linux-stable.git, branch v4.4.37 Linux kernel stable tree Linux 4.4.37 2016-12-08T06:15:46+00:00 Greg Kroah-Hartman gregkh@linuxfoundation.org 2016-12-08T06:15:46+00:00 e5f84c1444ae59c85bd25ba05393c6bc87067ddb 






arm64: suspend: Reconfigure PSTATE after resume from idle
2016-12-08T06:15:25+00:00

James Morse
james.morse@arm.com

2016-10-18T10:27:48+00:00

71710cd35a554b1f0a60f035642455beeaec0f06

commit d08544127d9fb4505635e3cb6871fd50a42947bd upstream.

The suspend/resume path in kernel/sleep.S, as used by cpu-idle, does not
save/restore PSTATE. As a result of this cpufeatures that were detected
and have bits in PSTATE get lost when we resume from idle.

UAO gets set appropriately on the next context switch. PAN will be
re-enabled next time we return from user-space, but on a preemptible
kernel we may run work accessing user space before this point.

Add code to re-enable theses two features in __cpu_suspend_exit().
We re-use uao_thread_switch() passing current.

Signed-off-by: James Morse <james.morse@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
[Removed UAO hooks and commit-message references: this feature is not
 present in v4.4]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>






commit d08544127d9fb4505635e3cb6871fd50a42947bd upstream.

The suspend/resume path in kernel/sleep.S, as used by cpu-idle, does not
save/restore PSTATE. As a result of this cpufeatures that were detected
and have bits in PSTATE get lost when we resume from idle.

UAO gets set appropriately on the next context switch. PAN will be
re-enabled next time we return from user-space, but on a preemptible
kernel we may run work accessing user space before this point.

Add code to re-enable theses two features in __cpu_suspend_exit().
We re-use uao_thread_switch() passing current.

Signed-off-by: James Morse <james.morse@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
[Removed UAO hooks and commit-message references: this feature is not
 present in v4.4]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>








arm64: mm: Set PSTATE.PAN from the cpu_enable_pan() call
2016-12-08T06:15:24+00:00

James Morse
james.morse@arm.com

2016-10-18T10:27:47+00:00

d24207a0d81cee81d0f06397074db99e12cc87c1

commit 7209c868600bd8926e37c10b9aae83124ccc1dd8 upstream.

Commit 338d4f49d6f7 ("arm64: kernel: Add support for Privileged Access
Never") enabled PAN by enabling the 'SPAN' feature-bit in SCTLR_EL1.
This means the PSTATE.PAN bit won't be set until the next return to the
kernel from userspace. On a preemptible kernel we may schedule work that
accesses userspace on a CPU before it has done this.

Now that cpufeature enable() calls are scheduled via stop_machine(), we
can set PSTATE.PAN from the cpu_enable_pan() call.

Add WARN_ON_ONCE(in_interrupt()) to check the PSTATE value we updated
is not immediately discarded.

Reported-by: Tony Thompson <anthony.thompson@arm.com>
Reported-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
[will: fixed typo in comment]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>






commit 7209c868600bd8926e37c10b9aae83124ccc1dd8 upstream.

Commit 338d4f49d6f7 ("arm64: kernel: Add support for Privileged Access
Never") enabled PAN by enabling the 'SPAN' feature-bit in SCTLR_EL1.
This means the PSTATE.PAN bit won't be set until the next return to the
kernel from userspace. On a preemptible kernel we may schedule work that
accesses userspace on a CPU before it has done this.

Now that cpufeature enable() calls are scheduled via stop_machine(), we
can set PSTATE.PAN from the cpu_enable_pan() call.

Add WARN_ON_ONCE(in_interrupt()) to check the PSTATE value we updated
is not immediately discarded.

Reported-by: Tony Thompson <anthony.thompson@arm.com>
Reported-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
[will: fixed typo in comment]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>








arm64: cpufeature: Schedule enable() calls instead of calling them via IPI
2016-12-08T06:15:24+00:00

James Morse
james.morse@arm.com

2016-10-18T10:27:46+00:00

da643dc17f20e04c089c93a3fe7d89e5be80d1af

commit 2a6dcb2b5f3e21592ca8dfa198dcce7bec09b020 upstream.

The enable() call for a cpufeature/errata is called using on_each_cpu().
This issues a cross-call IPI to get the work done. Implicitly, this
stashes the running PSTATE in SPSR when the CPU receives the IPI, and
restores it when we return. This means an enable() call can never modify
PSTATE.

To allow PAN to do this, change the on_each_cpu() call to use
stop_machine(). This schedules the work on each CPU which allows
us to modify PSTATE.

This involves changing the protype of all the enable() functions.

enable_cpu_capabilities() is called during boot and enables the feature
on all online CPUs. This path now uses stop_machine(). CPU features for
hotplug'd CPUs are enabled by verify_local_cpu_features() which only
acts on the local CPU, and can already modify the running PSTATE as it
is called from secondary_start_kernel().

Reported-by: Tony Thompson <anthony.thompson@arm.com>
Reported-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
[Removed enable() hunks for features/errata v4.4. doesn't have. Changed
 caps->enable arg in enable_cpu_capabilities()]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>






commit 2a6dcb2b5f3e21592ca8dfa198dcce7bec09b020 upstream.

The enable() call for a cpufeature/errata is called using on_each_cpu().
This issues a cross-call IPI to get the work done. Implicitly, this
stashes the running PSTATE in SPSR when the CPU receives the IPI, and
restores it when we return. This means an enable() call can never modify
PSTATE.

To allow PAN to do this, change the on_each_cpu() call to use
stop_machine(). This schedules the work on each CPU which allows
us to modify PSTATE.

This involves changing the protype of all the enable() functions.

enable_cpu_capabilities() is called during boot and enables the feature
on all online CPUs. This path now uses stop_machine(). CPU features for
hotplug'd CPUs are enabled by verify_local_cpu_features() which only
acts on the local CPU, and can already modify the running PSTATE as it
is called from secondary_start_kernel().

Reported-by: Tony Thompson <anthony.thompson@arm.com>
Reported-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
[Removed enable() hunks for features/errata v4.4. doesn't have. Changed
 caps->enable arg in enable_cpu_capabilities()]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>








pwm: Fix device reference leak
2016-12-08T06:15:24+00:00

Johan Hovold
johan@kernel.org

2016-11-01T10:46:39+00:00

4fd108fa1a7438566e2b16bee74228c3227c9597

commit 0e1614ac84f1719d87bed577963bb8140d0c9ce8 upstream.

Make sure to drop the reference to the parent device taken by
class_find_device() after "unexporting" any children when deregistering
a PWM chip.

Fixes: 0733424c9ba9 ("pwm: Unexport children before chip removal")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>






commit 0e1614ac84f1719d87bed577963bb8140d0c9ce8 upstream.

Make sure to drop the reference to the parent device taken by
class_find_device() after "unexporting" any children when deregistering
a PWM chip.

Fixes: 0733424c9ba9 ("pwm: Unexport children before chip removal")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>








mwifiex: printk() overflow with 32-byte SSIDs
2016-12-08T06:15:24+00:00

Brian Norris
briannorris@chromium.org

2016-11-09T02:28:24+00:00

d7a2c259fc1f41c3c030868b0344112c92f06c34

commit fcd2042e8d36cf644bd2d69c26378d17158b17df upstream.

SSIDs aren't guaranteed to be 0-terminated. Let's cap the max length
when we print them out.

This can be easily noticed by connecting to a network with a 32-octet
SSID:

[ 3903.502925] mwifiex_pcie 0000:01:00.0: info: trying to associate to
'0123456789abcdef0123456789abcdef <uninitialized mem>' bssid
xx:xx:xx:xx:xx:xx

Fixes: 5e6e3a92b9a4 ("wireless: mwifiex: initial commit for Marvell mwifiex driver")
Signed-off-by: Brian Norris <briannorris@chromium.org>
Acked-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>






commit fcd2042e8d36cf644bd2d69c26378d17158b17df upstream.

SSIDs aren't guaranteed to be 0-terminated. Let's cap the max length
when we print them out.

This can be easily noticed by connecting to a network with a 32-octet
SSID:

[ 3903.502925] mwifiex_pcie 0000:01:00.0: info: trying to associate to
'0123456789abcdef0123456789abcdef <uninitialized mem>' bssid
xx:xx:xx:xx:xx:xx

Fixes: 5e6e3a92b9a4 ("wireless: mwifiex: initial commit for Marvell mwifiex driver")
Signed-off-by: Brian Norris <briannorris@chromium.org>
Acked-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>








PCI: Set Read Completion Boundary to 128 iff Root Port supports it (_HPX)
2016-12-08T06:15:24+00:00

Johannes Thumshirn
jthumshirn@suse.de

2016-11-23T16:56:28+00:00

ac6e42d7a7201245e9a8db922ad795ef2a257568

commit e42010d8207f9d15a605ceb8e321bcd9648071b0 upstream.

Per PCIe spec r3.0, sec 2.3.1.1, the Read Completion Boundary (RCB)
determines the naturally aligned address boundaries on which a Read Request
may be serviced with multiple Completions:

  - For a Root Complex, RCB is 64 bytes or 128 bytes
    This value is reported in the Link Control Register

    Note: Bridges and Endpoints may implement a corresponding command bit
    which may be set by system software to indicate the RCB value for the
    Root Complex, allowing the Bridge/Endpoint to optimize its behavior
    when the Root Complex’s RCB is 128 bytes.

  - For all other system elements, RCB is 128 bytes

Per sec 7.8.7, if a Root Port only supports a 64-byte RCB, the RCB of all
downstream devices must be clear, indicating an RCB of 64 bytes.  If the
Root Port supports a 128-byte RCB, we may optionally set the RCB of
downstream devices so they know they can generate larger Completions.

Some BIOSes supply an _HPX that tells us to set RCB, even though the Root
Port doesn't have RCB set, which may lead to Malformed TLP errors if the
Endpoint generates completions larger than the Root Port can handle.

The IBM x3850 X6 with BIOS version -[A8E120CUS-1.30]- 08/22/2016 supplies
such an _HPX and a Mellanox MT27500 ConnectX-3 device fails to initialize:

  mlx4_core 0000:41:00.0: command 0xfff timed out (go bit not cleared)
  mlx4_core 0000:41:00.0: device is going to be reset
  mlx4_core 0000:41:00.0: Failed to obtain HW semaphore, aborting
  mlx4_core 0000:41:00.0: Fail to reset HCA
  ------------[ cut here ]------------
  kernel BUG at drivers/net/ethernet/mellanox/mlx4/catas.c:193!

After 6cd33649fa83 ("PCI: Add pci_configure_device() during enumeration")
and 7a1562d4f2d0 ("PCI: Apply _HPX Link Control settings to all devices
with a link"), we apply _HPX settings to *all* devices, not just those
hot-added after boot.

Before 7a1562d4f2d0, we didn't touch the Mellanox RCB, and the device
worked.  After 7a1562d4f2d0, we set its RCB to 128, and it failed.

Set the RCB to 128 iff the Root Port supports a 128-byte RCB.  Otherwise,
set RCB to 64 bytes.  This effectively ignores what _HPX tells us about
RCB.

Note that this change only affects _HPX handling.  If we have no _HPX, this
does nothing with RCB.

[bhelgaas: changelog, clear RCB if not set for Root Port]
Fixes: 6cd33649fa83 ("PCI: Add pci_configure_device() during enumeration")
Fixes: 7a1562d4f2d0 ("PCI: Apply _HPX Link Control settings to all devices with a link")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=187781
Tested-by: Frank Danapfel <fdanapfe@redhat.com>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Myron Stowe <myron.stowe@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>






commit e42010d8207f9d15a605ceb8e321bcd9648071b0 upstream.

Per PCIe spec r3.0, sec 2.3.1.1, the Read Completion Boundary (RCB)
determines the naturally aligned address boundaries on which a Read Request
may be serviced with multiple Completions:

  - For a Root Complex, RCB is 64 bytes or 128 bytes
    This value is reported in the Link Control Register

    Note: Bridges and Endpoints may implement a corresponding command bit
    which may be set by system software to indicate the RCB value for the
    Root Complex, allowing the Bridge/Endpoint to optimize its behavior
    when the Root Complex’s RCB is 128 bytes.

  - For all other system elements, RCB is 128 bytes

Per sec 7.8.7, if a Root Port only supports a 64-byte RCB, the RCB of all
downstream devices must be clear, indicating an RCB of 64 bytes.  If the
Root Port supports a 128-byte RCB, we may optionally set the RCB of
downstream devices so they know they can generate larger Completions.

Some BIOSes supply an _HPX that tells us to set RCB, even though the Root
Port doesn't have RCB set, which may lead to Malformed TLP errors if the
Endpoint generates completions larger than the Root Port can handle.

The IBM x3850 X6 with BIOS version -[A8E120CUS-1.30]- 08/22/2016 supplies
such an _HPX and a Mellanox MT27500 ConnectX-3 device fails to initialize:

  mlx4_core 0000:41:00.0: command 0xfff timed out (go bit not cleared)
  mlx4_core 0000:41:00.0: device is going to be reset
  mlx4_core 0000:41:00.0: Failed to obtain HW semaphore, aborting
  mlx4_core 0000:41:00.0: Fail to reset HCA
  ------------[ cut here ]------------
  kernel BUG at drivers/net/ethernet/mellanox/mlx4/catas.c:193!

After 6cd33649fa83 ("PCI: Add pci_configure_device() during enumeration")
and 7a1562d4f2d0 ("PCI: Apply _HPX Link Control settings to all devices
with a link"), we apply _HPX settings to *all* devices, not just those
hot-added after boot.

Before 7a1562d4f2d0, we didn't touch the Mellanox RCB, and the device
worked.  After 7a1562d4f2d0, we set its RCB to 128, and it failed.

Set the RCB to 128 iff the Root Port supports a 128-byte RCB.  Otherwise,
set RCB to 64 bytes.  This effectively ignores what _HPX tells us about
RCB.

Note that this change only affects _HPX handling.  If we have no _HPX, this
does nothing with RCB.

[bhelgaas: changelog, clear RCB if not set for Root Port]
Fixes: 6cd33649fa83 ("PCI: Add pci_configure_device() during enumeration")
Fixes: 7a1562d4f2d0 ("PCI: Apply _HPX Link Control settings to all devices with a link")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=187781
Tested-by: Frank Danapfel <fdanapfe@redhat.com>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Myron Stowe <myron.stowe@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>








PCI: Export pcie_find_root_port
2016-12-08T06:15:24+00:00

Johannes Thumshirn
jthumshirn@suse.de

2016-11-02T22:35:51+00:00

140ff0a348970430e4eb06a63afbbe5510f9c8d1

commit e784930bd645e7df78c66e7872fec282b0620075 upstream.

Export pcie_find_root_port() so we can use it outside of PCIe-AER error
injection.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>






commit e784930bd645e7df78c66e7872fec282b0620075 upstream.

Export pcie_find_root_port() so we can use it outside of PCIe-AER error
injection.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>








rcu: Fix soft lockup for rcu_nocb_kthread
2016-12-08T06:15:24+00:00

Ding Tianhong
dingtianhong@huawei.com

2016-06-15T07:27:36+00:00

dfb704f96cd190239e7b86b09810a136cf25506e

commit bedc1969150d480c462cdac320fa944b694a7162 upstream.

Carrying out the following steps results in a softlockup in the
RCU callback-offload (rcuo) kthreads:

1. Connect to ixgbevf, and set the speed to 10Gb/s.
2. Use ifconfig to bring the nic up and down repeatedly.

[  317.005148] IPv6: ADDRCONF(NETDEV_CHANGE): eth2: link becomes ready
[  368.106005] BUG: soft lockup - CPU#1 stuck for 22s! [rcuos/1:15]
[  368.106005] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  368.106005] task: ffff88057dd8a220 ti: ffff88057dd9c000 task.ti: ffff88057dd9c000
[  368.106005] RIP: 0010:[<ffffffff81579e04>]  [<ffffffff81579e04>] fib_table_lookup+0x14/0x390
[  368.106005] RSP: 0018:ffff88061fc83ce8  EFLAGS: 00000286
[  368.106005] RAX: 0000000000000001 RBX: 00000000020155c0 RCX: 0000000000000001
[  368.106005] RDX: ffff88061fc83d50 RSI: ffff88061fc83d70 RDI: ffff880036d11a00
[  368.106005] RBP: ffff88061fc83d08 R08: 0000000000000001 R09: 0000000000000000
[  368.106005] R10: ffff880036d11a00 R11: ffffffff819e0900 R12: ffff88061fc83c58
[  368.106005] R13: ffffffff816154dd R14: ffff88061fc83d08 R15: 00000000020155c0
[  368.106005] FS:  0000000000000000(0000) GS:ffff88061fc80000(0000) knlGS:0000000000000000
[  368.106005] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  368.106005] CR2: 00007f8c2aee9c40 CR3: 000000057b222000 CR4: 00000000000407e0
[  368.106005] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  368.106005] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[  368.106005] Stack:
[  368.106005]  00000000010000c0 ffff88057b766000 ffff8802e380b000 ffff88057af03e00
[  368.106005]  ffff88061fc83dc0 ffffffff815349a6 ffff88061fc83d40 ffffffff814ee146
[  368.106005]  ffff8802e380af00 00000000e380af00 ffffffff819e0900 020155c0010000c0
[  368.106005] Call Trace:
[  368.106005]  <IRQ>
[  368.106005]
[  368.106005]  [<ffffffff815349a6>] ip_route_input_noref+0x516/0xbd0
[  368.106005]  [<ffffffff814ee146>] ? skb_release_data+0xd6/0x110
[  368.106005]  [<ffffffff814ee20a>] ? kfree_skb+0x3a/0xa0
[  368.106005]  [<ffffffff8153698f>] ip_rcv_finish+0x29f/0x350
[  368.106005]  [<ffffffff81537034>] ip_rcv+0x234/0x380
[  368.106005]  [<ffffffff814fd656>] __netif_receive_skb_core+0x676/0x870
[  368.106005]  [<ffffffff814fd868>] __netif_receive_skb+0x18/0x60
[  368.106005]  [<ffffffff814fe4de>] process_backlog+0xae/0x180
[  368.106005]  [<ffffffff814fdcb2>] net_rx_action+0x152/0x240
[  368.106005]  [<ffffffff81077b3f>] __do_softirq+0xef/0x280
[  368.106005]  [<ffffffff8161619c>] call_softirq+0x1c/0x30
[  368.106005]  <EOI>
[  368.106005]
[  368.106005]  [<ffffffff81015d95>] do_softirq+0x65/0xa0
[  368.106005]  [<ffffffff81077174>] local_bh_enable+0x94/0xa0
[  368.106005]  [<ffffffff81114922>] rcu_nocb_kthread+0x232/0x370
[  368.106005]  [<ffffffff81098250>] ? wake_up_bit+0x30/0x30
[  368.106005]  [<ffffffff811146f0>] ? rcu_start_gp+0x40/0x40
[  368.106005]  [<ffffffff8109728f>] kthread+0xcf/0xe0
[  368.106005]  [<ffffffff810971c0>] ? kthread_create_on_node+0x140/0x140
[  368.106005]  [<ffffffff816147d8>] ret_from_fork+0x58/0x90
[  368.106005]  [<ffffffff810971c0>] ? kthread_create_on_node+0x140/0x140

==================================cut here==============================

It turns out that the rcuos callback-offload kthread is busy processing
a very large quantity of RCU callbacks, and it is not reliquishing the
CPU while doing so.  This commit therefore adds an cond_resched_rcu_qs()
within the loop to allow other tasks to run.

Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
[ paulmck: Substituted cond_resched_rcu_qs for cond_resched. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Dhaval Giani <dhaval.giani@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>






commit bedc1969150d480c462cdac320fa944b694a7162 upstream.

Carrying out the following steps results in a softlockup in the
RCU callback-offload (rcuo) kthreads:

1. Connect to ixgbevf, and set the speed to 10Gb/s.
2. Use ifconfig to bring the nic up and down repeatedly.

[  317.005148] IPv6: ADDRCONF(NETDEV_CHANGE): eth2: link becomes ready
[  368.106005] BUG: soft lockup - CPU#1 stuck for 22s! [rcuos/1:15]
[  368.106005] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  368.106005] task: ffff88057dd8a220 ti: ffff88057dd9c000 task.ti: ffff88057dd9c000
[  368.106005] RIP: 0010:[<ffffffff81579e04>]  [<ffffffff81579e04>] fib_table_lookup+0x14/0x390
[  368.106005] RSP: 0018:ffff88061fc83ce8  EFLAGS: 00000286
[  368.106005] RAX: 0000000000000001 RBX: 00000000020155c0 RCX: 0000000000000001
[  368.106005] RDX: ffff88061fc83d50 RSI: ffff88061fc83d70 RDI: ffff880036d11a00
[  368.106005] RBP: ffff88061fc83d08 R08: 0000000000000001 R09: 0000000000000000
[  368.106005] R10: ffff880036d11a00 R11: ffffffff819e0900 R12: ffff88061fc83c58
[  368.106005] R13: ffffffff816154dd R14: ffff88061fc83d08 R15: 00000000020155c0
[  368.106005] FS:  0000000000000000(0000) GS:ffff88061fc80000(0000) knlGS:0000000000000000
[  368.106005] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  368.106005] CR2: 00007f8c2aee9c40 CR3: 000000057b222000 CR4: 00000000000407e0
[  368.106005] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  368.106005] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[  368.106005] Stack:
[  368.106005]  00000000010000c0 ffff88057b766000 ffff8802e380b000 ffff88057af03e00
[  368.106005]  ffff88061fc83dc0 ffffffff815349a6 ffff88061fc83d40 ffffffff814ee146
[  368.106005]  ffff8802e380af00 00000000e380af00 ffffffff819e0900 020155c0010000c0
[  368.106005] Call Trace:
[  368.106005]  <IRQ>
[  368.106005]
[  368.106005]  [<ffffffff815349a6>] ip_route_input_noref+0x516/0xbd0
[  368.106005]  [<ffffffff814ee146>] ? skb_release_data+0xd6/0x110
[  368.106005]  [<ffffffff814ee20a>] ? kfree_skb+0x3a/0xa0
[  368.106005]  [<ffffffff8153698f>] ip_rcv_finish+0x29f/0x350
[  368.106005]  [<ffffffff81537034>] ip_rcv+0x234/0x380
[  368.106005]  [<ffffffff814fd656>] __netif_receive_skb_core+0x676/0x870
[  368.106005]  [<ffffffff814fd868>] __netif_receive_skb+0x18/0x60
[  368.106005]  [<ffffffff814fe4de>] process_backlog+0xae/0x180
[  368.106005]  [<ffffffff814fdcb2>] net_rx_action+0x152/0x240
[  368.106005]  [<ffffffff81077b3f>] __do_softirq+0xef/0x280
[  368.106005]  [<ffffffff8161619c>] call_softirq+0x1c/0x30
[  368.106005]  <EOI>
[  368.106005]
[  368.106005]  [<ffffffff81015d95>] do_softirq+0x65/0xa0
[  368.106005]  [<ffffffff81077174>] local_bh_enable+0x94/0xa0
[  368.106005]  [<ffffffff81114922>] rcu_nocb_kthread+0x232/0x370
[  368.106005]  [<ffffffff81098250>] ? wake_up_bit+0x30/0x30
[  368.106005]  [<ffffffff811146f0>] ? rcu_start_gp+0x40/0x40
[  368.106005]  [<ffffffff8109728f>] kthread+0xcf/0xe0
[  368.106005]  [<ffffffff810971c0>] ? kthread_create_on_node+0x140/0x140
[  368.106005]  [<ffffffff816147d8>] ret_from_fork+0x58/0x90
[  368.106005]  [<ffffffff810971c0>] ? kthread_create_on_node+0x140/0x140

==================================cut here==============================

It turns out that the rcuos callback-offload kthread is busy processing
a very large quantity of RCU callbacks, and it is not reliquishing the
CPU while doing so.  This commit therefore adds an cond_resched_rcu_qs()
within the loop to allow other tasks to run.

Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
[ paulmck: Substituted cond_resched_rcu_qs for cond_resched. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Dhaval Giani <dhaval.giani@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>








ALSA: pcm : Call kill_fasync() in stream lock
2016-12-08T06:15:24+00:00

Takashi Iwai
tiwai@suse.de

2016-04-14T16:02:37+00:00

58cebd1a08ed114e05cc9d16dee9e5423f564c82

commit 3aa02cb664c5fb1042958c8d1aa8c35055a2ebc4 upstream.

Currently kill_fasync() is called outside the stream lock in
snd_pcm_period_elapsed().  This is potentially racy, since the stream
may get released even during the irq handler is running.  Although
snd_pcm_release_substream() calls snd_pcm_drop(), this doesn't
guarantee that the irq handler finishes, thus the kill_fasync() call
outside the stream spin lock may be invoked after the substream is
detached, as recently reported by KASAN.

As a quick workaround, move kill_fasync() call inside the stream
lock.  The fasync is rarely used interface, so this shouldn't have a
big impact from the performance POV.

Ideally, we should implement some sync mechanism for the proper finish
of stream and irq handler.  But this oneliner should suffice for most
cases, so far.

Reported-by: Baozeng Ding <sploving1@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>






commit 3aa02cb664c5fb1042958c8d1aa8c35055a2ebc4 upstream.

Currently kill_fasync() is called outside the stream lock in
snd_pcm_period_elapsed().  This is potentially racy, since the stream
may get released even during the irq handler is running.  Although
snd_pcm_release_substream() calls snd_pcm_drop(), this doesn't
guarantee that the irq handler finishes, thus the kill_fasync() call
outside the stream spin lock may be invoked after the substream is
detached, as recently reported by KASAN.

As a quick workaround, move kill_fasync() call inside the stream
lock.  The fasync is rarely used interface, so this shouldn't have a
big impact from the performance POV.

Ideally, we should implement some sync mechanism for the proper finish
of stream and irq handler.  But this oneliner should suffice for most
cases, so far.

Reported-by: Baozeng Ding <sploving1@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>