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  1. 22 May, 2019 33 commits
  3. 16 May, 2019 7 commits
    • Greg Kroah-Hartman's avatar
      Linux 4.19.44 · dafc674b
      Greg Kroah-Hartman authored
      dafc674b
    • Dexuan Cui's avatar
      PCI: hv: Add pci_destroy_slot() in pci_devices_present_work(), if necessary · 9fa23ea1
      Dexuan Cui authored 
      commit 340d4556 upstream.

When we hot-remove a device, usually the host sends us a PCI_EJECT message,
and a PCI_BUS_RELATIONS message with bus_rel->device_count == 0.

When we execute the quick hot-add/hot-remove test, the host may not send
us the PCI_EJECT message if the guest has not fully finished the
initialization by sending the PCI_RESOURCES_ASSIGNED* message to the
host, so it's potentially unsafe to only depend on the
pci_destroy_slot() in hv_eject_device_work() because the code path

create_root_hv_pci_bus()
 -> hv_pci_assign_slots()

is not called in this case. Note: in this case, the host still sends the
guest a PCI_BUS_RELATIONS message with bus_rel->device_count == 0.

In the quick hot-add/hot-remove test, we can have such a race before
the code path

pci_devices_present_work()
 -> new_pcichild_device()

adds the new device into the hbus->children list, we may have already
received the PCI_EJECT message, and since the tasklet handler

hv_pci_onchannelcallback()

may fail to find the "hpdev" by calling

get_pcichild_wslot(hbus, dev_message->wslot.slot)

hv_pci_eject_device() is not called; Later, by continuing execution

create_root_hv_pci_bus()
 -> hv_pci_assign_slots()

creates the slot and the PCI_BUS_RELATIONS message with
bus_rel->device_count == 0 removes the device from hbus->children, and
we end up being unable to remove the slot in

hv_pci_remove()
 -> hv_pci_remove_slots()

Remove the slot in pci_devices_present_work() when the device
is removed to address this race.

pci_devices_present_work() and hv_eject_device_work() run in the
singled-threaded hbus->wq, so there is not a double-remove issue for the
slot.

We cannot offload hv_pci_eject_device() from hv_pci_onchannelcallback()
to the workqueue, because we need the hv_pci_onchannelcallback()
synchronously call hv_pci_eject_device() to poll the channel
ringbuffer to work around the "hangs in hv_compose_msi_msg()" issue
fixed in commit de0aa7b2 ("PCI: hv: Fix 2 hang issues in
hv_compose_msi_msg()")

Fixes: a15f2c08 ("PCI: hv: support reporting serial number as slot information")
Signed-off-by: default avatarDexuan Cui <decui@microsoft.com>
[lorenzo.pieralisi@arm.com: rewritten commit log]
Signed-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: default avatarStephen Hemminger <stephen@networkplumber.org>
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      9fa23ea1
    • Dexuan Cui's avatar
      PCI: hv: Add hv_pci_remove_slots() when we unload the driver · 76888d13
      Dexuan Cui authored 
      commit 15becc2b upstream.

When we unload the pci-hyperv host controller driver, the host does not
send us a PCI_EJECT message.

In this case we also need to make sure the sysfs PCI slot directory is
removed, otherwise a command on a slot file eg:

"cat /sys/bus/pci/slots/2/address"

will trigger a

"BUG: unable to handle kernel paging request"

and, if we unload/reload the driver several times we would end up with
stale slot entries in PCI slot directories in /sys/bus/pci/slots/

root@localhost:~# ls -rtl  /sys/bus/pci/slots/
total 0
drwxr-xr-x 2 root root 0 Feb  7 10:49 2
drwxr-xr-x 2 root root 0 Feb  7 10:49 2-1
drwxr-xr-x 2 root root 0 Feb  7 10:51 2-2

Add the missing code to remove the PCI slot and fix the current
behaviour.

Fixes: a15f2c08 ("PCI: hv: support reporting serial number as slot information")
Signed-off-by: default avatarDexuan Cui <decui@microsoft.com>
[lorenzo.pieralisi@arm.com: reformatted the log]
Signed-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: default avatarStephen Hemminger <sthemmin@microsoft.com>
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      76888d13
    • Dexuan Cui's avatar
      PCI: hv: Fix a memory leak in hv_eject_device_work() · a47e0054
      Dexuan Cui authored 
      commit 05f151a7 upstream.

When a device is created in new_pcichild_device(), hpdev->refs is set
to 2 (i.e. the initial value of 1 plus the get_pcichild()).

When we hot remove the device from the host, in a Linux VM we first call
hv_pci_eject_device(), which increases hpdev->refs by get_pcichild() and
then schedules a work of hv_eject_device_work(), so hpdev->refs becomes
3 (let's ignore the paired get/put_pcichild() in other places). But in
hv_eject_device_work(), currently we only call put_pcichild() twice,
meaning the 'hpdev' struct can't be freed in put_pcichild().

Add one put_pcichild() to fix the memory leak.

The device can also be removed when we run "rmmod pci-hyperv". On this
path (hv_pci_remove() -> hv_pci_bus_exit() -> hv_pci_devices_present()),
hpdev->refs is 2, and we do correctly call put_pcichild() twice in
pci_devices_present_work().

Fixes: 4daace0d ("PCI: hv: Add paravirtual PCI front-end for Microsoft Hyper-V VMs")
Signed-off-by: default avatarDexuan Cui <decui@microsoft.com>
[lorenzo.pieralisi@arm.com: commit log rework]
Signed-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: default avatarStephen Hemminger <stephen@networkplumber.org>
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      a47e0054
    • Laurentiu Tudor's avatar
      powerpc/booke64: set RI in default MSR · 4179b858
      Laurentiu Tudor authored 
      commit 5266e58d upstream.

Set RI in the default kernel's MSR so that the architected way of
detecting unrecoverable machine check interrupts has a chance to work.
This is inline with the MSR setup of the rest of booke powerpc
architectures configured here.
Signed-off-by: default avatarLaurentiu Tudor <laurentiu.tudor@nxp.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      4179b858
    • Russell Currey's avatar
      powerpc/powernv/idle: Restore IAMR after idle · 71b20cdb
      Russell Currey authored 
      commit a3f3072d upstream.

Without restoring the IAMR after idle, execution prevention on POWER9
with Radix MMU is overwritten and the kernel can freely execute
userspace without faulting.

This is necessary when returning from any stop state that modifies
user state, as well as hypervisor state.

To test how this fails without this patch, load the lkdtm driver and
do the following:

  $ echo EXEC_USERSPACE > /sys/kernel/debug/provoke-crash/DIRECT

which won't fault, then boot the kernel with powersave=off, where it
will fault. Applying this patch will fix this.

Fixes: 3b10d009 ("powerpc/mm/radix: Prevent kernel execution of user space")
Cc: stable@vger.kernel.org # v4.10+
Signed-off-by: default avatarRussell Currey <ruscur@russell.cc>
Reviewed-by: default avatarAkshay Adiga <akshay.adiga@linux.vnet.ibm.com>
Reviewed-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      71b20cdb
    • Rick Lindsley's avatar
      powerpc/book3s/64: check for NULL pointer in pgd_alloc() · 69c2b71c
      Rick Lindsley authored 
      commit f3935626 upstream.

When the memset code was added to pgd_alloc(), it failed to consider
that kmem_cache_alloc() can return NULL. It's uncommon, but not
impossible under heavy memory contention. Example oops:

  Unable to handle kernel paging request for data at address 0x00000000
  Faulting instruction address: 0xc0000000000a4000
  Oops: Kernel access of bad area, sig: 11 [#1]
  LE SMP NR_CPUS=2048 NUMA pSeries
  CPU: 70 PID: 48471 Comm: entrypoint.sh Kdump: loaded Not tainted 4.14.0-115.6.1.el7a.ppc64le #1
  task: c000000334a00000 task.stack: c000000331c00000
  NIP:  c0000000000a4000 LR: c00000000012f43c CTR: 0000000000000020
  REGS: c000000331c039c0 TRAP: 0300   Not tainted  (4.14.0-115.6.1.el7a.ppc64le)
  MSR:  800000010280b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE,TM[E]>  CR: 44022840  XER: 20040000
  CFAR: c000000000008874 DAR: 0000000000000000 DSISR: 42000000 SOFTE: 1
  ...
  NIP [c0000000000a4000] memset+0x68/0x104
  LR [c00000000012f43c] mm_init+0x27c/0x2f0
  Call Trace:
    mm_init+0x260/0x2f0 (unreliable)
    copy_mm+0x11c/0x638
    copy_process.isra.28.part.29+0x6fc/0x1080
    _do_fork+0xdc/0x4c0
    ppc_clone+0x8/0xc
  Instruction dump:
  409e000c b0860000 38c60002 409d000c 90860000 38c60004 78a0d183 78a506a0
  7c0903a6 41820034 60000000 60420000 <f8860000> f8860008 f8860010 f8860018

Fixes: fc5c2f4a ("powerpc/mm/hash64: Zero PGD pages on allocation")
Cc: stable@vger.kernel.org # v4.16+
Signed-off-by: default avatarRick Lindsley <ricklind@vnet.linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      69c2b71c
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