linux-toradex.git/include/linux, branch v3.2.48

net: force a reload of first item in hlist_nulls_for_each_entry_rcu

2013-06-29T03:06:40+00:00

[ Upstream commit c87a124a5d5e8cf8e21c4363c3372bcaf53ea190 ]

Roman Gushchin discovered that udp4_lib_lookup2() was not reloading
first item in the rcu protected list, in case the loop was restarted.

This produced soft lockups as in https://lkml.org/lkml/2013/4/16/37

rcu_dereference(X)/ACCESS_ONCE(X) seem to not work as intended if X is
ptr->field :

In some cases, gcc caches the value or ptr->field in a register.

Use a barrier() to disallow such caching, as documented in
Documentation/atomic_ops.txt line 114

Thanks a lot to Roman for providing analysis and numerous patches.

Diagnosed-by: Roman Gushchin 
Signed-off-by: Eric Dumazet 
Reported-by: Boris Zhmurov 
Signed-off-by: Roman Gushchin 
Acked-by: Paul E. McKenney 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

net: Block MSG_CMSG_COMPAT in send(m)msg and recv(m)msg

2013-06-29T03:06:39+00:00

[ Upstream commits 1be374a0518a288147c6a7398792583200a67261 and
  a7526eb5d06b0084ef12d7b168d008fcf516caab ]

MSG_CMSG_COMPAT is (AFAIK) not intended to be part of the API --
it's a hack that steals a bit to indicate to other networking code
that a compat entry was used.  So don't allow it from a non-compat
syscall.

This prevents an oops when running this code:

int main()
{
	int s;
	struct sockaddr_in addr;
	struct msghdr *hdr;

	char *highpage = mmap((void*)(TASK_SIZE_MAX - 4096), 4096,
	                      PROT_READ | PROT_WRITE,
	                      MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
	if (highpage == MAP_FAILED)
		err(1, "mmap");

	s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if (s == -1)
		err(1, "socket");

        addr.sin_family = AF_INET;
        addr.sin_port = htons(1);
        addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
	if (connect(s, (struct sockaddr*)&addr, sizeof(addr)) != 0)
		err(1, "connect");

	void *evil = highpage + 4096 - COMPAT_MSGHDR_SIZE;
	printf("Evil address is %p\n", evil);

	if (syscall(__NR_sendmmsg, s, evil, 1, MSG_CMSG_COMPAT) < 0)
		err(1, "sendmmsg");

	return 0;
}

Cc: David S. Miller 
Signed-off-by: Andy Lutomirski 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

mm: migration: add migrate_entry_wait_huge()

2013-06-19T01:17:01+00:00

commit 30dad30922ccc733cfdbfe232090cf674dc374dc upstream.

When we have a page fault for the address which is backed by a hugepage
under migration, the kernel can't wait correctly and do busy looping on
hugepage fault until the migration finishes.  As a result, users who try
to kick hugepage migration (via soft offlining, for example) occasionally
experience long delay or soft lockup.

This is because pte_offset_map_lock() can't get a correct migration entry
or a correct page table lock for hugepage.  This patch introduces
migration_entry_wait_huge() to solve this.

Signed-off-by: Naoya Horiguchi 
Reviewed-by: Rik van Riel 
Reviewed-by: Wanpeng Li 
Reviewed-by: Michal Hocko 
Cc: Mel Gorman 
Cc: Andi Kleen 
Cc: KOSAKI Motohiro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Ben Hutchings

CPU hotplug: provide a generic helper to disable/enable CPU hotplug

2013-06-19T01:16:59+00:00

commit 16e53dbf10a2d7e228709a7286310e629ede5e45 upstream.

There are instances in the kernel where we would like to disable CPU
hotplug (from sysfs) during some important operation.  Today the freezer
code depends on this and the code to do it was kinda tailor-made for
that.

Restructure the code and make it generic enough to be useful for other
usecases too.

Signed-off-by: Srivatsa S. Bhat 
Signed-off-by: Robin Holt 
Cc: H. Peter Anvin 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Russ Anderson 
Cc: Robin Holt 
Cc: Russell King 
Cc: Guan Xuetao 
Cc: Shawn Guo 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Ben Hutchings

net: Add net_ratelimited_function and net__ratelimited macros

2013-06-19T01:16:44+00:00

commit 3a3bfb61e64476ff1e4ac3122cb6dec9c79b795c upstream.

__ratelimit() can be considered an inverted bool test because
it returns true when not ratelimited.  Several tests in the
kernel tree use this __ratelimit() function incorrectly.

No net_ratelimit uses are incorrect currently though.

Most uses of net_ratelimit are to log something via printk or
pr_.

In order to minimize the uses of net_ratelimit, and to start
standardizing the code style used for __ratelimit() and net_ratelimit(),
add a net_ratelimited_function() macro and net__ratelimited()
logging macros similar to pr__ratelimited that use the global
net_ratelimit instead of a static per call site "struct ratelimit_state".

Signed-off-by: Joe Perches 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

macvlan: fix passthru mode race between dev removal and rx path

2013-05-30T13:35:14+00:00

[ Upstream commit 233c7df0821c4190e2d3f4be0f2ca0ab40a5ed8c, note
  that I had to add list_first_or_null_rcu to rculist.h in order
  to accomodate this fix. ]

Currently, if macvlan in passthru mode is created and data are rxed and
you remove this device, following panic happens:

NULL pointer dereference at 0000000000000198
IP: [] macvlan_handle_frame+0x153/0x1f7 [macvlan]

I'm using following script to trigger this:


I run this script while "ping -f" is running on another machine to send
packets to e1 rx.

Reason of the panic is that list_first_entry() is blindly called in
macvlan_handle_frame() even if the list was empty. vlan is set to
incorrect pointer which leads to the crash.

I'm fixing this by protecting port->vlans list by rcu and by preventing
from getting incorrect pointer in case the list is empty.

Introduced by: commit eb06acdc85585f2 "macvlan: Introduce 'passthru' mode to takeover the underlying device"

Signed-off-by: Jiri Pirko 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

if_cablemodem.h: Add parenthesis around ioctl macros

2013-05-30T13:35:13+00:00

[ Upstream commit 4f924b2aa4d3cb30f07e57d6b608838edcbc0d88 ]

Protect the SIOCGCM* ioctl macros with parenthesis.

Reported-by: Paul Wouters 
Signed-off-by: Josh Boyer 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

x86, efivars: firmware bug workarounds should be in platform code

2013-05-30T13:35:10+00:00

commit a6e4d5a03e9e3587e88aba687d8f225f4f04c792 upstream.

Let's not burden ia64 with checks in the common efivars code that we're not
writing too much data to the variable store. That kind of thing is an x86
firmware bug, plain and simple.

efi_query_variable_store() provides platforms with a wrapper in which they can
perform checks and workarounds for EFI variable storage bugs.

Cc: H. Peter Anvin 
Cc: Matthew Garrett 
Signed-off-by: Matt Fleming 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

wait: fix false timeouts when using wait_event_timeout()

2013-05-30T13:35:05+00:00

commit 4c663cfc523a88d97a8309b04a089c27dc57fd7e upstream.

Many callers of the wait_event_timeout() and
wait_event_interruptible_timeout() expect that the return value will be
positive if the specified condition becomes true before the timeout
elapses.  However, at the moment this isn't guaranteed.  If the wake-up
handler is delayed enough, the time remaining until timeout will be
calculated as 0 - and passed back as a return value - even if the
condition became true before the timeout has passed.

Fix this by returning at least 1 if the condition becomes true.  This
semantic is in line with what wait_for_condition_timeout() does; see
commit bb10ed09 ("sched: fix wait_for_completion_timeout() spurious
failure under heavy load").

Daniel said "We have 3 instances of this bug in drm/i915.  One case even
where we switch between the interruptible and not interruptible
wait_event_timeout variants, foolishly presuming they have the same
semantics.  I very much like this."

One such bug is reported at
  https://bugs.freedesktop.org/show_bug.cgi?id=64133

Signed-off-by: Imre Deak 
Acked-by: Daniel Vetter 
Acked-by: David Howells 
Acked-by: Jens Axboe 
Cc: "Paul E.  McKenney" 
Cc: Dave Jones 
Cc: Lukas Czerner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Ben Hutchings

virtio_console: fix uapi header

2013-05-30T13:35:03+00:00

commit 6407d75afd08545f2252bb39806ffd3f10c7faac upstream.

uapi should use __u32 not u32.
Fix a macro in virtio_console.h which uses u32.

Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Rusty Russell 
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings