<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git, branch v3.2.79</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>Linux 3.2.79</title>
<updated>2016-04-01T00:54:38+00:00</updated>
<author>
<name>Ben Hutchings</name>
<email>ben@decadent.org.uk</email>
</author>
<published>2016-04-01T00:54:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=161802562b8b7f546a4deafeb73f31f0afc7bd1e'/>
<id>161802562b8b7f546a4deafeb73f31f0afc7bd1e</id>
<content type='text'>
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
</pre>
</div>
</content>
</entry>
<entry>
<title>HID: usbhid: fix recursive deadlock</title>
<updated>2016-04-01T00:54:37+00:00</updated>
<author>
<name>Ioan-Adrian Ratiu</name>
<email>adi@adirat.com</email>
</author>
<published>2015-11-20T20:19:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7f6138522bb86c5e3fcfbcb81f5fea67d97b4f94'/>
<id>7f6138522bb86c5e3fcfbcb81f5fea67d97b4f94</id>
<content type='text'>
commit e470127e9606b1fa151c4184243e61296d1e0c0f upstream.

The critical section protected by usbhid-&gt;lock in hid_ctrl() is too
big and because of this it causes a recursive deadlock. "Too big" means
the case statement and the call to hid_input_report() do not need to be
protected by the spinlock (no URB operations are done inside them).

The deadlock happens because in certain rare cases drivers try to grab
the lock while handling the ctrl irq which grabs the lock before them
as described above. For example newer wacom tablets like 056a:033c try
to reschedule proximity reads from wacom_intuos_schedule_prox_event()
calling hid_hw_request() -&gt; usbhid_request() -&gt; usbhid_submit_report()
which tries to grab the usbhid lock already held by hid_ctrl().

There are two ways to get out of this deadlock:
    1. Make the drivers work "around" the ctrl critical region, in the
    wacom case for ex. by delaying the scheduling of the proximity read
    request itself to a workqueue.
    2. Shrink the critical region so the usbhid lock protects only the
    instructions which modify usbhid state, calling hid_input_report()
    with the spinlock unlocked, allowing the device driver to grab the
    lock first, finish and then grab the lock afterwards in hid_ctrl().

This patch implements the 2nd solution.

Signed-off-by: Ioan-Adrian Ratiu &lt;adi@adirat.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
[bwh: Backported to 3.2: adjust context]
Cc: Jason Gerecke &lt;jason.gerecke@wacom.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit e470127e9606b1fa151c4184243e61296d1e0c0f upstream.

The critical section protected by usbhid-&gt;lock in hid_ctrl() is too
big and because of this it causes a recursive deadlock. "Too big" means
the case statement and the call to hid_input_report() do not need to be
protected by the spinlock (no URB operations are done inside them).

The deadlock happens because in certain rare cases drivers try to grab
the lock while handling the ctrl irq which grabs the lock before them
as described above. For example newer wacom tablets like 056a:033c try
to reschedule proximity reads from wacom_intuos_schedule_prox_event()
calling hid_hw_request() -&gt; usbhid_request() -&gt; usbhid_submit_report()
which tries to grab the usbhid lock already held by hid_ctrl().

There are two ways to get out of this deadlock:
    1. Make the drivers work "around" the ctrl critical region, in the
    wacom case for ex. by delaying the scheduling of the proximity read
    request itself to a workqueue.
    2. Shrink the critical region so the usbhid lock protects only the
    instructions which modify usbhid state, calling hid_input_report()
    with the spinlock unlocked, allowing the device driver to grab the
    lock first, finish and then grab the lock afterwards in hid_ctrl().

This patch implements the 2nd solution.

Signed-off-by: Ioan-Adrian Ratiu &lt;adi@adirat.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
[bwh: Backported to 3.2: adjust context]
Cc: Jason Gerecke &lt;jason.gerecke@wacom.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>include/linux/poison.h: fix LIST_POISON{1,2} offset</title>
<updated>2016-04-01T00:54:37+00:00</updated>
<author>
<name>Vasily Kulikov</name>
<email>segoon@openwall.com</email>
</author>
<published>2015-09-09T22:36:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d7a1adecfd8254ea61c79585a9c56dd6e3d0f5b7'/>
<id>d7a1adecfd8254ea61c79585a9c56dd6e3d0f5b7</id>
<content type='text'>
commit 8a5e5e02fc83aaf67053ab53b359af08c6c49aaf upstream.

Poison pointer values should be small enough to find a room in
non-mmap'able/hardly-mmap'able space.  E.g.  on x86 "poison pointer space"
is located starting from 0x0.  Given unprivileged users cannot mmap
anything below mmap_min_addr, it should be safe to use poison pointers
lower than mmap_min_addr.

The current poison pointer values of LIST_POISON{1,2} might be too big for
mmap_min_addr values equal or less than 1 MB (common case, e.g.  Ubuntu
uses only 0x10000).  There is little point to use such a big value given
the "poison pointer space" below 1 MB is not yet exhausted.  Changing it
to a smaller value solves the problem for small mmap_min_addr setups.

The values are suggested by Solar Designer:
http://www.openwall.com/lists/oss-security/2015/05/02/6

Signed-off-by: Vasily Kulikov &lt;segoon@openwall.com&gt;
Cc: Solar Designer &lt;solar@openwall.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: "Kirill A. Shutemov" &lt;kirill.shutemov@linux.intel.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 8a5e5e02fc83aaf67053ab53b359af08c6c49aaf upstream.

Poison pointer values should be small enough to find a room in
non-mmap'able/hardly-mmap'able space.  E.g.  on x86 "poison pointer space"
is located starting from 0x0.  Given unprivileged users cannot mmap
anything below mmap_min_addr, it should be safe to use poison pointers
lower than mmap_min_addr.

The current poison pointer values of LIST_POISON{1,2} might be too big for
mmap_min_addr values equal or less than 1 MB (common case, e.g.  Ubuntu
uses only 0x10000).  There is little point to use such a big value given
the "poison pointer space" below 1 MB is not yet exhausted.  Changing it
to a smaller value solves the problem for small mmap_min_addr setups.

The values are suggested by Solar Designer:
http://www.openwall.com/lists/oss-security/2015/05/02/6

Signed-off-by: Vasily Kulikov &lt;segoon@openwall.com&gt;
Cc: Solar Designer &lt;solar@openwall.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: "Kirill A. Shutemov" &lt;kirill.shutemov@linux.intel.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Input: aiptek - fix crash on detecting device without endpoints</title>
<updated>2016-04-01T00:54:37+00:00</updated>
<author>
<name>Vladis Dronov</name>
<email>vdronov@redhat.com</email>
</author>
<published>2015-12-01T21:09:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=90eb3c037fe3f0f25f01713a92725a8daa2b41f3'/>
<id>90eb3c037fe3f0f25f01713a92725a8daa2b41f3</id>
<content type='text'>
commit 8e20cf2bce122ce9262d6034ee5d5b76fbb92f96 upstream.

The aiptek driver crashes in aiptek_probe() when a specially crafted USB
device without endpoints is detected. This fix adds a check that the device
has proper configuration expected by the driver. Also an error return value
is changed to more matching one in one of the error paths.

Reported-by: Ralf Spenneberg &lt;ralf@spenneberg.net&gt;
Signed-off-by: Vladis Dronov &lt;vdronov@redhat.com&gt;
Signed-off-by: Dmitry Torokhov &lt;dmitry.torokhov@gmail.com&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 8e20cf2bce122ce9262d6034ee5d5b76fbb92f96 upstream.

The aiptek driver crashes in aiptek_probe() when a specially crafted USB
device without endpoints is detected. This fix adds a check that the device
has proper configuration expected by the driver. Also an error return value
is changed to more matching one in one of the error paths.

Reported-by: Ralf Spenneberg &lt;ralf@spenneberg.net&gt;
Signed-off-by: Vladis Dronov &lt;vdronov@redhat.com&gt;
Signed-off-by: Dmitry Torokhov &lt;dmitry.torokhov@gmail.com&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>s390/mm: four page table levels vs. fork</title>
<updated>2016-04-01T00:54:37+00:00</updated>
<author>
<name>Martin Schwidefsky</name>
<email>schwidefsky@de.ibm.com</email>
</author>
<published>2016-02-15T13:46:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=03aeac3050c3ec92a50e1409e0b5037a97a20834'/>
<id>03aeac3050c3ec92a50e1409e0b5037a97a20834</id>
<content type='text'>
commit 3446c13b268af86391d06611327006b059b8bab1 upstream.

The fork of a process with four page table levels is broken since
git commit 6252d702c5311ce9 "[S390] dynamic page tables."

All new mm contexts are created with three page table levels and
an asce limit of 4TB. If the parent has four levels dup_mmap will
add vmas to the new context which are outside of the asce limit.
The subsequent call to copy_page_range will walk the three level
page table structure of the new process with non-zero pgd and pud
indexes. This leads to memory clobbers as the pgd_index *and* the
pud_index is added to the mm-&gt;pgd pointer without a pgd_deref
in between.

The init_new_context() function is selecting the number of page
table levels for a new context. The function is used by mm_init()
which in turn is called by dup_mm() and mm_alloc(). These two are
used by fork() and exec(). The init_new_context() function can
distinguish the two cases by looking at mm-&gt;context.asce_limit,
for fork() the mm struct has been copied and the number of page
table levels may not change. For exec() the mm_alloc() function
set the new mm structure to zero, in this case a three-level page
table is created as the temporary stack space is located at
STACK_TOP_MAX = 4TB.

This fixes CVE-2016-2143.

Reported-by: Marcin Kościelnicki &lt;koriakin@0x04.net&gt;
Reviewed-by: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt;
Signed-off-by: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
[bwh: Backported to 3.2:
 - 31-bit s390 is still supported so keep the #ifdef CONFIG_64BIT conditions
 - Split page table locks are not implemented for PMDs so don't call
   pgtable_pmd_page_{ctor,dtor}()
 - PMDs are not accounted so don't call mm_inc_nr_pmds()
 - Adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 3446c13b268af86391d06611327006b059b8bab1 upstream.

The fork of a process with four page table levels is broken since
git commit 6252d702c5311ce9 "[S390] dynamic page tables."

All new mm contexts are created with three page table levels and
an asce limit of 4TB. If the parent has four levels dup_mmap will
add vmas to the new context which are outside of the asce limit.
The subsequent call to copy_page_range will walk the three level
page table structure of the new process with non-zero pgd and pud
indexes. This leads to memory clobbers as the pgd_index *and* the
pud_index is added to the mm-&gt;pgd pointer without a pgd_deref
in between.

The init_new_context() function is selecting the number of page
table levels for a new context. The function is used by mm_init()
which in turn is called by dup_mm() and mm_alloc(). These two are
used by fork() and exec(). The init_new_context() function can
distinguish the two cases by looking at mm-&gt;context.asce_limit,
for fork() the mm struct has been copied and the number of page
table levels may not change. For exec() the mm_alloc() function
set the new mm structure to zero, in this case a three-level page
table is created as the temporary stack space is located at
STACK_TOP_MAX = 4TB.

This fixes CVE-2016-2143.

Reported-by: Marcin Kościelnicki &lt;koriakin@0x04.net&gt;
Reviewed-by: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt;
Signed-off-by: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
[bwh: Backported to 3.2:
 - 31-bit s390 is still supported so keep the #ifdef CONFIG_64BIT conditions
 - Split page table locks are not implemented for PMDs so don't call
   pgtable_pmd_page_{ctor,dtor}()
 - PMDs are not accounted so don't call mm_inc_nr_pmds()
 - Adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "drm/radeon: call hpd_irq_event on resume"</title>
<updated>2016-04-01T00:54:37+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2016-03-07T21:15:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=688d547754cafebe2d5e018ac8bbc6f01618c52a'/>
<id>688d547754cafebe2d5e018ac8bbc6f01618c52a</id>
<content type='text'>
commit 256faedcfd646161477d47a1a78c32a562d2e845 upstream.

This reverts commit dbb17a21c131eca94eb31136eee9a7fe5aff00d9.

It turns out that commit can cause problems for systems with multiple
GPUs, and causes X to hang on at least a HP Pavilion dv7 with hybrid
graphics.

This got noticed originally in 4.4.4, where this patch had already
gotten back-ported, but 4.5-rc7 was verified to have the same problem.

Alexander Deucher says:
 "It looks like you have a muxed system so I suspect what's happening is
  that one of the display is being reported as connected for both the
  IGP and the dGPU and then the desktop environment gets confused or
  there some sort problem in the detect functions since the mux is not
  switched to the dGPU.  I don't see an easy fix unless Dave has any
  ideas.  I'd say just revert for now"

Reported-by: Jörg-Volker Peetz &lt;jvpeetz@web.de&gt;
Acked-by: Alexander Deucher &lt;Alexander.Deucher@amd.com&gt;
Cc: Dave Airlie &lt;airlied@gmail.com&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 256faedcfd646161477d47a1a78c32a562d2e845 upstream.

This reverts commit dbb17a21c131eca94eb31136eee9a7fe5aff00d9.

It turns out that commit can cause problems for systems with multiple
GPUs, and causes X to hang on at least a HP Pavilion dv7 with hybrid
graphics.

This got noticed originally in 4.4.4, where this patch had already
gotten back-ported, but 4.5-rc7 was verified to have the same problem.

Alexander Deucher says:
 "It looks like you have a muxed system so I suspect what's happening is
  that one of the display is being reported as connected for both the
  IGP and the dGPU and then the desktop environment gets confused or
  there some sort problem in the detect functions since the mux is not
  switched to the dGPU.  I don't see an easy fix unless Dave has any
  ideas.  I'd say just revert for now"

Reported-by: Jörg-Volker Peetz &lt;jvpeetz@web.de&gt;
Acked-by: Alexander Deucher &lt;Alexander.Deucher@amd.com&gt;
Cc: Dave Airlie &lt;airlied@gmail.com&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ubi: Fix out of bounds write in volume update code</title>
<updated>2016-04-01T00:54:37+00:00</updated>
<author>
<name>Richard Weinberger</name>
<email>richard@nod.at</email>
</author>
<published>2016-02-21T09:53:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7aae79649d6a88e7104d4d22aa4ba21f4e699e40'/>
<id>7aae79649d6a88e7104d4d22aa4ba21f4e699e40</id>
<content type='text'>
commit e4f6daac20332448529b11f09388f1d55ef2084c upstream.

ubi_start_leb_change() allocates too few bytes.
ubi_more_leb_change_data() will write up to req-&gt;upd_bytes +
ubi-&gt;min_io_size bytes.

Signed-off-by: Richard Weinberger &lt;richard@nod.at&gt;
Reviewed-by: Boris Brezillon &lt;boris.brezillon@free-electrons.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit e4f6daac20332448529b11f09388f1d55ef2084c upstream.

ubi_start_leb_change() allocates too few bytes.
ubi_more_leb_change_data() will write up to req-&gt;upd_bytes +
ubi-&gt;min_io_size bytes.

Signed-off-by: Richard Weinberger &lt;richard@nod.at&gt;
Reviewed-by: Boris Brezillon &lt;boris.brezillon@free-electrons.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>MIPS: traps: Fix SIGFPE information leak from `do_ov' and `do_trap_or_bp'</title>
<updated>2016-04-01T00:54:37+00:00</updated>
<author>
<name>Maciej W. Rozycki</name>
<email>macro@imgtec.com</email>
</author>
<published>2016-03-04T01:42:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5476a24d66a7d275ed1e0a3113f26c1158684462'/>
<id>5476a24d66a7d275ed1e0a3113f26c1158684462</id>
<content type='text'>
commit e723e3f7f9591b79e8c56b3d7c5a204a9c571b55 upstream.

Avoid sending a partially initialised `siginfo_t' structure along SIGFPE
signals issued from `do_ov' and `do_trap_or_bp', leading to information
leaking from the kernel stack.

Signed-off-by: Maciej W. Rozycki &lt;macro@imgtec.com&gt;
Signed-off-by: Ralf Baechle &lt;ralf@linux-mips.org&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit e723e3f7f9591b79e8c56b3d7c5a204a9c571b55 upstream.

Avoid sending a partially initialised `siginfo_t' structure along SIGFPE
signals issued from `do_ov' and `do_trap_or_bp', leading to information
leaking from the kernel stack.

Signed-off-by: Maciej W. Rozycki &lt;macro@imgtec.com&gt;
Signed-off-by: Ralf Baechle &lt;ralf@linux-mips.org&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mld, igmp: Fix reserved tailroom calculation</title>
<updated>2016-04-01T00:54:37+00:00</updated>
<author>
<name>Benjamin Poirier</name>
<email>bpoirier@suse.com</email>
</author>
<published>2016-02-29T23:03:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a2a175739619bd59e8e963200561fc7d6e3bb916'/>
<id>a2a175739619bd59e8e963200561fc7d6e3bb916</id>
<content type='text'>
commit 1837b2e2bcd23137766555a63867e649c0b637f0 upstream.

The current reserved_tailroom calculation fails to take hlen and tlen into
account.

skb:
[__hlen__|__data____________|__tlen___|__extra__]
^                                               ^
head                                            skb_end_offset

In this representation, hlen + data + tlen is the size passed to alloc_skb.
"extra" is the extra space made available in __alloc_skb because of
rounding up by kmalloc. We can reorder the representation like so:

[__hlen__|__data____________|__extra__|__tlen___]
^                                               ^
head                                            skb_end_offset

The maximum space available for ip headers and payload without
fragmentation is min(mtu, data + extra). Therefore,
reserved_tailroom
= data + extra + tlen - min(mtu, data + extra)
= skb_end_offset - hlen - min(mtu, skb_end_offset - hlen - tlen)
= skb_tailroom - min(mtu, skb_tailroom - tlen) ; after skb_reserve(hlen)

Compare the second line to the current expression:
reserved_tailroom = skb_end_offset - min(mtu, skb_end_offset)
and we can see that hlen and tlen are not taken into account.

The min() in the third line can be expanded into:
if mtu &lt; skb_tailroom - tlen:
	reserved_tailroom = skb_tailroom - mtu
else:
	reserved_tailroom = tlen

Depending on hlen, tlen, mtu and the number of multicast address records,
the current code may output skbs that have less tailroom than
dev-&gt;needed_tailroom or it may output more skbs than needed because not all
space available is used.

Fixes: 4c672e4b ("ipv6: mld: fix add_grhead skb_over_panic for devs with large MTUs")
Signed-off-by: Benjamin Poirier &lt;bpoirier@suse.com&gt;
Acked-by: Hannes Frederic Sowa &lt;hannes@stressinduktion.org&gt;
Acked-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
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<pre>
commit 1837b2e2bcd23137766555a63867e649c0b637f0 upstream.

The current reserved_tailroom calculation fails to take hlen and tlen into
account.

skb:
[__hlen__|__data____________|__tlen___|__extra__]
^                                               ^
head                                            skb_end_offset

In this representation, hlen + data + tlen is the size passed to alloc_skb.
"extra" is the extra space made available in __alloc_skb because of
rounding up by kmalloc. We can reorder the representation like so:

[__hlen__|__data____________|__extra__|__tlen___]
^                                               ^
head                                            skb_end_offset

The maximum space available for ip headers and payload without
fragmentation is min(mtu, data + extra). Therefore,
reserved_tailroom
= data + extra + tlen - min(mtu, data + extra)
= skb_end_offset - hlen - min(mtu, skb_end_offset - hlen - tlen)
= skb_tailroom - min(mtu, skb_tailroom - tlen) ; after skb_reserve(hlen)

Compare the second line to the current expression:
reserved_tailroom = skb_end_offset - min(mtu, skb_end_offset)
and we can see that hlen and tlen are not taken into account.

The min() in the third line can be expanded into:
if mtu &lt; skb_tailroom - tlen:
	reserved_tailroom = skb_tailroom - mtu
else:
	reserved_tailroom = tlen

Depending on hlen, tlen, mtu and the number of multicast address records,
the current code may output skbs that have less tailroom than
dev-&gt;needed_tailroom or it may output more skbs than needed because not all
space available is used.

Fixes: 4c672e4b ("ipv6: mld: fix add_grhead skb_over_panic for devs with large MTUs")
Signed-off-by: Benjamin Poirier &lt;bpoirier@suse.com&gt;
Acked-by: Hannes Frederic Sowa &lt;hannes@stressinduktion.org&gt;
Acked-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
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</entry>
<entry>
<title>IB/core: Use GRH when the path hop-limit &gt; 0</title>
<updated>2016-04-01T00:54:36+00:00</updated>
<author>
<name>Or Gerlitz</name>
<email>ogerlitz@mellanox.com</email>
</author>
<published>2016-03-01T16:52:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a1663179bb1707a285258870914536a64cc1c90a'/>
<id>a1663179bb1707a285258870914536a64cc1c90a</id>
<content type='text'>
commit 11d8d645343efba0c975aefe7c2cf3b33c836c75 upstream.

According to IBTA spec v1.3 section 12.7.19, QPs should use GRH when
the path returned by the SA has hop-limit &gt; 0. Currently, we do that
only for the &gt; 1 case, fix that.

Fixes: 6d969a471ba1 ('IB/sa: Add ib_init_ah_from_path()')
Signed-off-by: Or Gerlitz &lt;ogerlitz@mellanox.com&gt;
Reviewed-by: Jason Gunthorpe &lt;jgunthorpe@obsidianresearch.com&gt;
Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
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<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 11d8d645343efba0c975aefe7c2cf3b33c836c75 upstream.

According to IBTA spec v1.3 section 12.7.19, QPs should use GRH when
the path returned by the SA has hop-limit &gt; 0. Currently, we do that
only for the &gt; 1 case, fix that.

Fixes: 6d969a471ba1 ('IB/sa: Add ib_init_ah_from_path()')
Signed-off-by: Or Gerlitz &lt;ogerlitz@mellanox.com&gt;
Reviewed-by: Jason Gunthorpe &lt;jgunthorpe@obsidianresearch.com&gt;
Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
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