 upstream.

Let's provide a function to lookup a VCPU by id.

Reviewed-by: Christian Borntraeger 
Reviewed-by: Dominik Dingel 
Signed-off-by: David Hildenbrand 
Signed-off-by: Christian Borntraeger 
[split patch from refactoring patch]
Signed-off-by: Greg Kroah-Hartman

block: don't release bdi while request_queue has live references

2015-11-09T22:37:36+00:00

commit b02176f30cd30acccd3b633ab7d9aed8b5da52ff upstream.

bdi's are initialized in two steps, bdi_init() and bdi_register(), but
destroyed in a single step by bdi_destroy() which, for a bdi embedded
in a request_queue, is called during blk_cleanup_queue() which makes
the queue invisible and starts the draining of remaining usages.

A request_queue's user can access the congestion state of the embedded
bdi as long as it holds a reference to the queue.  As such, it may
access the congested state of a queue which finished
blk_cleanup_queue() but hasn't reached blk_release_queue() yet.
Because the congested state was embedded in backing_dev_info which in
turn is embedded in request_queue, accessing the congested state after
bdi_destroy() was called was fine.  The bdi was destroyed but the
memory region for the congested state remained accessible till the
queue got released.

a13f35e87140 ("writeback: don't embed root bdi_writeback_congested in
bdi_writeback") changed the situation.  Now, the root congested state
which is expected to be pinned while request_queue remains accessible
is separately reference counted and the base ref is put during
bdi_destroy().  This means that the root congested state may go away
prematurely while the queue is between bdi_dstroy() and
blk_cleanup_queue(), which was detected by Andrey's KASAN tests.

The root cause of this problem is that bdi doesn't distinguish the two
steps of destruction, unregistration and release, and now the root
congested state actually requires a separate release step.  To fix the
issue, this patch separates out bdi_unregister() and bdi_exit() from
bdi_destroy().  bdi_unregister() is called from blk_cleanup_queue()
and bdi_exit() from blk_release_queue().  bdi_destroy() is now just a
simple wrapper calling the two steps back-to-back.

While at it, the prototype of bdi_destroy() is moved right below
bdi_setup_and_register() so that the counterpart operations are
located together.

Signed-off-by: Tejun Heo 
Fixes: a13f35e87140 ("writeback: don't embed root bdi_writeback_congested in bdi_writeback")
Reported-and-tested-by: Andrey Konovalov 
Link: http://lkml.kernel.org/g/CAAeHK+zUJ74Zn17=rOyxacHU18SgCfC6bsYW=6kCY5GXJBwGfQ@mail.gmail.com
Reviewed-by: Jan Kara 
Reviewed-by: Jeff Moyer 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

ARM: OMAP1: fix incorrect INT_DMA_LCD

2015-11-09T22:37:35+00:00

commit 1bd5dfe41b994a6e793363894befef76626965a9 upstream.

Commit 685e2d08c54b ("ARM: OMAP1: Change interrupt numbering for
sparse IRQ") turned on SPARSE_IRQ on OMAP1, but forgot to change
the number of INT_DMA_LCD. This broke the boot at least on Nokia 770,
where the device hangs during framebuffer initialization.

Fix by defining INT_DMA_LCD like the other interrupts.

Fixes: 685e2d08c54b ("ARM: OMAP1: Change interrupt numbering for sparse IRQ")
Signed-off-by: Aaro Koskinen 
Signed-off-by: Tony Lindgren 
Signed-off-by: Greg Kroah-Hartman

skbuff: Fix skb checksum partial check.

2015-10-27T00:53:35+00:00

[ Upstream commit 31b33dfb0a144469dd805514c9e63f4993729a48 ]

Earlier patch 6ae459bda tried to detect void ckecksum partial
skb by comparing pull length to checksum offset. But it does
not work for all cases since checksum-offset depends on
updates to skb->data.

Following patch fixes it by validating checksum start offset
after skb-data pointer is updated. Negative value of checksum
offset start means there is no need to checksum.

Fixes: 6ae459bda ("skbuff: Fix skb checksum flag on skb pull")
Reported-by: Andrew Vagin 
Signed-off-by: Pravin B Shelar 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

skbuff: Fix skb checksum flag on skb pull

2015-10-27T00:53:35+00:00

[ Upstream commit 6ae459bdaaeebc632b16e54dcbabb490c6931d61 ]

VXLAN device can receive skb with checksum partial. But the checksum
offset could be in outer header which is pulled on receive. This results
in negative checksum offset for the skb. Such skb can cause the assert
failure in skb_checksum_help(). Following patch fixes the bug by setting
checksum-none while pulling outer header.

Following is the kernel panic msg from old kernel hitting the bug.

------------[ cut here ]------------
kernel BUG at net/core/dev.c:1906!
RIP: 0010:[] skb_checksum_help+0x144/0x150
Call Trace:

[] queue_userspace_packet+0x408/0x470 [openvswitch]
[] ovs_dp_upcall+0x5d/0x60 [openvswitch]
[] ovs_dp_process_packet_with_key+0xe6/0x100 [openvswitch]
[] ovs_dp_process_received_packet+0x4b/0x80 [openvswitch]
[] ovs_vport_receive+0x2a/0x30 [openvswitch]
[] vxlan_rcv+0x53/0x60 [openvswitch]
[] vxlan_udp_encap_recv+0x8b/0xf0 [openvswitch]
[] udp_queue_rcv_skb+0x2dc/0x3b0
[] __udp4_lib_rcv+0x1cf/0x6c0
[] udp_rcv+0x1a/0x20
[] ip_local_deliver_finish+0xdd/0x280
[] ip_local_deliver+0x88/0x90
[] ip_rcv_finish+0x10d/0x370
[] ip_rcv+0x235/0x300
[] __netif_receive_skb+0x55d/0x620
[] netif_receive_skb+0x80/0x90
[] virtnet_poll+0x555/0x6f0
[] net_rx_action+0x134/0x290
[] __do_softirq+0xa8/0x210
[] call_softirq+0x1c/0x30
[] do_softirq+0x65/0xa0
[] irq_exit+0x8e/0xb0
[] do_IRQ+0x63/0xe0
[] common_interrupt+0x6e/0x6e

Reported-by: Anupam Chanda 
Signed-off-by: Pravin B Shelar 
Acked-by: Tom Herbert 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

sched/preempt: Fix cond_resched_lock() and cond_resched_softirq()

2015-10-22T21:49:35+00:00

commit fe32d3cd5e8eb0f82e459763374aa80797023403 upstream.

These functions check should_resched() before unlocking spinlock/bh-enable:
preempt_count always non-zero => should_resched() always returns false.
cond_resched_lock() worked iff spin_needbreak is set.

This patch adds argument "preempt_offset" to should_resched().

preempt_count offset constants for that:

  PREEMPT_DISABLE_OFFSET  - offset after preempt_disable()
  PREEMPT_LOCK_OFFSET     - offset after spin_lock()
  SOFTIRQ_DISABLE_OFFSET  - offset after local_bh_distable()
  SOFTIRQ_LOCK_OFFSET     - offset after spin_lock_bh()

Signed-off-by: Konstantin Khlebnikov 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Alexander Graf 
Cc: Boris Ostrovsky 
Cc: David Vrabel 
Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Fixes: bdb438065890 ("sched: Extract the basic add/sub preempt_count modifiers")
Link: http://lkml.kernel.org/r/20150715095204.12246.98268.stgit@buzz
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

security: fix typo in security_task_prctl

2015-10-22T21:49:29+00:00

commit b7f76ea2ef6739ee484a165ffbac98deb855d3d3 upstream.

Signed-off-by: Jann Horn 
Reviewed-by: Andy Lutomirski 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman