<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/net/core, branch v6.12.91</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>net: skbuff: propagate shared-frag marker through frag-transfer helpers</title>
<updated>2026-05-23T11:05:02+00:00</updated>
<author>
<name>Hyunwoo Kim</name>
<email>imv4bel@gmail.com</email>
</author>
<published>2026-05-15T22:28:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fc6eb39c55e97df2f94ad974b8a5bbcd019da2c8'/>
<id>fc6eb39c55e97df2f94ad974b8a5bbcd019da2c8</id>
<content type='text'>
commit 48f6a5356a33dd78e7144ae1faef95ffc990aae0 upstream.

Two frag-transfer helpers (__pskb_copy_fclone() and skb_shift()) fail
to propagate the SKBFL_SHARED_FRAG bit in skb_shinfo()-&gt;flags when
moving frags from source to destination.  __pskb_copy_fclone() defers
the rest of the shinfo metadata to skb_copy_header() after copying
frag descriptors, but that helper only carries over gso_{size,segs,
type} and never touches skb_shinfo()-&gt;flags; skb_shift() moves frag
descriptors directly and leaves flags untouched.  As a result, the
destination skb keeps a reference to the same externally-owned or
page-cache-backed pages while reporting skb_has_shared_frag() as
false.

The mismatch is harmful in any in-place writer that uses
skb_has_shared_frag() to decide whether shared pages must be detoured
through skb_cow_data().  ESP input is one such writer (esp4.c,
esp6.c), and a single nft 'dup to &lt;local&gt;' rule -- or any other
nf_dup_ipv4() / xt_TEE caller -- is enough to land a pskb_copy()'d
skb in esp_input() with the marker stripped, letting an unprivileged
user write into the page cache of a root-owned read-only file via
authencesn-ESN stray writes.

Set SKBFL_SHARED_FRAG on the destination whenever frag descriptors
were actually moved from the source.  skb_copy() and skb_copy_expand()
share skb_copy_header() too but linearize all paged data into freshly
allocated head storage and emerge with nr_frags == 0, so
skb_has_shared_frag() returns false on its own; they need no change.

The same omission exists in skb_gro_receive() and skb_gro_receive_list().
The former moves the incoming skb's frag descriptors into the
accumulator's last sub-skb via two paths (a direct frag-move loop and
the head_frag + memcpy path); the latter chains the incoming skb whole
onto p's frag_list.  Downstream skb_segment() reads only
skb_shinfo(p)-&gt;flags, and skb_segment_list() reuses each sub-skb's
shinfo as the nskb -- both p and lp must carry the marker.

The same omission also exists in tcp_clone_payload(), which builds an
MTU probe skb by moving frag descriptors from skbs on sk_write_queue
into a freshly allocated nskb.  The helper falls into the same family
and warrants the same fix for consistency; no TCP TX-side in-place
writer is currently known to reach a user page through this gap, but
a future consumer depending on the marker would regress silently.

The same omission exists in skb_segment(): the per-iteration flag
merge takes only head_skb's flag, and the inner switch that rebinds
frag_skb to list_skb on head_skb-frags exhaustion does not fold the
new frag_skb's flag into nskb.  Fold frag_skb's flag at both sites
so segments drawing frags from frag_list members carry the marker.

Fixes: cef401de7be8 ("net: fix possible wrong checksum generation")
Fixes: f4c50a4034e6 ("xfrm: esp: avoid in-place decrypt on shared skb frags")
Suggested-by: Sabrina Dubroca &lt;sd@queasysnail.net&gt;
Suggested-by: Sultan Alsawaf &lt;sultan@kerneltoast.com&gt;
Suggested-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Suggested-by: Lin Ma &lt;malin89@huawei.com&gt;
Suggested-by: Jingguo Tan &lt;tanjingguo@huawei.com&gt;
Suggested-by: Aaron Esau &lt;aaron1esau@gmail.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Hyunwoo Kim &lt;imv4bel@gmail.com&gt;
Tested-by: Rajat Gupta &lt;rajat.gupta@oss.qualcomm.com&gt;
Link: https://patch.msgid.link/ageeJfJHwgzmKXbh@v4bel
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.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 48f6a5356a33dd78e7144ae1faef95ffc990aae0 upstream.

Two frag-transfer helpers (__pskb_copy_fclone() and skb_shift()) fail
to propagate the SKBFL_SHARED_FRAG bit in skb_shinfo()-&gt;flags when
moving frags from source to destination.  __pskb_copy_fclone() defers
the rest of the shinfo metadata to skb_copy_header() after copying
frag descriptors, but that helper only carries over gso_{size,segs,
type} and never touches skb_shinfo()-&gt;flags; skb_shift() moves frag
descriptors directly and leaves flags untouched.  As a result, the
destination skb keeps a reference to the same externally-owned or
page-cache-backed pages while reporting skb_has_shared_frag() as
false.

The mismatch is harmful in any in-place writer that uses
skb_has_shared_frag() to decide whether shared pages must be detoured
through skb_cow_data().  ESP input is one such writer (esp4.c,
esp6.c), and a single nft 'dup to &lt;local&gt;' rule -- or any other
nf_dup_ipv4() / xt_TEE caller -- is enough to land a pskb_copy()'d
skb in esp_input() with the marker stripped, letting an unprivileged
user write into the page cache of a root-owned read-only file via
authencesn-ESN stray writes.

Set SKBFL_SHARED_FRAG on the destination whenever frag descriptors
were actually moved from the source.  skb_copy() and skb_copy_expand()
share skb_copy_header() too but linearize all paged data into freshly
allocated head storage and emerge with nr_frags == 0, so
skb_has_shared_frag() returns false on its own; they need no change.

The same omission exists in skb_gro_receive() and skb_gro_receive_list().
The former moves the incoming skb's frag descriptors into the
accumulator's last sub-skb via two paths (a direct frag-move loop and
the head_frag + memcpy path); the latter chains the incoming skb whole
onto p's frag_list.  Downstream skb_segment() reads only
skb_shinfo(p)-&gt;flags, and skb_segment_list() reuses each sub-skb's
shinfo as the nskb -- both p and lp must carry the marker.

The same omission also exists in tcp_clone_payload(), which builds an
MTU probe skb by moving frag descriptors from skbs on sk_write_queue
into a freshly allocated nskb.  The helper falls into the same family
and warrants the same fix for consistency; no TCP TX-side in-place
writer is currently known to reach a user page through this gap, but
a future consumer depending on the marker would regress silently.

The same omission exists in skb_segment(): the per-iteration flag
merge takes only head_skb's flag, and the inner switch that rebinds
frag_skb to list_skb on head_skb-frags exhaustion does not fold the
new frag_skb's flag into nskb.  Fold frag_skb's flag at both sites
so segments drawing frags from frag_list members carry the marker.

Fixes: cef401de7be8 ("net: fix possible wrong checksum generation")
Fixes: f4c50a4034e6 ("xfrm: esp: avoid in-place decrypt on shared skb frags")
Suggested-by: Sabrina Dubroca &lt;sd@queasysnail.net&gt;
Suggested-by: Sultan Alsawaf &lt;sultan@kerneltoast.com&gt;
Suggested-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Suggested-by: Lin Ma &lt;malin89@huawei.com&gt;
Suggested-by: Jingguo Tan &lt;tanjingguo@huawei.com&gt;
Suggested-by: Aaron Esau &lt;aaron1esau@gmail.com&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Hyunwoo Kim &lt;imv4bel@gmail.com&gt;
Tested-by: Rajat Gupta &lt;rajat.gupta@oss.qualcomm.com&gt;
Link: https://patch.msgid.link/ageeJfJHwgzmKXbh@v4bel
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: skbuff: preserve shared-frag marker during coalescing</title>
<updated>2026-05-23T11:05:02+00:00</updated>
<author>
<name>William Bowling</name>
<email>vakzz@zellic.io</email>
</author>
<published>2026-05-13T04:16:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=760e1addc27ba1a7beb4a0a7e8b3e9ec49e7a34e'/>
<id>760e1addc27ba1a7beb4a0a7e8b3e9ec49e7a34e</id>
<content type='text'>
commit f84eca5817390257cef78013d0112481c503b4a3 upstream.

skb_try_coalesce() can attach paged frags from @from to @to.  If @from
has SKBFL_SHARED_FRAG set, the resulting @to skb can contain the same
externally-owned or page-cache-backed frags, but the shared-frag marker
is currently lost.

That breaks the invariant relied on by later in-place writers.  In
particular, ESP input checks skb_has_shared_frag() before deciding
whether an uncloned nonlinear skb can skip skb_cow_data().  If TCP
receive coalescing has moved shared frags into an unmarked skb, ESP can
see skb_has_shared_frag() as false and decrypt in place over page-cache
backed frags.

Propagate SKBFL_SHARED_FRAG when skb_try_coalesce() transfers paged
frags.  The tailroom copy path does not need the marker because it copies
bytes into @to's linear data rather than transferring frag descriptors.

Fixes: cef401de7be8 ("net: fix possible wrong checksum generation")
Fixes: f4c50a4034e6 ("xfrm: esp: avoid in-place decrypt on shared skb frags")
Signed-off-by: William Bowling &lt;vakzz@zellic.io&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Tested-by: Jiayuan Chen &lt;jiayuan.chen@linux.dev&gt;
Link: https://patch.msgid.link/20260513041635.1289541-1-vakzz@zellic.io
Signed-off-by: Jakub Kicinski &lt;kuba@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 f84eca5817390257cef78013d0112481c503b4a3 upstream.

skb_try_coalesce() can attach paged frags from @from to @to.  If @from
has SKBFL_SHARED_FRAG set, the resulting @to skb can contain the same
externally-owned or page-cache-backed frags, but the shared-frag marker
is currently lost.

That breaks the invariant relied on by later in-place writers.  In
particular, ESP input checks skb_has_shared_frag() before deciding
whether an uncloned nonlinear skb can skip skb_cow_data().  If TCP
receive coalescing has moved shared frags into an unmarked skb, ESP can
see skb_has_shared_frag() as false and decrypt in place over page-cache
backed frags.

Propagate SKBFL_SHARED_FRAG when skb_try_coalesce() transfers paged
frags.  The tailroom copy path does not need the marker because it copies
bytes into @to's linear data rather than transferring frag descriptors.

Fixes: cef401de7be8 ("net: fix possible wrong checksum generation")
Fixes: f4c50a4034e6 ("xfrm: esp: avoid in-place decrypt on shared skb frags")
Signed-off-by: William Bowling &lt;vakzz@zellic.io&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Tested-by: Jiayuan Chen &lt;jiayuan.chen@linux.dev&gt;
Link: https://patch.msgid.link/20260513041635.1289541-1-vakzz@zellic.io
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>page_pool: fix incorrect mp_ops error handling</title>
<updated>2026-05-23T11:04:58+00:00</updated>
<author>
<name>Mina Almasry</name>
<email>almasrymina@google.com</email>
</author>
<published>2025-08-21T03:03:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e23a328a6d1a82c2b7a9439d8263bd59215d33c8'/>
<id>e23a328a6d1a82c2b7a9439d8263bd59215d33c8</id>
<content type='text'>
[ Upstream commit abadf0ff63be488dc502ecfc9f622929a21b7117 ]

Minor fix to the memory provider error handling, we should be jumping to
free_ptr_ring in this error case rather than returning directly.

Found by code-inspection.

Cc: skhawaja@google.com

Fixes: b400f4b87430 ("page_pool: Set `dma_sync` to false for devmem memory provider")
Signed-off-by: Mina Almasry &lt;almasrymina@google.com&gt;
Reviewed-by: Samiullah Khawaja &lt;skhawaja@google.com&gt;
Link: https://patch.msgid.link/20250821030349.705244-1-almasrymina@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@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 abadf0ff63be488dc502ecfc9f622929a21b7117 ]

Minor fix to the memory provider error handling, we should be jumping to
free_ptr_ring in this error case rather than returning directly.

Found by code-inspection.

Cc: skhawaja@google.com

Fixes: b400f4b87430 ("page_pool: Set `dma_sync` to false for devmem memory provider")
Signed-off-by: Mina Almasry &lt;almasrymina@google.com&gt;
Reviewed-by: Samiullah Khawaja &lt;skhawaja@google.com&gt;
Link: https://patch.msgid.link/20250821030349.705244-1-almasrymina@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netpoll: pass buffer size to egress_dev() to avoid MAC truncation</title>
<updated>2026-05-23T11:04:58+00:00</updated>
<author>
<name>Breno Leitao</name>
<email>leitao@debian.org</email>
</author>
<published>2026-05-01T09:58:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d6539ee405ad49721ba2b3df7e7fde07462ac4a3'/>
<id>d6539ee405ad49721ba2b3df7e7fde07462ac4a3</id>
<content type='text'>
[ Upstream commit 76b93a8107574006b25495664304ea9237494d70 ]

egress_dev() formats np-&gt;dev_mac via snprintf() but receives buf as
a bare char *, so it cannot derive the buffer size from the pointer. The
size argument was hardcoded to MAC_ADDR_STR_LEN (3 * ETH_ALEN - 1 = 17),
which is silly wrong in two ways:

 1) misleading kernel log output on the MAC-selected target path
    (np-&gt;dev_name[0] == '\0'); for example "aa:bb:cc:dd:ee:ff doesn't
    exist, aborting" was logged as "aa:bb:cc:dd:ee:f doesn't exist,
    aborting".

 2) the second argument of snprintf is the size of the buffer, not the
    size of what you want to write.

Add a bufsz parameter to egress_dev() and pass sizeof(buf) from each
caller, matching the standard snprintf() idiom and removing the
hardcoded size from the helper.

Every caller already declares "char buf[MAC_ADDR_STR_LEN + 1]" so the
formatted MAC continues to fit.

Tested by booting with
  netconsole=6665@/aa:bb:cc:dd:ee:ff,6666@10.0.0.1/00:11:22:33:44:55
on a kernel without a matching device. Pre-fix dmesg shows
"aa:bb:cc:dd:ee:f doesn't exist, aborting"; post-fix shows the full
"aa:bb:cc:dd:ee:ff doesn't exist, aborting".

Fixes: f8a10bed32f5 ("netconsole: allow selection of egress interface via MAC address")
Cc: stable@vger.kernel.org
Signed-off-by: Breno Leitao &lt;leitao@debian.org&gt;
Link: https://patch.msgid.link/20260501-netpoll_snprintf_fix-v1-1-84b0566e6597@debian.org
Signed-off-by: Jakub Kicinski &lt;kuba@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 76b93a8107574006b25495664304ea9237494d70 ]

egress_dev() formats np-&gt;dev_mac via snprintf() but receives buf as
a bare char *, so it cannot derive the buffer size from the pointer. The
size argument was hardcoded to MAC_ADDR_STR_LEN (3 * ETH_ALEN - 1 = 17),
which is silly wrong in two ways:

 1) misleading kernel log output on the MAC-selected target path
    (np-&gt;dev_name[0] == '\0'); for example "aa:bb:cc:dd:ee:ff doesn't
    exist, aborting" was logged as "aa:bb:cc:dd:ee:f doesn't exist,
    aborting".

 2) the second argument of snprintf is the size of the buffer, not the
    size of what you want to write.

Add a bufsz parameter to egress_dev() and pass sizeof(buf) from each
caller, matching the standard snprintf() idiom and removing the
hardcoded size from the helper.

Every caller already declares "char buf[MAC_ADDR_STR_LEN + 1]" so the
formatted MAC continues to fit.

Tested by booting with
  netconsole=6665@/aa:bb:cc:dd:ee:ff,6666@10.0.0.1/00:11:22:33:44:55
on a kernel without a matching device. Pre-fix dmesg shows
"aa:bb:cc:dd:ee:f doesn't exist, aborting"; post-fix shows the full
"aa:bb:cc:dd:ee:ff doesn't exist, aborting".

Fixes: f8a10bed32f5 ("netconsole: allow selection of egress interface via MAC address")
Cc: stable@vger.kernel.org
Signed-off-by: Breno Leitao &lt;leitao@debian.org&gt;
Link: https://patch.msgid.link/20260501-netpoll_snprintf_fix-v1-1-84b0566e6597@debian.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netpoll: Extract IPv6 address retrieval function</title>
<updated>2026-05-23T11:04:58+00:00</updated>
<author>
<name>Breno Leitao</name>
<email>leitao@debian.org</email>
</author>
<published>2025-06-18T09:32:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3eaf609fcb30e24f1219544887695e917203d49b'/>
<id>3eaf609fcb30e24f1219544887695e917203d49b</id>
<content type='text'>
[ Upstream commit 6ad7969a361cbec5822285fb39203678ff462b64 ]

Extract the IPv6 address retrieval logic from netpoll_setup() into
a dedicated helper function netpoll_take_ipv6() to improve code
organization and readability.

The function handles obtaining the local IPv6 address from the
network device, including proper address type matching between
local and remote addresses (link-local vs global), and includes
appropriate error handling when IPv6 is not supported or no
suitable address is available.

Signed-off-by: Breno Leitao &lt;leitao@debian.org&gt;
Reviewed-by: Simon Horman &lt;horms@kernel.org&gt;
Link: https://patch.msgid.link/20250618-netpoll_ip_ref-v1-3-c2ac00fe558f@debian.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Stable-dep-of: 76b93a810757 ("netpoll: pass buffer size to egress_dev() to avoid MAC truncation")
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 6ad7969a361cbec5822285fb39203678ff462b64 ]

Extract the IPv6 address retrieval logic from netpoll_setup() into
a dedicated helper function netpoll_take_ipv6() to improve code
organization and readability.

The function handles obtaining the local IPv6 address from the
network device, including proper address type matching between
local and remote addresses (link-local vs global), and includes
appropriate error handling when IPv6 is not supported or no
suitable address is available.

Signed-off-by: Breno Leitao &lt;leitao@debian.org&gt;
Reviewed-by: Simon Horman &lt;horms@kernel.org&gt;
Link: https://patch.msgid.link/20250618-netpoll_ip_ref-v1-3-c2ac00fe558f@debian.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Stable-dep-of: 76b93a810757 ("netpoll: pass buffer size to egress_dev() to avoid MAC truncation")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>page_pool: fix memory-provider leak in page_pool_create_percpu() error path</title>
<updated>2026-05-23T11:04:57+00:00</updated>
<author>
<name>Hasan Basbunar</name>
<email>basbunarhasan@gmail.com</email>
</author>
<published>2026-04-28T17:07:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fbe4adfe0834b84dc12b8eeb32c38e47b38d2ed5'/>
<id>fbe4adfe0834b84dc12b8eeb32c38e47b38d2ed5</id>
<content type='text'>
[ Upstream commit 5ef343614db766acdc01c56d66e780a1b43c6ac6 ]

When page_pool_create_percpu() fails on page_pool_list(), it falls
through to its err_uninit: label, which calls page_pool_uninit().
At that point page_pool_init() has already taken two references
when the user requested PP_FLAG_ALLOW_UNREADABLE_NETMEM:

	pool-&gt;mp_ops-&gt;init(pool)
	static_branch_inc(&amp;page_pool_mem_providers);

Neither is undone by page_pool_uninit(); both are only undone by
__page_pool_destroy() (success-side teardown). The error path
therefore leaks the per-provider reference taken by mp_ops-&gt;init
(io_zcrx_ifq-&gt;refs in the io_uring zcrx provider, the dmabuf
binding refcount in the devmem provider) plus one increment of
the page_pool_mem_providers static branch on every failure of
xa_alloc_cyclic() inside page_pool_list().

The leaked io_zcrx_ifq-&gt;refs in turn pins everything
io_zcrx_ifq_free() would release on cleanup: ifq-&gt;user (uid),
ifq-&gt;mm_account (mmdrop), ifq-&gt;dev (device refcount),
ifq-&gt;netdev_tracker (netdev refcount), and the rbuf region.
The leaked static branch increment forces all subsequent
page_pool_alloc_netmems() and page_pool_return_page() callers to
take the slow mp_ops branch for the lifetime of the kernel.

Reachable via the io_uring zcrx path:

	io_uring_register(IORING_REGISTER_ZCRX_IFQ)  /* CAP_NET_ADMIN */
	  -&gt; __io_uring_register
	  -&gt; io_register_zcrx
	  -&gt; zcrx_register_netdev
	  -&gt; netif_mp_open_rxq
	  -&gt; driver ndo_queue_mem_alloc
	  -&gt; page_pool_create_percpu
	    -&gt; page_pool_init succeeds (mp_ops-&gt;init runs, branch++)
	    -&gt; page_pool_list fails (xa_alloc_cyclic -ENOMEM)
	    -&gt; goto err_uninit         &lt;-- leak

The same shape applies to the devmem dmabuf provider via
mp_dmabuf_devmem_init()/mp_dmabuf_devmem_destroy().

Restore the cleanup symmetry by moving the mp_ops-&gt;destroy() and
static_branch_dec() calls out of __page_pool_destroy() and into
page_pool_uninit(), so page_pool_uninit() is again the strict
inverse of page_pool_init(). page_pool_uninit() has only two
callers (the err_uninit: path and __page_pool_destroy()), so this
preserves the single-call invariant on the success path while
fixing the err path. The error path of page_pool_init() itself
still skips the mp_ops cleanup correctly: mp_ops-&gt;init is the
last action that takes a reference before page_pool_init() returns
0, so when it returns an error neither the refcount nor the static
branch has been touched.

Triggering the bug requires xa_alloc_cyclic() to fail with -ENOMEM,
which under normal GFP_KERNEL retry behaviour is rare. It is
deterministic under CONFIG_FAULT_INJECTION with fail_page_alloc /
xa fault injection, or under sustained memory pressure. The leak
is silent: there is no warning, and the released kernel build
continues running with a permanently-incremented static branch.

Fixes: 0f9214046893 ("memory-provider: dmabuf devmem memory provider")
Signed-off-by: Hasan Basbunar &lt;basbunarhasan@gmail.com&gt;
Link: https://patch.msgid.link/20260428170739.34881-1-basbunarhasan@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@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 5ef343614db766acdc01c56d66e780a1b43c6ac6 ]

When page_pool_create_percpu() fails on page_pool_list(), it falls
through to its err_uninit: label, which calls page_pool_uninit().
At that point page_pool_init() has already taken two references
when the user requested PP_FLAG_ALLOW_UNREADABLE_NETMEM:

	pool-&gt;mp_ops-&gt;init(pool)
	static_branch_inc(&amp;page_pool_mem_providers);

Neither is undone by page_pool_uninit(); both are only undone by
__page_pool_destroy() (success-side teardown). The error path
therefore leaks the per-provider reference taken by mp_ops-&gt;init
(io_zcrx_ifq-&gt;refs in the io_uring zcrx provider, the dmabuf
binding refcount in the devmem provider) plus one increment of
the page_pool_mem_providers static branch on every failure of
xa_alloc_cyclic() inside page_pool_list().

The leaked io_zcrx_ifq-&gt;refs in turn pins everything
io_zcrx_ifq_free() would release on cleanup: ifq-&gt;user (uid),
ifq-&gt;mm_account (mmdrop), ifq-&gt;dev (device refcount),
ifq-&gt;netdev_tracker (netdev refcount), and the rbuf region.
The leaked static branch increment forces all subsequent
page_pool_alloc_netmems() and page_pool_return_page() callers to
take the slow mp_ops branch for the lifetime of the kernel.

Reachable via the io_uring zcrx path:

	io_uring_register(IORING_REGISTER_ZCRX_IFQ)  /* CAP_NET_ADMIN */
	  -&gt; __io_uring_register
	  -&gt; io_register_zcrx
	  -&gt; zcrx_register_netdev
	  -&gt; netif_mp_open_rxq
	  -&gt; driver ndo_queue_mem_alloc
	  -&gt; page_pool_create_percpu
	    -&gt; page_pool_init succeeds (mp_ops-&gt;init runs, branch++)
	    -&gt; page_pool_list fails (xa_alloc_cyclic -ENOMEM)
	    -&gt; goto err_uninit         &lt;-- leak

The same shape applies to the devmem dmabuf provider via
mp_dmabuf_devmem_init()/mp_dmabuf_devmem_destroy().

Restore the cleanup symmetry by moving the mp_ops-&gt;destroy() and
static_branch_dec() calls out of __page_pool_destroy() and into
page_pool_uninit(), so page_pool_uninit() is again the strict
inverse of page_pool_init(). page_pool_uninit() has only two
callers (the err_uninit: path and __page_pool_destroy()), so this
preserves the single-call invariant on the success path while
fixing the err path. The error path of page_pool_init() itself
still skips the mp_ops cleanup correctly: mp_ops-&gt;init is the
last action that takes a reference before page_pool_init() returns
0, so when it returns an error neither the refcount nor the static
branch has been touched.

Triggering the bug requires xa_alloc_cyclic() to fail with -ENOMEM,
which under normal GFP_KERNEL retry behaviour is rare. It is
deterministic under CONFIG_FAULT_INJECTION with fail_page_alloc /
xa fault injection, or under sustained memory pressure. The leak
is silent: there is no warning, and the released kernel build
continues running with a permanently-incremented static branch.

Fixes: 0f9214046893 ("memory-provider: dmabuf devmem memory provider")
Signed-off-by: Hasan Basbunar &lt;basbunarhasan@gmail.com&gt;
Link: https://patch.msgid.link/20260428170739.34881-1-basbunarhasan@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: page_pool: create hooks for custom memory providers</title>
<updated>2026-05-23T11:04:56+00:00</updated>
<author>
<name>Pavel Begunkov</name>
<email>asml.silence@gmail.com</email>
</author>
<published>2025-02-04T21:56:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a41ce5c172c357fd373ed43681e763ed86a2483b'/>
<id>a41ce5c172c357fd373ed43681e763ed86a2483b</id>
<content type='text'>
[ Upstream commit 57afb483015768903029c8336ee287f4b03c1235 ]

A spin off from the original page pool memory providers patch by Jakub,
which allows extending page pools with custom allocators. One of such
providers is devmem TCP, and the other is io_uring zerocopy added in
following patches.

Link: https://lore.kernel.org/netdev/20230707183935.997267-7-kuba@kernel.org/
Co-developed-by: Jakub Kicinski &lt;kuba@kernel.org&gt; # initial mp proposal
Signed-off-by: Pavel Begunkov &lt;asml.silence@gmail.com&gt;
Signed-off-by: David Wei &lt;dw@davidwei.uk&gt;
Link: https://patch.msgid.link/20250204215622.695511-5-dw@davidwei.uk
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Stable-dep-of: 5ef343614db7 ("page_pool: fix memory-provider leak in page_pool_create_percpu() error path")
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 57afb483015768903029c8336ee287f4b03c1235 ]

A spin off from the original page pool memory providers patch by Jakub,
which allows extending page pools with custom allocators. One of such
providers is devmem TCP, and the other is io_uring zerocopy added in
following patches.

Link: https://lore.kernel.org/netdev/20230707183935.997267-7-kuba@kernel.org/
Co-developed-by: Jakub Kicinski &lt;kuba@kernel.org&gt; # initial mp proposal
Signed-off-by: Pavel Begunkov &lt;asml.silence@gmail.com&gt;
Signed-off-by: David Wei &lt;dw@davidwei.uk&gt;
Link: https://patch.msgid.link/20250204215622.695511-5-dw@davidwei.uk
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Stable-dep-of: 5ef343614db7 ("page_pool: fix memory-provider leak in page_pool_create_percpu() error path")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>page_pool: Set `dma_sync` to false for devmem memory provider</title>
<updated>2026-05-23T11:04:56+00:00</updated>
<author>
<name>Samiullah Khawaja</name>
<email>skhawaja@google.com</email>
</author>
<published>2024-12-11T21:20:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ab964dd74421d8bd39fa24cd1d805cf31a685914'/>
<id>ab964dd74421d8bd39fa24cd1d805cf31a685914</id>
<content type='text'>
[ Upstream commit b400f4b87430c105d92550cee5a72aea01fdf3d6 ]

Move the `dma_map` and `dma_sync` checks to `page_pool_init` to make
them generic. Set dma_sync to false for devmem memory provider because
the dma_sync APIs should not be used for dma_buf backed devmem memory
provider.

Cc: Jason Gunthorpe &lt;jgg@ziepe.ca&gt;
Signed-off-by: Samiullah Khawaja &lt;skhawaja@google.com&gt;
Signed-off-by: Mina Almasry &lt;almasrymina@google.com&gt;
Link: https://patch.msgid.link/20241211212033.1684197-4-almasrymina@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Stable-dep-of: 5ef343614db7 ("page_pool: fix memory-provider leak in page_pool_create_percpu() error path")
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 b400f4b87430c105d92550cee5a72aea01fdf3d6 ]

Move the `dma_map` and `dma_sync` checks to `page_pool_init` to make
them generic. Set dma_sync to false for devmem memory provider because
the dma_sync APIs should not be used for dma_buf backed devmem memory
provider.

Cc: Jason Gunthorpe &lt;jgg@ziepe.ca&gt;
Signed-off-by: Samiullah Khawaja &lt;skhawaja@google.com&gt;
Signed-off-by: Mina Almasry &lt;almasrymina@google.com&gt;
Link: https://patch.msgid.link/20241211212033.1684197-4-almasrymina@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Stable-dep-of: 5ef343614db7 ("page_pool: fix memory-provider leak in page_pool_create_percpu() error path")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netpoll: fix IPv6 local-address corruption</title>
<updated>2026-05-23T11:04:54+00:00</updated>
<author>
<name>Breno Leitao</name>
<email>leitao@debian.org</email>
</author>
<published>2026-04-24T15:31:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=484996b55913a0cc9ee5094c7ff0ce98ed97e93b'/>
<id>484996b55913a0cc9ee5094c7ff0ce98ed97e93b</id>
<content type='text'>
[ Upstream commit 3bc179bc7146c26c9dff75d2943d10528274e301 ]

netpoll_setup() decides whether to auto-populate the local source
address by testing np-&gt;local_ip.ip, which only inspects the first 4
bytes of the union inet_addr storage.

For an IPv6 netpoll whose caller-supplied local address has a zero
high-32 bits (::1, ::&lt;suffix&gt;, IPv4-mapped ::ffff:a.b.c.d, etc.), this
misdetects the address as unset (which they are not, but the first
4 bytes are empty), calls netpoll_take_ipv6() and overwrites it with
whatever matching link-local/global address the device happens to expose
first.

Introduce a helper netpoll_local_ip_unset() that picks the correct
family-aware test (ipv6_addr_any() for IPv6, !.ip for IPv4) and use it
from netpoll_setup().

Reproducer is something like:

  echo "::2" &gt; local_ip
  echo 1     &gt; enabled
  cat local_ip
  # before this fix: 2001:db8::1   (caller-supplied ::2 was clobbered)
  # after  this fix: ::2

Fixes: b7394d2429c1 ("netpoll: prepare for ipv6")
Signed-off-by: Breno Leitao &lt;leitao@debian.org&gt;
Link: https://patch.msgid.link/20260424-netpoll_fix-v1-1-3a55348c625f@debian.org
Signed-off-by: Jakub Kicinski &lt;kuba@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 3bc179bc7146c26c9dff75d2943d10528274e301 ]

netpoll_setup() decides whether to auto-populate the local source
address by testing np-&gt;local_ip.ip, which only inspects the first 4
bytes of the union inet_addr storage.

For an IPv6 netpoll whose caller-supplied local address has a zero
high-32 bits (::1, ::&lt;suffix&gt;, IPv4-mapped ::ffff:a.b.c.d, etc.), this
misdetects the address as unset (which they are not, but the first
4 bytes are empty), calls netpoll_take_ipv6() and overwrites it with
whatever matching link-local/global address the device happens to expose
first.

Introduce a helper netpoll_local_ip_unset() that picks the correct
family-aware test (ipv6_addr_any() for IPv6, !.ip for IPv4) and use it
from netpoll_setup().

Reproducer is something like:

  echo "::2" &gt; local_ip
  echo 1     &gt; enabled
  cat local_ip
  # before this fix: 2001:db8::1   (caller-supplied ::2 was clobbered)
  # after  this fix: ::2

Fixes: b7394d2429c1 ("netpoll: prepare for ipv6")
Signed-off-by: Breno Leitao &lt;leitao@debian.org&gt;
Link: https://patch.msgid.link/20260424-netpoll_fix-v1-1-3a55348c625f@debian.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netpoll: extract IPv4 address retrieval into helper function</title>
<updated>2026-05-23T11:04:54+00:00</updated>
<author>
<name>Breno Leitao</name>
<email>leitao@debian.org</email>
</author>
<published>2025-06-18T09:32:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ebeb8414aff9312e3aceefec37142305a3cd16ee'/>
<id>ebeb8414aff9312e3aceefec37142305a3cd16ee</id>
<content type='text'>
[ Upstream commit 3699f992e8c22d3ce54d2c1a5774e2c49028f99c ]

Move the IPv4 address retrieval logic from netpoll_setup() into a
separate netpoll_take_ipv4() function to improve code organization
and readability. This change consolidates the IPv4-specific logic
and error handling into a dedicated function while maintaining
the same functionality.

No functional changes.

Signed-off-by: Breno Leitao &lt;leitao@debian.org&gt;
Reviewed-by: Simon Horman &lt;horms@kernel.org&gt;
Link: https://patch.msgid.link/20250618-netpoll_ip_ref-v1-2-c2ac00fe558f@debian.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Stable-dep-of: 3bc179bc7146 ("netpoll: fix IPv6 local-address corruption")
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 3699f992e8c22d3ce54d2c1a5774e2c49028f99c ]

Move the IPv4 address retrieval logic from netpoll_setup() into a
separate netpoll_take_ipv4() function to improve code organization
and readability. This change consolidates the IPv4-specific logic
and error handling into a dedicated function while maintaining
the same functionality.

No functional changes.

Signed-off-by: Breno Leitao &lt;leitao@debian.org&gt;
Reviewed-by: Simon Horman &lt;horms@kernel.org&gt;
Link: https://patch.msgid.link/20250618-netpoll_ip_ref-v1-2-c2ac00fe558f@debian.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Stable-dep-of: 3bc179bc7146 ("netpoll: fix IPv6 local-address corruption")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
