<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/xen, branch v6.0.3</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>xen/gntdev: Accommodate VMA splitting</title>
<updated>2022-10-21T10:37:43+00:00</updated>
<author>
<name>M. Vefa Bicakci</name>
<email>m.v.b@runbox.com</email>
</author>
<published>2022-10-02T22:20:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=cdafa219ace013c594e2491158ad1b51f9923dde'/>
<id>cdafa219ace013c594e2491158ad1b51f9923dde</id>
<content type='text'>
commit 5c13a4a0291b30191eff9ead8d010e1ca43a4d0c upstream.

Prior to this commit, the gntdev driver code did not handle the
following scenario correctly with paravirtualized (PV) Xen domains:

* User process sets up a gntdev mapping composed of two grant mappings
  (i.e., two pages shared by another Xen domain).
* User process munmap()s one of the pages.
* User process munmap()s the remaining page.
* User process exits.

In the scenario above, the user process would cause the kernel to log
the following messages in dmesg for the first munmap(), and the second
munmap() call would result in similar log messages:

  BUG: Bad page map in process doublemap.test  pte:... pmd:...
  page:0000000057c97bff refcount:1 mapcount:-1 \
    mapping:0000000000000000 index:0x0 pfn:...
  ...
  page dumped because: bad pte
  ...
  file:gntdev fault:0x0 mmap:gntdev_mmap [xen_gntdev] readpage:0x0
  ...
  Call Trace:
   &lt;TASK&gt;
   dump_stack_lvl+0x46/0x5e
   print_bad_pte.cold+0x66/0xb6
   unmap_page_range+0x7e5/0xdc0
   unmap_vmas+0x78/0xf0
   unmap_region+0xa8/0x110
   __do_munmap+0x1ea/0x4e0
   __vm_munmap+0x75/0x120
   __x64_sys_munmap+0x28/0x40
   do_syscall_64+0x38/0x90
   entry_SYSCALL_64_after_hwframe+0x61/0xcb
   ...

For each munmap() call, the Xen hypervisor (if built with CONFIG_DEBUG)
would print out the following and trigger a general protection fault in
the affected Xen PV domain:

  (XEN) d0v... Attempt to implicitly unmap d0's grant PTE ...
  (XEN) d0v... Attempt to implicitly unmap d0's grant PTE ...

As of this writing, gntdev_grant_map structure's vma field (referred to
as map-&gt;vma below) is mainly used for checking the start and end
addresses of mappings. However, with split VMAs, these may change, and
there could be more than one VMA associated with a gntdev mapping.
Hence, remove the use of map-&gt;vma and rely on map-&gt;pages_vm_start for
the original start address and on (map-&gt;count &lt;&lt; PAGE_SHIFT) for the
original mapping size. Let the invalidate() and find_special_page()
hooks use these.

Also, given that there can be multiple VMAs associated with a gntdev
mapping, move the "mmu_interval_notifier_remove(&amp;map-&gt;notifier)" call to
the end of gntdev_put_map, so that the MMU notifier is only removed
after the closing of the last remaining VMA.

Finally, use an atomic to prevent inadvertent gntdev mapping re-use,
instead of using the map-&gt;live_grants atomic counter and/or the map-&gt;vma
pointer (the latter of which is now removed). This prevents the
userspace from mmap()'ing (with MAP_FIXED) a gntdev mapping over the
same address range as a previously set up gntdev mapping. This scenario
can be summarized with the following call-trace, which was valid prior
to this commit:

  mmap
    gntdev_mmap
  mmap (repeat mmap with MAP_FIXED over the same address range)
    gntdev_invalidate
      unmap_grant_pages (sets 'being_removed' entries to true)
        gnttab_unmap_refs_async
    unmap_single_vma
    gntdev_mmap (maps the shared pages again)
  munmap
    gntdev_invalidate
      unmap_grant_pages
        (no-op because 'being_removed' entries are true)
    unmap_single_vma (For PV domains, Xen reports that a granted page
      is being unmapped and triggers a general protection fault in the
      affected domain, if Xen was built with CONFIG_DEBUG)

The fix for this last scenario could be worth its own commit, but we
opted for a single commit, because removing the gntdev_grant_map
structure's vma field requires guarding the entry to gntdev_mmap(), and
the live_grants atomic counter is not sufficient on its own to prevent
the mmap() over a pre-existing mapping.

Link: https://github.com/QubesOS/qubes-issues/issues/7631
Fixes: ab31523c2fca ("xen/gntdev: allow usermode to map granted pages")
Cc: stable@vger.kernel.org
Signed-off-by: M. Vefa Bicakci &lt;m.v.b@runbox.com&gt;
Reviewed-by: Juergen Gross &lt;jgross@suse.com&gt;
Link: https://lore.kernel.org/r/20221002222006.2077-3-m.v.b@runbox.com
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 5c13a4a0291b30191eff9ead8d010e1ca43a4d0c upstream.

Prior to this commit, the gntdev driver code did not handle the
following scenario correctly with paravirtualized (PV) Xen domains:

* User process sets up a gntdev mapping composed of two grant mappings
  (i.e., two pages shared by another Xen domain).
* User process munmap()s one of the pages.
* User process munmap()s the remaining page.
* User process exits.

In the scenario above, the user process would cause the kernel to log
the following messages in dmesg for the first munmap(), and the second
munmap() call would result in similar log messages:

  BUG: Bad page map in process doublemap.test  pte:... pmd:...
  page:0000000057c97bff refcount:1 mapcount:-1 \
    mapping:0000000000000000 index:0x0 pfn:...
  ...
  page dumped because: bad pte
  ...
  file:gntdev fault:0x0 mmap:gntdev_mmap [xen_gntdev] readpage:0x0
  ...
  Call Trace:
   &lt;TASK&gt;
   dump_stack_lvl+0x46/0x5e
   print_bad_pte.cold+0x66/0xb6
   unmap_page_range+0x7e5/0xdc0
   unmap_vmas+0x78/0xf0
   unmap_region+0xa8/0x110
   __do_munmap+0x1ea/0x4e0
   __vm_munmap+0x75/0x120
   __x64_sys_munmap+0x28/0x40
   do_syscall_64+0x38/0x90
   entry_SYSCALL_64_after_hwframe+0x61/0xcb
   ...

For each munmap() call, the Xen hypervisor (if built with CONFIG_DEBUG)
would print out the following and trigger a general protection fault in
the affected Xen PV domain:

  (XEN) d0v... Attempt to implicitly unmap d0's grant PTE ...
  (XEN) d0v... Attempt to implicitly unmap d0's grant PTE ...

As of this writing, gntdev_grant_map structure's vma field (referred to
as map-&gt;vma below) is mainly used for checking the start and end
addresses of mappings. However, with split VMAs, these may change, and
there could be more than one VMA associated with a gntdev mapping.
Hence, remove the use of map-&gt;vma and rely on map-&gt;pages_vm_start for
the original start address and on (map-&gt;count &lt;&lt; PAGE_SHIFT) for the
original mapping size. Let the invalidate() and find_special_page()
hooks use these.

Also, given that there can be multiple VMAs associated with a gntdev
mapping, move the "mmu_interval_notifier_remove(&amp;map-&gt;notifier)" call to
the end of gntdev_put_map, so that the MMU notifier is only removed
after the closing of the last remaining VMA.

Finally, use an atomic to prevent inadvertent gntdev mapping re-use,
instead of using the map-&gt;live_grants atomic counter and/or the map-&gt;vma
pointer (the latter of which is now removed). This prevents the
userspace from mmap()'ing (with MAP_FIXED) a gntdev mapping over the
same address range as a previously set up gntdev mapping. This scenario
can be summarized with the following call-trace, which was valid prior
to this commit:

  mmap
    gntdev_mmap
  mmap (repeat mmap with MAP_FIXED over the same address range)
    gntdev_invalidate
      unmap_grant_pages (sets 'being_removed' entries to true)
        gnttab_unmap_refs_async
    unmap_single_vma
    gntdev_mmap (maps the shared pages again)
  munmap
    gntdev_invalidate
      unmap_grant_pages
        (no-op because 'being_removed' entries are true)
    unmap_single_vma (For PV domains, Xen reports that a granted page
      is being unmapped and triggers a general protection fault in the
      affected domain, if Xen was built with CONFIG_DEBUG)

The fix for this last scenario could be worth its own commit, but we
opted for a single commit, because removing the gntdev_grant_map
structure's vma field requires guarding the entry to gntdev_mmap(), and
the live_grants atomic counter is not sufficient on its own to prevent
the mmap() over a pre-existing mapping.

Link: https://github.com/QubesOS/qubes-issues/issues/7631
Fixes: ab31523c2fca ("xen/gntdev: allow usermode to map granted pages")
Cc: stable@vger.kernel.org
Signed-off-by: M. Vefa Bicakci &lt;m.v.b@runbox.com&gt;
Reviewed-by: Juergen Gross &lt;jgross@suse.com&gt;
Link: https://lore.kernel.org/r/20221002222006.2077-3-m.v.b@runbox.com
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>xen/gntdev: Prevent leaking grants</title>
<updated>2022-10-21T10:37:43+00:00</updated>
<author>
<name>M. Vefa Bicakci</name>
<email>m.v.b@runbox.com</email>
</author>
<published>2022-10-02T22:20:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=273f6a4f71be12e2ec80a4919837d6e4fa933a04'/>
<id>273f6a4f71be12e2ec80a4919837d6e4fa933a04</id>
<content type='text'>
commit 0991028cd49567d7016d1b224fe0117c35059f86 upstream.

Prior to this commit, if a grant mapping operation failed partially,
some of the entries in the map_ops array would be invalid, whereas all
of the entries in the kmap_ops array would be valid. This in turn would
cause the following logic in gntdev_map_grant_pages to become invalid:

  for (i = 0; i &lt; map-&gt;count; i++) {
    if (map-&gt;map_ops[i].status == GNTST_okay) {
      map-&gt;unmap_ops[i].handle = map-&gt;map_ops[i].handle;
      if (!use_ptemod)
        alloced++;
    }
    if (use_ptemod) {
      if (map-&gt;kmap_ops[i].status == GNTST_okay) {
        if (map-&gt;map_ops[i].status == GNTST_okay)
          alloced++;
        map-&gt;kunmap_ops[i].handle = map-&gt;kmap_ops[i].handle;
      }
    }
  }
  ...
  atomic_add(alloced, &amp;map-&gt;live_grants);

Assume that use_ptemod is true (i.e., the domain mapping the granted
pages is a paravirtualized domain). In the code excerpt above, note that
the "alloced" variable is only incremented when both kmap_ops[i].status
and map_ops[i].status are set to GNTST_okay (i.e., both mapping
operations are successful).  However, as also noted above, there are
cases where a grant mapping operation fails partially, breaking the
assumption of the code excerpt above.

The aforementioned causes map-&gt;live_grants to be incorrectly set. In
some cases, all of the map_ops mappings fail, but all of the kmap_ops
mappings succeed, meaning that live_grants may remain zero. This in turn
makes it impossible to unmap the successfully grant-mapped pages pointed
to by kmap_ops, because unmap_grant_pages has the following snippet of
code at its beginning:

  if (atomic_read(&amp;map-&gt;live_grants) == 0)
    return; /* Nothing to do */

In other cases where only some of the map_ops mappings fail but all
kmap_ops mappings succeed, live_grants is made positive, but when the
user requests unmapping the grant-mapped pages, __unmap_grant_pages_done
will then make map-&gt;live_grants negative, because the latter function
does not check if all of the pages that were requested to be unmapped
were actually unmapped, and the same function unconditionally subtracts
"data-&gt;count" (i.e., a value that can be greater than map-&gt;live_grants)
from map-&gt;live_grants. The side effects of a negative live_grants value
have not been studied.

The net effect of all of this is that grant references are leaked in one
of the above conditions. In Qubes OS v4.1 (which uses Xen's grant
mechanism extensively for X11 GUI isolation), this issue manifests
itself with warning messages like the following to be printed out by the
Linux kernel in the VM that had granted pages (that contain X11 GUI
window data) to dom0: "g.e. 0x1234 still pending", especially after the
user rapidly resizes GUI VM windows (causing some grant-mapping
operations to partially or completely fail, due to the fact that the VM
unshares some of the pages as part of the window resizing, making the
pages impossible to grant-map from dom0).

The fix for this issue involves counting all successful map_ops and
kmap_ops mappings separately, and then adding the sum to live_grants.
During unmapping, only the number of successfully unmapped grants is
subtracted from live_grants. The code is also modified to check for
negative live_grants values after the subtraction and warn the user.

Link: https://github.com/QubesOS/qubes-issues/issues/7631
Fixes: dbe97cff7dd9 ("xen/gntdev: Avoid blocking in unmap_grant_pages()")
Cc: stable@vger.kernel.org
Signed-off-by: M. Vefa Bicakci &lt;m.v.b@runbox.com&gt;
Acked-by: Demi Marie Obenour &lt;demi@invisiblethingslab.com&gt;
Reviewed-by: Juergen Gross &lt;jgross@suse.com&gt;
Link: https://lore.kernel.org/r/20221002222006.2077-2-m.v.b@runbox.com
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 0991028cd49567d7016d1b224fe0117c35059f86 upstream.

Prior to this commit, if a grant mapping operation failed partially,
some of the entries in the map_ops array would be invalid, whereas all
of the entries in the kmap_ops array would be valid. This in turn would
cause the following logic in gntdev_map_grant_pages to become invalid:

  for (i = 0; i &lt; map-&gt;count; i++) {
    if (map-&gt;map_ops[i].status == GNTST_okay) {
      map-&gt;unmap_ops[i].handle = map-&gt;map_ops[i].handle;
      if (!use_ptemod)
        alloced++;
    }
    if (use_ptemod) {
      if (map-&gt;kmap_ops[i].status == GNTST_okay) {
        if (map-&gt;map_ops[i].status == GNTST_okay)
          alloced++;
        map-&gt;kunmap_ops[i].handle = map-&gt;kmap_ops[i].handle;
      }
    }
  }
  ...
  atomic_add(alloced, &amp;map-&gt;live_grants);

Assume that use_ptemod is true (i.e., the domain mapping the granted
pages is a paravirtualized domain). In the code excerpt above, note that
the "alloced" variable is only incremented when both kmap_ops[i].status
and map_ops[i].status are set to GNTST_okay (i.e., both mapping
operations are successful).  However, as also noted above, there are
cases where a grant mapping operation fails partially, breaking the
assumption of the code excerpt above.

The aforementioned causes map-&gt;live_grants to be incorrectly set. In
some cases, all of the map_ops mappings fail, but all of the kmap_ops
mappings succeed, meaning that live_grants may remain zero. This in turn
makes it impossible to unmap the successfully grant-mapped pages pointed
to by kmap_ops, because unmap_grant_pages has the following snippet of
code at its beginning:

  if (atomic_read(&amp;map-&gt;live_grants) == 0)
    return; /* Nothing to do */

In other cases where only some of the map_ops mappings fail but all
kmap_ops mappings succeed, live_grants is made positive, but when the
user requests unmapping the grant-mapped pages, __unmap_grant_pages_done
will then make map-&gt;live_grants negative, because the latter function
does not check if all of the pages that were requested to be unmapped
were actually unmapped, and the same function unconditionally subtracts
"data-&gt;count" (i.e., a value that can be greater than map-&gt;live_grants)
from map-&gt;live_grants. The side effects of a negative live_grants value
have not been studied.

The net effect of all of this is that grant references are leaked in one
of the above conditions. In Qubes OS v4.1 (which uses Xen's grant
mechanism extensively for X11 GUI isolation), this issue manifests
itself with warning messages like the following to be printed out by the
Linux kernel in the VM that had granted pages (that contain X11 GUI
window data) to dom0: "g.e. 0x1234 still pending", especially after the
user rapidly resizes GUI VM windows (causing some grant-mapping
operations to partially or completely fail, due to the fact that the VM
unshares some of the pages as part of the window resizing, making the
pages impossible to grant-map from dom0).

The fix for this issue involves counting all successful map_ops and
kmap_ops mappings separately, and then adding the sum to live_grants.
During unmapping, only the number of successfully unmapped grants is
subtracted from live_grants. The code is also modified to check for
negative live_grants values after the subtraction and warn the user.

Link: https://github.com/QubesOS/qubes-issues/issues/7631
Fixes: dbe97cff7dd9 ("xen/gntdev: Avoid blocking in unmap_grant_pages()")
Cc: stable@vger.kernel.org
Signed-off-by: M. Vefa Bicakci &lt;m.v.b@runbox.com&gt;
Acked-by: Demi Marie Obenour &lt;demi@invisiblethingslab.com&gt;
Reviewed-by: Juergen Gross &lt;jgross@suse.com&gt;
Link: https://lore.kernel.org/r/20221002222006.2077-2-m.v.b@runbox.com
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'for-linus-6.0-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip</title>
<updated>2022-09-23T15:31:24+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-09-23T15:31:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=526e8262856027cea38c45a5ff45fbe4204aed04'/>
<id>526e8262856027cea38c45a5ff45fbe4204aed04</id>
<content type='text'>
Pull xen fix from Juergen Gross:
 "A single fix for an issue in the xenbus driver (initialization of
  multi-page rings for Xen PV devices)"

* tag 'for-linus-6.0-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/xenbus: fix xenbus_setup_ring()
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull xen fix from Juergen Gross:
 "A single fix for an issue in the xenbus driver (initialization of
  multi-page rings for Xen PV devices)"

* tag 'for-linus-6.0-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/xenbus: fix xenbus_setup_ring()
</pre>
</div>
</content>
</entry>
<entry>
<title>xen/xenbus: fix xenbus_setup_ring()</title>
<updated>2022-09-16T07:50:47+00:00</updated>
<author>
<name>Juergen Gross</name>
<email>jgross@suse.com</email>
</author>
<published>2022-09-15T13:05:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ce6b8ccdef959ba86b2711e090e84a987a000bf7'/>
<id>ce6b8ccdef959ba86b2711e090e84a987a000bf7</id>
<content type='text'>
Commit 4573240f0764 ("xen/xenbus: eliminate xenbus_grant_ring()")
introduced an error for initialization of multi-page rings.

Cc: stable@vger.kernel.org
Fixes: 4573240f0764 ("xen/xenbus: eliminate xenbus_grant_ring()")
Reported-by: Sander Eikelenboom &lt;linux@eikelenboom.it&gt;
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
Reviewed-by: Jan Beulich &lt;jbeulich@suse.com&gt;
Reviewed-by: Oleksandr Tyshchenko &lt;oleksandr_tyshchenko@epam.com&gt;
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit 4573240f0764 ("xen/xenbus: eliminate xenbus_grant_ring()")
introduced an error for initialization of multi-page rings.

Cc: stable@vger.kernel.org
Fixes: 4573240f0764 ("xen/xenbus: eliminate xenbus_grant_ring()")
Reported-by: Sander Eikelenboom &lt;linux@eikelenboom.it&gt;
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
Reviewed-by: Jan Beulich &lt;jbeulich@suse.com&gt;
Reviewed-by: Oleksandr Tyshchenko &lt;oleksandr_tyshchenko@epam.com&gt;
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'for-linus-6.0-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip</title>
<updated>2022-09-03T20:23:11+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-09-03T20:23:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=65eea2c060aee3bf6d27ea365360059fbd4eeff4'/>
<id>65eea2c060aee3bf6d27ea365360059fbd4eeff4</id>
<content type='text'>
Pull xen fixes from Juergen Gross:

 - a minor fix for the Xen grant driver

 - a small series fixing a recently introduced problem in the Xen
   blkfront/blkback drivers with negotiation of feature usage

* tag 'for-linus-6.0-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/grants: prevent integer overflow in gnttab_dma_alloc_pages()
  xen-blkfront: Cache feature_persistent value before advertisement
  xen-blkfront: Advertise feature-persistent as user requested
  xen-blkback: Advertise feature-persistent as user requested
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull xen fixes from Juergen Gross:

 - a minor fix for the Xen grant driver

 - a small series fixing a recently introduced problem in the Xen
   blkfront/blkback drivers with negotiation of feature usage

* tag 'for-linus-6.0-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/grants: prevent integer overflow in gnttab_dma_alloc_pages()
  xen-blkfront: Cache feature_persistent value before advertisement
  xen-blkfront: Advertise feature-persistent as user requested
  xen-blkback: Advertise feature-persistent as user requested
</pre>
</div>
</content>
</entry>
<entry>
<title>xen/grants: prevent integer overflow in gnttab_dma_alloc_pages()</title>
<updated>2022-09-02T09:05:19+00:00</updated>
<author>
<name>Dan Carpenter</name>
<email>dan.carpenter@oracle.com</email>
</author>
<published>2022-09-01T15:35:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e9ea0b30ada008f4e65933f449db6894832cb242'/>
<id>e9ea0b30ada008f4e65933f449db6894832cb242</id>
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The change from kcalloc() to kvmalloc() means that arg-&gt;nr_pages
might now be large enough that the "args-&gt;nr_pages &lt;&lt; PAGE_SHIFT" can
result in an integer overflow.

Fixes: b3f7931f5c61 ("xen/gntdev: switch from kcalloc() to kvcalloc()")
Signed-off-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Reviewed-by: Juergen Gross &lt;jgross@suse.com&gt;
Link: https://lore.kernel.org/r/YxDROJqu/RPvR0bi@kili
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
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<pre>
The change from kcalloc() to kvmalloc() means that arg-&gt;nr_pages
might now be large enough that the "args-&gt;nr_pages &lt;&lt; PAGE_SHIFT" can
result in an integer overflow.

Fixes: b3f7931f5c61 ("xen/gntdev: switch from kcalloc() to kvcalloc()")
Signed-off-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Reviewed-by: Juergen Gross &lt;jgross@suse.com&gt;
Link: https://lore.kernel.org/r/YxDROJqu/RPvR0bi@kili
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'for-linus-6.0-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip</title>
<updated>2022-08-27T22:38:00+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-08-27T22:38:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=05519f2480a3e71053b892d4ea864e641949a77f'/>
<id>05519f2480a3e71053b892d4ea864e641949a77f</id>
<content type='text'>
Pull xen fixes from Juergen Gross:

 - two minor cleanups

 - a fix of the xen/privcmd driver avoiding a possible NULL dereference
   in an error case

* tag 'for-linus-6.0-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/privcmd: fix error exit of privcmd_ioctl_dm_op()
  xen: move from strlcpy with unused retval to strscpy
  xen: x86: remove setting the obsolete config XEN_MAX_DOMAIN_MEMORY
</content>
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<pre>
Pull xen fixes from Juergen Gross:

 - two minor cleanups

 - a fix of the xen/privcmd driver avoiding a possible NULL dereference
   in an error case

* tag 'for-linus-6.0-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/privcmd: fix error exit of privcmd_ioctl_dm_op()
  xen: move from strlcpy with unused retval to strscpy
  xen: x86: remove setting the obsolete config XEN_MAX_DOMAIN_MEMORY
</pre>
</div>
</content>
</entry>
<entry>
<title>xen/privcmd: fix error exit of privcmd_ioctl_dm_op()</title>
<updated>2022-08-25T14:40:28+00:00</updated>
<author>
<name>Juergen Gross</name>
<email>jgross@suse.com</email>
</author>
<published>2022-08-25T14:19:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c5deb27895e017a0267de0a20d140ad5fcc55a54'/>
<id>c5deb27895e017a0267de0a20d140ad5fcc55a54</id>
<content type='text'>
The error exit of privcmd_ioctl_dm_op() is calling unlock_pages()
potentially with pages being NULL, leading to a NULL dereference.

Additionally lock_pages() doesn't check for pin_user_pages_fast()
having been completely successful, resulting in potentially not
locking all pages into memory. This could result in sporadic failures
when using the related memory in user mode.

Fix all of that by calling unlock_pages() always with the real number
of pinned pages, which will be zero in case pages being NULL, and by
checking the number of pages pinned by pin_user_pages_fast() matching
the expected number of pages.

Cc: &lt;stable@vger.kernel.org&gt;
Fixes: ab520be8cd5d ("xen/privcmd: Add IOCTL_PRIVCMD_DM_OP")
Reported-by: Rustam Subkhankulov &lt;subkhankulov@ispras.ru&gt;
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
Reviewed-by: Jan Beulich &lt;jbeulich@suse.com&gt;
Reviewed-by: Oleksandr Tyshchenko &lt;oleksandr_tyshchenko@epam.com&gt;
Link: https://lore.kernel.org/r/20220825141918.3581-1-jgross@suse.com
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The error exit of privcmd_ioctl_dm_op() is calling unlock_pages()
potentially with pages being NULL, leading to a NULL dereference.

Additionally lock_pages() doesn't check for pin_user_pages_fast()
having been completely successful, resulting in potentially not
locking all pages into memory. This could result in sporadic failures
when using the related memory in user mode.

Fix all of that by calling unlock_pages() always with the real number
of pinned pages, which will be zero in case pages being NULL, and by
checking the number of pages pinned by pin_user_pages_fast() matching
the expected number of pages.

Cc: &lt;stable@vger.kernel.org&gt;
Fixes: ab520be8cd5d ("xen/privcmd: Add IOCTL_PRIVCMD_DM_OP")
Reported-by: Rustam Subkhankulov &lt;subkhankulov@ispras.ru&gt;
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
Reviewed-by: Jan Beulich &lt;jbeulich@suse.com&gt;
Reviewed-by: Oleksandr Tyshchenko &lt;oleksandr_tyshchenko@epam.com&gt;
Link: https://lore.kernel.org/r/20220825141918.3581-1-jgross@suse.com
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>xen: move from strlcpy with unused retval to strscpy</title>
<updated>2022-08-25T11:38:07+00:00</updated>
<author>
<name>Wolfram Sang</name>
<email>wsa+renesas@sang-engineering.com</email>
</author>
<published>2022-08-18T21:01:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6bb79f5b4c84a09cd6bed46ef3e46ef4fc21407d'/>
<id>6bb79f5b4c84a09cd6bed46ef3e46ef4fc21407d</id>
<content type='text'>
Follow the advice of the below link and prefer 'strscpy' in this
subsystem. Conversion is 1:1 because the return value is not used.
Generated by a coccinelle script.

Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/
Signed-off-by: Wolfram Sang &lt;wsa+renesas@sang-engineering.com&gt;
Reviewed-by: Oleksandr Tyshchenko &lt;oleksandr_tyshchenko@epam.com&gt;
Link: https://lore.kernel.org/r/20220818210122.7613-1-wsa+renesas@sang-engineering.com
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Follow the advice of the below link and prefer 'strscpy' in this
subsystem. Conversion is 1:1 because the return value is not used.
Generated by a coccinelle script.

Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/
Signed-off-by: Wolfram Sang &lt;wsa+renesas@sang-engineering.com&gt;
Reviewed-by: Oleksandr Tyshchenko &lt;oleksandr_tyshchenko@epam.com&gt;
Link: https://lore.kernel.org/r/20220818210122.7613-1-wsa+renesas@sang-engineering.com
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'for-linus-6.0-rc1b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip</title>
<updated>2022-08-14T16:28:54+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-08-14T16:28:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5d6a0f4da9275f6c212de33777778673ba91241a'/>
<id>5d6a0f4da9275f6c212de33777778673ba91241a</id>
<content type='text'>
Pull more xen updates from Juergen Gross:

 - fix the handling of the "persistent grants" feature negotiation
   between Xen blkfront and Xen blkback drivers

 - a cleanup of xen.config and adding xen.config to Xen section in
   MAINTAINERS

 - support HVMOP_set_evtchn_upcall_vector, which is more compliant to
   "normal" interrupt handling than the global callback used up to now

 - further small cleanups

* tag 'for-linus-6.0-rc1b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  MAINTAINERS: add xen config fragments to XEN HYPERVISOR sections
  xen: remove XEN_SCRUB_PAGES in xen.config
  xen/pciback: Fix comment typo
  xen/xenbus: fix return type in xenbus_file_read()
  xen-blkfront: Apply 'feature_persistent' parameter when connect
  xen-blkback: Apply 'feature_persistent' parameter when connect
  xen-blkback: fix persistent grants negotiation
  x86/xen: Add support for HVMOP_set_evtchn_upcall_vector
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull more xen updates from Juergen Gross:

 - fix the handling of the "persistent grants" feature negotiation
   between Xen blkfront and Xen blkback drivers

 - a cleanup of xen.config and adding xen.config to Xen section in
   MAINTAINERS

 - support HVMOP_set_evtchn_upcall_vector, which is more compliant to
   "normal" interrupt handling than the global callback used up to now

 - further small cleanups

* tag 'for-linus-6.0-rc1b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  MAINTAINERS: add xen config fragments to XEN HYPERVISOR sections
  xen: remove XEN_SCRUB_PAGES in xen.config
  xen/pciback: Fix comment typo
  xen/xenbus: fix return type in xenbus_file_read()
  xen-blkfront: Apply 'feature_persistent' parameter when connect
  xen-blkback: Apply 'feature_persistent' parameter when connect
  xen-blkback: fix persistent grants negotiation
  x86/xen: Add support for HVMOP_set_evtchn_upcall_vector
</pre>
</div>
</content>
</entry>
</feed>
