<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/include, branch v6.13.7</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>mm: hugetlb: Add huge page size param to huge_ptep_get_and_clear()</title>
<updated>2025-03-13T12:08:07+00:00</updated>
<author>
<name>Ryan Roberts</name>
<email>ryan.roberts@arm.com</email>
</author>
<published>2025-02-26T12:06:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=cc0f59effb60406e3c6b1b8205be98b6d5932308'/>
<id>cc0f59effb60406e3c6b1b8205be98b6d5932308</id>
<content type='text'>
commit 02410ac72ac3707936c07ede66e94360d0d65319 upstream.

In order to fix a bug, arm64 needs to be told the size of the huge page
for which the huge_pte is being cleared in huge_ptep_get_and_clear().
Provide for this by adding an `unsigned long sz` parameter to the
function. This follows the same pattern as huge_pte_clear() and
set_huge_pte_at().

This commit makes the required interface modifications to the core mm as
well as all arches that implement this function (arm64, loongarch, mips,
parisc, powerpc, riscv, s390, sparc). The actual arm64 bug will be fixed
in a separate commit.

Cc: stable@vger.kernel.org
Fixes: 66b3923a1a0f ("arm64: hugetlb: add support for PTE contiguous bit")
Acked-by: David Hildenbrand &lt;david@redhat.com&gt;
Reviewed-by: Alexandre Ghiti &lt;alexghiti@rivosinc.com&gt; # riscv
Reviewed-by: Christophe Leroy &lt;christophe.leroy@csgroup.eu&gt;
Reviewed-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Reviewed-by: Anshuman Khandual &lt;anshuman.khandual@arm.com&gt;
Signed-off-by: Ryan Roberts &lt;ryan.roberts@arm.com&gt;
Acked-by: Alexander Gordeev &lt;agordeev@linux.ibm.com&gt; # s390
Link: https://lore.kernel.org/r/20250226120656.2400136-2-ryan.roberts@arm.com
Signed-off-by: Will Deacon &lt;will@kernel.org&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 02410ac72ac3707936c07ede66e94360d0d65319 upstream.

In order to fix a bug, arm64 needs to be told the size of the huge page
for which the huge_pte is being cleared in huge_ptep_get_and_clear().
Provide for this by adding an `unsigned long sz` parameter to the
function. This follows the same pattern as huge_pte_clear() and
set_huge_pte_at().

This commit makes the required interface modifications to the core mm as
well as all arches that implement this function (arm64, loongarch, mips,
parisc, powerpc, riscv, s390, sparc). The actual arm64 bug will be fixed
in a separate commit.

Cc: stable@vger.kernel.org
Fixes: 66b3923a1a0f ("arm64: hugetlb: add support for PTE contiguous bit")
Acked-by: David Hildenbrand &lt;david@redhat.com&gt;
Reviewed-by: Alexandre Ghiti &lt;alexghiti@rivosinc.com&gt; # riscv
Reviewed-by: Christophe Leroy &lt;christophe.leroy@csgroup.eu&gt;
Reviewed-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Reviewed-by: Anshuman Khandual &lt;anshuman.khandual@arm.com&gt;
Signed-off-by: Ryan Roberts &lt;ryan.roberts@arm.com&gt;
Acked-by: Alexander Gordeev &lt;agordeev@linux.ibm.com&gt; # s390
Link: https://lore.kernel.org/r/20250226120656.2400136-2-ryan.roberts@arm.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: ethtool: plumb PHY stats to PHY drivers</title>
<updated>2025-03-13T12:07:57+00:00</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2025-01-10T06:05:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=824821651de4f25fe418d99ae0a09d5f7274d7ae'/>
<id>824821651de4f25fe418d99ae0a09d5f7274d7ae</id>
<content type='text'>
[ Upstream commit b7a2c1fe6b55364e61b4b54b991eb43a47bb1104 ]

Introduce support for standardized PHY statistics reporting in ethtool
by extending the PHYLIB framework. Add the functions
phy_ethtool_get_phy_stats() and phy_ethtool_get_link_ext_stats() to
provide a consistent interface for retrieving PHY-level and
link-specific statistics. These functions are used within the ethtool
implementation to avoid direct access to the phy_device structure
outside of the PHYLIB framework.

A new structure, ethtool_phy_stats, is introduced to standardize PHY
statistics such as packet counts, byte counts, and error counters.
Drivers are updated to include callbacks for retrieving PHY and
link-specific statistics, ensuring values are explicitly set only for
supported fields, initialized with ETHTOOL_STAT_NOT_SET to avoid
ambiguity.

Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Oleksij Rempel &lt;o.rempel@pengutronix.de&gt;
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Stable-dep-of: 637399bf7e77 ("net: ethtool: netlink: Allow NULL nlattrs when getting a phy_device")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit b7a2c1fe6b55364e61b4b54b991eb43a47bb1104 ]

Introduce support for standardized PHY statistics reporting in ethtool
by extending the PHYLIB framework. Add the functions
phy_ethtool_get_phy_stats() and phy_ethtool_get_link_ext_stats() to
provide a consistent interface for retrieving PHY-level and
link-specific statistics. These functions are used within the ethtool
implementation to avoid direct access to the phy_device structure
outside of the PHYLIB framework.

A new structure, ethtool_phy_stats, is introduced to standardize PHY
statistics such as packet counts, byte counts, and error counters.
Drivers are updated to include callbacks for retrieving PHY and
link-specific statistics, ensuring values are explicitly set only for
supported fields, initialized with ETHTOOL_STAT_NOT_SET to avoid
ambiguity.

Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Oleksij Rempel &lt;o.rempel@pengutronix.de&gt;
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Stable-dep-of: 637399bf7e77 ("net: ethtool: netlink: Allow NULL nlattrs when getting a phy_device")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cred: Fix RCU warnings in override/revert_creds</title>
<updated>2025-03-13T12:07:54+00:00</updated>
<author>
<name>Herbert Xu</name>
<email>herbert@gondor.apana.org.au</email>
</author>
<published>2025-03-02T07:18:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=37450849f581a4f1c7582c62c1221bc720133513'/>
<id>37450849f581a4f1c7582c62c1221bc720133513</id>
<content type='text'>
[ Upstream commit e04918dc594669068f5d59d567d08db531167188 ]

Fix RCU warnings in override_creds and revert_creds by turning
the RCU pointer into a normal pointer using rcu_replace_pointer.

These warnings were previously private to the cred code, but due
to the move into the header file they are now polluting unrelated
subsystems.

Fixes: 49dffdfde462 ("cred: Add a light version of override/revert_creds()")
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Link: https://lore.kernel.org/r/Z8QGQGW0IaSklKG7@gondor.apana.org.au
Signed-off-by: Christian Brauner &lt;brauner@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit e04918dc594669068f5d59d567d08db531167188 ]

Fix RCU warnings in override_creds and revert_creds by turning
the RCU pointer into a normal pointer using rcu_replace_pointer.

These warnings were previously private to the cred code, but due
to the move into the header file they are now polluting unrelated
subsystems.

Fixes: 49dffdfde462 ("cred: Add a light version of override/revert_creds()")
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Link: https://lore.kernel.org/r/Z8QGQGW0IaSklKG7@gondor.apana.org.au
Signed-off-by: Christian Brauner &lt;brauner@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cred: return old creds from revert_creds_light()</title>
<updated>2025-03-13T12:07:54+00:00</updated>
<author>
<name>Christian Brauner</name>
<email>brauner@kernel.org</email>
</author>
<published>2024-11-25T14:09:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c14dfae47de788aafb74da1d836d427f00593e5a'/>
<id>c14dfae47de788aafb74da1d836d427f00593e5a</id>
<content type='text'>
[ Upstream commit 95c54bc81791c210b131f2b1013942487e74896f ]

So we can easily convert revert_creds() callers over to drop the
reference count explicitly.

Link: https://lore.kernel.org/r/20241125-work-cred-v2-2-68b9d38bb5b2@kernel.org
Reviewed-by: Jeff Layton &lt;jlayton@kernel.org&gt;
Reviewed-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Christian Brauner &lt;brauner@kernel.org&gt;
Stable-dep-of: e04918dc5946 ("cred: Fix RCU warnings in override/revert_creds")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 95c54bc81791c210b131f2b1013942487e74896f ]

So we can easily convert revert_creds() callers over to drop the
reference count explicitly.

Link: https://lore.kernel.org/r/20241125-work-cred-v2-2-68b9d38bb5b2@kernel.org
Reviewed-by: Jeff Layton &lt;jlayton@kernel.org&gt;
Reviewed-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Christian Brauner &lt;brauner@kernel.org&gt;
Stable-dep-of: e04918dc5946 ("cred: Fix RCU warnings in override/revert_creds")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>nvme-tcp: add basic support for the C2HTermReq PDU</title>
<updated>2025-03-13T12:07:53+00:00</updated>
<author>
<name>Maurizio Lombardi</name>
<email>mlombard@redhat.com</email>
</author>
<published>2025-02-17T16:08:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=442a3614ace4a03955ba6e20d2a9f316445ed69d'/>
<id>442a3614ace4a03955ba6e20d2a9f316445ed69d</id>
<content type='text'>
[ Upstream commit 84e009042d0f3dfe91bec60bcd208ee3f866cbcd ]

Previously, the NVMe/TCP host driver did not handle the C2HTermReq PDU,
instead printing "unsupported pdu type (3)" when received. This patch adds
support for processing the C2HTermReq PDU, allowing the driver
to print the Fatal Error Status field.

Example of output:
nvme nvme4: Received C2HTermReq (FES = Invalid PDU Header Field)

Signed-off-by: Maurizio Lombardi &lt;mlombard@redhat.com&gt;
Reviewed-by: Sagi Grimberg &lt;sagi@grimberg.me&gt;
Signed-off-by: Keith Busch &lt;kbusch@kernel.org&gt;
Stable-dep-of: ad95bab0cd28 ("nvme-tcp: fix potential memory corruption in nvme_tcp_recv_pdu()")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 84e009042d0f3dfe91bec60bcd208ee3f866cbcd ]

Previously, the NVMe/TCP host driver did not handle the C2HTermReq PDU,
instead printing "unsupported pdu type (3)" when received. This patch adds
support for processing the C2HTermReq PDU, allowing the driver
to print the Fatal Error Status field.

Example of output:
nvme nvme4: Received C2HTermReq (FES = Invalid PDU Header Field)

Signed-off-by: Maurizio Lombardi &lt;mlombard@redhat.com&gt;
Reviewed-by: Sagi Grimberg &lt;sagi@grimberg.me&gt;
Signed-off-by: Keith Busch &lt;kbusch@kernel.org&gt;
Stable-dep-of: ad95bab0cd28 ("nvme-tcp: fix potential memory corruption in nvme_tcp_recv_pdu()")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>NFS: fix nfs_release_folio() to not deadlock via kcompactd writeback</title>
<updated>2025-03-13T12:07:48+00:00</updated>
<author>
<name>Mike Snitzer</name>
<email>snitzer@kernel.org</email>
</author>
<published>2025-02-25T02:20:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=8253ff29edcb429a9a6c75710941c6a16a9a34b1'/>
<id>8253ff29edcb429a9a6c75710941c6a16a9a34b1</id>
<content type='text'>
commit ce6d9c1c2b5cc785016faa11b48b6cd317eb367e upstream.

Add PF_KCOMPACTD flag and current_is_kcompactd() helper to check for it so
nfs_release_folio() can skip calling nfs_wb_folio() from kcompactd.

Otherwise NFS can deadlock waiting for kcompactd enduced writeback which
recurses back to NFS (which triggers writeback to NFSD via NFS loopback
mount on the same host, NFSD blocks waiting for XFS's call to
__filemap_get_folio):

6070.550357] INFO: task kcompactd0:58 blocked for more than 4435 seconds.

{---
[58] "kcompactd0"
[&lt;0&gt;] folio_wait_bit+0xe8/0x200
[&lt;0&gt;] folio_wait_writeback+0x2b/0x80
[&lt;0&gt;] nfs_wb_folio+0x80/0x1b0 [nfs]
[&lt;0&gt;] nfs_release_folio+0x68/0x130 [nfs]
[&lt;0&gt;] split_huge_page_to_list_to_order+0x362/0x840
[&lt;0&gt;] migrate_pages_batch+0x43d/0xb90
[&lt;0&gt;] migrate_pages_sync+0x9a/0x240
[&lt;0&gt;] migrate_pages+0x93c/0x9f0
[&lt;0&gt;] compact_zone+0x8e2/0x1030
[&lt;0&gt;] compact_node+0xdb/0x120
[&lt;0&gt;] kcompactd+0x121/0x2e0
[&lt;0&gt;] kthread+0xcf/0x100
[&lt;0&gt;] ret_from_fork+0x31/0x40
[&lt;0&gt;] ret_from_fork_asm+0x1a/0x30
---}

[akpm@linux-foundation.org: fix build]
Link: https://lkml.kernel.org/r/20250225022002.26141-1-snitzer@kernel.org
Fixes: 96780ca55e3c ("NFS: fix up nfs_release_folio() to try to release the page")
Signed-off-by: Mike Snitzer &lt;snitzer@kernel.org&gt;
Cc: Anna Schumaker &lt;anna.schumaker@oracle.com&gt;
Cc: Trond Myklebust &lt;trond.myklebust@hammerspace.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&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 ce6d9c1c2b5cc785016faa11b48b6cd317eb367e upstream.

Add PF_KCOMPACTD flag and current_is_kcompactd() helper to check for it so
nfs_release_folio() can skip calling nfs_wb_folio() from kcompactd.

Otherwise NFS can deadlock waiting for kcompactd enduced writeback which
recurses back to NFS (which triggers writeback to NFSD via NFS loopback
mount on the same host, NFSD blocks waiting for XFS's call to
__filemap_get_folio):

6070.550357] INFO: task kcompactd0:58 blocked for more than 4435 seconds.

{---
[58] "kcompactd0"
[&lt;0&gt;] folio_wait_bit+0xe8/0x200
[&lt;0&gt;] folio_wait_writeback+0x2b/0x80
[&lt;0&gt;] nfs_wb_folio+0x80/0x1b0 [nfs]
[&lt;0&gt;] nfs_release_folio+0x68/0x130 [nfs]
[&lt;0&gt;] split_huge_page_to_list_to_order+0x362/0x840
[&lt;0&gt;] migrate_pages_batch+0x43d/0xb90
[&lt;0&gt;] migrate_pages_sync+0x9a/0x240
[&lt;0&gt;] migrate_pages+0x93c/0x9f0
[&lt;0&gt;] compact_zone+0x8e2/0x1030
[&lt;0&gt;] compact_node+0xdb/0x120
[&lt;0&gt;] kcompactd+0x121/0x2e0
[&lt;0&gt;] kthread+0xcf/0x100
[&lt;0&gt;] ret_from_fork+0x31/0x40
[&lt;0&gt;] ret_from_fork_asm+0x1a/0x30
---}

[akpm@linux-foundation.org: fix build]
Link: https://lkml.kernel.org/r/20250225022002.26141-1-snitzer@kernel.org
Fixes: 96780ca55e3c ("NFS: fix up nfs_release_folio() to try to release the page")
Signed-off-by: Mike Snitzer &lt;snitzer@kernel.org&gt;
Cc: Anna Schumaker &lt;anna.schumaker@oracle.com&gt;
Cc: Trond Myklebust &lt;trond.myklebust@hammerspace.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rcuref: Plug slowpath race in rcuref_put()</title>
<updated>2025-03-07T17:27:12+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2025-01-18T23:55:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d82176973caab7daee9297f68a05aa5330b74f12'/>
<id>d82176973caab7daee9297f68a05aa5330b74f12</id>
<content type='text'>
commit b9a49520679e98700d3d89689cc91c08a1c88c1d upstream.

Kernel test robot reported an "imbalanced put" in the rcuref_put() slow
path, which turned out to be a false positive. Consider the following race:

            ref  = 0 (via rcuref_init(ref, 1))
 T1                                      T2
 rcuref_put(ref)
 -&gt; atomic_add_negative_release(-1, ref)                                         # ref -&gt; 0xffffffff
 -&gt; rcuref_put_slowpath(ref)
                                         rcuref_get(ref)
                                         -&gt; atomic_add_negative_relaxed(1, &amp;ref-&gt;refcnt)
                                           -&gt; return true;                       # ref -&gt; 0

                                         rcuref_put(ref)
                                         -&gt; atomic_add_negative_release(-1, ref) # ref -&gt; 0xffffffff
                                         -&gt; rcuref_put_slowpath()

    -&gt; cnt = atomic_read(&amp;ref-&gt;refcnt);                                          # cnt -&gt; 0xffffffff / RCUREF_NOREF
    -&gt; atomic_try_cmpxchg_release(&amp;ref-&gt;refcnt, &amp;cnt, RCUREF_DEAD))              # ref -&gt; 0xe0000000 / RCUREF_DEAD
       -&gt; return true
                                           -&gt; cnt = atomic_read(&amp;ref-&gt;refcnt);   # cnt -&gt; 0xe0000000 / RCUREF_DEAD
                                           -&gt; if (cnt &gt; RCUREF_RELEASED)         # 0xe0000000 &gt; 0xc0000000
                                             -&gt; WARN_ONCE(cnt &gt;= RCUREF_RELEASED, "rcuref - imbalanced put()")

The problem is the additional read in the slow path (after it
decremented to RCUREF_NOREF) which can happen after the counter has been
marked RCUREF_DEAD.

Prevent this by reusing the return value of the decrement. Now every "final"
put uses RCUREF_NOREF in the slow path and attempts the final cmpxchg() to
RCUREF_DEAD.

[ bigeasy: Add changelog ]

Fixes: ee1ee6db07795 ("atomics: Provide rcuref - scalable reference counting")
Reported-by: kernel test robot &lt;oliver.sang@intel.com&gt;
Debugged-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Cc: stable@vger.kernel.org
Closes: https://lore.kernel.org/oe-lkp/202412311453.9d7636a2-lkp@intel.com
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 b9a49520679e98700d3d89689cc91c08a1c88c1d upstream.

Kernel test robot reported an "imbalanced put" in the rcuref_put() slow
path, which turned out to be a false positive. Consider the following race:

            ref  = 0 (via rcuref_init(ref, 1))
 T1                                      T2
 rcuref_put(ref)
 -&gt; atomic_add_negative_release(-1, ref)                                         # ref -&gt; 0xffffffff
 -&gt; rcuref_put_slowpath(ref)
                                         rcuref_get(ref)
                                         -&gt; atomic_add_negative_relaxed(1, &amp;ref-&gt;refcnt)
                                           -&gt; return true;                       # ref -&gt; 0

                                         rcuref_put(ref)
                                         -&gt; atomic_add_negative_release(-1, ref) # ref -&gt; 0xffffffff
                                         -&gt; rcuref_put_slowpath()

    -&gt; cnt = atomic_read(&amp;ref-&gt;refcnt);                                          # cnt -&gt; 0xffffffff / RCUREF_NOREF
    -&gt; atomic_try_cmpxchg_release(&amp;ref-&gt;refcnt, &amp;cnt, RCUREF_DEAD))              # ref -&gt; 0xe0000000 / RCUREF_DEAD
       -&gt; return true
                                           -&gt; cnt = atomic_read(&amp;ref-&gt;refcnt);   # cnt -&gt; 0xe0000000 / RCUREF_DEAD
                                           -&gt; if (cnt &gt; RCUREF_RELEASED)         # 0xe0000000 &gt; 0xc0000000
                                             -&gt; WARN_ONCE(cnt &gt;= RCUREF_RELEASED, "rcuref - imbalanced put()")

The problem is the additional read in the slow path (after it
decremented to RCUREF_NOREF) which can happen after the counter has been
marked RCUREF_DEAD.

Prevent this by reusing the return value of the decrement. Now every "final"
put uses RCUREF_NOREF in the slow path and attempts the final cmpxchg() to
RCUREF_DEAD.

[ bigeasy: Add changelog ]

Fixes: ee1ee6db07795 ("atomics: Provide rcuref - scalable reference counting")
Reported-by: kernel test robot &lt;oliver.sang@intel.com&gt;
Debugged-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Cc: stable@vger.kernel.org
Closes: https://lore.kernel.org/oe-lkp/202412311453.9d7636a2-lkp@intel.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>vmlinux.lds: Ensure that const vars with relocations are mapped R/O</title>
<updated>2025-03-07T17:27:12+00:00</updated>
<author>
<name>Ard Biesheuvel</name>
<email>ardb@kernel.org</email>
</author>
<published>2025-02-21T13:57:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=21e8fc67309b345d0713b118855759d3c9444ab9'/>
<id>21e8fc67309b345d0713b118855759d3c9444ab9</id>
<content type='text'>
commit 68f3ea7ee199ef77551e090dfef5a49046ea8443 upstream.

In the kernel, there are architectures (x86, arm64) that perform
boot-time relocation (for KASLR) without relying on PIE codegen. In this
case, all const global objects are emitted into .rodata, including const
objects with fields that will be fixed up by the boot-time relocation
code.  This implies that .rodata (and .text in some cases) need to be
writable at boot, but they will usually be mapped read-only as soon as
the boot completes.

When using PIE codegen, the compiler will emit const global objects into
.data.rel.ro rather than .rodata if the object contains fields that need
such fixups at boot-time. This permits the linker to annotate such
regions as requiring read-write access only at load time, but not at
execution time (in user space), while keeping .rodata truly const (in
user space, this is important for reducing the CoW footprint of dynamic
executables).

This distinction does not matter for the kernel, but it does imply that
const data will end up in writable memory if the .data.rel.ro sections
are not treated in a special way, as they will end up in the writable
.data segment by default.

So emit .data.rel.ro into the .rodata segment.

Cc: stable@vger.kernel.org
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Link: https://lore.kernel.org/r/20250221135704.431269-5-ardb+git@google.com
Signed-off-by: Josh Poimboeuf &lt;jpoimboe@kernel.org&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 68f3ea7ee199ef77551e090dfef5a49046ea8443 upstream.

In the kernel, there are architectures (x86, arm64) that perform
boot-time relocation (for KASLR) without relying on PIE codegen. In this
case, all const global objects are emitted into .rodata, including const
objects with fields that will be fixed up by the boot-time relocation
code.  This implies that .rodata (and .text in some cases) need to be
writable at boot, but they will usually be mapped read-only as soon as
the boot completes.

When using PIE codegen, the compiler will emit const global objects into
.data.rel.ro rather than .rodata if the object contains fields that need
such fixups at boot-time. This permits the linker to annotate such
regions as requiring read-write access only at load time, but not at
execution time (in user space), while keeping .rodata truly const (in
user space, this is important for reducing the CoW footprint of dynamic
executables).

This distinction does not matter for the kernel, but it does imply that
const data will end up in writable memory if the .data.rel.ro sections
are not treated in a special way, as they will end up in the writable
.data segment by default.

So emit .data.rel.ro into the .rodata segment.

Cc: stable@vger.kernel.org
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Link: https://lore.kernel.org/r/20250221135704.431269-5-ardb+git@google.com
Signed-off-by: Josh Poimboeuf &lt;jpoimboe@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>block: Remove zone write plugs when handling native zone append writes</title>
<updated>2025-03-07T17:27:07+00:00</updated>
<author>
<name>Damien Le Moal</name>
<email>dlemoal@kernel.org</email>
</author>
<published>2025-02-14T04:14:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=abc63d1944a63983c2459c0eba6033f55566f7da'/>
<id>abc63d1944a63983c2459c0eba6033f55566f7da</id>
<content type='text'>
commit a6aa36e957a1bfb5341986dec32d013d23228fe1 upstream.

For devices that natively support zone append operations,
REQ_OP_ZONE_APPEND BIOs are not processed through zone write plugging
and are immediately issued to the zoned device. This means that there is
no write pointer offset tracking done for these operations and that a
zone write plug is not necessary.

However, when receiving a zone append BIO, we may already have a zone
write plug for the target zone if that zone was previously partially
written using regular write operations. In such case, since the write
pointer offset of the zone write plug is not incremented by the amount
of sectors appended to the zone, 2 issues arise:
1) we risk leaving the plug in the disk hash table if the zone is fully
   written using zone append or regular write operations, because the
   write pointer offset will never reach the "zone full" state.
2) Regular write operations that are issued after zone append operations
   will always be failed by blk_zone_wplug_prepare_bio() as the write
   pointer alignment check will fail, even if the user correctly
   accounted for the zone append operations and issued the regular
   writes with a correct sector.

Avoid these issues by immediately removing the zone write plug of zones
that are the target of zone append operations when blk_zone_plug_bio()
is called. The new function blk_zone_wplug_handle_native_zone_append()
implements this for devices that natively support zone append. The
removal of the zone write plug using disk_remove_zone_wplug() requires
aborting all plugged regular write using disk_zone_wplug_abort() as
otherwise the plugged write BIOs would never be executed (with the plug
removed, the completion path will never see again the zone write plug as
disk_get_zone_wplug() will return NULL). Rate-limited warnings are added
to blk_zone_wplug_handle_native_zone_append() and to
disk_zone_wplug_abort() to signal this.

Since blk_zone_wplug_handle_native_zone_append() is called in the hot
path for operations that will not be plugged, disk_get_zone_wplug() is
optimized under the assumption that a user issuing zone append
operations is not at the same time issuing regular writes and that there
are no hashed zone write plugs. The struct gendisk atomic counter
nr_zone_wplugs is added to check this, with this counter incremented in
disk_insert_zone_wplug() and decremented in disk_remove_zone_wplug().

To be consistent with this fix, we do not need to fill the zone write
plug hash table with zone write plugs for zones that are partially
written for a device that supports native zone append operations.
So modify blk_revalidate_seq_zone() to return early to avoid allocating
and inserting a zone write plug for partially written sequential zones
if the device natively supports zone append.

Reported-by: Jorgen Hansen &lt;Jorgen.Hansen@wdc.com&gt;
Fixes: 9b1ce7f0c6f8 ("block: Implement zone append emulation")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal &lt;dlemoal@kernel.org&gt;
Tested-by: Jorgen Hansen &lt;Jorgen.Hansen@wdc.com&gt;
Link: https://lore.kernel.org/r/20250214041434.82564-1-dlemoal@kernel.org
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&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 a6aa36e957a1bfb5341986dec32d013d23228fe1 upstream.

For devices that natively support zone append operations,
REQ_OP_ZONE_APPEND BIOs are not processed through zone write plugging
and are immediately issued to the zoned device. This means that there is
no write pointer offset tracking done for these operations and that a
zone write plug is not necessary.

However, when receiving a zone append BIO, we may already have a zone
write plug for the target zone if that zone was previously partially
written using regular write operations. In such case, since the write
pointer offset of the zone write plug is not incremented by the amount
of sectors appended to the zone, 2 issues arise:
1) we risk leaving the plug in the disk hash table if the zone is fully
   written using zone append or regular write operations, because the
   write pointer offset will never reach the "zone full" state.
2) Regular write operations that are issued after zone append operations
   will always be failed by blk_zone_wplug_prepare_bio() as the write
   pointer alignment check will fail, even if the user correctly
   accounted for the zone append operations and issued the regular
   writes with a correct sector.

Avoid these issues by immediately removing the zone write plug of zones
that are the target of zone append operations when blk_zone_plug_bio()
is called. The new function blk_zone_wplug_handle_native_zone_append()
implements this for devices that natively support zone append. The
removal of the zone write plug using disk_remove_zone_wplug() requires
aborting all plugged regular write using disk_zone_wplug_abort() as
otherwise the plugged write BIOs would never be executed (with the plug
removed, the completion path will never see again the zone write plug as
disk_get_zone_wplug() will return NULL). Rate-limited warnings are added
to blk_zone_wplug_handle_native_zone_append() and to
disk_zone_wplug_abort() to signal this.

Since blk_zone_wplug_handle_native_zone_append() is called in the hot
path for operations that will not be plugged, disk_get_zone_wplug() is
optimized under the assumption that a user issuing zone append
operations is not at the same time issuing regular writes and that there
are no hashed zone write plugs. The struct gendisk atomic counter
nr_zone_wplugs is added to check this, with this counter incremented in
disk_insert_zone_wplug() and decremented in disk_remove_zone_wplug().

To be consistent with this fix, we do not need to fill the zone write
plug hash table with zone write plugs for zones that are partially
written for a device that supports native zone append operations.
So modify blk_revalidate_seq_zone() to return early to avoid allocating
and inserting a zone write plug for partially written sequential zones
if the device natively supports zone append.

Reported-by: Jorgen Hansen &lt;Jorgen.Hansen@wdc.com&gt;
Fixes: 9b1ce7f0c6f8 ("block: Implement zone append emulation")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal &lt;dlemoal@kernel.org&gt;
Tested-by: Jorgen Hansen &lt;Jorgen.Hansen@wdc.com&gt;
Link: https://lore.kernel.org/r/20250214041434.82564-1-dlemoal@kernel.org
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>objtool: Fix C jump table annotations for Clang</title>
<updated>2025-03-07T17:27:03+00:00</updated>
<author>
<name>Ard Biesheuvel</name>
<email>ardb@kernel.org</email>
</author>
<published>2025-02-21T13:57:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=03f56d000a7e828fe33f4c55c8b28e0df7c427f9'/>
<id>03f56d000a7e828fe33f4c55c8b28e0df7c427f9</id>
<content type='text'>
[ Upstream commit 73cfc53cc3b6380eccf013049574485f64cb83ca ]

A C jump table (such as the one used by the BPF interpreter) is a const
global array of absolute code addresses, and this means that the actual
values in the table may not be known until the kernel is booted (e.g.,
when using KASLR or when the kernel VA space is sized dynamically).

When using PIE codegen, the compiler will default to placing such const
global objects in .data.rel.ro (which is annotated as writable), rather
than .rodata (which is annotated as read-only). As C jump tables are
explicitly emitted into .rodata, this used to result in warnings for
LoongArch builds (which uses PIE codegen for the entire kernel) like

  Warning: setting incorrect section attributes for .rodata..c_jump_table

due to the fact that the explicitly specified .rodata section inherited
the read-write annotation that the compiler uses for such objects when
using PIE codegen.

This warning was suppressed by explicitly adding the read-only
annotation to the __attribute__((section(""))) string, by commit

  c5b1184decc8 ("compiler.h: specify correct attribute for .rodata..c_jump_table")

Unfortunately, this hack does not work on Clang's integrated assembler,
which happily interprets the appended section type and permission
specifiers as part of the section name, which therefore no longer
matches the hard-coded pattern '.rodata..c_jump_table' that objtool
expects, causing it to emit a warning

  kernel/bpf/core.o: warning: objtool: ___bpf_prog_run+0x20: sibling call from callable instruction with modified stack frame

Work around this, by emitting C jump tables into .data.rel.ro instead,
which is treated as .rodata by the linker script for all builds, not
just PIE based ones.

Fixes: c5b1184decc8 ("compiler.h: specify correct attribute for .rodata..c_jump_table")
Tested-by: Tiezhu Yang &lt;yangtiezhu@loongson.cn&gt; # on LoongArch
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Link: https://lore.kernel.org/r/20250221135704.431269-6-ardb+git@google.com
Signed-off-by: Josh Poimboeuf &lt;jpoimboe@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 73cfc53cc3b6380eccf013049574485f64cb83ca ]

A C jump table (such as the one used by the BPF interpreter) is a const
global array of absolute code addresses, and this means that the actual
values in the table may not be known until the kernel is booted (e.g.,
when using KASLR or when the kernel VA space is sized dynamically).

When using PIE codegen, the compiler will default to placing such const
global objects in .data.rel.ro (which is annotated as writable), rather
than .rodata (which is annotated as read-only). As C jump tables are
explicitly emitted into .rodata, this used to result in warnings for
LoongArch builds (which uses PIE codegen for the entire kernel) like

  Warning: setting incorrect section attributes for .rodata..c_jump_table

due to the fact that the explicitly specified .rodata section inherited
the read-write annotation that the compiler uses for such objects when
using PIE codegen.

This warning was suppressed by explicitly adding the read-only
annotation to the __attribute__((section(""))) string, by commit

  c5b1184decc8 ("compiler.h: specify correct attribute for .rodata..c_jump_table")

Unfortunately, this hack does not work on Clang's integrated assembler,
which happily interprets the appended section type and permission
specifiers as part of the section name, which therefore no longer
matches the hard-coded pattern '.rodata..c_jump_table' that objtool
expects, causing it to emit a warning

  kernel/bpf/core.o: warning: objtool: ___bpf_prog_run+0x20: sibling call from callable instruction with modified stack frame

Work around this, by emitting C jump tables into .data.rel.ro instead,
which is treated as .rodata by the linker script for all builds, not
just PIE based ones.

Fixes: c5b1184decc8 ("compiler.h: specify correct attribute for .rodata..c_jump_table")
Tested-by: Tiezhu Yang &lt;yangtiezhu@loongson.cn&gt; # on LoongArch
Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Link: https://lore.kernel.org/r/20250221135704.431269-6-ardb+git@google.com
Signed-off-by: Josh Poimboeuf &lt;jpoimboe@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
