<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/include/linux, branch v5.13-rc7</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge tag 'net-5.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net</title>
<updated>2021-06-19T01:55:29+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-06-19T01:55:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=9ed13a17e38e0537e24d9b507645002bf8d0201f'/>
<id>9ed13a17e38e0537e24d9b507645002bf8d0201f</id>
<content type='text'>
Pull networking fixes from Jakub Kicinski:
 "Networking fixes for 5.13-rc7, including fixes from wireless, bpf,
  bluetooth, netfilter and can.

  Current release - regressions:

   - mlxsw: spectrum_qdisc: Pass handle, not band number to find_class()
     to fix modifying offloaded qdiscs

   - lantiq: net: fix duplicated skb in rx descriptor ring

   - rtnetlink: fix regression in bridge VLAN configuration, empty info
     is not an error, bot-generated "fix" was not needed

   - libbpf: s/rx/tx/ typo on umem-&gt;rx_ring_setup_done to fix umem
     creation

  Current release - new code bugs:

   - ethtool: fix NULL pointer dereference during module EEPROM dump via
     the new netlink API

   - mlx5e: don't update netdev RQs with PTP-RQ, the special purpose
     queue should not be visible to the stack

   - mlx5e: select special PTP queue only for SKBTX_HW_TSTAMP skbs

   - mlx5e: verify dev is present in get devlink port ndo, avoid a panic

  Previous releases - regressions:

   - neighbour: allow NUD_NOARP entries to be force GCed

   - further fixes for fallout from reorg of WiFi locking (staging:
     rtl8723bs, mac80211, cfg80211)

   - skbuff: fix incorrect msg_zerocopy copy notifications

   - mac80211: fix NULL ptr deref for injected rate info

   - Revert "net/mlx5: Arm only EQs with EQEs" it may cause missed IRQs

  Previous releases - always broken:

   - bpf: more speculative execution fixes

   - netfilter: nft_fib_ipv6: skip ipv6 packets from any to link-local

   - udp: fix race between close() and udp_abort() resulting in a panic

   - fix out of bounds when parsing TCP options before packets are
     validated (in netfilter: synproxy, tc: sch_cake and mptcp)

   - mptcp: improve operation under memory pressure, add missing
     wake-ups

   - mptcp: fix double-lock/soft lookup in subflow_error_report()

   - bridge: fix races (null pointer deref and UAF) in vlan tunnel
     egress

   - ena: fix DMA mapping function issues in XDP

   - rds: fix memory leak in rds_recvmsg

  Misc:

   - vrf: allow larger MTUs

   - icmp: don't send out ICMP messages with a source address of 0.0.0.0

   - cdc_ncm: switch to eth%d interface naming"

* tag 'net-5.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (139 commits)
  net: ethernet: fix potential use-after-free in ec_bhf_remove
  selftests/net: Add icmp.sh for testing ICMP dummy address responses
  icmp: don't send out ICMP messages with a source address of 0.0.0.0
  net: ll_temac: Avoid ndo_start_xmit returning NETDEV_TX_BUSY
  net: ll_temac: Fix TX BD buffer overwrite
  net: ll_temac: Add memory-barriers for TX BD access
  net: ll_temac: Make sure to free skb when it is completely used
  MAINTAINERS: add Guvenc as SMC maintainer
  bnxt_en: Call bnxt_ethtool_free() in bnxt_init_one() error path
  bnxt_en: Fix TQM fastpath ring backing store computation
  bnxt_en: Rediscover PHY capabilities after firmware reset
  cxgb4: fix wrong shift.
  mac80211: handle various extensible elements correctly
  mac80211: reset profile_periodicity/ema_ap
  cfg80211: avoid double free of PMSR request
  cfg80211: make certificate generation more robust
  mac80211: minstrel_ht: fix sample time check
  net: qed: Fix memcpy() overflow of qed_dcbx_params()
  net: cdc_eem: fix tx fixup skb leak
  net: hamradio: fix memory leak in mkiss_close
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull networking fixes from Jakub Kicinski:
 "Networking fixes for 5.13-rc7, including fixes from wireless, bpf,
  bluetooth, netfilter and can.

  Current release - regressions:

   - mlxsw: spectrum_qdisc: Pass handle, not band number to find_class()
     to fix modifying offloaded qdiscs

   - lantiq: net: fix duplicated skb in rx descriptor ring

   - rtnetlink: fix regression in bridge VLAN configuration, empty info
     is not an error, bot-generated "fix" was not needed

   - libbpf: s/rx/tx/ typo on umem-&gt;rx_ring_setup_done to fix umem
     creation

  Current release - new code bugs:

   - ethtool: fix NULL pointer dereference during module EEPROM dump via
     the new netlink API

   - mlx5e: don't update netdev RQs with PTP-RQ, the special purpose
     queue should not be visible to the stack

   - mlx5e: select special PTP queue only for SKBTX_HW_TSTAMP skbs

   - mlx5e: verify dev is present in get devlink port ndo, avoid a panic

  Previous releases - regressions:

   - neighbour: allow NUD_NOARP entries to be force GCed

   - further fixes for fallout from reorg of WiFi locking (staging:
     rtl8723bs, mac80211, cfg80211)

   - skbuff: fix incorrect msg_zerocopy copy notifications

   - mac80211: fix NULL ptr deref for injected rate info

   - Revert "net/mlx5: Arm only EQs with EQEs" it may cause missed IRQs

  Previous releases - always broken:

   - bpf: more speculative execution fixes

   - netfilter: nft_fib_ipv6: skip ipv6 packets from any to link-local

   - udp: fix race between close() and udp_abort() resulting in a panic

   - fix out of bounds when parsing TCP options before packets are
     validated (in netfilter: synproxy, tc: sch_cake and mptcp)

   - mptcp: improve operation under memory pressure, add missing
     wake-ups

   - mptcp: fix double-lock/soft lookup in subflow_error_report()

   - bridge: fix races (null pointer deref and UAF) in vlan tunnel
     egress

   - ena: fix DMA mapping function issues in XDP

   - rds: fix memory leak in rds_recvmsg

  Misc:

   - vrf: allow larger MTUs

   - icmp: don't send out ICMP messages with a source address of 0.0.0.0

   - cdc_ncm: switch to eth%d interface naming"

* tag 'net-5.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (139 commits)
  net: ethernet: fix potential use-after-free in ec_bhf_remove
  selftests/net: Add icmp.sh for testing ICMP dummy address responses
  icmp: don't send out ICMP messages with a source address of 0.0.0.0
  net: ll_temac: Avoid ndo_start_xmit returning NETDEV_TX_BUSY
  net: ll_temac: Fix TX BD buffer overwrite
  net: ll_temac: Add memory-barriers for TX BD access
  net: ll_temac: Make sure to free skb when it is completely used
  MAINTAINERS: add Guvenc as SMC maintainer
  bnxt_en: Call bnxt_ethtool_free() in bnxt_init_one() error path
  bnxt_en: Fix TQM fastpath ring backing store computation
  bnxt_en: Rediscover PHY capabilities after firmware reset
  cxgb4: fix wrong shift.
  mac80211: handle various extensible elements correctly
  mac80211: reset profile_periodicity/ema_ap
  cfg80211: avoid double free of PMSR request
  cfg80211: make certificate generation more robust
  mac80211: minstrel_ht: fix sample time check
  net: qed: Fix memcpy() overflow of qed_dcbx_params()
  net: cdc_eem: fix tx fixup skb leak
  net: hamradio: fix memory leak in mkiss_close
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'pm-5.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm</title>
<updated>2021-06-18T17:42:36+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-06-18T17:42:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=944293bcee92acb1cfbbd315f833b4384bfd35fa'/>
<id>944293bcee92acb1cfbbd315f833b4384bfd35fa</id>
<content type='text'>
Pull power management fix from Rafael Wysocki:
 "Remove recently added frequency invariance support from the CPPC
  cpufreq driver, because it has turned out to be problematic and it
  cannot be fixed properly on time for 5.13 (Viresh Kumar)"

* tag 'pm-5.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  Revert "cpufreq: CPPC: Add support for frequency invariance"
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull power management fix from Rafael Wysocki:
 "Remove recently added frequency invariance support from the CPPC
  cpufreq driver, because it has turned out to be problematic and it
  cannot be fixed properly on time for 5.13 (Viresh Kumar)"

* tag 'pm-5.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  Revert "cpufreq: CPPC: Add support for frequency invariance"
</pre>
</div>
</content>
</entry>
<entry>
<title>net/mlx5e: Don't create devices during unload flow</title>
<updated>2021-06-16T22:36:47+00:00</updated>
<author>
<name>Dmytro Linkin</name>
<email>dlinkin@nvidia.com</email>
</author>
<published>2021-05-14T08:14:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=a5ae8fc9058e37437c8c1f82b3d412b4abd1b9e6'/>
<id>a5ae8fc9058e37437c8c1f82b3d412b4abd1b9e6</id>
<content type='text'>
Running devlink reload command for port in switchdev mode cause
resources to corrupt: driver can't release allocated EQ and reclaim
memory pages, because "rdma" auxiliary device had add CQs which blocks
EQ from deletion.
Erroneous sequence happens during reload-down phase, and is following:

1. detach device - suspends auxiliary devices which support it, destroys
   others. During this step "eth-rep" and "rdma-rep" are destroyed,
   "eth" - suspended.
2. disable SRIOV - moves device to legacy mode; as part of disablement -
   rescans drivers. This step adds "rdma" auxiliary device.
3. destroy EQ table - &lt;failure&gt;.

Driver shouldn't create any device during unload flows. To handle that
implement MLX5_PRIV_FLAGS_DETACH flag, set it on device detach and unset
on device attach. If flag is set do no-op on drivers rescan.

Fixes: a925b5e309c9 ("net/mlx5: Register mlx5 devices to auxiliary virtual bus")
Signed-off-by: Dmytro Linkin &lt;dlinkin@nvidia.com&gt;
Reviewed-by: Leon Romanovsky &lt;leonro@nvidia.com&gt;
Reviewed-by: Roi Dayan &lt;roid@nvidia.com&gt;
Signed-off-by: Saeed Mahameed &lt;saeedm@nvidia.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Running devlink reload command for port in switchdev mode cause
resources to corrupt: driver can't release allocated EQ and reclaim
memory pages, because "rdma" auxiliary device had add CQs which blocks
EQ from deletion.
Erroneous sequence happens during reload-down phase, and is following:

1. detach device - suspends auxiliary devices which support it, destroys
   others. During this step "eth-rep" and "rdma-rep" are destroyed,
   "eth" - suspended.
2. disable SRIOV - moves device to legacy mode; as part of disablement -
   rescans drivers. This step adds "rdma" auxiliary device.
3. destroy EQ table - &lt;failure&gt;.

Driver shouldn't create any device during unload flows. To handle that
implement MLX5_PRIV_FLAGS_DETACH flag, set it on device detach and unset
on device attach. If flag is set do no-op on drivers rescan.

Fixes: a925b5e309c9 ("net/mlx5: Register mlx5 devices to auxiliary virtual bus")
Signed-off-by: Dmytro Linkin &lt;dlinkin@nvidia.com&gt;
Reviewed-by: Leon Romanovsky &lt;leonro@nvidia.com&gt;
Reviewed-by: Roi Dayan &lt;roid@nvidia.com&gt;
Signed-off-by: Saeed Mahameed &lt;saeedm@nvidia.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm/thp: unmap_mapping_page() to fix THP truncate_cleanup_page()</title>
<updated>2021-06-16T16:24:42+00:00</updated>
<author>
<name>Hugh Dickins</name>
<email>hughd@google.com</email>
</author>
<published>2021-06-16T01:24:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=22061a1ffabdb9c3385de159c5db7aac3a4df1cc'/>
<id>22061a1ffabdb9c3385de159c5db7aac3a4df1cc</id>
<content type='text'>
There is a race between THP unmapping and truncation, when truncate sees
pmd_none() and skips the entry, after munmap's zap_huge_pmd() cleared
it, but before its page_remove_rmap() gets to decrement
compound_mapcount: generating false "BUG: Bad page cache" reports that
the page is still mapped when deleted.  This commit fixes that, but not
in the way I hoped.

The first attempt used try_to_unmap(page, TTU_SYNC|TTU_IGNORE_MLOCK)
instead of unmap_mapping_range() in truncate_cleanup_page(): it has
often been an annoyance that we usually call unmap_mapping_range() with
no pages locked, but there apply it to a single locked page.
try_to_unmap() looks more suitable for a single locked page.

However, try_to_unmap_one() contains a VM_BUG_ON_PAGE(!pvmw.pte,page):
it is used to insert THP migration entries, but not used to unmap THPs.
Copy zap_huge_pmd() and add THP handling now? Perhaps, but their TLB
needs are different, I'm too ignorant of the DAX cases, and couldn't
decide how far to go for anon+swap.  Set that aside.

The second attempt took a different tack: make no change in truncate.c,
but modify zap_huge_pmd() to insert an invalidated huge pmd instead of
clearing it initially, then pmd_clear() between page_remove_rmap() and
unlocking at the end.  Nice.  But powerpc blows that approach out of the
water, with its serialize_against_pte_lookup(), and interesting pgtable
usage.  It would need serious help to get working on powerpc (with a
minor optimization issue on s390 too).  Set that aside.

Just add an "if (page_mapped(page)) synchronize_rcu();" or other such
delay, after unmapping in truncate_cleanup_page()? Perhaps, but though
that's likely to reduce or eliminate the number of incidents, it would
give less assurance of whether we had identified the problem correctly.

This successful iteration introduces "unmap_mapping_page(page)" instead
of try_to_unmap(), and goes the usual unmap_mapping_range_tree() route,
with an addition to details.  Then zap_pmd_range() watches for this
case, and does spin_unlock(pmd_lock) if so - just like
page_vma_mapped_walk() now does in the PVMW_SYNC case.  Not pretty, but
safe.

Note that unmap_mapping_page() is doing a VM_BUG_ON(!PageLocked) to
assert its interface; but currently that's only used to make sure that
page-&gt;mapping is stable, and zap_pmd_range() doesn't care if the page is
locked or not.  Along these lines, in invalidate_inode_pages2_range()
move the initial unmap_mapping_range() out from under page lock, before
then calling unmap_mapping_page() under page lock if still mapped.

Link: https://lkml.kernel.org/r/a2a4a148-cdd8-942c-4ef8-51b77f643dbe@google.com
Fixes: fc127da085c2 ("truncate: handle file thp")
Signed-off-by: Hugh Dickins &lt;hughd@google.com&gt;
Acked-by: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Reviewed-by: Yang Shi &lt;shy828301@gmail.com&gt;
Cc: Alistair Popple &lt;apopple@nvidia.com&gt;
Cc: Jan Kara &lt;jack@suse.cz&gt;
Cc: Jue Wang &lt;juew@google.com&gt;
Cc: "Matthew Wilcox (Oracle)" &lt;willy@infradead.org&gt;
Cc: Miaohe Lin &lt;linmiaohe@huawei.com&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Naoya Horiguchi &lt;naoya.horiguchi@nec.com&gt;
Cc: Oscar Salvador &lt;osalvador@suse.de&gt;
Cc: Peter Xu &lt;peterx@redhat.com&gt;
Cc: Ralph Campbell &lt;rcampbell@nvidia.com&gt;
Cc: Shakeel Butt &lt;shakeelb@google.com&gt;
Cc: Wang Yugui &lt;wangyugui@e16-tech.com&gt;
Cc: Zi Yan &lt;ziy@nvidia.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
There is a race between THP unmapping and truncation, when truncate sees
pmd_none() and skips the entry, after munmap's zap_huge_pmd() cleared
it, but before its page_remove_rmap() gets to decrement
compound_mapcount: generating false "BUG: Bad page cache" reports that
the page is still mapped when deleted.  This commit fixes that, but not
in the way I hoped.

The first attempt used try_to_unmap(page, TTU_SYNC|TTU_IGNORE_MLOCK)
instead of unmap_mapping_range() in truncate_cleanup_page(): it has
often been an annoyance that we usually call unmap_mapping_range() with
no pages locked, but there apply it to a single locked page.
try_to_unmap() looks more suitable for a single locked page.

However, try_to_unmap_one() contains a VM_BUG_ON_PAGE(!pvmw.pte,page):
it is used to insert THP migration entries, but not used to unmap THPs.
Copy zap_huge_pmd() and add THP handling now? Perhaps, but their TLB
needs are different, I'm too ignorant of the DAX cases, and couldn't
decide how far to go for anon+swap.  Set that aside.

The second attempt took a different tack: make no change in truncate.c,
but modify zap_huge_pmd() to insert an invalidated huge pmd instead of
clearing it initially, then pmd_clear() between page_remove_rmap() and
unlocking at the end.  Nice.  But powerpc blows that approach out of the
water, with its serialize_against_pte_lookup(), and interesting pgtable
usage.  It would need serious help to get working on powerpc (with a
minor optimization issue on s390 too).  Set that aside.

Just add an "if (page_mapped(page)) synchronize_rcu();" or other such
delay, after unmapping in truncate_cleanup_page()? Perhaps, but though
that's likely to reduce or eliminate the number of incidents, it would
give less assurance of whether we had identified the problem correctly.

This successful iteration introduces "unmap_mapping_page(page)" instead
of try_to_unmap(), and goes the usual unmap_mapping_range_tree() route,
with an addition to details.  Then zap_pmd_range() watches for this
case, and does spin_unlock(pmd_lock) if so - just like
page_vma_mapped_walk() now does in the PVMW_SYNC case.  Not pretty, but
safe.

Note that unmap_mapping_page() is doing a VM_BUG_ON(!PageLocked) to
assert its interface; but currently that's only used to make sure that
page-&gt;mapping is stable, and zap_pmd_range() doesn't care if the page is
locked or not.  Along these lines, in invalidate_inode_pages2_range()
move the initial unmap_mapping_range() out from under page lock, before
then calling unmap_mapping_page() under page lock if still mapped.

Link: https://lkml.kernel.org/r/a2a4a148-cdd8-942c-4ef8-51b77f643dbe@google.com
Fixes: fc127da085c2 ("truncate: handle file thp")
Signed-off-by: Hugh Dickins &lt;hughd@google.com&gt;
Acked-by: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Reviewed-by: Yang Shi &lt;shy828301@gmail.com&gt;
Cc: Alistair Popple &lt;apopple@nvidia.com&gt;
Cc: Jan Kara &lt;jack@suse.cz&gt;
Cc: Jue Wang &lt;juew@google.com&gt;
Cc: "Matthew Wilcox (Oracle)" &lt;willy@infradead.org&gt;
Cc: Miaohe Lin &lt;linmiaohe@huawei.com&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Naoya Horiguchi &lt;naoya.horiguchi@nec.com&gt;
Cc: Oscar Salvador &lt;osalvador@suse.de&gt;
Cc: Peter Xu &lt;peterx@redhat.com&gt;
Cc: Ralph Campbell &lt;rcampbell@nvidia.com&gt;
Cc: Shakeel Butt &lt;shakeelb@google.com&gt;
Cc: Wang Yugui &lt;wangyugui@e16-tech.com&gt;
Cc: Zi Yan &lt;ziy@nvidia.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm/thp: try_to_unmap() use TTU_SYNC for safe splitting</title>
<updated>2021-06-16T16:24:42+00:00</updated>
<author>
<name>Hugh Dickins</name>
<email>hughd@google.com</email>
</author>
<published>2021-06-16T01:23:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=732ed55823fc3ad998d43b86bf771887bcc5ec67'/>
<id>732ed55823fc3ad998d43b86bf771887bcc5ec67</id>
<content type='text'>
Stressing huge tmpfs often crashed on unmap_page()'s VM_BUG_ON_PAGE
(!unmap_success): with dump_page() showing mapcount:1, but then its raw
struct page output showing _mapcount ffffffff i.e.  mapcount 0.

And even if that particular VM_BUG_ON_PAGE(!unmap_success) is removed,
it is immediately followed by a VM_BUG_ON_PAGE(compound_mapcount(head)),
and further down an IS_ENABLED(CONFIG_DEBUG_VM) total_mapcount BUG():
all indicative of some mapcount difficulty in development here perhaps.
But the !CONFIG_DEBUG_VM path handles the failures correctly and
silently.

I believe the problem is that once a racing unmap has cleared pte or
pmd, try_to_unmap_one() may skip taking the page table lock, and emerge
from try_to_unmap() before the racing task has reached decrementing
mapcount.

Instead of abandoning the unsafe VM_BUG_ON_PAGE(), and the ones that
follow, use PVMW_SYNC in try_to_unmap_one() in this case: adding
TTU_SYNC to the options, and passing that from unmap_page().

When CONFIG_DEBUG_VM, or for non-debug too? Consensus is to do the same
for both: the slight overhead added should rarely matter, except perhaps
if splitting sparsely-populated multiply-mapped shmem.  Once confident
that bugs are fixed, TTU_SYNC here can be removed, and the race
tolerated.

Link: https://lkml.kernel.org/r/c1e95853-8bcd-d8fd-55fa-e7f2488e78f@google.com
Fixes: fec89c109f3a ("thp: rewrite freeze_page()/unfreeze_page() with generic rmap walkers")
Signed-off-by: Hugh Dickins &lt;hughd@google.com&gt;
Cc: Alistair Popple &lt;apopple@nvidia.com&gt;
Cc: Jan Kara &lt;jack@suse.cz&gt;
Cc: Jue Wang &lt;juew@google.com&gt;
Cc: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Cc: "Matthew Wilcox (Oracle)" &lt;willy@infradead.org&gt;
Cc: Miaohe Lin &lt;linmiaohe@huawei.com&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Naoya Horiguchi &lt;naoya.horiguchi@nec.com&gt;
Cc: Oscar Salvador &lt;osalvador@suse.de&gt;
Cc: Peter Xu &lt;peterx@redhat.com&gt;
Cc: Ralph Campbell &lt;rcampbell@nvidia.com&gt;
Cc: Shakeel Butt &lt;shakeelb@google.com&gt;
Cc: Wang Yugui &lt;wangyugui@e16-tech.com&gt;
Cc: Yang Shi &lt;shy828301@gmail.com&gt;
Cc: Zi Yan &lt;ziy@nvidia.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Stressing huge tmpfs often crashed on unmap_page()'s VM_BUG_ON_PAGE
(!unmap_success): with dump_page() showing mapcount:1, but then its raw
struct page output showing _mapcount ffffffff i.e.  mapcount 0.

And even if that particular VM_BUG_ON_PAGE(!unmap_success) is removed,
it is immediately followed by a VM_BUG_ON_PAGE(compound_mapcount(head)),
and further down an IS_ENABLED(CONFIG_DEBUG_VM) total_mapcount BUG():
all indicative of some mapcount difficulty in development here perhaps.
But the !CONFIG_DEBUG_VM path handles the failures correctly and
silently.

I believe the problem is that once a racing unmap has cleared pte or
pmd, try_to_unmap_one() may skip taking the page table lock, and emerge
from try_to_unmap() before the racing task has reached decrementing
mapcount.

Instead of abandoning the unsafe VM_BUG_ON_PAGE(), and the ones that
follow, use PVMW_SYNC in try_to_unmap_one() in this case: adding
TTU_SYNC to the options, and passing that from unmap_page().

When CONFIG_DEBUG_VM, or for non-debug too? Consensus is to do the same
for both: the slight overhead added should rarely matter, except perhaps
if splitting sparsely-populated multiply-mapped shmem.  Once confident
that bugs are fixed, TTU_SYNC here can be removed, and the race
tolerated.

Link: https://lkml.kernel.org/r/c1e95853-8bcd-d8fd-55fa-e7f2488e78f@google.com
Fixes: fec89c109f3a ("thp: rewrite freeze_page()/unfreeze_page() with generic rmap walkers")
Signed-off-by: Hugh Dickins &lt;hughd@google.com&gt;
Cc: Alistair Popple &lt;apopple@nvidia.com&gt;
Cc: Jan Kara &lt;jack@suse.cz&gt;
Cc: Jue Wang &lt;juew@google.com&gt;
Cc: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Cc: "Matthew Wilcox (Oracle)" &lt;willy@infradead.org&gt;
Cc: Miaohe Lin &lt;linmiaohe@huawei.com&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Naoya Horiguchi &lt;naoya.horiguchi@nec.com&gt;
Cc: Oscar Salvador &lt;osalvador@suse.de&gt;
Cc: Peter Xu &lt;peterx@redhat.com&gt;
Cc: Ralph Campbell &lt;rcampbell@nvidia.com&gt;
Cc: Shakeel Butt &lt;shakeelb@google.com&gt;
Cc: Wang Yugui &lt;wangyugui@e16-tech.com&gt;
Cc: Yang Shi &lt;shy828301@gmail.com&gt;
Cc: Zi Yan &lt;ziy@nvidia.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm/thp: make is_huge_zero_pmd() safe and quicker</title>
<updated>2021-06-16T16:24:42+00:00</updated>
<author>
<name>Hugh Dickins</name>
<email>hughd@google.com</email>
</author>
<published>2021-06-16T01:23:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=3b77e8c8cde581dadab9a0f1543a347e24315f11'/>
<id>3b77e8c8cde581dadab9a0f1543a347e24315f11</id>
<content type='text'>
Most callers of is_huge_zero_pmd() supply a pmd already verified
present; but a few (notably zap_huge_pmd()) do not - it might be a pmd
migration entry, in which the pfn is encoded differently from a present
pmd: which might pass the is_huge_zero_pmd() test (though not on x86,
since L1TF forced us to protect against that); or perhaps even crash in
pmd_page() applied to a swap-like entry.

Make it safe by adding pmd_present() check into is_huge_zero_pmd()
itself; and make it quicker by saving huge_zero_pfn, so that
is_huge_zero_pmd() will not need to do that pmd_page() lookup each time.

__split_huge_pmd_locked() checked pmd_trans_huge() before: that worked,
but is unnecessary now that is_huge_zero_pmd() checks present.

Link: https://lkml.kernel.org/r/21ea9ca-a1f5-8b90-5e88-95fb1c49bbfa@google.com
Fixes: e71769ae5260 ("mm: enable thp migration for shmem thp")
Signed-off-by: Hugh Dickins &lt;hughd@google.com&gt;
Acked-by: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Reviewed-by: Yang Shi &lt;shy828301@gmail.com&gt;
Cc: Alistair Popple &lt;apopple@nvidia.com&gt;
Cc: Jan Kara &lt;jack@suse.cz&gt;
Cc: Jue Wang &lt;juew@google.com&gt;
Cc: "Matthew Wilcox (Oracle)" &lt;willy@infradead.org&gt;
Cc: Miaohe Lin &lt;linmiaohe@huawei.com&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Naoya Horiguchi &lt;naoya.horiguchi@nec.com&gt;
Cc: Oscar Salvador &lt;osalvador@suse.de&gt;
Cc: Peter Xu &lt;peterx@redhat.com&gt;
Cc: Ralph Campbell &lt;rcampbell@nvidia.com&gt;
Cc: Shakeel Butt &lt;shakeelb@google.com&gt;
Cc: Wang Yugui &lt;wangyugui@e16-tech.com&gt;
Cc: Zi Yan &lt;ziy@nvidia.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Most callers of is_huge_zero_pmd() supply a pmd already verified
present; but a few (notably zap_huge_pmd()) do not - it might be a pmd
migration entry, in which the pfn is encoded differently from a present
pmd: which might pass the is_huge_zero_pmd() test (though not on x86,
since L1TF forced us to protect against that); or perhaps even crash in
pmd_page() applied to a swap-like entry.

Make it safe by adding pmd_present() check into is_huge_zero_pmd()
itself; and make it quicker by saving huge_zero_pfn, so that
is_huge_zero_pmd() will not need to do that pmd_page() lookup each time.

__split_huge_pmd_locked() checked pmd_trans_huge() before: that worked,
but is unnecessary now that is_huge_zero_pmd() checks present.

Link: https://lkml.kernel.org/r/21ea9ca-a1f5-8b90-5e88-95fb1c49bbfa@google.com
Fixes: e71769ae5260 ("mm: enable thp migration for shmem thp")
Signed-off-by: Hugh Dickins &lt;hughd@google.com&gt;
Acked-by: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Reviewed-by: Yang Shi &lt;shy828301@gmail.com&gt;
Cc: Alistair Popple &lt;apopple@nvidia.com&gt;
Cc: Jan Kara &lt;jack@suse.cz&gt;
Cc: Jue Wang &lt;juew@google.com&gt;
Cc: "Matthew Wilcox (Oracle)" &lt;willy@infradead.org&gt;
Cc: Miaohe Lin &lt;linmiaohe@huawei.com&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Naoya Horiguchi &lt;naoya.horiguchi@nec.com&gt;
Cc: Oscar Salvador &lt;osalvador@suse.de&gt;
Cc: Peter Xu &lt;peterx@redhat.com&gt;
Cc: Ralph Campbell &lt;rcampbell@nvidia.com&gt;
Cc: Shakeel Butt &lt;shakeelb@google.com&gt;
Cc: Wang Yugui &lt;wangyugui@e16-tech.com&gt;
Cc: Zi Yan &lt;ziy@nvidia.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm/hugetlb: expand restore_reserve_on_error functionality</title>
<updated>2021-06-16T16:24:42+00:00</updated>
<author>
<name>Mike Kravetz</name>
<email>mike.kravetz@oracle.com</email>
</author>
<published>2021-06-16T01:23:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=846be08578edb81f02bc8534577e6c367ef34f41'/>
<id>846be08578edb81f02bc8534577e6c367ef34f41</id>
<content type='text'>
The routine restore_reserve_on_error is called to restore reservation
information when an error occurs after page allocation.  The routine
alloc_huge_page modifies the mapping reserve map and potentially the
reserve count during allocation.  If code calling alloc_huge_page
encounters an error after allocation and needs to free the page, the
reservation information needs to be adjusted.

Currently, restore_reserve_on_error only takes action on pages for which
the reserve count was adjusted(HPageRestoreReserve flag).  There is
nothing wrong with these adjustments.  However, alloc_huge_page ALWAYS
modifies the reserve map during allocation even if the reserve count is
not adjusted.  This can cause issues as observed during development of
this patch [1].

One specific series of operations causing an issue is:

 - Create a shared hugetlb mapping
   Reservations for all pages created by default

 - Fault in a page in the mapping
   Reservation exists so reservation count is decremented

 - Punch a hole in the file/mapping at index previously faulted
   Reservation and any associated pages will be removed

 - Allocate a page to fill the hole
   No reservation entry, so reserve count unmodified
   Reservation entry added to map by alloc_huge_page

 - Error after allocation and before instantiating the page
   Reservation entry remains in map

 - Allocate a page to fill the hole
   Reservation entry exists, so decrement reservation count

This will cause a reservation count underflow as the reservation count
was decremented twice for the same index.

A user would observe a very large number for HugePages_Rsvd in
/proc/meminfo.  This would also likely cause subsequent allocations of
hugetlb pages to fail as it would 'appear' that all pages are reserved.

This sequence of operations is unlikely to happen, however they were
easily reproduced and observed using hacked up code as described in [1].

Address the issue by having the routine restore_reserve_on_error take
action on pages where HPageRestoreReserve is not set.  In this case, we
need to remove any reserve map entry created by alloc_huge_page.  A new
helper routine vma_del_reservation assists with this operation.

There are three callers of alloc_huge_page which do not currently call
restore_reserve_on error before freeing a page on error paths.  Add
those missing calls.

[1] https://lore.kernel.org/linux-mm/20210528005029.88088-1-almasrymina@google.com/

Link: https://lkml.kernel.org/r/20210607204510.22617-1-mike.kravetz@oracle.com
Fixes: 96b96a96ddee ("mm/hugetlb: fix huge page reservation leak in private mapping error paths"
Signed-off-by: Mike Kravetz &lt;mike.kravetz@oracle.com&gt;
Reviewed-by: Mina Almasry &lt;almasrymina@google.com&gt;
Cc: Axel Rasmussen &lt;axelrasmussen@google.com&gt;
Cc: Peter Xu &lt;peterx@redhat.com&gt;
Cc: Muchun Song &lt;songmuchun@bytedance.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Naoya Horiguchi &lt;naoya.horiguchi@nec.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The routine restore_reserve_on_error is called to restore reservation
information when an error occurs after page allocation.  The routine
alloc_huge_page modifies the mapping reserve map and potentially the
reserve count during allocation.  If code calling alloc_huge_page
encounters an error after allocation and needs to free the page, the
reservation information needs to be adjusted.

Currently, restore_reserve_on_error only takes action on pages for which
the reserve count was adjusted(HPageRestoreReserve flag).  There is
nothing wrong with these adjustments.  However, alloc_huge_page ALWAYS
modifies the reserve map during allocation even if the reserve count is
not adjusted.  This can cause issues as observed during development of
this patch [1].

One specific series of operations causing an issue is:

 - Create a shared hugetlb mapping
   Reservations for all pages created by default

 - Fault in a page in the mapping
   Reservation exists so reservation count is decremented

 - Punch a hole in the file/mapping at index previously faulted
   Reservation and any associated pages will be removed

 - Allocate a page to fill the hole
   No reservation entry, so reserve count unmodified
   Reservation entry added to map by alloc_huge_page

 - Error after allocation and before instantiating the page
   Reservation entry remains in map

 - Allocate a page to fill the hole
   Reservation entry exists, so decrement reservation count

This will cause a reservation count underflow as the reservation count
was decremented twice for the same index.

A user would observe a very large number for HugePages_Rsvd in
/proc/meminfo.  This would also likely cause subsequent allocations of
hugetlb pages to fail as it would 'appear' that all pages are reserved.

This sequence of operations is unlikely to happen, however they were
easily reproduced and observed using hacked up code as described in [1].

Address the issue by having the routine restore_reserve_on_error take
action on pages where HPageRestoreReserve is not set.  In this case, we
need to remove any reserve map entry created by alloc_huge_page.  A new
helper routine vma_del_reservation assists with this operation.

There are three callers of alloc_huge_page which do not currently call
restore_reserve_on error before freeing a page on error paths.  Add
those missing calls.

[1] https://lore.kernel.org/linux-mm/20210528005029.88088-1-almasrymina@google.com/

Link: https://lkml.kernel.org/r/20210607204510.22617-1-mike.kravetz@oracle.com
Fixes: 96b96a96ddee ("mm/hugetlb: fix huge page reservation leak in private mapping error paths"
Signed-off-by: Mike Kravetz &lt;mike.kravetz@oracle.com&gt;
Reviewed-by: Mina Almasry &lt;almasrymina@google.com&gt;
Cc: Axel Rasmussen &lt;axelrasmussen@google.com&gt;
Cc: Peter Xu &lt;peterx@redhat.com&gt;
Cc: Muchun Song &lt;songmuchun@bytedance.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Naoya Horiguchi &lt;naoya.horiguchi@nec.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm/swap: fix pte_same_as_swp() not removing uffd-wp bit when compare</title>
<updated>2021-06-16T16:24:42+00:00</updated>
<author>
<name>Peter Xu</name>
<email>peterx@redhat.com</email>
</author>
<published>2021-06-16T01:23:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=099dd6878b9b12d6bbfa6bf29ce0c8ddd38f6901'/>
<id>099dd6878b9b12d6bbfa6bf29ce0c8ddd38f6901</id>
<content type='text'>
I found it by pure code review, that pte_same_as_swp() of unuse_vma()
didn't take uffd-wp bit into account when comparing ptes.
pte_same_as_swp() returning false negative could cause failure to
swapoff swap ptes that was wr-protected by userfaultfd.

Link: https://lkml.kernel.org/r/20210603180546.9083-1-peterx@redhat.com
Fixes: f45ec5ff16a7 ("userfaultfd: wp: support swap and page migration")
Signed-off-by: Peter Xu &lt;peterx@redhat.com&gt;
Acked-by: Hugh Dickins &lt;hughd@google.com&gt;
Cc: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;	[5.7+]
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
I found it by pure code review, that pte_same_as_swp() of unuse_vma()
didn't take uffd-wp bit into account when comparing ptes.
pte_same_as_swp() returning false negative could cause failure to
swapoff swap ptes that was wr-protected by userfaultfd.

Link: https://lkml.kernel.org/r/20210603180546.9083-1-peterx@redhat.com
Fixes: f45ec5ff16a7 ("userfaultfd: wp: support swap and page migration")
Signed-off-by: Peter Xu &lt;peterx@redhat.com&gt;
Acked-by: Hugh Dickins &lt;hughd@google.com&gt;
Cc: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;	[5.7+]
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm,hwpoison: fix race with hugetlb page allocation</title>
<updated>2021-06-16T16:24:42+00:00</updated>
<author>
<name>Naoya Horiguchi</name>
<email>naoya.horiguchi@nec.com</email>
</author>
<published>2021-06-16T01:23:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=25182f05ffed0b45602438693e4eed5d7f3ebadd'/>
<id>25182f05ffed0b45602438693e4eed5d7f3ebadd</id>
<content type='text'>
When hugetlb page fault (under overcommitting situation) and
memory_failure() race, VM_BUG_ON_PAGE() is triggered by the following
race:

    CPU0:                           CPU1:

                                    gather_surplus_pages()
                                      page = alloc_surplus_huge_page()
    memory_failure_hugetlb()
      get_hwpoison_page(page)
        __get_hwpoison_page(page)
          get_page_unless_zero(page)
                                      zero = put_page_testzero(page)
                                      VM_BUG_ON_PAGE(!zero, page)
                                      enqueue_huge_page(h, page)
      put_page(page)

__get_hwpoison_page() only checks the page refcount before taking an
additional one for memory error handling, which is not enough because
there's a time window where compound pages have non-zero refcount during
hugetlb page initialization.

So make __get_hwpoison_page() check page status a bit more for hugetlb
pages with get_hwpoison_huge_page().  Checking hugetlb-specific flags
under hugetlb_lock makes sure that the hugetlb page is not transitive.
It's notable that another new function, HWPoisonHandlable(), is helpful
to prevent a race against other transitive page states (like a generic
compound page just before PageHuge becomes true).

Link: https://lkml.kernel.org/r/20210603233632.2964832-2-nao.horiguchi@gmail.com
Fixes: ead07f6a867b ("mm/memory-failure: introduce get_hwpoison_page() for consistent refcount handling")
Signed-off-by: Naoya Horiguchi &lt;naoya.horiguchi@nec.com&gt;
Reported-by: Muchun Song &lt;songmuchun@bytedance.com&gt;
Acked-by: Mike Kravetz &lt;mike.kravetz@oracle.com&gt;
Cc: Oscar Salvador &lt;osalvador@suse.de&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;	[5.12+]
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When hugetlb page fault (under overcommitting situation) and
memory_failure() race, VM_BUG_ON_PAGE() is triggered by the following
race:

    CPU0:                           CPU1:

                                    gather_surplus_pages()
                                      page = alloc_surplus_huge_page()
    memory_failure_hugetlb()
      get_hwpoison_page(page)
        __get_hwpoison_page(page)
          get_page_unless_zero(page)
                                      zero = put_page_testzero(page)
                                      VM_BUG_ON_PAGE(!zero, page)
                                      enqueue_huge_page(h, page)
      put_page(page)

__get_hwpoison_page() only checks the page refcount before taking an
additional one for memory error handling, which is not enough because
there's a time window where compound pages have non-zero refcount during
hugetlb page initialization.

So make __get_hwpoison_page() check page status a bit more for hugetlb
pages with get_hwpoison_huge_page().  Checking hugetlb-specific flags
under hugetlb_lock makes sure that the hugetlb page is not transitive.
It's notable that another new function, HWPoisonHandlable(), is helpful
to prevent a race against other transitive page states (like a generic
compound page just before PageHuge becomes true).

Link: https://lkml.kernel.org/r/20210603233632.2964832-2-nao.horiguchi@gmail.com
Fixes: ead07f6a867b ("mm/memory-failure: introduce get_hwpoison_page() for consistent refcount handling")
Signed-off-by: Naoya Horiguchi &lt;naoya.horiguchi@nec.com&gt;
Reported-by: Muchun Song &lt;songmuchun@bytedance.com&gt;
Acked-by: Mike Kravetz &lt;mike.kravetz@oracle.com&gt;
Cc: Oscar Salvador &lt;osalvador@suse.de&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;	[5.12+]
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ptp: improve max_adj check against unreasonable values</title>
<updated>2021-06-15T17:59:46+00:00</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2021-06-14T22:24:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=475b92f932168a78da8109acd10bfb7578b8f2bb'/>
<id>475b92f932168a78da8109acd10bfb7578b8f2bb</id>
<content type='text'>
Scaled PPM conversion to PPB may (on 64bit systems) result
in a value larger than s32 can hold (freq/scaled_ppm is a long).
This means the kernel will not correctly reject unreasonably
high -&gt;freq values (e.g. &gt; 4294967295ppb, 281474976645 scaled PPM).

The conversion is equivalent to a division by ~66 (65.536),
so the value of ppb is always smaller than ppm, but not small
enough to assume narrowing the type from long -&gt; s32 is okay.

Note that reasonable user space (e.g. ptp4l) will not use such
high values, anyway, 4289046510ppb ~= 4.3x, so the fix is
somewhat pedantic.

Fixes: d39a743511cd ("ptp: validate the requested frequency adjustment.")
Fixes: d94ba80ebbea ("ptp: Added a brand new class driver for ptp clocks.")
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Acked-by: Richard Cochran &lt;richardcochran@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Scaled PPM conversion to PPB may (on 64bit systems) result
in a value larger than s32 can hold (freq/scaled_ppm is a long).
This means the kernel will not correctly reject unreasonably
high -&gt;freq values (e.g. &gt; 4294967295ppb, 281474976645 scaled PPM).

The conversion is equivalent to a division by ~66 (65.536),
so the value of ppb is always smaller than ppm, but not small
enough to assume narrowing the type from long -&gt; s32 is okay.

Note that reasonable user space (e.g. ptp4l) will not use such
high values, anyway, 4289046510ppb ~= 4.3x, so the fix is
somewhat pedantic.

Fixes: d39a743511cd ("ptp: validate the requested frequency adjustment.")
Fixes: d94ba80ebbea ("ptp: Added a brand new class driver for ptp clocks.")
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Acked-by: Richard Cochran &lt;richardcochran@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
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