1. 06 2月, 2015 4 次提交
  2. 04 2月, 2015 14 次提交
    • N
      md: protect ->pers changes with mddev->lock · 36d091f4
      NeilBrown 提交于
      ->pers is already protected by ->reconfig_mutex, and
      cannot possibly change when there are threads running or
      outstanding IO.
      
      However there are some places where we access ->pers
      not in a thread or IO context, and where ->reconfig_mutex
      is unnecessarily heavy-weight:  level_show and md_seq_show().
      
      So protect all changes, and those accesses, with ->lock.
      This is a step toward taking those accesses out from under
      reconfig_mutex.
      
      [Fixed missing "mddev->pers" -> "pers" conversion, thanks to
       Dan Carpenter <dan.carpenter@oracle.com>]
      Signed-off-by: NNeilBrown <neilb@suse.de>
      36d091f4
    • N
      md: level_store: group all important changes into one place. · db721d32
      NeilBrown 提交于
      Gather all the changes that can happen atomically and might
      be relevant to other code into one place.  This will
      make it easier to refine the locking.
      
      Note that this puts quite a few things between mddev_detach()
      and ->free().  Enabling this was the point of some recent patches.
      Signed-off-by: NNeilBrown <neilb@suse.de>
      db721d32
    • N
      md: rename ->stop to ->free · afa0f557
      NeilBrown 提交于
      Now that the ->stop function only frees the private data,
      rename is accordingly.
      
      Also pass in the private pointer as an arg rather than using
      mddev->private.  This flexibility will be useful in level_store().
      
      Finally, don't clear ->private.  It doesn't make sense to clear
      it seeing that isn't what we free, and it is no longer necessary
      to clear ->private (it was some time ago before  ->to_remove was
      introduced).
      
      Setting ->to_remove in ->free() is a bit of a wart, but not a
      big problem at the moment.
      Signed-off-by: NNeilBrown <neilb@suse.de>
      afa0f557
    • N
      md: split detach operation out from ->stop. · 5aa61f42
      NeilBrown 提交于
      Each md personality has a 'stop' operation which does two
      things:
       1/ it finalizes some aspects of the array to ensure nothing
          is accessing the ->private data
       2/ it frees the ->private data.
      
      All the steps in '1' can apply to all arrays and so can be
      performed in common code.
      
      This is useful as in the case where we change the personality which
      manages an array (in level_store()), it would be helpful to do
      step 1 early, and step 2 later.
      
      So split the 'step 1' functionality out into a new mddev_detach().
      Signed-off-by: NNeilBrown <neilb@suse.de>
      5aa61f42
    • N
      md/linear: remove rcu protections in favour of suspend/resume · 3be260cc
      NeilBrown 提交于
      The use of 'rcu' to protect accesses to ->private_data so that
      the ->private_data could be updated predates the introduction
      of mddev_suspend/mddev_resume.
      These are a cleaner mechanism for providing stability while
      swapping in a new ->private data - it is used by level_store()
      to support changing of raid levels.
      
      So get rid of the RCU stuff and just use mddev_suspend, mddev_resume.
      
      As these function call ->quiesce(), we add an empty function for
      linear just like for raid0.
      Signed-off-by: NNeilBrown <neilb@suse.de>
      3be260cc
    • N
      md: make merge_bvec_fn more robust in face of personality changes. · 64590f45
      NeilBrown 提交于
      There is no locking around calls to merge_bvec_fn(), so
      it is possible that calls which coincide with a level (or personality)
      change could go wrong.
      
      So create a central dispatch point for these functions and use
      rcu_read_lock().
      If the array is suspended, reject any merge that can be rejected.
      If not, we know it is safe to call the function.
      Signed-off-by: NNeilBrown <neilb@suse.de>
      64590f45
    • N
      md: make ->congested robust against personality changes. · 5c675f83
      NeilBrown 提交于
      There is currently no locking around calls to the 'congested'
      bdi function.  If called at an awkward time while an array is
      being converted from one level (or personality) to another, there
      is a tiny chance of running code in an unreferenced module etc.
      
      So add a 'congested' function to the md_personality operations
      structure, and call it with appropriate locking from a central
      'mddev_congested'.
      
      When the array personality is changing the array will be 'suspended'
      so no IO is processed.
      If mddev_congested detects this, it simply reports that the
      array is congested, which is a safe guess.
      As mddev_suspend calls synchronize_rcu(), mddev_congested can
      avoid races by included the whole call inside an rcu_read_lock()
      region.
      This require that the congested functions for all subordinate devices
      can be run under rcu_lock.  Fortunately this is the case.
      Signed-off-by: NNeilBrown <neilb@suse.de>
      5c675f83
    • N
      md: rename mddev->write_lock to mddev->lock · 85572d7c
      NeilBrown 提交于
      This lock is used for (slightly) more than helping with writing
      superblocks, and it will soon be extended further.  So the
      name is inappropriate.
      
      Also, the _irq variant hasn't been needed since 2.6.37 as it is
      never taking from interrupt or bh context.
      
      So:
        -rename write_lock to lock
        -document what it protects
        -remove _irq ... except in md_flush_request() as there
           is no wait_event_lock() (with no _irq).  This can be
           cleaned up after appropriate changes to wait.h.
      Signed-off-by: NNeilBrown <neilb@suse.de>
      85572d7c
    • N
      md/raid5: need_this_block: tidy/fix last condition. · ea664c82
      NeilBrown 提交于
      That last condition is unclear and over cautious.
      
      There are two related issues here.
      
      If a partial write is destined for a missing device, then
      either RMW or RCW can work.  We must read all the available
      block.  Only then can the missing blocks be calculated, and
      then the parity update performed.
      
      If RMW is not an option, then there is a complication even
      without partial writes.  If we would need to read a missing
      device to perform the reconstruction, then we must first read every
      block so the missing device data can be computed.
      This is the case for RAID6 (Which currently does not support
      RMW) and for times when we don't trust the parity (after a crash)
      and so are in the process of resyncing it.
      
      So make these two cases more clear and separate, and perform
      the relevant tests more  thoroughly.
      Signed-off-by: NNeilBrown <neilb@suse.de>
      ea664c82
    • N
      md/raid5: need_this_block: start simplifying the last two conditions. · a9d56950
      NeilBrown 提交于
      Both the last two cases are only relevant if something has failed and
      something needs to be written (but not over-written), and if it is OK
      to pre-read blocks at this point.  So factor out those tests and
      explain them.
      Signed-off-by: NNeilBrown <neilb@suse.de>
      a9d56950
    • N
      md/raid5: separate out the easy conditions in need_this_block. · a79cfe12
      NeilBrown 提交于
      Some of the conditions in need_this_block have very straight
      forward motivation.  Separate those out and document them.
      Signed-off-by: NNeilBrown <neilb@suse.de>
      a79cfe12
    • N
      md/raid5: separate large if clause out of fetch_block(). · 2c58f06e
      NeilBrown 提交于
      fetch_block() has a very large and hard to read 'if' condition.
      
      Separate it into its own function so that it can be
      made more readable.
      Signed-off-by: NNeilBrown <neilb@suse.de>
      2c58f06e
    • J
      md: do_release_stripe(): No need to call md_wakeup_thread() twice · ad3ab8b6
      Jes Sorensen 提交于
      67f45548 introduced a call to
      md_wakeup_thread() when adding to the delayed_list. However the md
      thread is woken up unconditionally just below.
      
      Remove the unnecessary wakeup call.
      Signed-off-by: NJes Sorensen <Jes.Sorensen@redhat.com>
      Signed-off-by: NNeilBrown <neilb@suse.de>
      ad3ab8b6
    • J
      x86/raid6: correctly check for assembler capabilities · 75aaf4c3
      Jan Beulich 提交于
      Just like for AVX2 (which simply needs an #if -> #ifdef conversion),
      SSSE3 assembler support should be checked for before using it.
      Signed-off-by: NJan Beulich <jbeulich@suse.com>
      Cc: Jim Kukunas <james.t.kukunas@linux.intel.com>
      Acked-by: NThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: NNeilBrown <neilb@suse.de>
      75aaf4c3
  3. 02 2月, 2015 2 次提交
  4. 28 1月, 2015 5 次提交
    • L
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net · 59343cd7
      Linus Torvalds 提交于
      Pull networking fixes from David Miller:
      
       1) Don't OOPS on socket AIO, from Christoph Hellwig.
      
       2) Scheduled scans should be aborted upon RFKILL, from Emmanuel
          Grumbach.
      
       3) Fix sleep in atomic context in kvaser_usb, from Ahmed S Darwish.
      
       4) Fix RCU locking across copy_to_user() in bpf code, from Alexei
          Starovoitov.
      
       5) Lots of crash, memory leak, short TX packet et al bug fixes in
          sh_eth from Ben Hutchings.
      
       6) Fix memory corruption in SCTP wrt.  INIT collitions, from Daniel
          Borkmann.
      
       7) Fix return value logic for poll handlers in netxen, enic, and bnx2x.
          From Eric Dumazet and Govindarajulu Varadarajan.
      
       8) Header length calculation fix in mac80211 from Fred Chou.
      
       9) mv643xx_eth doesn't handle highmem correctly in non-TSO code paths.
          From Ezequiel Garcia.
      
      10) udp_diag has bogus logic in it's hash chain skipping, copy same fix
          tcp diag used.  From Herbert Xu.
      
      11) amd-xgbe programs wrong rx flow control register, from Thomas
          Lendacky.
      
      12) Fix race leading to use after free in ping receive path, from Subash
          Abhinov Kasiviswanathan.
      
      13) Cache redirect routes otherwise we can get a heavy backlog of rcu
          jobs liberating DST_NOCACHE entries.  From Hannes Frederic Sowa.
      
      * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (48 commits)
        net: don't OOPS on socket aio
        stmmac: prevent probe drivers to crash kernel
        bnx2x: fix napi poll return value for repoll
        ipv6: replacing a rt6_info needs to purge possible propagated rt6_infos too
        sh_eth: Fix DMA-API usage for RX buffers
        sh_eth: Check for DMA mapping errors on transmit
        sh_eth: Ensure DMA engines are stopped before freeing buffers
        sh_eth: Remove RX overflow log messages
        ping: Fix race in free in receive path
        udp_diag: Fix socket skipping within chain
        can: kvaser_usb: Fix state handling upon BUS_ERROR events
        can: kvaser_usb: Retry the first bulk transfer on -ETIMEDOUT
        can: kvaser_usb: Send correct context to URB completion
        can: kvaser_usb: Do not sleep in atomic context
        ipv4: try to cache dst_entries which would cause a redirect
        samples: bpf: relax test_maps check
        bpf: rcu lock must not be held when calling copy_to_user()
        net: sctp: fix slab corruption from use after free on INIT collisions
        net: mv643xx_eth: Fix highmem support in non-TSO egress path
        sh_eth: Fix serialisation of interrupt disable with interrupt & NAPI handlers
        ...
      59343cd7
    • C
      net: don't OOPS on socket aio · 06539d30
      Christoph Hellwig 提交于
      Signed-off-by: NChristoph Hellwig <hch@lst.de>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      06539d30
    • A
      stmmac: prevent probe drivers to crash kernel · 9afec6ef
      Andy Shevchenko 提交于
      In the case when alloc_netdev fails we return NULL to a caller. But there is no
      check for NULL in the probe drivers. This patch changes NULL to an error
      pointer. The function description is amended to reflect what we may get
      returned.
      Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      9afec6ef
    • L
      Merge tag 'powerpc-3.19-5' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux · 7da323bb
      Linus Torvalds 提交于
      Pull powerpc fixes from Michael Ellerman:
       "Two powerpc fixes"
      
      * tag 'powerpc-3.19-5' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux:
        powerpc/powernv: Restore LPCR with LPCR_PECE1 cleared
        powerpc/xmon: Fix another endiannes issue in RTAS call from xmon
      7da323bb
    • L
      Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux · 41592e2f
      Linus Torvalds 提交于
      Pull one more module fix from Rusty Russell:
       "SCSI was using module_refcount() to figure out when the module was
        unloading: this broke with new atomic refcounting.  The code is still
        suspicious, but this solves the WARN_ON()"
      
      * tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
        scsi: always increment reference count
      41592e2f
  5. 27 1月, 2015 15 次提交
    • G
      bnx2x: fix napi poll return value for repoll · 24e579c8
      Govindarajulu Varadarajan 提交于
      With the commit d75b1ade ("net: less interrupt masking in NAPI") napi
      repoll is done only when work_done == budget. When in busy_poll is we return 0
      in napi_poll. We should return budget.
      Signed-off-by: NGovindarajulu Varadarajan <_govind@gmx.com>
      Acked-by: NEric Dumazet <edumazet@google.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      24e579c8
    • D
      Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec · bf693f7b
      David S. Miller 提交于
      Steffen Klassert says:
      
      ====================
      ipsec 2015-01-26
      
      Just two small fixes for _decode_session6() where we
      might decode to wrong header information in some rare
      situations.
      
      Please pull or let me know if there are problems.
      ====================
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      bf693f7b
    • H
      ipv6: replacing a rt6_info needs to purge possible propagated rt6_infos too · 6e9e16e6
      Hannes Frederic Sowa 提交于
      Lubomir Rintel reported that during replacing a route the interface
      reference counter isn't correctly decremented.
      
      To quote bug <https://bugzilla.kernel.org/show_bug.cgi?id=91941>:
      | [root@rhel7-5 lkundrak]# sh -x lal
      | + ip link add dev0 type dummy
      | + ip link set dev0 up
      | + ip link add dev1 type dummy
      | + ip link set dev1 up
      | + ip addr add 2001:db8:8086::2/64 dev dev0
      | + ip route add 2001:db8:8086::/48 dev dev0 proto static metric 20
      | + ip route add 2001:db8:8088::/48 dev dev1 proto static metric 10
      | + ip route replace 2001:db8:8086::/48 dev dev1 proto static metric 20
      | + ip link del dev0 type dummy
      | Message from syslogd@rhel7-5 at Jan 23 10:54:41 ...
      |  kernel:unregister_netdevice: waiting for dev0 to become free. Usage count = 2
      |
      | Message from syslogd@rhel7-5 at Jan 23 10:54:51 ...
      |  kernel:unregister_netdevice: waiting for dev0 to become free. Usage count = 2
      
      During replacement of a rt6_info we must walk all parent nodes and check
      if the to be replaced rt6_info got propagated. If so, replace it with
      an alive one.
      
      Fixes: 4a287eba ("IPv6 routing, NLM_F_* flag support: REPLACE and EXCL flags support, warn about missing CREATE flag")
      Reported-by: NLubomir Rintel <lkundrak@v3.sk>
      Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
      Tested-by: NLubomir Rintel <lkundrak@v3.sk>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      6e9e16e6
    • D
      Merge branch 'sh_eth' · 22577609
      David S. Miller 提交于
      Ben Hutchings says:
      
      ====================
      Fixes for sh_eth #3
      
      I'm continuing review and testing of Ethernet support on the R-Car H2
      chip.  This series fixes the last of the more serious issues I've found.
      
      These are not tested on any of the other supported chips.
      ====================
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      22577609
    • B
      sh_eth: Fix DMA-API usage for RX buffers · 52b9fa36
      Ben Hutchings 提交于
      - Use the return value of dma_map_single(), rather than calling
        virt_to_page() separately
      - Check for mapping failue
      - Call dma_unmap_single() rather than dma_sync_single_for_cpu()
      Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      52b9fa36
    • B
      sh_eth: Check for DMA mapping errors on transmit · aa3933b8
      Ben Hutchings 提交于
      dma_map_single() may fail if an IOMMU or swiotlb is in use, so
      we need to check for this.
      Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      aa3933b8
    • B
      sh_eth: Ensure DMA engines are stopped before freeing buffers · 740c7f31
      Ben Hutchings 提交于
      Currently we try to clear EDRRR and EDTRR and immediately continue to
      free buffers.  This is unsafe because:
      
      - In general, register writes are not serialised with DMA, so we still
        have to wait for DMA to complete somehow
      - The R8A7790 (R-Car H2) manual states that the TX running flag cannot
        be cleared by writing to EDTRR
      - The same manual states that clearing the RX running flag only stops
        RX DMA at the next packet boundary
      
      I applied this patch to the driver to detect DMA writes to freed
      buffers:
      
      > --- a/drivers/net/ethernet/renesas/sh_eth.c
      > +++ b/drivers/net/ethernet/renesas/sh_eth.c
      > @@ -1098,7 +1098,14 @@ static void sh_eth_ring_free(struct net_device *ndev)
      >  	/* Free Rx skb ringbuffer */
      >  	if (mdp->rx_skbuff) {
      >  		for (i = 0; i < mdp->num_rx_ring; i++)
      > +			memcpy(mdp->rx_skbuff[i]->data,
      > +			       "Hello, world", 12);
      > +		msleep(100);
      > +		for (i = 0; i < mdp->num_rx_ring; i++) {
      > +			WARN_ON(memcmp(mdp->rx_skbuff[i]->data,
      > +				       "Hello, world", 12));
      >  			dev_kfree_skb(mdp->rx_skbuff[i]);
      > +		}
      >  	}
      >  	kfree(mdp->rx_skbuff);
      >  	mdp->rx_skbuff = NULL;
      
      then ran the loop:
      
          while ethtool -G eth0 rx 128 ; ethtool -G eth0 rx 64; do echo -n .; done
      
      and 'ping -f' toward the sh_eth port from another machine.  The
      warning fired several times a minute.
      
      To fix these issues:
      
      - Deactivate all TX descriptors rather than writing to EDTRR
      - As there seems to be no way of telling when RX DMA is stopped,
        perform a soft reset to ensure that both DMA enginess are stopped
      - To reduce the possibility of the reset truncating a transmitted
        frame, disable egress and wait a reasonable time to reach a
        packet boundary before resetting
      - Update statistics before resetting
      
      (The 'reasonable time' does not allow for CS/CD in half-duplex
      mode, but half-duplex no longer seems reasonable!)
      Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      740c7f31
    • B
      sh_eth: Remove RX overflow log messages · dc1d0e6d
      Ben Hutchings 提交于
      If RX traffic is overflowing the FIFO or DMA ring, logging every time
      this happens just makes things worse.  These errors are visible in the
      statistics anyway.
      Signed-off-by: NBen Hutchings <ben.hutchings@codethink.co.uk>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      dc1d0e6d
    • D
      Merge tag 'linux-can-fixes-for-3.19-20150127' of... · 8d8d67f1
      David S. Miller 提交于
      Merge tag 'linux-can-fixes-for-3.19-20150127' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can
      
      Marc Kleine-Budde says:
      
      ====================
      pull-request: can 2015-01-27
      
      this is another pull request for net/master which consists of 4 patches.
      
      All 4 patches are contributed by Ahmed S. Darwish, he fixes more problems in
      the kvaser_usb driver.
      
      David, please merge net/master to net-next/master, as we have more kvaser_usb
      patches in the queue, that target net-next.
      ====================
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      8d8d67f1
    • S
      ping: Fix race in free in receive path · fc752f1f
      subashab@codeaurora.org 提交于
      An exception is seen in ICMP ping receive path where the skb
      destructor sock_rfree() tries to access a freed socket. This happens
      because ping_rcv() releases socket reference with sock_put() and this
      internally frees up the socket. Later icmp_rcv() will try to free the
      skb and as part of this, skb destructor is called and which leads
      to a kernel panic as the socket is freed already in ping_rcv().
      
      -->|exception
      -007|sk_mem_uncharge
      -007|sock_rfree
      -008|skb_release_head_state
      -009|skb_release_all
      -009|__kfree_skb
      -010|kfree_skb
      -011|icmp_rcv
      -012|ip_local_deliver_finish
      
      Fix this incorrect free by cloning this skb and processing this cloned
      skb instead.
      
      This patch was suggested by Eric Dumazet
      Signed-off-by: NSubash Abhinov Kasiviswanathan <subashab@codeaurora.org>
      Cc: Eric Dumazet <edumazet@google.com>
      Signed-off-by: NEric Dumazet <edumazet@google.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      fc752f1f
    • H
      udp_diag: Fix socket skipping within chain · 86f3cddb
      Herbert Xu 提交于
      While working on rhashtable walking I noticed that the UDP diag
      dumping code is buggy.  In particular, the socket skipping within
      a chain never happens, even though we record the number of sockets
      that should be skipped.
      
      As this code was supposedly copied from TCP, this patch does what
      TCP does and resets num before we walk a chain.
      Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
      Acked-by: NPavel Emelyanov <xemul@parallels.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      86f3cddb
    • A
      can: kvaser_usb: Fix state handling upon BUS_ERROR events · e638642b
      Ahmed S. Darwish 提交于
      While being in an ERROR_WARNING state, and receiving further
      bus error events with error counters still in the ERROR_WARNING
      range of 97-127 inclusive, the state handling code erroneously
      reverts back to ERROR_ACTIVE.
      
      Per the CAN standard, only revert to ERROR_ACTIVE when the
      error counters are less than 96.
      
      Moreover, in certain Kvaser models, the BUS_ERROR flag is
      always set along with undefined bits in the M16C status
      register. Thus use bitwise operators instead of full equality
      for checking that register against bus errors.
      Signed-off-by: NAhmed S. Darwish <ahmed.darwish@valeo.com>
      Cc: linux-stable <stable@vger.kernel.org>
      Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>
      e638642b
    • A
      can: kvaser_usb: Retry the first bulk transfer on -ETIMEDOUT · 14c10c2a
      Ahmed S. Darwish 提交于
      On some x86 laptops, plugging a Kvaser device again after an
      unplug makes the firmware always ignore the very first command.
      For such a case, provide some room for retries instead of
      completely exiting the driver init code.
      Signed-off-by: NAhmed S. Darwish <ahmed.darwish@valeo.com>
      Cc: linux-stable <stable@vger.kernel.org>
      Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>
      14c10c2a
    • A
      can: kvaser_usb: Send correct context to URB completion · 3803fa69
      Ahmed S. Darwish 提交于
      Send expected argument to the URB completion hander: a CAN
      netdevice instead of the network interface private context
      `kvaser_usb_net_priv'.
      
      This was discovered by having some garbage in the kernel
      log in place of the netdevice names: can0 and can1.
      Signed-off-by: NAhmed S. Darwish <ahmed.darwish@valeo.com>
      Cc: linux-stable <stable@vger.kernel.org>
      Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>
      3803fa69
    • A
      can: kvaser_usb: Do not sleep in atomic context · ded50066
      Ahmed S. Darwish 提交于
      Upon receiving a hardware event with the BUS_RESET flag set,
      the driver kills all of its anchored URBs and resets all of
      its transmit URB contexts.
      
      Unfortunately it does so under the context of URB completion
      handler `kvaser_usb_read_bulk_callback()', which is often
      called in an atomic context.
      
      While the device is flooded with many received error packets,
      usb_kill_urb() typically sleeps/reschedules till the transfer
      request of each killed URB in question completes, leading to
      the sleep in atomic bug. [3]
      
      In v2 submission of the original driver patch [1], it was
      stated that the URBs kill and tx contexts reset was needed
      since we don't receive any tx acknowledgments later and thus
      such resources will be locked down forever. Fortunately this
      is no longer needed since an earlier bugfix in this patch
      series is now applied: all tx URB contexts are reset upon CAN
      channel close. [2]
      
      Moreover, a BUS_RESET is now treated _exactly_ like a BUS_OFF
      event, which is the recommended handling method advised by
      the device manufacturer.
      
      [1] http://article.gmane.org/gmane.linux.network/239442
          http://www.webcitation.org/6Vr2yagAQ
      
      [2] can: kvaser_usb: Reset all URB tx contexts upon channel close
          889b77f7
      
      [3] Stacktrace:
      
       <IRQ>  [<ffffffff8158de87>] dump_stack+0x45/0x57
       [<ffffffff8158b60c>] __schedule_bug+0x41/0x4f
       [<ffffffff815904b1>] __schedule+0x5f1/0x700
       [<ffffffff8159360a>] ? _raw_spin_unlock_irqrestore+0xa/0x10
       [<ffffffff81590684>] schedule+0x24/0x70
       [<ffffffff8147d0a5>] usb_kill_urb+0x65/0xa0
       [<ffffffff81077970>] ? prepare_to_wait_event+0x110/0x110
       [<ffffffff8147d7d8>] usb_kill_anchored_urbs+0x48/0x80
       [<ffffffffa01f4028>] kvaser_usb_unlink_tx_urbs+0x18/0x50 [kvaser_usb]
       [<ffffffffa01f45d0>] kvaser_usb_rx_error+0xc0/0x400 [kvaser_usb]
       [<ffffffff8108b14a>] ? vprintk_default+0x1a/0x20
       [<ffffffffa01f5241>] kvaser_usb_read_bulk_callback+0x4c1/0x5f0 [kvaser_usb]
       [<ffffffff8147a73e>] __usb_hcd_giveback_urb+0x5e/0xc0
       [<ffffffff8147a8a1>] usb_hcd_giveback_urb+0x41/0x110
       [<ffffffffa0008748>] finish_urb+0x98/0x180 [ohci_hcd]
       [<ffffffff810cd1a7>] ? acct_account_cputime+0x17/0x20
       [<ffffffff81069f65>] ? local_clock+0x15/0x30
       [<ffffffffa000a36b>] ohci_work+0x1fb/0x5a0 [ohci_hcd]
       [<ffffffff814fbb31>] ? process_backlog+0xb1/0x130
       [<ffffffffa000cd5b>] ohci_irq+0xeb/0x270 [ohci_hcd]
       [<ffffffff81479fc1>] usb_hcd_irq+0x21/0x30
       [<ffffffff8108bfd3>] handle_irq_event_percpu+0x43/0x120
       [<ffffffff8108c0ed>] handle_irq_event+0x3d/0x60
       [<ffffffff8108ec84>] handle_fasteoi_irq+0x74/0x110
       [<ffffffff81004dfd>] handle_irq+0x1d/0x30
       [<ffffffff81004727>] do_IRQ+0x57/0x100
       [<ffffffff8159482a>] common_interrupt+0x6a/0x6a
      Signed-off-by: NAhmed S. Darwish <ahmed.darwish@valeo.com>
      Cc: linux-stable <stable@vger.kernel.org>
      Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>
      ded50066