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  1. 28 Jun, 2015 37 commits
  3. 22 Jun, 2015 1 commit
    • Mel Gorman's avatar
      sched, numa: Do not hint for NUMA balancing on VM_MIXEDMAP mappings · 90b934b1
      Mel Gorman authored 
      commit 8e76d4ee upstream.

Jovi Zhangwei reported the following problem

  Below kernel vm bug can be triggered by tcpdump which mmaped a lot of pages
  with GFP_COMP flag.

  [Mon May 25 05:29:33 2015] page:ffffea0015414000 count:66 mapcount:1 mapping:          (null) index:0x0
  [Mon May 25 05:29:33 2015] flags: 0x20047580004000(head)
  [Mon May 25 05:29:33 2015] page dumped because: VM_BUG_ON_PAGE(compound_order(page) && !PageTransHuge(page))
  [Mon May 25 05:29:33 2015] ------------[ cut here ]------------
  [Mon May 25 05:29:33 2015] kernel BUG at mm/migrate.c:1661!
  [Mon May 25 05:29:33 2015] invalid opcode: 0000 [#1] SMP

In this case it was triggered by running tcpdump but it's not necessary
reproducible on all systems.

  sudo tcpdump -i bond0.100 'tcp port 4242' -c 100000000000 -w 4242.pcap

Compound pages cannot be migrated and it was not expected that such pages
be marked for NUMA balancing.  This did not take into account that drivers
such as net/packet/af_packet.c may insert compound pages into userspace
with vm_insert_page.  This patch tells the NUMA balancing protection
scanner to skip all VM_MIXEDMAP mappings which avoids the possibility that
compound pages are marked for migration.
Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
Reported-by: default avatarJovi Zhangwei <jovi@cloudflare.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
[jovi: Backported to 3.18: adjust context]
Signed-off-by: default avatarJovi Zhangwei <jovi@cloudflare.com>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      90b934b1
  5. 15 Jun, 2015 2 commits
    • Ilya Dryomov's avatar
      crush: ensuring at most num-rep osds are selected · 3ca9f5f9
      Ilya Dryomov authored 
      [ Upstream commit 45002267 ]

Crush temporary buffers are allocated as per replica size configured
by the user.  When there are more final osds (to be selected as per
rule) than the replicas, buffer overlaps and it causes crash.  Now, it
ensures that at most num-rep osds are selected even if more number of
osds are allowed by the rule.

Reflects ceph.git commits 6b4d1aa99718e3b367496326c1e64551330fabc0,
                          234b066ba04976783d15ff2abc3e81b6cc06fb10.
Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      3ca9f5f9
    • Nikolay Aleksandrov's avatar
      bridge: disable softirqs around br_fdb_update to avoid lockup · b824a7f0
      Nikolay Aleksandrov authored 
      [ Upstream commit c4c832f8 ]

br_fdb_update() can be called in process context in the following way:
br_fdb_add() -> __br_fdb_add() -> br_fdb_update() (if NTF_USE flag is set)
so we need to disable softirqs because there are softirq users of the
hash_lock. One easy way to reproduce this is to modify the bridge utility
to set NTF_USE, enable stp and then set maxageing to a low value so
br_fdb_cleanup() is called frequently and then just add new entries in
a loop. This happens because br_fdb_cleanup() is called from timer/softirq
context. The spin locks in br_fdb_update were _bh before commit f8ae737d
("[BRIDGE]: forwarding remove unneeded preempt and bh diasables")
and at the time that commit was correct because br_fdb_update() couldn't be
called from process context, but that changed after commit:
292d1398 ("bridge: add NTF_USE support")
Using local_bh_disable/enable around br_fdb_update() allows us to keep
using the spin_lock/unlock in br_fdb_update for the fast-path.
Signed-off-by: default avatarNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Fixes: 292d1398 ("bridge: add NTF_USE support")
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      b824a7f0
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