<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/tools, branch v5.4.294</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>bpftool: Fix readlink usage in get_fd_type</title>
<updated>2025-06-04T12:32:34+00:00</updated>
<author>
<name>Viktor Malik</name>
<email>vmalik@redhat.com</email>
</author>
<published>2025-01-29T07:18:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=8079ba28438806f2d967ac5a08f236bf970feb44'/>
<id>8079ba28438806f2d967ac5a08f236bf970feb44</id>
<content type='text'>
[ Upstream commit 0053f7d39d491b6138d7c526876d13885cbb65f1 ]

The `readlink(path, buf, sizeof(buf))` call reads at most sizeof(buf)
bytes and *does not* append null-terminator to buf. With respect to
that, fix two pieces in get_fd_type:

1. Change the truncation check to contain sizeof(buf) rather than
   sizeof(path).
2. Append null-terminator to buf.

Reported by Coverity.

Signed-off-by: Viktor Malik &lt;vmalik@redhat.com&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Reviewed-by: Quentin Monnet &lt;qmo@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20250129071857.75182-1-vmalik@redhat.com
Signed-off-by: Alexei Starovoitov &lt;ast@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 0053f7d39d491b6138d7c526876d13885cbb65f1 ]

The `readlink(path, buf, sizeof(buf))` call reads at most sizeof(buf)
bytes and *does not* append null-terminator to buf. With respect to
that, fix two pieces in get_fd_type:

1. Change the truncation check to contain sizeof(buf) rather than
   sizeof(path).
2. Append null-terminator to buf.

Reported by Coverity.

Signed-off-by: Viktor Malik &lt;vmalik@redhat.com&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Reviewed-by: Quentin Monnet &lt;qmo@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20250129071857.75182-1-vmalik@redhat.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tools/build: Don't pass test log files to linker</title>
<updated>2025-06-04T12:32:30+00:00</updated>
<author>
<name>Ian Rogers</name>
<email>irogers@google.com</email>
</author>
<published>2025-03-11T21:36:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=cf7c3d7e8796dce2e518ad529161c2dfb7c90352'/>
<id>cf7c3d7e8796dce2e518ad529161c2dfb7c90352</id>
<content type='text'>
[ Upstream commit 935e7cb5bb80106ff4f2fe39640f430134ef8cd8 ]

Separate test log files from object files. Depend on test log output
but don't pass to the linker.

Reviewed-by: James Clark &lt;james.clark@linaro.org&gt;
Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Link: https://lore.kernel.org/r/20250311213628.569562-2-irogers@google.com
Signed-off-by: Namhyung Kim &lt;namhyung@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 935e7cb5bb80106ff4f2fe39640f430134ef8cd8 ]

Separate test log files from object files. Depend on test log output
but don't pass to the linker.

Reviewed-by: James Clark &lt;james.clark@linaro.org&gt;
Signed-off-by: Ian Rogers &lt;irogers@google.com&gt;
Link: https://lore.kernel.org/r/20250311213628.569562-2-irogers@google.com
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>selftests: ublk: fix test_stripe_04</title>
<updated>2025-05-02T05:39:29+00:00</updated>
<author>
<name>Ming Lei</name>
<email>ming.lei@redhat.com</email>
</author>
<published>2025-04-04T00:18:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3e7f0febf96273bb2c4ecef3f72933c9f891a3cf'/>
<id>3e7f0febf96273bb2c4ecef3f72933c9f891a3cf</id>
<content type='text'>
[ Upstream commit 72070e57b0a518ec8e562a2b68fdfc796ef5c040 ]

Commit 57ed58c13256 ("selftests: ublk: enable zero copy for stripe target")
added test entry of test_stripe_04, but forgot to add the test script.

So fix the test by adding the script file.

Reported-by: Uday Shankar &lt;ushankar@purestorage.com&gt;
Signed-off-by: Ming Lei &lt;ming.lei@redhat.com&gt;
Reviewed-by: Uday Shankar &lt;ushankar@purestorage.com&gt;
Link: https://lore.kernel.org/r/20250404001849.1443064-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&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 72070e57b0a518ec8e562a2b68fdfc796ef5c040 ]

Commit 57ed58c13256 ("selftests: ublk: enable zero copy for stripe target")
added test entry of test_stripe_04, but forgot to add the test script.

So fix the test by adding the script file.

Reported-by: Uday Shankar &lt;ushankar@purestorage.com&gt;
Signed-off-by: Ming Lei &lt;ming.lei@redhat.com&gt;
Reviewed-by: Uday Shankar &lt;ushankar@purestorage.com&gt;
Link: https://lore.kernel.org/r/20250404001849.1443064-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>pm: cpupower: bench: Prevent NULL dereference on malloc failure</title>
<updated>2025-05-02T05:39:09+00:00</updated>
<author>
<name>Zhongqiu Han</name>
<email>quic_zhonhan@quicinc.com</email>
</author>
<published>2025-02-19T12:27:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=34a9394794b0f97af6afedc0c9ee2012c24b28ed'/>
<id>34a9394794b0f97af6afedc0c9ee2012c24b28ed</id>
<content type='text'>
[ Upstream commit 208baa3ec9043a664d9acfb8174b332e6b17fb69 ]

If malloc returns NULL due to low memory, 'config' pointer can be NULL.
Add a check to prevent NULL dereference.

Link: https://lore.kernel.org/r/20250219122715.3892223-1-quic_zhonhan@quicinc.com
Signed-off-by: Zhongqiu Han &lt;quic_zhonhan@quicinc.com&gt;
Signed-off-by: Shuah Khan &lt;skhan@linuxfoundation.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 208baa3ec9043a664d9acfb8174b332e6b17fb69 ]

If malloc returns NULL due to low memory, 'config' pointer can be NULL.
Add a check to prevent NULL dereference.

Link: https://lore.kernel.org/r/20250219122715.3892223-1-quic_zhonhan@quicinc.com
Signed-off-by: Zhongqiu Han &lt;quic_zhonhan@quicinc.com&gt;
Signed-off-by: Shuah Khan &lt;skhan@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf python: Check if there is space to copy all the event</title>
<updated>2025-04-10T12:29:42+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2025-03-12T20:31:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=38dffe995b7a68e797a843197c1b70d0135e7026'/>
<id>38dffe995b7a68e797a843197c1b70d0135e7026</id>
<content type='text'>
[ Upstream commit 89aaeaf84231157288035b366cb6300c1c6cac64 ]

The pyrf_event__new() method copies the event obtained from the perf
ring buffer to a structure that will then be turned into a python object
for further consumption, so it copies perf_event.header.size bytes to
its 'event' member:

  $ pahole -C pyrf_event /tmp/build/perf-tools-next/python/perf.cpython-312-x86_64-linux-gnu.so
  struct pyrf_event {
  	PyObject                   ob_base;              /*     0    16 */
  	struct evsel *             evsel;                /*    16     8 */
  	struct perf_sample         sample;               /*    24   312 */

  	/* XXX last struct has 7 bytes of padding, 2 holes */

  	/* --- cacheline 5 boundary (320 bytes) was 16 bytes ago --- */
  	union perf_event           event;                /*   336  4168 */

  	/* size: 4504, cachelines: 71, members: 4 */
  	/* member types with holes: 1, total: 2 */
  	/* paddings: 1, sum paddings: 7 */
  	/* last cacheline: 24 bytes */
  };

  $

It was doing so without checking if the event just obtained has more
than that space, fix it.

This isn't a proper, final solution, as we need to support larger
events, but for the time being we at least bounds check and document it.

Fixes: 877108e42b1b9ba6 ("perf tools: Initial python binding")
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Reviewed-by: Ian Rogers &lt;irogers@google.com&gt;
Link: https://lore.kernel.org/r/20250312203141.285263-7-acme@kernel.org
Signed-off-by: Namhyung Kim &lt;namhyung@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 89aaeaf84231157288035b366cb6300c1c6cac64 ]

The pyrf_event__new() method copies the event obtained from the perf
ring buffer to a structure that will then be turned into a python object
for further consumption, so it copies perf_event.header.size bytes to
its 'event' member:

  $ pahole -C pyrf_event /tmp/build/perf-tools-next/python/perf.cpython-312-x86_64-linux-gnu.so
  struct pyrf_event {
  	PyObject                   ob_base;              /*     0    16 */
  	struct evsel *             evsel;                /*    16     8 */
  	struct perf_sample         sample;               /*    24   312 */

  	/* XXX last struct has 7 bytes of padding, 2 holes */

  	/* --- cacheline 5 boundary (320 bytes) was 16 bytes ago --- */
  	union perf_event           event;                /*   336  4168 */

  	/* size: 4504, cachelines: 71, members: 4 */
  	/* member types with holes: 1, total: 2 */
  	/* paddings: 1, sum paddings: 7 */
  	/* last cacheline: 24 bytes */
  };

  $

It was doing so without checking if the event just obtained has more
than that space, fix it.

This isn't a proper, final solution, as we need to support larger
events, but for the time being we at least bounds check and document it.

Fixes: 877108e42b1b9ba6 ("perf tools: Initial python binding")
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Reviewed-by: Ian Rogers &lt;irogers@google.com&gt;
Link: https://lore.kernel.org/r/20250312203141.285263-7-acme@kernel.org
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf python: Decrement the refcount of just created event on failure</title>
<updated>2025-04-10T12:29:41+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2025-03-12T20:31:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=213ee3d7385812045ecd351dc9f7bc38259e23a4'/>
<id>213ee3d7385812045ecd351dc9f7bc38259e23a4</id>
<content type='text'>
[ Upstream commit 3de5a2bf5b4847f7a59a184568f969f8fe05d57f ]

To avoid a leak if we have the python object but then something happens
and we need to return the operation, decrement the offset of the newly
created object.

Fixes: 377f698db12150a1 ("perf python: Add struct evsel into struct pyrf_event")
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Reviewed-by: Ian Rogers &lt;irogers@google.com&gt;
Link: https://lore.kernel.org/r/20250312203141.285263-5-acme@kernel.org
Signed-off-by: Namhyung Kim &lt;namhyung@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 3de5a2bf5b4847f7a59a184568f969f8fe05d57f ]

To avoid a leak if we have the python object but then something happens
and we need to return the operation, decrement the offset of the newly
created object.

Fixes: 377f698db12150a1 ("perf python: Add struct evsel into struct pyrf_event")
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Reviewed-by: Ian Rogers &lt;irogers@google.com&gt;
Link: https://lore.kernel.org/r/20250312203141.285263-5-acme@kernel.org
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf python: Fixup description of sample.id event member</title>
<updated>2025-04-10T12:29:41+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2025-03-12T20:31:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=58edf5e6a3e1e40fb3dcc452dea23ac68a4b06b4'/>
<id>58edf5e6a3e1e40fb3dcc452dea23ac68a4b06b4</id>
<content type='text'>
[ Upstream commit 1376c195e8ad327bb9f2d32e0acc5ac39e7cb30a ]

Some old cut'n'paste error, its "ip", so the description should be
"event ip", not "event type".

Fixes: 877108e42b1b9ba6 ("perf tools: Initial python binding")
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Reviewed-by: Ian Rogers &lt;irogers@google.com&gt;
Link: https://lore.kernel.org/r/20250312203141.285263-2-acme@kernel.org
Signed-off-by: Namhyung Kim &lt;namhyung@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 1376c195e8ad327bb9f2d32e0acc5ac39e7cb30a ]

Some old cut'n'paste error, its "ip", so the description should be
"event ip", not "event type".

Fixes: 877108e42b1b9ba6 ("perf tools: Initial python binding")
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Reviewed-by: Ian Rogers &lt;irogers@google.com&gt;
Link: https://lore.kernel.org/r/20250312203141.285263-2-acme@kernel.org
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf units: Fix insufficient array space</title>
<updated>2025-04-10T12:29:41+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2025-03-10T19:45:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=466806997acc5e40630debe7df0be1b5b789e133'/>
<id>466806997acc5e40630debe7df0be1b5b789e133</id>
<content type='text'>
[ Upstream commit cf67629f7f637fb988228abdb3aae46d0c1748fe ]

No need to specify the array size, let the compiler figure that out.

This addresses this compiler warning that was noticed while build
testing on fedora rawhide:

  31    15.81 fedora:rawhide                : FAIL gcc version 15.0.1 20250225 (Red Hat 15.0.1-0) (GCC)
    util/units.c: In function 'unit_number__scnprintf':
    util/units.c:67:24: error: initializer-string for array of 'char' is too long [-Werror=unterminated-string-initialization]
       67 |         char unit[4] = "BKMG";
          |                        ^~~~~~
    cc1: all warnings being treated as errors

Fixes: 9808143ba2e54818 ("perf tools: Add unit_number__scnprintf function")
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Link: https://lore.kernel.org/r/20250310194534.265487-3-acme@kernel.org
Signed-off-by: Namhyung Kim &lt;namhyung@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 cf67629f7f637fb988228abdb3aae46d0c1748fe ]

No need to specify the array size, let the compiler figure that out.

This addresses this compiler warning that was noticed while build
testing on fedora rawhide:

  31    15.81 fedora:rawhide                : FAIL gcc version 15.0.1 20250225 (Red Hat 15.0.1-0) (GCC)
    util/units.c: In function 'unit_number__scnprintf':
    util/units.c:67:24: error: initializer-string for array of 'char' is too long [-Werror=unterminated-string-initialization]
       67 |         char unit[4] = "BKMG";
          |                        ^~~~~~
    cc1: all warnings being treated as errors

Fixes: 9808143ba2e54818 ("perf tools: Add unit_number__scnprintf function")
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Link: https://lore.kernel.org/r/20250310194534.265487-3-acme@kernel.org
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf bench: Fix undefined behavior in cmpworker()</title>
<updated>2025-03-13T11:43:08+00:00</updated>
<author>
<name>Kuan-Wei Chiu</name>
<email>visitorckw@gmail.com</email>
</author>
<published>2025-01-16T11:08:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7cd71d75745ba29bb670dfca05e0fccd02ae3b37'/>
<id>7cd71d75745ba29bb670dfca05e0fccd02ae3b37</id>
<content type='text'>
commit 62892e77b8a64b9dc0e1da75980aa145347b6820 upstream.

The comparison function cmpworker() violates the C standard's
requirements for qsort() comparison functions, which mandate symmetry
and transitivity:

Symmetry: If x &lt; y, then y &gt; x.
Transitivity: If x &lt; y and y &lt; z, then x &lt; z.

In its current implementation, cmpworker() incorrectly returns 0 when
w1-&gt;tid &lt; w2-&gt;tid, which breaks both symmetry and transitivity. This
violation causes undefined behavior, potentially leading to issues such
as memory corruption in glibc [1].

Fix the issue by returning -1 when w1-&gt;tid &lt; w2-&gt;tid, ensuring
compliance with the C standard and preventing undefined behavior.

Link: https://www.qualys.com/2024/01/30/qsort.txt [1]
Fixes: 121dd9ea0116 ("perf bench: Add epoll parallel epoll_wait benchmark")
Cc: stable@vger.kernel.org
Signed-off-by: Kuan-Wei Chiu &lt;visitorckw@gmail.com&gt;
Reviewed-by: James Clark &lt;james.clark@linaro.org&gt;
Link: https://lore.kernel.org/r/20250116110842.4087530-1-visitorckw@gmail.com
Signed-off-by: Namhyung Kim &lt;namhyung@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 62892e77b8a64b9dc0e1da75980aa145347b6820 upstream.

The comparison function cmpworker() violates the C standard's
requirements for qsort() comparison functions, which mandate symmetry
and transitivity:

Symmetry: If x &lt; y, then y &gt; x.
Transitivity: If x &lt; y and y &lt; z, then x &lt; z.

In its current implementation, cmpworker() incorrectly returns 0 when
w1-&gt;tid &lt; w2-&gt;tid, which breaks both symmetry and transitivity. This
violation causes undefined behavior, potentially leading to issues such
as memory corruption in glibc [1].

Fix the issue by returning -1 when w1-&gt;tid &lt; w2-&gt;tid, ensuring
compliance with the C standard and preventing undefined behavior.

Link: https://www.qualys.com/2024/01/30/qsort.txt [1]
Fixes: 121dd9ea0116 ("perf bench: Add epoll parallel epoll_wait benchmark")
Cc: stable@vger.kernel.org
Signed-off-by: Kuan-Wei Chiu &lt;visitorckw@gmail.com&gt;
Reviewed-by: James Clark &lt;james.clark@linaro.org&gt;
Link: https://lore.kernel.org/r/20250116110842.4087530-1-visitorckw@gmail.com
Signed-off-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>udp: gso: do not drop small packets when PMTU reduces</title>
<updated>2025-03-13T11:43:06+00:00</updated>
<author>
<name>Yan Zhai</name>
<email>yan@cloudflare.com</email>
</author>
<published>2025-01-31T08:31:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4fae092c3c49cdacf1fb45680cc088fefe4ad02b'/>
<id>4fae092c3c49cdacf1fb45680cc088fefe4ad02b</id>
<content type='text'>
[ Upstream commit 235174b2bed88501fda689c113c55737f99332d8 ]

Commit 4094871db1d6 ("udp: only do GSO if # of segs &gt; 1") avoided GSO
for small packets. But the kernel currently dismisses GSO requests only
after checking MTU/PMTU on gso_size. This means any packets, regardless
of their payload sizes, could be dropped when PMTU becomes smaller than
requested gso_size. We encountered this issue in production and it
caused a reliability problem that new QUIC connection cannot be
established before PMTU cache expired, while non GSO sockets still
worked fine at the same time.

Ideally, do not check any GSO related constraints when payload size is
smaller than requested gso_size, and return EMSGSIZE instead of EINVAL
on MTU/PMTU check failure to be more specific on the error cause.

Fixes: 4094871db1d6 ("udp: only do GSO if # of segs &gt; 1")
Signed-off-by: Yan Zhai &lt;yan@cloudflare.com&gt;
Suggested-by: Willem de Bruijn &lt;willemdebruijn.kernel@gmail.com&gt;
Reviewed-by: Willem de Bruijn &lt;willemb@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
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[ Upstream commit 235174b2bed88501fda689c113c55737f99332d8 ]

Commit 4094871db1d6 ("udp: only do GSO if # of segs &gt; 1") avoided GSO
for small packets. But the kernel currently dismisses GSO requests only
after checking MTU/PMTU on gso_size. This means any packets, regardless
of their payload sizes, could be dropped when PMTU becomes smaller than
requested gso_size. We encountered this issue in production and it
caused a reliability problem that new QUIC connection cannot be
established before PMTU cache expired, while non GSO sockets still
worked fine at the same time.

Ideally, do not check any GSO related constraints when payload size is
smaller than requested gso_size, and return EMSGSIZE instead of EINVAL
on MTU/PMTU check failure to be more specific on the error cause.

Fixes: 4094871db1d6 ("udp: only do GSO if # of segs &gt; 1")
Signed-off-by: Yan Zhai &lt;yan@cloudflare.com&gt;
Suggested-by: Willem de Bruijn &lt;willemdebruijn.kernel@gmail.com&gt;
Reviewed-by: Willem de Bruijn &lt;willemb@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
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