1. 23 10月, 2012 2 次提交
    • J
      blkcg: stop iteration early if root_rl is the only request list · 65c77fd9
      Jun'ichi Nomura 提交于
      __blk_queue_next_rl() finds next request list based on blkg_list
      while skipping root_blkg in the list.
      OTOH, root_rl is special as it may exist even without root_blkg.
      
      Though the later part of the function handles such a case correctly,
      exiting early is good for readability of the code.
      Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com>
      Cc: Tejun Heo <tj@kernel.org>
      Acked-by: NVivek Goyal <vgoyal@redhat.com>
      Signed-off-by: NJens Axboe <axboe@kernel.dk>
      65c77fd9
    • J
      blkcg: Fix use-after-free of q->root_blkg and q->root_rl.blkg · 65635cbc
      Jun'ichi Nomura 提交于
      blk_put_rl() does not call blkg_put() for q->root_rl because we
      don't take request list reference on q->root_blkg.
      However, if root_blkg is once attached then detached (freed),
      blk_put_rl() is confused by the bogus pointer in q->root_blkg.
      
      For example, with !CONFIG_BLK_DEV_THROTTLING &&
      CONFIG_CFQ_GROUP_IOSCHED,
      switching IO scheduler from cfq to deadline will cause system stall
      after the following warning with 3.6:
      
      > WARNING: at /work/build/linux/block/blk-cgroup.h:250
      > blk_put_rl+0x4d/0x95()
      > Modules linked in: bridge stp llc sunrpc acpi_cpufreq freq_table mperf
      > ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4
      > Pid: 0, comm: swapper/0 Not tainted 3.6.0 #1
      > Call Trace:
      >  <IRQ>  [<ffffffff810453bd>] warn_slowpath_common+0x85/0x9d
      >  [<ffffffff810453ef>] warn_slowpath_null+0x1a/0x1c
      >  [<ffffffff811d5f8d>] blk_put_rl+0x4d/0x95
      >  [<ffffffff811d614a>] __blk_put_request+0xc3/0xcb
      >  [<ffffffff811d71a3>] blk_finish_request+0x232/0x23f
      >  [<ffffffff811d76c3>] ? blk_end_bidi_request+0x34/0x5d
      >  [<ffffffff811d76d1>] blk_end_bidi_request+0x42/0x5d
      >  [<ffffffff811d7728>] blk_end_request+0x10/0x12
      >  [<ffffffff812cdf16>] scsi_io_completion+0x207/0x4d5
      >  [<ffffffff812c6fcf>] scsi_finish_command+0xfa/0x103
      >  [<ffffffff812ce2f8>] scsi_softirq_done+0xff/0x108
      >  [<ffffffff811dcea5>] blk_done_softirq+0x8d/0xa1
      >  [<ffffffff810915d5>] ?
      >  generic_smp_call_function_single_interrupt+0x9f/0xd7
      >  [<ffffffff8104cf5b>] __do_softirq+0x102/0x213
      >  [<ffffffff8108a5ec>] ? lock_release_holdtime+0xb6/0xbb
      >  [<ffffffff8104d2b4>] ? raise_softirq_irqoff+0x9/0x3d
      >  [<ffffffff81424dfc>] call_softirq+0x1c/0x30
      >  [<ffffffff81011beb>] do_softirq+0x4b/0xa3
      >  [<ffffffff8104cdb0>] irq_exit+0x53/0xd5
      >  [<ffffffff8102d865>] smp_call_function_single_interrupt+0x34/0x36
      >  [<ffffffff8142486f>] call_function_single_interrupt+0x6f/0x80
      >  <EOI>  [<ffffffff8101800b>] ? mwait_idle+0x94/0xcd
      >  [<ffffffff81018002>] ? mwait_idle+0x8b/0xcd
      >  [<ffffffff81017811>] cpu_idle+0xbb/0x114
      >  [<ffffffff81401fbd>] rest_init+0xc1/0xc8
      >  [<ffffffff81401efc>] ? csum_partial_copy_generic+0x16c/0x16c
      >  [<ffffffff81cdbd3d>] start_kernel+0x3d4/0x3e1
      >  [<ffffffff81cdb79e>] ? kernel_init+0x1f7/0x1f7
      >  [<ffffffff81cdb2dd>] x86_64_start_reservations+0xb8/0xbd
      >  [<ffffffff81cdb3e3>] x86_64_start_kernel+0x101/0x110
      
      This patch clears q->root_blkg and q->root_rl.blkg when root blkg
      is destroyed.
      Signed-off-by: NJun'ichi Nomura <j-nomura@ce.jp.nec.com>
      Acked-by: NVivek Goyal <vgoyal@redhat.com>
      Acked-by: NTejun Heo <tj@kernel.org>
      Cc: stable@kernel.org
      Signed-off-by: NJens Axboe <axboe@kernel.dk>
      65635cbc
  2. 22 10月, 2012 4 次提交
  3. 21 10月, 2012 2 次提交
  4. 20 10月, 2012 32 次提交
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