ARM: 7755/1: handle user space mapped pages in flush_kernel_dcache_page

commit 1bc39742aab09248169ef9d3727c9def3528b3f3 upstream.

Commit f8b63c1 made flush_kernel_dcache_page a no-op assuming that
the pages it needs to handle are kernel mapped only.  However, for
example when doing direct I/O, pages with user space mappings may
occur.

Thus, continue to do lazy flushing if there are no user space
mappings.  Otherwise, flush the kernel cache lines directly.

Signed-off-by: Simon Baatz <gmbnomis@gmail.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ARM: 7772/1: Fix missing flush_kernel_dcache_page() for noMMU

commit 63384fd0b1509acf522a8a8fcede09087eedb7df upstream.

Commit 1bc3974 (ARM: 7755/1: handle user space mapped pages in
flush_kernel_dcache_page) moved the implementation of
flush_kernel_dcache_page() into mm/flush.c but did not implement it
on noMMU ARM.

Signed-off-by: Simon Baatz <gmbnomis@gmail.com>
Acked-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Bluetooth: Fix crash in l2cap_build_cmd() with small MTU

commit 300b962e5244a1ea010df7e88595faa0085b461d upstream.

If a too small MTU value is set with ioctl(HCISETACLMTU) or by a bogus
controller, memory corruption happens due to a memcpy() call with
negative length.

Fix this crash on either incoming or outgoing connections with a MTU
smaller than L2CAP_HDR_SIZE + L2CAP_CMD_HDR_SIZE:

[   46.885433] BUG: unable to handle kernel paging request at f56ad000
[   46.888037] IP: [<c03d94cd>] memcpy+0x1d/0x40
[   46.888037] *pdpt = 0000000000ac3001 *pde = 00000000373f8067 *pte = 80000000356ad060
[   46.888037] Oops: 0002 [#1] SMP DEBUG_PAGEALLOC
[   46.888037] Modules linked in: hci_vhci bluetooth virtio_balloon i2c_piix4 uhci_hcd usbcore usb_common
[   46.888037] CPU: 0 PID: 1044 Comm: kworker/u3:0 Not tainted 3.10.0-rc1+ #12
[   46.888037] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
[   46.888037] Workqueue: hci0 hci_rx_work [bluetooth]
[   46.888037] task: f59b15b0 ti: f55c4000 task.ti: f55c4000
[   46.888037] EIP: 0060:[<c03d94cd>] EFLAGS: 00010212 CPU: 0
[   46.888037] EIP is at memcpy+0x1d/0x40
[   46.888037] EAX: f56ac1c0 EBX: fffffff8 ECX: 3ffffc6e EDX: f55c5cf2
[   46.888037] ESI: f55c6b32 EDI: f56ad000 EBP: f55c5c68 ESP: f55c5c5c
[   46.888037]  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
[   46.888037] CR0: 8005003b CR2: f56ad000 CR3: 3557d000 CR4: 000006f0
[   46.888037] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[   46.888037] DR6: ffff0ff0 DR7: 00000400
[   46.888037] Stack:
[   46.888037]  fffffff8 00000010 00000003 f55c5cac f8c6a54c ffffffff f8c69eb2 00000000
[   46.888037]  f4783cdc f57f0070 f759c590 1001c580 00000003 0200000a 00000000 f5a88560
[   46.888037]  f5ba2600 f5a88560 00000041 00000000 f55c5d90 f8c6f4c7 00000008 f55c5cf2
[   46.888037] Call Trace:
[   46.888037]  [<f8c6a54c>] l2cap_send_cmd+0x1cc/0x230 [bluetooth]
[   46.888037]  [<f8c69eb2>] ? l2cap_global_chan_by_psm+0x152/0x1a0 [bluetooth]
[   46.888037]  [<f8c6f4c7>] l2cap_connect+0x3f7/0x540 [bluetooth]
[   46.888037]  [<c019b37b>] ? trace_hardirqs_off+0xb/0x10
[   46.888037]  [<c01a0ff8>] ? mark_held_locks+0x68/0x110
[   46.888037]  [<c064ad20>] ? mutex_lock_nested+0x280/0x360
[   46.888037]  [<c064b9d9>] ? __mutex_unlock_slowpath+0xa9/0x150
[   46.888037]  [<c01a118c>] ? trace_hardirqs_on_caller+0xec/0x1b0
[   46.888037]  [<c064ad08>] ? mutex_lock_nested+0x268/0x360
[   46.888037]  [<c01a125b>] ? trace_hardirqs_on+0xb/0x10
[   46.888037]  [<f8c72f8d>] l2cap_recv_frame+0xb2d/0x1d30 [bluetooth]
[   46.888037]  [<c01a0ff8>] ? mark_held_locks+0x68/0x110
[   46.888037]  [<c064b9d9>] ? __mutex_unlock_slowpath+0xa9/0x150
[   46.888037]  [<c01a118c>] ? trace_hardirqs_on_caller+0xec/0x1b0
[   46.888037]  [<f8c754f1>] l2cap_recv_acldata+0x2a1/0x320 [bluetooth]
[   46.888037]  [<f8c491d8>] hci_rx_work+0x518/0x810 [bluetooth]
[   46.888037]  [<f8c48df2>] ? hci_rx_work+0x132/0x810 [bluetooth]
[   46.888037]  [<c0158979>] process_one_work+0x1a9/0x600
[   46.888037]  [<c01588fb>] ? process_one_work+0x12b/0x600
[   46.888037]  [<c015922e>] ? worker_thread+0x19e/0x320
[   46.888037]  [<c015922e>] ? worker_thread+0x19e/0x320
[   46.888037]  [<c0159187>] worker_thread+0xf7/0x320
[   46.888037]  [<c0159090>] ? rescuer_thread+0x290/0x290
[   46.888037]  [<c01602f8>] kthread+0xa8/0xb0
[   46.888037]  [<c0656777>] ret_from_kernel_thread+0x1b/0x28
[   46.888037]  [<c0160250>] ? flush_kthread_worker+0x120/0x120
[   46.888037] Code: c3 90 8d 74 26 00 e8 63 fc ff ff eb e8 90 55 89 e5 83 ec 0c 89 5d f4 89 75 f8 89 7d fc 3e 8d 74 26 00 89 cb 89 c7 c1 e9 02 89 d6 <f3> a5 89 d9 83 e1 03 74 02 f3 a4 8b 5d f4 8b 75 f8 8b 7d fc 89
[   46.888037] EIP: [<c03d94cd>] memcpy+0x1d/0x40 SS:ESP 0068:f55c5c5c
[   46.888037] CR2: 00000000f56ad000
[   46.888037] ---[ end trace 0217c1f4d78714a9 ]---

Signed-off-by: Anderson Lizardo <anderson.lizardo@openbossa.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
hw_breakpoint: Use cpu_possible_mask in {reserve,release}_bp_slot()

commit c790b0ad23f427c7522ffed264706238c57c007e upstream.

fetch_bp_busy_slots() and toggle_bp_slot() use
for_each_online_cpu(), this is obviously wrong wrt cpu_up() or
cpu_down(), we can over/under account the per-cpu numbers.

For example:

	# echo 0 >> /sys/devices/system/cpu/cpu1/online
	# perf record -e mem:0x10 -p 1 &
	# echo 1 >> /sys/devices/system/cpu/cpu1/online
	# perf record -e mem:0x10,mem:0x10,mem:0x10,mem:0x10 -C1 -a &
	# taskset -p 0x2 1

triggers the same WARN_ONCE("Can't find any breakpoint slot") in
arch_install_hw_breakpoint().

Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20130620155009.GA6327@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
dlci: acquire rtnl_lock before calling __dev_get_by_name()

commit 11eb2645cbf38a08ae491bf6c602eea900ec0bb5 upstream.

Otherwise the net device returned can be freed at anytime.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
dlci: validate the net device in dlci_del()

commit 578a1310f2592ba90c5674bca21c1dbd1adf3f0a upstream.

We triggered an oops while running trinity with 3.4 kernel:

BUG: unable to handle kernel paging request at 0000000100000d07
IP: [<ffffffffa0109738>] dlci_ioctl+0xd8/0x2d4 [dlci]
PGD 640c0d067 PUD 0
Oops: 0000 [#1] PREEMPT SMP
CPU 3
...
Pid: 7302, comm: trinity-child3 Not tainted 3.4.24.09+ 40 Huawei Technologies Co., Ltd. Tecal RH2285          /BC11BTSA
RIP: 0010:[<ffffffffa0109738>]  [<ffffffffa0109738>] dlci_ioctl+0xd8/0x2d4 [dlci]
...
Call Trace:
  [<ffffffff8137c5c3>] sock_ioctl+0x153/0x280
  [<ffffffff81195494>] do_vfs_ioctl+0xa4/0x5e0
  [<ffffffff8118354a>] ? fget_light+0x3ea/0x490
  [<ffffffff81195a1f>] sys_ioctl+0x4f/0x80
  [<ffffffff81478b69>] system_call_fastpath+0x16/0x1b
...

It's because the net device is not a dlci device.

Reported-by: Li Jinyue <lijinyue@huawei.com>
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
perf: Disable monitoring on setuid processes for regular users

commit 2976b10f05bd7f6dab9f9e7524451ddfed656a89 upstream.

There was a a bug in setup_new_exec(), whereby
the test to disabled perf monitoring was not
correct because the new credentials for the
process were not yet committed and therefore
the get_dumpable() test was never firing.

The patch fixes the problem by moving the
perf_event test until after the credentials
are committed.

Signed-off-by: Stephane Eranian <eranian@google.com>
Tested-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
UBIFS: prepare to fix a horrid bug

commit 33f1a63ae84dfd9ad298cf275b8f1887043ced36 upstream.

Al Viro pointed me to the fact that '->readdir()' and '->llseek()' have no
mutual exclusion, which means the 'ubifs_dir_llseek()' can be run while we are
in the middle of 'ubifs_readdir()'.

First of all, this means that 'file->private_data' can be freed while
'ubifs_readdir()' uses it.  But this particular patch does not fix the problem.
This patch is only a preparation, and the fix will follow next.

In this patch we make 'ubifs_readdir()' stop using 'file->f_pos' directly,
because 'file->f_pos' can be changed by '->llseek()' at any point. This may
lead 'ubifs_readdir()' to returning inconsistent data: directory entry names
may correspond to incorrect file positions.

So here we introduce a local variable 'pos', read 'file->f_pose' once at very
the beginning, and then stick to 'pos'. The result of this is that when
'ubifs_dir_llseek()' changes 'file->f_pos' while we are in the middle of
'ubifs_readdir()', the latter "wins".

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
UBIFS: fix a horrid bug

commit 605c912bb843c024b1ed173dc427cd5c08e5d54d upstream.

Al Viro pointed me to the fact that '->readdir()' and '->llseek()' have no
mutual exclusion, which means the 'ubifs_dir_llseek()' can be run while we are
in the middle of 'ubifs_readdir()'.

This means that 'file->private_data' can be freed while 'ubifs_readdir()' uses
it, and this is a very bad bug: not only 'ubifs_readdir()' can return garbage,
but this may corrupt memory and lead to all kinds of problems like crashes an
security holes.

This patch fixes the problem by using the 'file->f_version' field, which
'->llseek()' always unconditionally sets to zero. We set it to 1 in
'ubifs_readdir()' and whenever we detect that it became 0, we know there was a
seek and it is time to clear the state saved in 'file->private_data'.

I tested this patch by writing a user-space program which runds readdir and
seek in parallell. I could easily crash the kernel without these patches, but
could not crash it with these patches.

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pch_uart: fix a deadlock when pch_uart as console

commit 384e301e3519599b000c1a2ecd938b533fc15d85 upstream.

When we use pch_uart as system console like 'console=ttyPCH0,115200',
then 'send break' to it. We'll encounter the deadlock on a cpu/core,
with interrupts disabled on the core. When we happen to have all irqs
affinity to cpu0 then the deadlock on cpu0 actually deadlock whole
system.

In pch_uart_interrupt, we have spin_lock_irqsave(&priv->lock, flags)
then call pch_uart_err_ir when break is received. Then the call to
dev_err would actually call to pch_console_write then we'll run into
another spin_lock(&priv->lock), with interrupts disabled.

So in the call sequence lead by pch_uart_interrupt, we should be
carefully to call functions that will 'print message to console' only
in case the uart port is not being used as serial console.

Signed-off-by: Liang Li <liang.li@windriver.com>
Cc: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
perf: Fix perf mmap bugs

commit 26cb63ad11e04047a64309362674bcbbd6a6f246 upstream.

Vince reported a problem found by his perf specific trinity
fuzzer.

Al noticed 2 problems with perf's mmap():

 - it has issues against fork() since we use vma->vm_mm for accounting.
 - it has an rb refcount leak on double mmap().

We fix the issues against fork() by using VM_DONTCOPY; I don't
think there's code out there that uses this; we didn't hear
about weird accounting problems/crashes. If we do need this to
work, the previously proposed VM_PINNED could make this work.

Aside from the rb reference leak spotted by Al, Vince's example
prog was indeed doing a double mmap() through the use of
perf_event_set_output().

This exposes another problem, since we now have 2 events with
one buffer, the accounting gets screwy because we account per
event. Fix this by making the buffer responsible for its own
accounting.

[Backporting for 3.4-stable.
VM_RESERVED flag was replaced with pair 'VM_DONTEXPAND | VM_DONTDUMP' in
314e51b9 since 3.7.0-rc1, and 314e51b9 comes from a big patchset, we didn't
backport the patchset, so I restored 'VM_DNOTEXPAND | VM_DONTDUMP' as before:
-       vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
+       vma->vm_flags |= VM_DONTCOPY | VM_RESERVED;
 -- zliu]

Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Link: http://lkml.kernel.org/r/20130528085548.GA12193@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Zhouping Liu <zliu@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
perf: Fix mmap() accounting hole

commit 9bb5d40cd93c9dd4be74834b1dcb1ba03629716b upstream.

Vince's fuzzer once again found holes. This time it spotted a leak in
the locked page accounting.

When an event had redirected output and its close() was the last
reference to the buffer we didn't have a vm context to undo accounting.

Change the code to destroy the buffer on the last munmap() and detach
all redirected events at that time. This provides us the right context
to undo the vm accounting.

[Backporting for 3.4-stable.
VM_RESERVED flag was replaced with pair 'VM_DONTEXPAND | VM_DONTDUMP' in
314e51b9 since 3.7.0-rc1, and 314e51b9 comes from a big patchset, we didn't
backport the patchset, so I restored 'VM_DNOTEXPAND | VM_DONTDUMP' as before:
-	vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
+	vma->vm_flags |= VM_DONTCOPY | VM_RESERVED;
 -- zliu]

Reported-and-tested-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130604084421.GI8923@twins.programming.kicks-ass.net
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Zhouping Liu <zliu@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux 3.4.52