linux-stable.git/drivers/char, branch v3.4.92

random: fix accounting race condition with lockless irq entropy_count update

2014-06-07T23:02:14+00:00

commit 10b3a32d292c21ea5b3ad5ca5975e88bb20b8d68 upstream.

Commit 902c098a3663 ("random: use lockless techniques in the interrupt
path") turned IRQ path from being spinlock protected into lockless
cmpxchg-retry update.

That commit removed r->lock serialization between crediting entropy bits
from IRQ context and accounting when extracting entropy on userspace
read path, but didn't turn the r->entropy_count reads/updates in
account() to use cmpxchg as well.

It has been observed, that under certain circumstances this leads to
read() on /dev/urandom to return 0 (EOF), as r->entropy_count gets
corrupted and becomes negative, which in turn results in propagating 0
all the way from account() to the actual read() call.

Convert the accounting code to be the proper lockless counterpart of
what has been partially done by 902c098a3663.

Signed-off-by: Jiri Kosina 
Cc: Theodore Ts'o 
Cc: Greg KH 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings 
Cc: Qiang Huang 
Signed-off-by: Greg Kroah-Hartman

ipmi: Reset the KCS timeout when starting error recovery

2014-06-07T23:02:00+00:00

commit eb6d78ec213e6938559b801421d64714dafcf4b2 upstream.

The OBF timer in KCS was not reset in one situation when error recovery
was started, resulting in an immediate timeout.

Reported-by: Bodo Stroesser 
Signed-off-by: Corey Minyard 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

ipmi: Fix a race restarting the timer

2014-06-07T23:02:00+00:00

commit 48e8ac2979920ffa39117e2d725afa3a749bfe8d upstream.

With recent changes it is possible for the timer handler to detect an
idle interface and not start the timer, but the thread to start an
operation at the same time.  The thread will not start the timer in that
instance, resulting in the timer not running.

Instead, move all timer operations under the lock and start the timer in
the thread if it detect non-idle and the timer is not already running.
Moving under locks allows the last timeout to be set in both the thread
and the timer.  'Timer is not running' means that the timer is not
pending and smi_timeout() is not running.  So we need a flag to detect
this correctly.

Also fix a few other timeout bugs: setting the last timeout when the
interrupt has to be disabled and the timer started, and setting the last
timeout in check_start_timer_thread possibly racing with the timer

Signed-off-by: Corey Minyard 
Signed-off-by: Bodo Stroesser 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

Char: ipmi_bt_sm, fix infinite loop

2014-04-27T00:13:19+00:00

commit a94cdd1f4d30f12904ab528152731fb13a812a16 upstream.

In read_all_bytes, we do

  unsigned char i;
  ...
  bt->read_data[0] = BMC2HOST;
  bt->read_count = bt->read_data[0];
  ...
  for (i = 1; i <= bt->read_count; i++)
    bt->read_data[i] = BMC2HOST;

If bt->read_data[0] == bt->read_count == 255, we loop infinitely in the
'for' loop.  Make 'i' an 'int' instead of 'char' to get rid of the
overflow and finish the loop after 255 iterations every time.

Signed-off-by: Jiri Slaby 
Reported-and-debugged-by: Rui Hui Dian 
Cc: Tomas Cech 
Cc: Corey Minyard 
Cc: 
Signed-off-by: Corey Minyard 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

raw: test against runtime value of max_raw_minors

2014-02-22T18:32:45+00:00

commit 5bbb2ae3d6f896f8d2082d1eceb6131c2420b7cf upstream.

bind_get() checks the device number it is called with. It uses
MAX_RAW_MINORS for the upper bound. But MAX_RAW_MINORS is set at compile
time while the actual number of raw devices can be set at runtime. This
means the test can either be too strict or too lenient. And if the test
ends up being too lenient bind_get() might try to access memory beyond
what was allocated for "raw_devices".

So check against the runtime value (max_raw_minors) in this function.

Signed-off-by: Paul Bolle 
Acked-by: Jan Kara 
Signed-off-by: Greg Kroah-Hartman

drivers/char/i8k.c: add Dell XPLS L421X

2013-12-12T06:34:12+00:00

commit 9aa5b0181bdf335f0b731d8502e128a862884bcd upstream.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=60772

Signed-off-by: Alan Cox 
Reported-by: Leho Kraav 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

random: run random_int_secret_init() run after all late_initcalls

2013-10-22T08:02:25+00:00

commit 47d06e532e95b71c0db3839ebdef3fe8812fca2c upstream.

The some platforms (e.g., ARM) initializes their clocks as
late_initcalls for some unknown reason.  So make sure
random_int_secret_init() is run after all of the late_initcalls are
run.

Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Greg Kroah-Hartman

virtio: console: return -ENODEV on all read operations after unplug

2013-08-15T05:57:07+00:00

commit 96f97a83910cdb9d89d127c5ee523f8fc040a804 upstream.

If a port gets unplugged while a user is blocked on read(), -ENODEV is
returned.  However, subsequent read()s returned 0, indicating there's no
host-side connection (but not indicating the device went away).

This also happened when a port was unplugged and the user didn't have
any blocking operation pending.  If the user didn't monitor the SIGIO
signal, they won't have a chance to find out if the port went away.

Fix by returning -ENODEV on all read()s after the port gets unplugged.
write() already behaves this way.

Signed-off-by: Amit Shah 
Signed-off-by: Rusty Russell 
Signed-off-by: Greg Kroah-Hartman

virtio: console: fix raising SIGIO after port unplug

2013-08-15T05:57:07+00:00

commit 92d3453815fbe74d539c86b60dab39ecdf01bb99 upstream.

SIGIO should be sent when a port gets unplugged.  It should only be sent
to prcesses that have the port opened, and have asked for SIGIO to be
delivered.  We were clearing out guest_connected before calling
send_sigio_to_port(), resulting in a sigio not getting sent to
processes.

Fix by setting guest_connected to false after invoking the sigio
function.

Signed-off-by: Amit Shah 
Signed-off-by: Rusty Russell 
Signed-off-by: Greg Kroah-Hartman

virtio: console: clean up port data immediately at time of unplug

2013-08-15T05:57:06+00:00

commit ea3768b4386a8d1790f4cc9a35de4f55b92d6442 upstream.

We used to keep the port's char device structs and the /sys entries
around till the last reference to the port was dropped.  This is
actually unnecessary, and resulted in buggy behaviour:

1. Open port in guest
2. Hot-unplug port
3. Hot-plug a port with the same 'name' property as the unplugged one

This resulted in hot-plug being unsuccessful, as a port with the same
name already exists (even though it was unplugged).

This behaviour resulted in a warning message like this one:

-------------------8<---------------------------------------
WARNING: at fs/sysfs/dir.c:512 sysfs_add_one+0xc9/0x130() (Not tainted)
Hardware name: KVM
sysfs: cannot create duplicate filename
'/devices/pci0000:00/0000:00:04.0/virtio0/virtio-ports/vport0p1'

Call Trace:
 [] ? warn_slowpath_common+0x87/0xc0
 [] ? warn_slowpath_fmt+0x46/0x50
 [] ? sysfs_add_one+0xc9/0x130
 [] ? create_dir+0x68/0xb0
 [] ? sysfs_create_dir+0x39/0x50
 [] ? kobject_add_internal+0xb9/0x260
 [] ? kobject_add_varg+0x38/0x60
 [] ? kobject_add+0x44/0x70
 [] ? get_device_parent+0xf4/0x1d0
 [] ? device_add+0xc9/0x650

-------------------8<---------------------------------------

Instead of relying on guest applications to release all references to
the ports, we should go ahead and unregister the port from all the core
layers.  Any open/read calls on the port will then just return errors,
and an unplug/plug operation on the host will succeed as expected.

This also caused buggy behaviour in case of the device removal (not just
a port): when the device was removed (which means all ports on that
device are removed automatically as well), the ports with active
users would clean up only when the last references were dropped -- and
it would be too late then to be referencing char device pointers,
resulting in oopses:

-------------------8<---------------------------------------
PID: 6162   TASK: ffff8801147ad500  CPU: 0   COMMAND: "cat"
 #0 [ffff88011b9d5a90] machine_kexec at ffffffff8103232b
 #1 [ffff88011b9d5af0] crash_kexec at ffffffff810b9322
 #2 [ffff88011b9d5bc0] oops_end at ffffffff814f4a50
 #3 [ffff88011b9d5bf0] die at ffffffff8100f26b
 #4 [ffff88011b9d5c20] do_general_protection at ffffffff814f45e2
 #5 [ffff88011b9d5c50] general_protection at ffffffff814f3db5
    [exception RIP: strlen+2]
    RIP: ffffffff81272ae2  RSP: ffff88011b9d5d00  RFLAGS: 00010246
    RAX: 0000000000000000  RBX: ffff880118901c18  RCX: 0000000000000000
    RDX: ffff88011799982c  RSI: 00000000000000d0  RDI: 3a303030302f3030
    RBP: ffff88011b9d5d38   R8: 0000000000000006   R9: ffffffffa0134500
    R10: 0000000000001000  R11: 0000000000001000  R12: ffff880117a1cc10
    R13: 00000000000000d0  R14: 0000000000000017  R15: ffffffff81aff700
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #6 [ffff88011b9d5d00] kobject_get_path at ffffffff8126dc5d
 #7 [ffff88011b9d5d40] kobject_uevent_env at ffffffff8126e551
 #8 [ffff88011b9d5dd0] kobject_uevent at ffffffff8126e9eb
 #9 [ffff88011b9d5de0] device_del at ffffffff813440c7

-------------------8<---------------------------------------

So clean up when we have all the context, and all that's left to do when
the references to the port have dropped is to free up the port struct
itself.

Reported-by: chayang 
Reported-by: YOGANANTH SUBRAMANIAN 
Reported-by: FuXiangChun 
Reported-by: Qunfang Zhang 
Reported-by: Sibiao Luo 
Signed-off-by: Amit Shah 
Signed-off-by: Rusty Russell 
Signed-off-by: Greg Kroah-Hartman