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<title>user/sven/linux.git/include, branch v4.9.225</title>
<subtitle>Linux Kernel
</subtitle>
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<updated>2020-05-27T14:42:00Z</updated>
<entry>
<title>l2tp: device MTU setup, tunnel socket needs a lock</title>
<updated>2020-05-27T14:42:00Z</updated>
<author>
<name>R. Parameswaran</name>
<email>parameswaran.r7@gmail.com</email>
</author>
<published>2017-04-13T01:31:04Z</published>
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<id>urn:sha1:e6cfc1098ef08ba5d1398f1d9c21530538d9005b</id>
<content type='text'>
commit 57240d007816486131bee88cd474c2a71f0fe224 upstream.

The MTU overhead calculation in L2TP device set-up
merged via commit b784e7ebfce8cfb16c6f95e14e8532d0768ab7ff
needs to be adjusted to lock the tunnel socket while
referencing the sub-data structures to derive the
socket's IP overhead.

Reported-by: Guillaume Nault &lt;g.nault@alphalink.fr&gt;
Tested-by: Guillaume Nault &lt;g.nault@alphalink.fr&gt;
Signed-off-by: R. Parameswaran &lt;rparames@brocade.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Cc: Giuliano Procida &lt;gprocida@google.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>New kernel function to get IP overhead on a socket.</title>
<updated>2020-05-27T14:41:54Z</updated>
<author>
<name>R. Parameswaran</name>
<email>parameswaran.r7@gmail.com</email>
</author>
<published>2020-05-21T23:39:19Z</published>
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<id>urn:sha1:b25415f9f0d539c587a80a608c3e2211f1c079af</id>
<content type='text'>
commit 113c3075931a334f899008f6c753abe70a3a9323 upstream.

A new function, kernel_sock_ip_overhead(), is provided
to calculate the cumulative overhead imposed by the IP
Header and IP options, if any, on a socket's payload.
The new function returns an overhead of zero for sockets
that do not belong to the IPv4 or IPv6 address families.
This is used in the L2TP code path to compute the
total outer IP overhead on the L2TP tunnel socket when
calculating the default MTU for Ethernet pseudowires.

Signed-off-by: R. Parameswaran &lt;rparames@brocade.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Giuliano Procida &lt;gprocida@google.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>net: l2tp: deprecate PPPOL2TP_MSG_* in favour of L2TP_MSG_*</title>
<updated>2020-05-27T14:41:53Z</updated>
<author>
<name>Asbjørn Sloth Tønnesen</name>
<email>asbjorn@asbjorn.st</email>
</author>
<published>2020-05-21T23:39:17Z</published>
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<id>urn:sha1:cc84b4ddee15d4082da6653ea5548c04ff32057b</id>
<content type='text'>
commit 47c3e7783be4e142b861d34b5c2e223330b05d8a upstream.

PPPOL2TP_MSG_* and L2TP_MSG_* are duplicates, and are being used
interchangeably in the kernel, so let's standardize on L2TP_MSG_*
internally, and keep PPPOL2TP_MSG_* defined in UAPI for compatibility.

Signed-off-by: Asbjoern Sloth Toennesen &lt;asbjorn@asbjorn.st&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Giuliano Procida &lt;gprocida@google.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>net: l2tp: export debug flags to UAPI</title>
<updated>2020-05-27T14:41:53Z</updated>
<author>
<name>Asbjørn Sloth Tønnesen</name>
<email>asbjorn@asbjorn.st</email>
</author>
<published>2020-05-21T23:39:16Z</published>
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<id>urn:sha1:18dc6fbbd9d7416b69cff63a1568365836ec22eb</id>
<content type='text'>
commit 41c43fbee68f4f9a2a9675d83bca91c77862d7f0 upstream.

Move the L2TP_MSG_* definitions to UAPI, as it is part of
the netlink API.

Signed-off-by: Asbjoern Sloth Toennesen &lt;asbjorn@asbjorn.st&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Giuliano Procida &lt;gprocida@google.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>padata: Replace delayed timer with immediate workqueue in padata_reorder</title>
<updated>2020-05-27T14:41:52Z</updated>
<author>
<name>Herbert Xu</name>
<email>herbert@gondor.apana.org.au</email>
</author>
<published>2020-05-21T20:48:45Z</published>
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<id>urn:sha1:f501513bd2dda34c73bf12785163bfe713af0d99</id>
<content type='text'>
[ Upstream commit 6fc4dbcf0276279d488c5fbbfabe94734134f4fa ]

The function padata_reorder will use a timer when it cannot progress
while completed jobs are outstanding (pd-&gt;reorder_objects &gt; 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-&gt;processed with pd-&gt;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 &lt;herbert@gondor.apana.org.au&gt;
[dj: - adjust context
     - corrected setup_timer -&gt; timer_setup to delete hunk
     - skip padata_flush_queues() hunk, function already removed
       in 4.9]
Signed-off-by: Daniel Jordan &lt;daniel.m.jordan@oracle.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>padata: ensure padata_do_serial() runs on the correct CPU</title>
<updated>2020-05-27T14:41:38Z</updated>
<author>
<name>Mathias Krause</name>
<email>minipli@googlemail.com</email>
</author>
<published>2017-09-08T18:57:11Z</published>
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<id>urn:sha1:6953f88cd3e7ba0be11863604215a7e68d8e203d</id>
<content type='text'>
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 &lt;minipli@googlemail.com&gt;
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Cc: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>padata: ensure the reorder timer callback runs on the correct CPU</title>
<updated>2020-05-27T14:41:38Z</updated>
<author>
<name>Mathias Krause</name>
<email>minipli@googlemail.com</email>
</author>
<published>2017-09-08T18:57:10Z</published>
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<id>urn:sha1:08257da7e755584852c972d35f3d3ac32b297685</id>
<content type='text'>
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 &lt;minipli@googlemail.com&gt;
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Cc: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>x86: Fix early boot crash on gcc-10, third try</title>
<updated>2020-05-20T06:15:41Z</updated>
<author>
<name>Borislav Petkov</name>
<email>bp@suse.de</email>
</author>
<published>2020-04-22T16:11:30Z</published>
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<id>urn:sha1:b263060dba4096b74bf5dbf796c535aa85fb73c6</id>
<content type='text'>
commit a9a3ed1eff3601b63aea4fb462d8b3b92c7c1e7e upstream.

... or the odyssey of trying to disable the stack protector for the
function which generates the stack canary value.

The whole story started with Sergei reporting a boot crash with a kernel
built with gcc-10:

  Kernel panic — not syncing: stack-protector: Kernel stack is corrupted in: start_secondary
  CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.6.0-rc5—00235—gfffb08b37df9 #139
  Hardware name: Gigabyte Technology Co., Ltd. To be filled by O.E.M./H77M—D3H, BIOS F12 11/14/2013
  Call Trace:
    dump_stack
    panic
    ? start_secondary
    __stack_chk_fail
    start_secondary
    secondary_startup_64
  -—-[ end Kernel panic — not syncing: stack—protector: Kernel stack is corrupted in: start_secondary

This happens because gcc-10 tail-call optimizes the last function call
in start_secondary() - cpu_startup_entry() - and thus emits a stack
canary check which fails because the canary value changes after the
boot_init_stack_canary() call.

To fix that, the initial attempt was to mark the one function which
generates the stack canary with:

  __attribute__((optimize("-fno-stack-protector"))) ... start_secondary(void *unused)

however, using the optimize attribute doesn't work cumulatively
as the attribute does not add to but rather replaces previously
supplied optimization options - roughly all -fxxx options.

The key one among them being -fno-omit-frame-pointer and thus leading to
not present frame pointer - frame pointer which the kernel needs.

The next attempt to prevent compilers from tail-call optimizing
the last function call cpu_startup_entry(), shy of carving out
start_secondary() into a separate compilation unit and building it with
-fno-stack-protector, was to add an empty asm("").

This current solution was short and sweet, and reportedly, is supported
by both compilers but we didn't get very far this time: future (LTO?)
optimization passes could potentially eliminate this, which leads us
to the third attempt: having an actual memory barrier there which the
compiler cannot ignore or move around etc.

That should hold for a long time, but hey we said that about the other
two solutions too so...

Reported-by: Sergei Trofimovich &lt;slyfox@gentoo.org&gt;
Signed-off-by: Borislav Petkov &lt;bp@suse.de&gt;
Tested-by: Kalle Valo &lt;kvalo@codeaurora.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lkml.kernel.org/r/20200314164451.346497-1-slyfox@gentoo.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>ALSA: rawmidi: Fix racy buffer resize under concurrent accesses</title>
<updated>2020-05-20T06:15:40Z</updated>
<author>
<name>Takashi Iwai</name>
<email>tiwai@suse.de</email>
</author>
<published>2020-05-07T11:44:56Z</published>
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<id>urn:sha1:c13f1463d84b86bedb664e509838bef37e6ea317</id>
<content type='text'>
commit c1f6e3c818dd734c30f6a7eeebf232ba2cf3181d upstream.

The rawmidi core allows user to resize the runtime buffer via ioctl,
and this may lead to UAF when performed during concurrent reads or
writes: the read/write functions unlock the runtime lock temporarily
during copying form/to user-space, and that's the race window.

This patch fixes the hole by introducing a reference counter for the
runtime buffer read/write access and returns -EBUSY error when the
resize is performed concurrently against read/write.

Note that the ref count field is a simple integer instead of
refcount_t here, since the all contexts accessing the buffer is
basically protected with a spinlock, hence we need no expensive atomic
ops.  Also, note that this busy check is needed only against read /
write functions, and not in receive/transmit callbacks; the race can
happen only at the spinlock hole mentioned in the above, while the
whole function is protected for receive / transmit callbacks.

Reported-by: butt3rflyh4ck &lt;butterflyhuangxx@gmail.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/CAFcO6XMWpUVK_yzzCpp8_XP7+=oUpQvuBeCbMffEDkpe8jWrfg@mail.gmail.com
Link: https://lore.kernel.org/r/s5heerw3r5z.wl-tiwai@suse.de
Signed-off-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
<entry>
<title>gcc-10 warnings: fix low-hanging fruit</title>
<updated>2020-05-20T06:15:37Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2020-05-04T16:16:37Z</published>
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<content type='text'>
commit 9d82973e032e246ff5663c9805fbb5407ae932e3 upstream.

Due to a bug-report that was compiler-dependent, I updated one of my
machines to gcc-10.  That shows a lot of new warnings.  Happily they
seem to be mostly the valid kind, but it's going to cause a round of
churn for getting rid of them..

This is the really low-hanging fruit of removing a couple of zero-sized
arrays in some core code.  We have had a round of these patches before,
and we'll have many more coming, and there is nothing special about
these except that they were particularly trivial, and triggered more
warnings than most.

Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
</entry>
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