linux-stable.git/kernel, branch v4.4.225

padata: purge get_cpu and reorder_via_wq from padata_do_serial

2020-05-27T14:40:27+00:00

[ Upstream commit 065cf577135a4977931c7a1e1edf442bfd9773dd]

With the removal of the padata timer, padata_do_serial no longer
needs special CPU handling, so remove it.

Signed-off-by: Daniel Jordan 
Cc: Herbert Xu 
Cc: Steffen Klassert 
Cc: linux-crypto@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Herbert Xu 
Signed-off-by: Daniel Jordan 
Signed-off-by: Sasha Levin

padata: initialize pd->cpu with effective cpumask

2020-05-27T14:40:27+00:00

[ Upstream commit ec9c7d19336ee98ecba8de80128aa405c45feebb ]

Exercising CPU hotplug on a 5.2 kernel with recent padata fixes from
cryptodev-2.6.git in an 8-CPU kvm guest...

    # modprobe tcrypt alg="pcrypt(rfc4106(gcm(aes)))" type=3
    # echo 0 > /sys/devices/system/cpu/cpu1/online
    # echo c > /sys/kernel/pcrypt/pencrypt/parallel_cpumask
    # modprobe tcrypt mode=215

...caused the following crash:

    BUG: kernel NULL pointer dereference, address: 0000000000000000
    #PF: supervisor read access in kernel mode
    #PF: error_code(0x0000) - not-present page
    PGD 0 P4D 0
    Oops: 0000 [#1] SMP PTI
    CPU: 2 PID: 134 Comm: kworker/2:2 Not tainted 5.2.0-padata-base+ #7
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-
    Workqueue: pencrypt padata_parallel_worker
    RIP: 0010:padata_reorder+0xcb/0x180
    ...
    Call Trace:
     padata_do_serial+0x57/0x60
     pcrypt_aead_enc+0x3a/0x50 [pcrypt]
     padata_parallel_worker+0x9b/0xe0
     process_one_work+0x1b5/0x3f0
     worker_thread+0x4a/0x3c0
     ...

In padata_alloc_pd, pd->cpu is set using the user-supplied cpumask
instead of the effective cpumask, and in this case cpumask_first picked
an offline CPU.

The offline CPU's reorder->list.next is NULL in padata_reorder because
the list wasn't initialized in padata_init_pqueues, which only operates
on CPUs in the effective mask.

Fix by using the effective mask in padata_alloc_pd.

Fixes: 6fc4dbcf0276 ("padata: Replace delayed timer with immediate workqueue in padata_reorder")
Signed-off-by: Daniel Jordan 
Cc: Herbert Xu 
Cc: Steffen Klassert 
Cc: linux-crypto@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Herbert Xu 
Signed-off-by: Daniel Jordan 
Signed-off-by: Sasha Levin

padata: Replace delayed timer with immediate workqueue in padata_reorder

2020-05-27T14:40:27+00:00

[ Upstream commit 6fc4dbcf0276279d488c5fbbfabe94734134f4fa ]

The function padata_reorder will use a timer when it cannot progress
while completed jobs are outstanding (pd->reorder_objects > 0).  This
is suboptimal as if we do end up using the timer then it would have
introduced a gratuitous delay of one second.

In fact we can easily distinguish between whether completed jobs
are outstanding and whether we can make progress.  All we have to
do is look at the next pqueue list.

This patch does that by replacing pd->processed with pd->cpu so
that the next pqueue is more accessible.

A work queue is used instead of the original try_again to avoid
hogging the CPU.

Note that we don't bother removing the work queue in
padata_flush_queues because the whole premise is broken.  You
cannot flush async crypto requests so it makes no sense to even
try.  A subsequent patch will fix it by replacing it with a ref
counting scheme.

Signed-off-by: Herbert Xu 
[dj: - adjust context
     - corrected setup_timer -> timer_setup to delete hunk
     - skip padata_flush_queues() hunk, function already removed
       in 4.4]
Signed-off-by: Daniel Jordan 
Signed-off-by: Sasha Levin

padata: set cpu_index of unused CPUs to -1

2020-05-27T14:40:27+00:00

[ Upstream commit 1bd845bcb41d5b7f83745e0cb99273eb376f2ec5 ]

The parallel queue per-cpu data structure gets initialized only for CPUs
in the 'pcpu' CPU mask set. This is not sufficient as the reorder timer
may run on a different CPU and might wrongly decide it's the target CPU
for the next reorder item as per-cpu memory gets memset(0) and we might
be waiting for the first CPU in cpumask.pcpu, i.e. cpu_index 0.

Make the '__this_cpu_read(pd->pqueue->cpu_index) == next_queue->cpu_index'
compare in padata_get_next() fail in this case by initializing the
cpu_index member of all per-cpu parallel queues. Use -1 for unused ones.

Signed-off-by: Mathias Krause 
Signed-off-by: Herbert Xu 
Signed-off-by: Daniel Jordan 
Signed-off-by: Sasha Levin

padata: ensure padata_do_serial() runs on the correct CPU

2020-05-27T14:40:23+00:00

commit 350ef88e7e922354f82a931897ad4a4ce6c686ff upstream.

If the algorithm we're parallelizing is asynchronous we might change
CPUs between padata_do_parallel() and padata_do_serial(). However, we
don't expect this to happen as we need to enqueue the padata object into
the per-cpu reorder queue we took it from, i.e. the same-cpu's parallel
queue.

Ensure we're not switching CPUs for a given padata object by tracking
the CPU within the padata object. If the serial callback gets called on
the wrong CPU, defer invoking padata_reorder() via a kernel worker on
the CPU we're expected to run on.

Signed-off-by: Mathias Krause 
Signed-off-by: Herbert Xu 
Cc: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

padata: ensure the reorder timer callback runs on the correct CPU

2020-05-27T14:40:23+00:00

commit cf5868c8a22dc2854b96e9569064bb92365549ca upstream.

The reorder timer function runs on the CPU where the timer interrupt was
handled which is not necessarily one of the CPUs of the 'pcpu' CPU mask
set.

Ensure the padata_reorder() callback runs on the correct CPU, which is
one in the 'pcpu' CPU mask set and, preferrably, the next expected one.
Do so by comparing the current CPU with the expected target CPU. If they
match, call padata_reorder() right away. If they differ, schedule a work
item on the target CPU that does the padata_reorder() call for us.

Signed-off-by: Mathias Krause 
Signed-off-by: Herbert Xu 
Cc: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

padata: get_next is never NULL

2020-05-27T14:40:23+00:00

commit 69b348449bda0f9588737539cfe135774c9939a7 upstream.

Per Dan's static checker warning, the code that returns NULL was removed
in 2010, so this patch updates the comments and fixes the code
assumptions.

Signed-off-by: Jason A. Donenfeld 
Reported-by: Dan Carpenter 
Acked-by: Steffen Klassert 
Signed-off-by: Herbert Xu 
Cc: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

padata: Remove unused but set variables

2020-05-27T14:40:23+00:00

commit 119a0798dc42ed4c4f96d39b8b676efcea73aec6 upstream.

Remove the unused but set variable pinst in padata_parallel_worker to
fix the following warning when building with 'W=1':

  kernel/padata.c: In function ‘padata_parallel_worker’:
  kernel/padata.c:68:26: warning: variable ‘pinst’ set but not used [-Wunused-but-set-variable]

Also remove the now unused variable pd which is only used to set pinst.

Signed-off-by: Tobias Klauser 
Acked-by: Steffen Klassert 
Signed-off-by: Herbert Xu 
Cc: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

Stop the ad-hoc games with -Wno-maybe-initialized

2020-05-20T06:11:49+00:00

commit 78a5255ffb6a1af189a83e493d916ba1c54d8c75 upstream.

We have some rather random rules about when we accept the
"maybe-initialized" warnings, and when we don't.

For example, we consider it unreliable for gcc versions < 4.9, but also
if -O3 is enabled, or if optimizing for size.  And then various kernel
config options disabled it, because they know that they trigger that
warning by confusing gcc sufficiently (ie PROFILE_ALL_BRANCHES).

And now gcc-10 seems to be introducing a lot of those warnings too, so
it falls under the same heading as 4.9 did.

At the same time, we have a very straightforward way to _enable_ that
warning when wanted: use "W=2" to enable more warnings.

So stop playing these ad-hoc games, and just disable that warning by
default, with the known and straight-forward "if you want to work on the
extra compiler warnings, use W=123".

Would it be great to have code that is always so obvious that it never
confuses the compiler whether a variable is used initialized or not?
Yes, it would.  In a perfect world, the compilers would be smarter, and
our source code would be simpler.

That's currently not the world we live in, though.

Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

kbuild: compute false-positive -Wmaybe-uninitialized cases in Kconfig

2020-05-20T06:11:49+00:00

commit b303c6df80c9f8f13785aa83a0471fca7e38b24d upstream.

Since -Wmaybe-uninitialized was introduced by GCC 4.7, we have patched
various false positives:

 - commit e74fc973b6e5 ("Turn off -Wmaybe-uninitialized when building
   with -Os") turned off this option for -Os.

 - commit 815eb71e7149 ("Kbuild: disable 'maybe-uninitialized' warning
   for CONFIG_PROFILE_ALL_BRANCHES") turned off this option for
   CONFIG_PROFILE_ALL_BRANCHES

 - commit a76bcf557ef4 ("Kbuild: enable -Wmaybe-uninitialized warning
   for "make W=1"") turned off this option for GCC < 4.9
   Arnd provided more explanation in https://lkml.org/lkml/2017/3/14/903

I think this looks better by shifting the logic from Makefile to Kconfig.

Link: https://github.com/ClangBuiltLinux/linux/issues/350
Signed-off-by: Masahiro Yamada 
Reviewed-by: Nathan Chancellor 
Tested-by: Nick Desaulniers 
Signed-off-by: Greg Kroah-Hartman