1. 06 May, 2015 5 commits
    • Filipe Manana's avatar
      Btrfs: fix inode eviction infinite loop after cloning into it · 6073c416
      Filipe Manana authored
      commit ccccf3d6 upstream.
      
      If we attempt to clone a 0 length region into a file we can end up
      inserting a range in the inode's extent_io tree with a start offset
      that is greater then the end offset, which triggers immediately the
      following warning:
      
      [ 3914.619057] WARNING: CPU: 17 PID: 4199 at fs/btrfs/extent_io.c:435 insert_state+0x4b/0x10b [btrfs]()
      [ 3914.620886] BTRFS: end < start 4095 4096
      (...)
      [ 3914.638093] Call Trace:
      [ 3914.638636]  [<ffffffff81425fd9>] dump_stack+0x4c/0x65
      [ 3914.639620]  [<ffffffff81045390>] warn_slowpath_common+0xa1/0xbb
      [ 3914.640789]  [<ffffffffa03ca44f>] ? insert_state+0x4b/0x10b [btrfs]
      [ 3914.642041]  [<ffffffff810453f0>] warn_slowpath_fmt+0x46/0x48
      [ 3914.643236]  [<ffffffffa03ca44f>] insert_state+0x4b/0x10b [btrfs]
      [ 3914.644441]  [<ffffffffa03ca729>] __set_extent_bit+0x107/0x3f4 [btrfs]
      [ 3914.645711]  [<ffffffffa03cb256>] lock_extent_bits+0x65/0x1bf [btrfs]
      [ 3914.646914]  [<ffffffff8142b2fb>] ? _raw_spin_unlock+0x28/0x33
      [ 3914.648058]  [<ffffffffa03cbac4>] ? test_range_bit+0xcc/0xde [btrfs]
      [ 3914.650105]  [<ffffffffa03cb3c3>] lock_extent+0x13/0x15 [btrfs]
      [ 3914.651361]  [<ffffffffa03db39e>] lock_extent_range+0x3d/0xcd [btrfs]
      [ 3914.652761]  [<ffffffffa03de1fe>] btrfs_ioctl_clone+0x278/0x388 [btrfs]
      [ 3914.654128]  [<ffffffff811226dd>] ? might_fault+0x58/0xb5
      [ 3914.655320]  [<ffffffffa03e0909>] btrfs_ioctl+0xb51/0x2195 [btrfs]
      (...)
      [ 3914.669271] ---[ end trace 14843d3e2e622fc1 ]---
      
      This later makes the inode eviction handler enter an infinite loop that
      keeps dumping the following warning over and over:
      
      [ 3915.117629] WARNING: CPU: 22 PID: 4228 at fs/btrfs/extent_io.c:435 insert_state+0x4b/0x10b [btrfs]()
      [ 3915.119913] BTRFS: end < start 4095 4096
      (...)
      [ 3915.137394] Call Trace:
      [ 3915.137913]  [<ffffffff81425fd9>] dump_stack+0x4c/0x65
      [ 3915.139154]  [<ffffffff81045390>] warn_slowpath_common+0xa1/0xbb
      [ 3915.140316]  [<ffffffffa03ca44f>] ? insert_state+0x4b/0x10b [btrfs]
      [ 3915.141505]  [<ffffffff810453f0>] warn_slowpath_fmt+0x46/0x48
      [ 3915.142709]  [<ffffffffa03ca44f>] insert_state+0x4b/0x10b [btrfs]
      [ 3915.143849]  [<ffffffffa03ca729>] __set_extent_bit+0x107/0x3f4 [btrfs]
      [ 3915.145120]  [<ffffffffa038c1e3>] ? btrfs_kill_super+0x17/0x23 [btrfs]
      [ 3915.146352]  [<ffffffff811548f6>] ? deactivate_locked_super+0x3b/0x50
      [ 3915.147565]  [<ffffffffa03cb256>] lock_extent_bits+0x65/0x1bf [btrfs]
      [ 3915.148785]  [<ffffffff8142b7e2>] ? _raw_write_unlock+0x28/0x33
      [ 3915.149931]  [<ffffffffa03bc325>] btrfs_evict_inode+0x196/0x482 [btrfs]
      [ 3915.151154]  [<ffffffff81168904>] evict+0xa0/0x148
      [ 3915.152094]  [<ffffffff811689e5>] dispose_list+0x39/0x43
      [ 3915.153081]  [<ffffffff81169564>] evict_inodes+0xdc/0xeb
      [ 3915.154062]  [<ffffffff81154418>] generic_shutdown_super+0x49/0xef
      [ 3915.155193]  [<ffffffff811546d1>] kill_anon_super+0x13/0x1e
      [ 3915.156274]  [<ffffffffa038c1e3>] btrfs_kill_super+0x17/0x23 [btrfs]
      (...)
      [ 3915.167404] ---[ end trace 14843d3e2e622fc2 ]---
      
      So just bail out of the clone ioctl if the length of the region to clone
      is zero, without locking any extent range, in order to prevent this issue
      (same behaviour as a pwrite with a 0 length for example).
      
      This is trivial to reproduce. For example, the steps for the test I just
      made for fstests:
      
        mkfs.btrfs -f SCRATCH_DEV
        mount SCRATCH_DEV $SCRATCH_MNT
      
        touch $SCRATCH_MNT/foo
        touch $SCRATCH_MNT/bar
      
        $CLONER_PROG -s 0 -d 4096 -l 0 $SCRATCH_MNT/foo $SCRATCH_MNT/bar
        umount $SCRATCH_MNT
      
      A test case for fstests follows soon.
      Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
      Reviewed-by: default avatarOmar Sandoval <osandov@osandov.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      6073c416
    • Filipe Manana's avatar
      Btrfs: fix log tree corruption when fs mounted with -o discard · bf339141
      Filipe Manana authored
      commit dcc82f47 upstream.
      
      While committing a transaction we free the log roots before we write the
      new super block. Freeing the log roots implies marking the disk location
      of every node/leaf (metadata extent) as pinned before the new super block
      is written. This is to prevent the disk location of log metadata extents
      from being reused before the new super block is written, otherwise we
      would have a corrupted log tree if before the new super block is written
      a crash/reboot happens and the location of any log tree metadata extent
      ended up being reused and rewritten.
      
      Even though we pinned the log tree's metadata extents, we were issuing a
      discard against them if the fs was mounted with the -o discard option,
      resulting in corruption of the log tree if a crash/reboot happened before
      writing the new super block - the next time the fs was mounted, during
      the log replay process we would find nodes/leafs of the log btree with
      a content full of zeroes, causing the process to fail and require the
      use of the tool btrfs-zero-log to wipeout the log tree (and all data
      previously fsynced becoming lost forever).
      
      Fix this by not doing a discard when pinning an extent. The discard will
      be done later when it's safe (after the new super block is committed) at
      extent-tree.c:btrfs_finish_extent_commit().
      
      Fixes: e688b725 (Btrfs: fix extent pinning bugs in the tree log)
      Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      bf339141
    • Eric Dumazet's avatar
      tcp: avoid looping in tcp_send_fin() · bc9f0ea1
      Eric Dumazet authored
      [ Upstream commit 845704a5 ]
      
      Presence of an unbound loop in tcp_send_fin() had always been hard
      to explain when analyzing crash dumps involving gigantic dying processes
      with millions of sockets.
      
      Lets try a different strategy :
      
      In case of memory pressure, try to add the FIN flag to last packet
      in write queue, even if packet was already sent. TCP stack will
      be able to deliver this FIN after a timeout event. Note that this
      FIN being delivered by a retransmit, it also carries a Push flag
      given our current implementation.
      
      By checking sk_under_memory_pressure(), we anticipate that cooking
      many FIN packets might deplete tcp memory.
      
      In the case we could not allocate a packet, even with __GFP_WAIT
      allocation, then not sending a FIN seems quite reasonable if it allows
      to get rid of this socket, free memory, and not block the process from
      eventually doing other useful work.
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      bc9f0ea1
    • Eric Dumazet's avatar
      tcp: fix possible deadlock in tcp_send_fin() · aac9fda3
      Eric Dumazet authored
      [ Upstream commit d83769a5 ]
      
      Using sk_stream_alloc_skb() in tcp_send_fin() is dangerous in
      case a huge process is killed by OOM, and tcp_mem[2] is hit.
      
      To be able to free memory we need to make progress, so this
      patch allows FIN packets to not care about tcp_mem[2], if
      skb allocation succeeded.
      
      In a follow-up patch, we might abort tcp_send_fin() infinite loop
      in case TIF_MEMDIE is set on this thread, as memory allocator
      did its best getting extra memory already.
      
      This patch reverts d22e1537 ("tcp: fix tcp fin memory accounting")
      
      Fixes: d22e1537 ("tcp: fix tcp fin memory accounting")
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      aac9fda3
    • Sebastian Pöhn's avatar
      ip_forward: Drop frames with attached skb->sk · fb138c46
      Sebastian Pöhn authored
      [ Upstream commit 2ab95749 ]
      
      Initial discussion was:
      [FYI] xfrm: Don't lookup sk_policy for timewait sockets
      
      Forwarded frames should not have a socket attached. Especially
      tw sockets will lead to panics later-on in the stack.
      
      This was observed with TPROXY assigning a tw socket and broken
      policy routing (misconfigured). As a result frame enters
      forwarding path instead of input. We cannot solve this in
      TPROXY as it cannot know that policy routing is broken.
      
      v2:
      Remove useless comment
      Signed-off-by: default avatarSebastian Poehn <sebastian.poehn@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      fb138c46
  2. 29 Apr, 2015 34 commits
  3. 19 Apr, 2015 1 commit