linux-stable.git/include/linux, branch v4.9.94

sched/deadline: Use the revised wakeup rule for suspending constrained dl tasks

2018-04-13T17:48:23+00:00

[ Upstream commit 3effcb4247e74a51f5d8b775a1ee4abf87cc089a ]

We have been facing some problems with self-suspending constrained
deadline tasks. The main reason is that the original CBS was not
designed for such sort of tasks.

One problem reported by Xunlei Pang takes place when a task
suspends, and then is awakened before the deadline, but so close
to the deadline that its remaining runtime can cause the task
to have an absolute density higher than allowed. In such situation,
the original CBS assumes that the task is facing an early activation,
and so it replenishes the task and set another deadline, one deadline
in the future. This rule works fine for implicit deadline tasks.
Moreover, it allows the system to adapt the period of a task in which
the external event source suffered from a clock drift.

However, this opens the window for bandwidth leakage for constrained
deadline tasks. For instance, a task with the following parameters:

  runtime   = 5 ms
  deadline  = 7 ms
  [density] = 5 / 7 = 0.71
  period    = 1000 ms

If the task runs for 1 ms, and then suspends for another 1ms,
it will be awakened with the following parameters:

  remaining runtime = 4
  laxity = 5

presenting a absolute density of 4 / 5 = 0.80.

In this case, the original CBS would assume the task had an early
wakeup. Then, CBS will reset the runtime, and the absolute deadline will
be postponed by one relative deadline, allowing the task to run.

The problem is that, if the task runs this pattern forever, it will keep
receiving bandwidth, being able to run 1ms every 2ms. Following this
behavior, the task would be able to run 500 ms in 1 sec. Thus running
more than the 5 ms / 1 sec the admission control allowed it to run.

Trying to address the self-suspending case, Luca Abeni, Giuseppe
Lipari, and Juri Lelli [1] revisited the CBS in order to deal with
self-suspending tasks. In the new approach, rather than
replenishing/postponing the absolute deadline, the revised wakeup rule
adjusts the remaining runtime, reducing it to fit into the allowed
density.

A revised version of the idea is:

At a given time t, the maximum absolute density of a task cannot be
higher than its relative density, that is:

  runtime / (deadline - t) <= dl_runtime / dl_deadline

Knowing the laxity of a task (deadline - t), it is possible to move
it to the other side of the equality, thus enabling to define max
remaining runtime a task can use within the absolute deadline, without
over-running the allowed density:

  runtime = (dl_runtime / dl_deadline) * (deadline - t)

For instance, in our previous example, the task could still run:

  runtime = ( 5 / 7 ) * 5
  runtime = 3.57 ms

Without causing damage for other deadline tasks. It is note worthy
that the laxity cannot be negative because that would cause a negative
runtime. Thus, this patch depends on the patch:

  df8eac8cafce ("sched/deadline: Throttle a constrained deadline task activated after the deadline")

Which throttles a constrained deadline task activated after the
deadline.

Finally, it is also possible to use the revised wakeup rule for
all other tasks, but that would require some more discussions
about pros and cons.

Reported-by: Xunlei Pang 
Signed-off-by: Daniel Bristot de Oliveira 
[peterz: replaced dl_is_constrained with dl_is_implicit]
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Juri Lelli 
Cc: Linus Torvalds 
Cc: Luca Abeni 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Romulo Silva de Oliveira 
Cc: Steven Rostedt 
Cc: Thomas Gleixner 
Cc: Tommaso Cucinotta 
Link: http://lkml.kernel.org/r/5c800ab3a74a168a84ee5f3f84d12a02e11383be.1495803804.git.bristot@redhat.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

net/mlx4: Fix the check in attaching steering rules

2018-04-13T17:48:19+00:00

[ Upstream commit 6dc06c08bef1c746ff8da33dab677cfbacdcad32 ]

Our previous patch (cited below) introduced a regression
for RAW Eth QPs.

Fix it by checking if the QP number provided by user-space
exists, hence allowing steering rules to be added for valid
QPs only.

Fixes: 89c557687a32 ("net/mlx4_en: Avoid adding steering rules with invalid ring")
Reported-by: Or Gerlitz 
Signed-off-by: Talat Batheesh 
Signed-off-by: Tariq Toukan 
Acked-by: Or Gerlitz 
Reviewed-by: Leon Romanovsky 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

skbuff: return -EMSGSIZE in skb_to_sgvec to prevent overflow

2018-04-13T17:48:19+00:00

[ Upstream commit 48a1df65334b74bd7531f932cca5928932abf769 ]

This is a defense-in-depth measure in response to bugs like
4d6fa57b4dab ("macsec: avoid heap overflow in skb_to_sgvec"). There's
not only a potential overflow of sglist items, but also a stack overflow
potential, so we fix this by limiting the amount of recursion this function
is allowed to do. Not actually providing a bounded base case is a future
disaster that we can easily avoid here.

As a small matter of house keeping, we take this opportunity to move the
documentation comment over the actual function the documentation is for.

While this could be implemented by using an explicit stack of skbuffs,
when implementing this, the function complexity increased considerably,
and I don't think such complexity and bloat is actually worth it. So,
instead I built this and tested it on x86, x86_64, ARM, ARM64, and MIPS,
and measured the stack usage there. I also reverted the recent MIPS
changes that give it a separate IRQ stack, so that I could experience
some worst-case situations. I found that limiting it to 24 layers deep
yielded a good stack usage with room for safety, as well as being much
deeper than any driver actually ever creates.

Signed-off-by: Jason A. Donenfeld 
Cc: Steffen Klassert 
Cc: Herbert Xu 
Cc: "David S. Miller" 
Cc: David Howells 
Cc: Sabrina Dubroca 
Cc: "Michael S. Tsirkin" 
Cc: Jason Wang 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

PCI/msi: fix the pci_alloc_irq_vectors_affinity stub

2018-04-13T17:48:07+00:00

[ Upstream commit 83b4605b0c16cde5b00c8cf192408d51eab75402 ]

We need to return an error for any call that asks for MSI / MSI-X
vectors only, so that non-trivial fallback logic can work properly.

Also valid dev->irq and use the "correct" errno value based on feedback
from Linus.

Signed-off-by: Christoph Hellwig 
Reported-by: Steven Rostedt 
Fixes: aff17164 ("PCI: Provide sensible IRQ vector alloc/free routines")
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

mlx5: fix bug reading rss_hash_type from CQE

2018-04-13T17:48:04+00:00

[ Upstream commit 12e8b570e732eaa5eae3a2895ba3fbcf91bde2b4 ]

Masks for extracting part of the Completion Queue Entry (CQE)
field rss_hash_type was swapped, namely CQE_RSS_HTYPE_IP and
CQE_RSS_HTYPE_L4.

The bug resulted in setting skb->l4_hash, even-though the
rss_hash_type indicated that hash was NOT computed over the
L4 (UDP or TCP) part of the packet.

Added comments from the datasheet, to make it more clear what
these masks are selecting.

Signed-off-by: Jesper Dangaard Brouer 
Acked-by: Saeed Mahameed 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

module: extend 'rodata=off' boot cmdline parameter to module mappings

2018-04-08T10:12:52+00:00

commit 39290b389ea upstream.

The current "rodata=off" parameter disables read-only kernel mappings
under CONFIG_DEBUG_RODATA:
    commit d2aa1acad22f ("mm/init: Add 'rodata=off' boot cmdline parameter
    to disable read-only kernel mappings")

This patch is a logical extension to module mappings ie. read-only mappings
at module loading can be disabled even if CONFIG_DEBUG_SET_MODULE_RONX
(mainly for debug use). Please note, however, that it only affects RO/RW
permissions, keeping NX set.

This is the first step to make CONFIG_DEBUG_SET_MODULE_RONX mandatory
(always-on) in the future as CONFIG_DEBUG_RODATA on x86 and arm64.

Suggested-by: and Acked-by: Mark Rutland 
Signed-off-by: AKASHI Takahiro 
Reviewed-by: Kees Cook 
Acked-by: Rusty Russell 
Link: http://lkml.kernel.org/r/20161114061505.15238-1-takahiro.akashi@linaro.org
Signed-off-by: Jessica Yu 
Signed-off-by: Alex Shi  [v4.9 backport]
Signed-off-by: Mark Rutland  [v4.9 backport]
Tested-by: Will Deacon 
Tested-by: Greg Hackmann 
Signed-off-by: Greg Kroah-Hartman

llist: clang: introduce member_address_is_nonnull()

2018-04-08T10:12:50+00:00

commit beaec533fc2701a28a4d667f67c9f59c6e4e0d13 upstream.

Currently llist_for_each_entry() and llist_for_each_entry_safe() iterate
until &pos->member != NULL.  But when building the kernel with Clang,
the compiler assumes &pos->member cannot be NULL if the member's offset
is greater than 0 (which would be equivalent to the object being
non-contiguous in memory).  Therefore the loop condition is always true,
and the loops become infinite.

To work around this, introduce the member_address_is_nonnull() macro,
which casts object pointer to uintptr_t, thus letting the member pointer
to be NULL.

Signed-off-by: Alexander Potapenko 
Tested-by: Sodagudi Prasad 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

netfilter: x_tables: add and use xt_check_proc_name

2018-04-08T10:12:50+00:00

commit b1d0a5d0cba4597c0394997b2d5fced3e3841b4e upstream.

recent and hashlimit both create /proc files, but only check that
name is 0 terminated.

This can trigger WARN() from procfs when name is "" or "/".
Add helper for this and then use it for both.

Cc: Eric Dumazet 
Reported-by: Eric Dumazet 
Reported-by: 
Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Greg Kroah-Hartman

frv: declare jiffies to be located in the .data section

2018-04-08T10:12:45+00:00

commit 60b0a8c3d2480f3b57282b47b7cae7ee71c48635 upstream.

Commit 7c30f352c852 ("jiffies.h: declare jiffies and jiffies_64 with
____cacheline_aligned_in_smp") removed a section specification from the
jiffies declaration that caused conflicts on some platforms.

Unfortunately this change broke the build for frv:

  kernel/built-in.o: In function `__do_softirq': (.text+0x6460): relocation truncated to fit: R_FRV_GPREL12 against symbol
      `jiffies' defined in *ABS* section in .tmp_vmlinux1
  kernel/built-in.o: In function `__do_softirq': (.text+0x6574): relocation truncated to fit: R_FRV_GPREL12 against symbol
      `jiffies' defined in *ABS* section in .tmp_vmlinux1
  kernel/built-in.o: In function `pwq_activate_delayed_work': workqueue.c:(.text+0x15b9c): relocation truncated to fit: R_FRV_GPREL12 against
      symbol `jiffies' defined in *ABS* section in .tmp_vmlinux1
  ...

Add __jiffy_arch_data to the declaration of jiffies and use it on frv to
include the section specification.  For all other platforms
__jiffy_arch_data (currently) has no effect.

Fixes: 7c30f352c852 ("jiffies.h: declare jiffies and jiffies_64 with ____cacheline_aligned_in_smp")
Link: http://lkml.kernel.org/r/20170516221333.177280-1-mka@chromium.org
Signed-off-by: Matthias Kaehlcke 
Reported-by: Guenter Roeck 
Tested-by: Guenter Roeck 
Reviewed-by: David Howells 
Cc: Sudip Mukherjee 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

jiffies.h: declare jiffies and jiffies_64 with ____cacheline_aligned_in_smp

2018-04-08T10:12:45+00:00

commit 7c30f352c852bae2715ad65ac4a38ca9af7d7696 upstream.

jiffies_64 is defined in kernel/time/timer.c with
____cacheline_aligned_in_smp, however this macro is not part of the
declaration of jiffies and jiffies_64 in jiffies.h.

As a result clang generates the following warning:

  kernel/time/timer.c:57:26: error: section does not match previous declaration [-Werror,-Wsection]
  __visible u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;
                           ^
  include/linux/cache.h:39:36: note: expanded from macro '__cacheline_aligned_in_smp'
                                     ^
  include/linux/cache.h:34:4: note: expanded from macro '__cacheline_aligned'
                   __section__(".data..cacheline_aligned")))
                   ^
  include/linux/jiffies.h:77:12: note: previous attribute is here
  extern u64 __jiffy_data jiffies_64;
             ^
  include/linux/jiffies.h:70:38: note: expanded from macro '__jiffy_data'

Link: http://lkml.kernel.org/r/20170403190200.70273-1-mka@chromium.org
Signed-off-by: Matthias Kaehlcke 
Cc: "Jason A . Donenfeld" 
Cc: Grant Grundler 
Cc: Michael Davidson 
Cc: Greg Hackmann 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Cc: Nathan Chancellor 
Signed-off-by: Greg Kroah-Hartman