<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/kernel, branch v4.5-rc4</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2016-02-14T20:02:05+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2016-02-14T20:02:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=cb490d632b9c7a3f08a9c73b88956132b6ad299c'/>
<id>cb490d632b9c7a3f08a9c73b88956132b6ad299c</id>
<content type='text'>
Pull lockdep fix from Thomas Gleixner:
 "A single fix for the stack trace caching logic in lockdep, where the
  duplicate avoidance managed to store no back trace at all"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/lockdep: Fix stack trace caching logic
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull lockdep fix from Thomas Gleixner:
 "A single fix for the stack trace caching logic in lockdep, where the
  duplicate avoidance managed to store no back trace at all"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/lockdep: Fix stack trace caching logic
</pre>
</div>
</content>
</entry>
<entry>
<title>mm: fix pfn_t vs highmem</title>
<updated>2016-02-12T02:35:48+00:00</updated>
<author>
<name>Dan Williams</name>
<email>dan.j.williams@intel.com</email>
</author>
<published>2016-02-12T00:13:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=db78c22230d0bcc8b27b81f05b39f104f08232c5'/>
<id>db78c22230d0bcc8b27b81f05b39f104f08232c5</id>
<content type='text'>
The pfn_t type uses an unsigned long to store a pfn + flags value.  On a
64-bit platform the upper 12 bits of an unsigned long are never used for
storing the value of a pfn.  However, this is not true on highmem
platforms, all 32-bits of a pfn value are used to address a 44-bit
physical address space.  A pfn_t needs to store a 64-bit value.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=112211
Fixes: 01c8f1c44b83 ("mm, dax, gpu: convert vm_insert_mixed to pfn_t")
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Reported-by: Stuart Foster &lt;smf.linux@ntlworld.com&gt;
Reported-by: Julian Margetson &lt;runaway@candw.ms&gt;
Tested-by: Julian Margetson &lt;runaway@candw.ms&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The pfn_t type uses an unsigned long to store a pfn + flags value.  On a
64-bit platform the upper 12 bits of an unsigned long are never used for
storing the value of a pfn.  However, this is not true on highmem
platforms, all 32-bits of a pfn value are used to address a 44-bit
physical address space.  A pfn_t needs to store a 64-bit value.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=112211
Fixes: 01c8f1c44b83 ("mm, dax, gpu: convert vm_insert_mixed to pfn_t")
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Reported-by: Stuart Foster &lt;smf.linux@ntlworld.com&gt;
Reported-by: Julian Margetson &lt;runaway@candw.ms&gt;
Tested-by: Julian Margetson &lt;runaway@candw.ms&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>kernel/locking/lockdep.c: convert hash tables to hlists</title>
<updated>2016-02-12T02:35:48+00:00</updated>
<author>
<name>Andrew Morton</name>
<email>akpm@linux-foundation.org</email>
</author>
<published>2016-02-12T00:13:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=4a389810bc3cb0e73443104f0827e81e23cb1e12'/>
<id>4a389810bc3cb0e73443104f0827e81e23cb1e12</id>
<content type='text'>
Mike said:

: CONFIG_UBSAN_ALIGNMENT breaks x86-64 kernel with lockdep enabled, i.  e
: kernel with CONFIG_UBSAN_ALIGNMENT fails to load without even any error
: message.
:
: The problem is that ubsan callbacks use spinlocks and might be called
: before lockdep is initialized.  Particularly this line in the
: reserve_ebda_region function causes problem:
:
: lowmem = *(unsigned short *)__va(BIOS_LOWMEM_KILOBYTES);
:
: If i put lockdep_init() before reserve_ebda_region call in
: x86_64_start_reservations kernel loads well.

Fix this ordering issue permanently: change lockdep so that it uses
hlists for the hash tables.  Unlike a list_head, an hlist_head is in its
initialized state when it is all-zeroes, so lockdep is ready for
operation immediately upon boot - lockdep_init() need not have run.

The patch will also save some memory.

lockdep_init() and lockdep_initialized can be done away with now - a 4.6
patch has been prepared to do this.

Reported-by: Mike Krinkin &lt;krinkin.m.u@gmail.com&gt;
Suggested-by: Mike Krinkin &lt;krinkin.m.u@gmail.com&gt;
Cc: Andrey Ryabinin &lt;aryabinin@virtuozzo.com&gt;
Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Mike said:

: CONFIG_UBSAN_ALIGNMENT breaks x86-64 kernel with lockdep enabled, i.  e
: kernel with CONFIG_UBSAN_ALIGNMENT fails to load without even any error
: message.
:
: The problem is that ubsan callbacks use spinlocks and might be called
: before lockdep is initialized.  Particularly this line in the
: reserve_ebda_region function causes problem:
:
: lowmem = *(unsigned short *)__va(BIOS_LOWMEM_KILOBYTES);
:
: If i put lockdep_init() before reserve_ebda_region call in
: x86_64_start_reservations kernel loads well.

Fix this ordering issue permanently: change lockdep so that it uses
hlists for the hash tables.  Unlike a list_head, an hlist_head is in its
initialized state when it is all-zeroes, so lockdep is ready for
operation immediately upon boot - lockdep_init() need not have run.

The patch will also save some memory.

lockdep_init() and lockdep_initialized can be done away with now - a 4.6
patch has been prepared to do this.

Reported-by: Mike Krinkin &lt;krinkin.m.u@gmail.com&gt;
Suggested-by: Mike Krinkin &lt;krinkin.m.u@gmail.com&gt;
Cc: Andrey Ryabinin &lt;aryabinin@virtuozzo.com&gt;
Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net</title>
<updated>2016-02-11T19:00:34+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2016-02-11T19:00:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=5de6ac75d928358063f37c874a91ca1ef28ac308'/>
<id>5de6ac75d928358063f37c874a91ca1ef28ac308</id>
<content type='text'>
Pull networking fixes from David Miller:

 1) Fix BPF handling of branch offset adjustmnets on backjumps, from
    Daniel Borkmann.

 2) Make sure selinux knows about SOCK_DESTROY netlink messages, from
    Lorenzo Colitti.

 3) Fix openvswitch tunnel mtu regression, from David Wragg.

 4) Fix ICMP handling of TCP sockets in syn_recv state, from Eric
    Dumazet.

 5) Fix SCTP user hmacid byte ordering bug, from Xin Long.

 6) Fix recursive locking in ipv6 addrconf, from Subash Abhinov
    Kasiviswanathan.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
  bpf: fix branch offset adjustment on backjumps after patching ctx expansion
  vxlan, gre, geneve: Set a large MTU on ovs-created tunnel devices
  geneve: Relax MTU constraints
  vxlan: Relax MTU constraints
  flow_dissector: Fix unaligned access in __skb_flow_dissector when used by eth_get_headlen
  of: of_mdio: Add marvell, 88e1145 to whitelist of PHY compatibilities.
  selinux: nlmsgtab: add SOCK_DESTROY to the netlink mapping tables
  sctp: translate network order to host order when users get a hmacid
  enic: increment devcmd2 result ring in case of timeout
  tg3: Fix for tg3 transmit queue 0 timed out when too many gso_segs
  net:Add sysctl_max_skb_frags
  tcp: do not drop syn_recv on all icmp reports
  ipv6: fix a lockdep splat
  unix: correctly track in-flight fds in sending process user_struct
  update be2net maintainers' email addresses
  dwc_eth_qos: Reset hardware before PHY start
  ipv6: addrconf: Fix recursive spin lock call
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull networking fixes from David Miller:

 1) Fix BPF handling of branch offset adjustmnets on backjumps, from
    Daniel Borkmann.

 2) Make sure selinux knows about SOCK_DESTROY netlink messages, from
    Lorenzo Colitti.

 3) Fix openvswitch tunnel mtu regression, from David Wragg.

 4) Fix ICMP handling of TCP sockets in syn_recv state, from Eric
    Dumazet.

 5) Fix SCTP user hmacid byte ordering bug, from Xin Long.

 6) Fix recursive locking in ipv6 addrconf, from Subash Abhinov
    Kasiviswanathan.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
  bpf: fix branch offset adjustment on backjumps after patching ctx expansion
  vxlan, gre, geneve: Set a large MTU on ovs-created tunnel devices
  geneve: Relax MTU constraints
  vxlan: Relax MTU constraints
  flow_dissector: Fix unaligned access in __skb_flow_dissector when used by eth_get_headlen
  of: of_mdio: Add marvell, 88e1145 to whitelist of PHY compatibilities.
  selinux: nlmsgtab: add SOCK_DESTROY to the netlink mapping tables
  sctp: translate network order to host order when users get a hmacid
  enic: increment devcmd2 result ring in case of timeout
  tg3: Fix for tg3 transmit queue 0 timed out when too many gso_segs
  net:Add sysctl_max_skb_frags
  tcp: do not drop syn_recv on all icmp reports
  ipv6: fix a lockdep splat
  unix: correctly track in-flight fds in sending process user_struct
  update be2net maintainers' email addresses
  dwc_eth_qos: Reset hardware before PHY start
  ipv6: addrconf: Fix recursive spin lock call
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: fix branch offset adjustment on backjumps after patching ctx expansion</title>
<updated>2016-02-10T21:56:47+00:00</updated>
<author>
<name>Daniel Borkmann</name>
<email>daniel@iogearbox.net</email>
</author>
<published>2016-02-10T15:47:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=a1b14d27ed0965838350f1377ff97c93ee383492'/>
<id>a1b14d27ed0965838350f1377ff97c93ee383492</id>
<content type='text'>
When ctx access is used, the kernel often needs to expand/rewrite
instructions, so after that patching, branch offsets have to be
adjusted for both forward and backward jumps in the new eBPF program,
but for backward jumps it fails to account the delta. Meaning, for
example, if the expansion happens exactly on the insn that sits at
the jump target, it doesn't fix up the back jump offset.

Analysis on what the check in adjust_branches() is currently doing:

  /* adjust offset of jmps if necessary */
  if (i &lt; pos &amp;&amp; i + insn-&gt;off + 1 &gt; pos)
    insn-&gt;off += delta;
  else if (i &gt; pos &amp;&amp; i + insn-&gt;off + 1 &lt; pos)
    insn-&gt;off -= delta;

First condition (forward jumps):

  Before:                         After:

  insns[0]                        insns[0]
  insns[1] &lt;--- i/insn            insns[1] &lt;--- i/insn
  insns[2] &lt;--- pos               insns[P] &lt;--- pos
  insns[3]                        insns[P]  `------| delta
  insns[4] &lt;--- target_X          insns[P]   `-----|
  insns[5]                        insns[3]
                                  insns[4] &lt;--- target_X
                                  insns[5]

First case is if we cross pos-boundary and the jump instruction was
before pos. This is handeled correctly. I.e. if i == pos, then this
would mean our jump that we currently check was the patchlet itself
that we just injected. Since such patchlets are self-contained and
have no awareness of any insns before or after the patched one, the
delta is correctly not adjusted. Also, for the second condition in
case of i + insn-&gt;off + 1 == pos, means we jump to that newly patched
instruction, so no offset adjustment are needed. That part is correct.

Second condition (backward jumps):

  Before:                         After:

  insns[0]                        insns[0]
  insns[1] &lt;--- target_X          insns[1] &lt;--- target_X
  insns[2] &lt;--- pos &lt;-- target_Y  insns[P] &lt;--- pos &lt;-- target_Y
  insns[3]                        insns[P]  `------| delta
  insns[4] &lt;--- i/insn            insns[P]   `-----|
  insns[5]                        insns[3]
                                  insns[4] &lt;--- i/insn
                                  insns[5]

Second interesting case is where we cross pos-boundary and the jump
instruction was after pos. Backward jump with i == pos would be
impossible and pose a bug somewhere in the patchlet, so the first
condition checking i &gt; pos is okay only by itself. However, i +
insn-&gt;off + 1 &lt; pos does not always work as intended to trigger the
adjustment. It works when jump targets would be far off where the
delta wouldn't matter. But, for example, where the fixed insn-&gt;off
before pointed to pos (target_Y), it now points to pos + delta, so
that additional room needs to be taken into account for the check.
This means that i) both tests here need to be adjusted into pos + delta,
and ii) for the second condition, the test needs to be &lt;= as pos
itself can be a target in the backjump, too.

Fixes: 9bac3d6d548e ("bpf: allow extended BPF programs access skb fields")
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When ctx access is used, the kernel often needs to expand/rewrite
instructions, so after that patching, branch offsets have to be
adjusted for both forward and backward jumps in the new eBPF program,
but for backward jumps it fails to account the delta. Meaning, for
example, if the expansion happens exactly on the insn that sits at
the jump target, it doesn't fix up the back jump offset.

Analysis on what the check in adjust_branches() is currently doing:

  /* adjust offset of jmps if necessary */
  if (i &lt; pos &amp;&amp; i + insn-&gt;off + 1 &gt; pos)
    insn-&gt;off += delta;
  else if (i &gt; pos &amp;&amp; i + insn-&gt;off + 1 &lt; pos)
    insn-&gt;off -= delta;

First condition (forward jumps):

  Before:                         After:

  insns[0]                        insns[0]
  insns[1] &lt;--- i/insn            insns[1] &lt;--- i/insn
  insns[2] &lt;--- pos               insns[P] &lt;--- pos
  insns[3]                        insns[P]  `------| delta
  insns[4] &lt;--- target_X          insns[P]   `-----|
  insns[5]                        insns[3]
                                  insns[4] &lt;--- target_X
                                  insns[5]

First case is if we cross pos-boundary and the jump instruction was
before pos. This is handeled correctly. I.e. if i == pos, then this
would mean our jump that we currently check was the patchlet itself
that we just injected. Since such patchlets are self-contained and
have no awareness of any insns before or after the patched one, the
delta is correctly not adjusted. Also, for the second condition in
case of i + insn-&gt;off + 1 == pos, means we jump to that newly patched
instruction, so no offset adjustment are needed. That part is correct.

Second condition (backward jumps):

  Before:                         After:

  insns[0]                        insns[0]
  insns[1] &lt;--- target_X          insns[1] &lt;--- target_X
  insns[2] &lt;--- pos &lt;-- target_Y  insns[P] &lt;--- pos &lt;-- target_Y
  insns[3]                        insns[P]  `------| delta
  insns[4] &lt;--- i/insn            insns[P]   `-----|
  insns[5]                        insns[3]
                                  insns[4] &lt;--- i/insn
                                  insns[5]

Second interesting case is where we cross pos-boundary and the jump
instruction was after pos. Backward jump with i == pos would be
impossible and pose a bug somewhere in the patchlet, so the first
condition checking i &gt; pos is okay only by itself. However, i +
insn-&gt;off + 1 &lt; pos does not always work as intended to trigger the
adjustment. It works when jump targets would be far off where the
delta wouldn't matter. But, for example, where the fixed insn-&gt;off
before pointed to pos (target_Y), it now points to pos + delta, so
that additional room needs to be taken into account for the check.
This means that i) both tests here need to be adjusted into pos + delta,
and ii) for the second condition, the test needs to be &lt;= as pos
itself can be a target in the backjump, too.

Fixes: 9bac3d6d548e ("bpf: allow extended BPF programs access skb fields")
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'for-4.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup</title>
<updated>2016-02-10T19:36:19+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2016-02-10T19:36:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=fb0dc5f129bc2d4763bdc237b8df0e1708c03e1e'/>
<id>fb0dc5f129bc2d4763bdc237b8df0e1708c03e1e</id>
<content type='text'>
Pull cgroup fixes from Tejun Heo:

 - The destruction path of cgroup objects are asynchronous and
   multi-staged and some of them ended up destroying parents before
   children leading to failures in cpu and memory controllers.  Ensure
   that parents are always destroyed after children.

 - cpuset mm node migration was performed synchronously while holding
   threadgroup and cgroup mutexes and the recent threadgroup locking
   update resulted in a possible deadlock.  The migration is best effort
   and shouldn't have been performed under those locks to begin with.
   Made asynchronous.

 - Minor documentation fix.

* 'for-4.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  Documentation: cgroup: Fix 'cgroup-legacy' -&gt; 'cgroup-v1'
  cgroup: make sure a parent css isn't freed before its children
  cgroup: make sure a parent css isn't offlined before its children
  cpuset: make mm migration asynchronous
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull cgroup fixes from Tejun Heo:

 - The destruction path of cgroup objects are asynchronous and
   multi-staged and some of them ended up destroying parents before
   children leading to failures in cpu and memory controllers.  Ensure
   that parents are always destroyed after children.

 - cpuset mm node migration was performed synchronously while holding
   threadgroup and cgroup mutexes and the recent threadgroup locking
   update resulted in a possible deadlock.  The migration is best effort
   and shouldn't have been performed under those locks to begin with.
   Made asynchronous.

 - Minor documentation fix.

* 'for-4.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  Documentation: cgroup: Fix 'cgroup-legacy' -&gt; 'cgroup-v1'
  cgroup: make sure a parent css isn't freed before its children
  cgroup: make sure a parent css isn't offlined before its children
  cpuset: make mm migration asynchronous
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'for-4.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq</title>
<updated>2016-02-10T19:04:05+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2016-02-10T19:04:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=9aece75c138d93bde79a2baeb9187a1109b4e952'/>
<id>9aece75c138d93bde79a2baeb9187a1109b4e952</id>
<content type='text'>
Pull workqueue fixes from Tejun Heo:
 "Workqueue fixes for v4.5-rc3.

   - Remove a spurious triggering of flush dependency warning.

   - Officially break local execution guarantee of unbound work items
     and add a debug feature to flush out usages which depend on it.

   - Work around CPU -&gt; NODE mapping becoming invalid on CPU offline.

  The branch is young but pushing out early as stable kernels are being
  affected"

* 'for-4.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: handle NUMA_NO_NODE for unbound pool_workqueue lookup
  workqueue: implement "workqueue.debug_force_rr_cpu" debug feature
  workqueue: schedule WORK_CPU_UNBOUND work on wq_unbound_cpumask CPUs
  Revert "workqueue: make sure delayed work run in local cpu"
  workqueue: skip flush dependency checks for legacy workqueues
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull workqueue fixes from Tejun Heo:
 "Workqueue fixes for v4.5-rc3.

   - Remove a spurious triggering of flush dependency warning.

   - Officially break local execution guarantee of unbound work items
     and add a debug feature to flush out usages which depend on it.

   - Work around CPU -&gt; NODE mapping becoming invalid on CPU offline.

  The branch is young but pushing out early as stable kernels are being
  affected"

* 'for-4.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: handle NUMA_NO_NODE for unbound pool_workqueue lookup
  workqueue: implement "workqueue.debug_force_rr_cpu" debug feature
  workqueue: schedule WORK_CPU_UNBOUND work on wq_unbound_cpumask CPUs
  Revert "workqueue: make sure delayed work run in local cpu"
  workqueue: skip flush dependency checks for legacy workqueues
</pre>
</div>
</content>
</entry>
<entry>
<title>workqueue: handle NUMA_NO_NODE for unbound pool_workqueue lookup</title>
<updated>2016-02-10T17:13:05+00:00</updated>
<author>
<name>Tejun Heo</name>
<email>tj@kernel.org</email>
</author>
<published>2016-02-03T18:54:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=d6e022f1d207a161cd88e08ef0371554680ffc46'/>
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<content type='text'>
When looking up the pool_workqueue to use for an unbound workqueue,
workqueue assumes that the target CPU is always bound to a valid NUMA
node.  However, currently, when a CPU goes offline, the mapping is
destroyed and cpu_to_node() returns NUMA_NO_NODE.

This has always been broken but hasn't triggered often enough before
874bbfe600a6 ("workqueue: make sure delayed work run in local cpu").
After the commit, workqueue forcifully assigns the local CPU for
delayed work items without explicit target CPU to fix a different
issue.  This widens the window where CPU can go offline while a
delayed work item is pending causing delayed work items dispatched
with target CPU set to an already offlined CPU.  The resulting
NUMA_NO_NODE mapping makes workqueue try to queue the work item on a
NULL pool_workqueue and thus crash.

While 874bbfe600a6 has been reverted for a different reason making the
bug less visible again, it can still happen.  Fix it by mapping
NUMA_NO_NODE to the default pool_workqueue from unbound_pwq_by_node().
This is a temporary workaround.  The long term solution is keeping CPU
-&gt; NODE mapping stable across CPU off/online cycles which is being
worked on.

Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
Reported-by: Mike Galbraith &lt;umgwanakikbuti@gmail.com&gt;
Cc: Tang Chen &lt;tangchen@cn.fujitsu.com&gt;
Cc: Rafael J. Wysocki &lt;rafael@kernel.org&gt;
Cc: Len Brown &lt;len.brown@intel.com&gt;
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/g/1454424264.11183.46.camel@gmail.com
Link: http://lkml.kernel.org/g/1453702100-2597-1-git-send-email-tangchen@cn.fujitsu.com
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<pre>
When looking up the pool_workqueue to use for an unbound workqueue,
workqueue assumes that the target CPU is always bound to a valid NUMA
node.  However, currently, when a CPU goes offline, the mapping is
destroyed and cpu_to_node() returns NUMA_NO_NODE.

This has always been broken but hasn't triggered often enough before
874bbfe600a6 ("workqueue: make sure delayed work run in local cpu").
After the commit, workqueue forcifully assigns the local CPU for
delayed work items without explicit target CPU to fix a different
issue.  This widens the window where CPU can go offline while a
delayed work item is pending causing delayed work items dispatched
with target CPU set to an already offlined CPU.  The resulting
NUMA_NO_NODE mapping makes workqueue try to queue the work item on a
NULL pool_workqueue and thus crash.

While 874bbfe600a6 has been reverted for a different reason making the
bug less visible again, it can still happen.  Fix it by mapping
NUMA_NO_NODE to the default pool_workqueue from unbound_pwq_by_node().
This is a temporary workaround.  The long term solution is keeping CPU
-&gt; NODE mapping stable across CPU off/online cycles which is being
worked on.

Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
Reported-by: Mike Galbraith &lt;umgwanakikbuti@gmail.com&gt;
Cc: Tang Chen &lt;tangchen@cn.fujitsu.com&gt;
Cc: Rafael J. Wysocki &lt;rafael@kernel.org&gt;
Cc: Len Brown &lt;len.brown@intel.com&gt;
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/g/1454424264.11183.46.camel@gmail.com
Link: http://lkml.kernel.org/g/1453702100-2597-1-git-send-email-tangchen@cn.fujitsu.com
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux</title>
<updated>2016-02-10T00:40:59+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2016-02-10T00:40:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2178cbc68f3602dc0b5949b9be2c8383ad3d93ef'/>
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Pull module fixes from Rusty Russell:
 "Fix for async_probe module param added in 4.3 (clearly not widely used
  yet), and a much more interesting kallsyms race which has been around
  approximately forever.  This fix is more invasive, and will require
  some care in backporting, but I hated all the bandaids I could think
  of, so...

  There are some more coming, which are only for breakages introduced
  this cycle (livepatch), but wanted these in now"

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  modules: fix longstanding /proc/kallsyms vs module insertion race.
  module: wrapper for symbol name.
  modules: fix modparam async_probe request
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<pre>
Pull module fixes from Rusty Russell:
 "Fix for async_probe module param added in 4.3 (clearly not widely used
  yet), and a much more interesting kallsyms race which has been around
  approximately forever.  This fix is more invasive, and will require
  some care in backporting, but I hated all the bandaids I could think
  of, so...

  There are some more coming, which are only for breakages introduced
  this cycle (livepatch), but wanted these in now"

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  modules: fix longstanding /proc/kallsyms vs module insertion race.
  module: wrapper for symbol name.
  modules: fix modparam async_probe request
</pre>
</div>
</content>
</entry>
<entry>
<title>workqueue: implement "workqueue.debug_force_rr_cpu" debug feature</title>
<updated>2016-02-09T22:59:38+00:00</updated>
<author>
<name>Tejun Heo</name>
<email>tj@kernel.org</email>
</author>
<published>2016-02-09T22:59:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=f303fccb82928790ec58eea82722bd5c54d300b3'/>
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<content type='text'>
Workqueue used to guarantee local execution for work items queued
without explicit target CPU.  The guarantee is gone now which can
break some usages in subtle ways.  To flush out those cases, this
patch implements a debug feature which forces round-robin CPU
selection for all such work items.

The debug feature defaults to off and can be enabled with a kernel
parameter.  The default can be flipped with a debug config option.

If you hit this commit during bisection, please refer to 041bd12e272c
("Revert "workqueue: make sure delayed work run in local cpu"") for
more information and ping me.

Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Workqueue used to guarantee local execution for work items queued
without explicit target CPU.  The guarantee is gone now which can
break some usages in subtle ways.  To flush out those cases, this
patch implements a debug feature which forces round-robin CPU
selection for all such work items.

The debug feature defaults to off and can be enabled with a kernel
parameter.  The default can be flipped with a debug config option.

If you hit this commit during bisection, please refer to 041bd12e272c
("Revert "workqueue: make sure delayed work run in local cpu"") for
more information and ping me.

Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
