<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/linux.git/tools/testing/selftests, branch v6.12.93</title>
<subtitle>Linux kernel stable tree (mirror)</subtitle>
<id>https://git.radix-linux.su/kernel/linux.git/atom?h=v6.12.93</id>
<link rel='self' href='https://git.radix-linux.su/kernel/linux.git/atom?h=v6.12.93'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/'/>
<updated>2026-06-09T10:26:03+00:00</updated>
<entry>
<title>selftests: mptcp: drop nanoseconds width specifier</title>
<updated>2026-06-09T10:26:03+00:00</updated>
<author>
<name>Matthieu Baerts (NGI0)</name>
<email>matttbe@kernel.org</email>
</author>
<published>2026-05-30T00:25:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=8a168db9fe5afaf5bf51549c9851508c7c242c02'/>
<id>urn:sha1:8a168db9fe5afaf5bf51549c9851508c7c242c02</id>
<content type='text'>
[ Upstream commit 01ff78e4b3d98689184c52d97f9575dfbdc3b10f ]

Using the format specifier +%s%3N with GNU date is honoured, and only
prints 3 digits of the nanoseconds portion of the seconds since epoch,
which corresponds to the milliseconds.

The uutils implementation of date currently does not honour this, and
always prints all 9 digits. This is a known issue [1], but can be worked
around by adapting this test to use nanoseconds instead of microseconds,
and then divide it by 1e6.

This fix is similar to what has been done on systemd side [2], and it is
needed to run the selftests on Ubuntu 26.04, containing uutils 0.8.0.

Note that the Fixes tag is there even if this patch doesn't fix an issue
in the kernel selftests, but it is useful for those using uutils 0.8.0.

Fixes: 048d19d444be ("mptcp: add basic kselftest for mptcp")
Cc: stable@vger.kernel.org
Link: https://github.com/uutils/coreutils/issues/11658 [1]
Link: https://github.com/systemd/systemd/pull/41627 [2]
Signed-off-by: Matthieu Baerts (NGI0) &lt;matttbe@kernel.org&gt;
Link: https://patch.msgid.link/20260515-net-mptcp-misc-fixes-7-1-rc4-v2-6-701e96419f2f@kernel.org
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
[ kept `timeout ${timeout_test}` wrapper in do_transfer() ]
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm/memory: fix spurious warning when unmapping device-private/exclusive pages</title>
<updated>2026-06-09T10:26:02+00:00</updated>
<author>
<name>Alistair Popple</name>
<email>apopple@nvidia.com</email>
</author>
<published>2026-05-29T17:47:59+00:00</published>
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<id>urn:sha1:a825691b804b35141aaf4eac91003a70846e316d</id>
<content type='text'>
[ Upstream commit be3f38d05cc5a7c3f13e51994c5dd043ab604d28 ]

Device private and exclusive entries are only supported for anonymous
folios.  This condition is tested in __migrate_device_pages() and
make_device_exclusive() using folio_test_anon().  However the unmap path
tests this assumption using vma_is_anonymous().

This is wrong because whilst anonymous VMAs can only contain folios where
folio_test_anon() is true the opposite relation does not hold.  A folio
for which folio_test_anon() is true does not imply vma_is_anonymous() is
true.  Such a condition can occur if for example a folio is part of a
private filebacked mapping.

In this case vma_is_anonymous() is false as the mapping is filebacked, but
folio_test_anon() may be true, thus permitting devices to migrate the
folio to device private memory.  This can lead to the following spurious
warnings during process teardown:

[  772.737706] ------------[ cut here ]------------
[  772.739201] WARNING: mm/memory.c:1754 at unmap_page_range.cold+0x26/0x18a, CPU#17: hmm-tests/2041
[  772.742050] Modules linked in: test_hmm nvidia_uvm(O) nvidia(O)
[  772.743959] CPU: 17 UID: 0 PID: 2041 Comm: hmm-tests Tainted: G        W  O        7.0.0+ #387 PREEMPT(full)
[  772.747104] Tainted: [W]=WARN, [O]=OOT_MODULE
[  772.748509] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014
[  772.752117] RIP: 0010:unmap_page_range.cold+0x26/0x18a
[  772.753780] Code: 7e fe ff ff 48 89 4c 24 78 4c 89 44 24 38 e8 f2 ff b1 00 48 8b 4c 24 78 4c 8b 44 24 38 48 8b 44 24 18 48 83 78 48 00 74 04 90 &lt;0f&gt; 0b 90 48 89 ca b8 ff ff 37 00 48 c1 ea 03 48 c1 e0 2a 80 3c 02
[  772.759602] RSP: 0018:ffff888112607550 EFLAGS: 00010286
[  772.761310] RAX: ffff88811bbf4dc0 RBX: dffffc0000000000 RCX: ffffea03e9bfffd8
[  772.763583] RDX: 1ffff1102377e9c1 RSI: 0000000000000008 RDI: ffff88811bbf4e08
[  772.765914] RBP: 0000000000000006 R08: ffff8881059f7448 R09: ffffed10224c0e68
[  772.768184] R10: ffff888112607347 R11: 0000000000000001 R12: 0000000000000001
[  772.770461] R13: ffffea03e9bfffc0 R14: ffff888112607908 R15: ffffea03e9bfffc0
[  772.772782] FS:  00007f327caa2780(0000) GS:ffff888427b7d000(0000) knlGS:0000000000000000
[  772.775328] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  772.777187] CR2: 00007f327ca89000 CR3: 00000001994d5000 CR4: 00000000000006f0
[  772.779135] Call Trace:
[  772.779792]  &lt;TASK&gt;
[  772.780317]  ? dmirror_interval_invalidate+0x1a3/0x290 [test_hmm]
[  772.781873]  ? vm_normal_page_pud+0x2b0/0x2b0
[  772.782992]  ? __rwlock_init+0x150/0x150
[  772.784006]  ? lock_release+0x216/0x2b0
[  772.785008]  ? __mmu_notifier_invalidate_range_start+0x505/0x6e0
[  772.786522]  ? lock_release+0x216/0x2b0
[  772.787498]  ? unmap_single_vma+0xb6/0x210
[  772.788573]  unmap_vmas+0x27d/0x520
[  772.789506]  ? unmap_single_vma+0x210/0x210
[  772.790607]  ? mas_update_gap.part.0+0x620/0x620
[  772.791834]  unmap_region+0x19e/0x350
[  772.792769]  ? remove_vma+0x130/0x130
[  772.793684]  ? mas_alloc_nodes+0x1f2/0x300
[  772.794730]  vms_complete_munmap_vmas+0x8c1/0xe20
[  772.795926]  ? unmap_region+0x350/0x350
[  772.796917]  do_vmi_align_munmap+0x36a/0x4e0
[  772.798018]  ? lock_release+0x216/0x2b0
[  772.799024]  ? vma_shrink+0x620/0x620
[  772.799983]  do_vmi_munmap+0x150/0x2c0
[  772.800939]  __vm_munmap+0x161/0x2c0
[  772.801872]  ? expand_downwards+0xd60/0xd60
[  772.802948]  ? clockevents_program_event+0x1ef/0x540
[  772.804217]  ? lock_release+0x216/0x2b0
[  772.805158]  __x64_sys_munmap+0x59/0x80
[  772.805776]  do_syscall_64+0xfc/0x670
[  772.806336]  ? irqentry_exit+0xda/0x580
[  772.806976]  entry_SYSCALL_64_after_hwframe+0x4b/0x53
[  772.807772] RIP: 0033:0x7f327cbb2717
[  772.808323] Code: 73 01 c3 48 8b 0d f9 76 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 0b 00 00 00 0f 05 &lt;48&gt; 3d 01 f0 ff ff 73 01 c3 48 8b 0d c9 76 0d 00 f7 d8 64 89 01 48
[  772.811337] RSP: 002b:00007ffde7f57d38 EFLAGS: 00000202 ORIG_RAX: 000000000000000b
[  772.812564] RAX: ffffffffffffffda RBX: 00007f327cc9c000 RCX: 00007f327cbb2717
[  772.813733] RDX: 0000000000000000 RSI: 0000000000400000 RDI: 00007f327c289000
[  772.814867] RBP: 0000000000421360 R08: 000000000000001a R09: 0000000000000000
[  772.815991] R10: 0000000000000003 R11: 0000000000000202 R12: 00007ffde7f57d74
[  772.817121] R13: 00007f327c689010 R14: 0000000000100000 R15: 00007f327c289000
[  772.818272]  &lt;/TASK&gt;
[  772.818614] irq event stamp: 0
[  772.819159] hardirqs last  enabled at (0): [&lt;0000000000000000&gt;] 0x0
[  772.820174] hardirqs last disabled at (0): [&lt;ffffffff82a57ab3&gt;] copy_process+0x19f3/0x6440
[  772.821511] softirqs last  enabled at (0): [&lt;ffffffff82a57b00&gt;] copy_process+0x1a40/0x6440
[  772.822869] softirqs last disabled at (0): [&lt;0000000000000000&gt;] 0x0
[  772.823871] ---[ end trace 0000000000000000 ]---

Fix this by using the same check for folio_test_anon() in
zap_nonpresent_ptes(). Also add a hmm-test case for this.

Link: https://lore.kernel.org/20260501065116.2057242-1-apopple@nvidia.com
Fixes: 999dad824c39 ("mm/shmem: persist uffd-wp bit across zapping for file-backed")
Signed-off-by: Alistair Popple &lt;apopple@nvidia.com&gt;
Reported-by: Arsen Arsenović &lt;aarsenovic@baylibre.com&gt;
Reviewed-by: Balbir Singh &lt;balbirs@nvidia.com&gt;
Cc: David Hildenbrand &lt;david@kernel.org&gt;
Cc: Jason Gunthorpe &lt;jgg@ziepe.ca&gt;
Cc: John Hubbard &lt;jhubbard@nvidia.com&gt;
Cc: Leon Romanovsky &lt;leon@kernel.org&gt;
Cc: Liam R. Howlett &lt;liam@infradead.org&gt;
Cc: Lorenzo Stoakes &lt;ljs@kernel.org&gt;
Cc: Peter Xu &lt;peterx@redhat.com&gt;
Cc: Matthew Brost &lt;matthew.brost@intel.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Mike Rapoport &lt;rppt@kernel.org&gt;
Cc: Shuah Khan &lt;shuah@kernel.org&gt;
Cc: Suren Baghdasaryan &lt;surenb@google.com&gt;
Cc: Thomas Hellström &lt;thomas.hellstrom@linux.intel.com&gt;
Cc: Vlastimil Babka &lt;vbabka@kernel.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
[ applied the change in `zap_pte_range()` instead of `zap_nonpresent_ptes()` ]
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>selftests/mm: run_vmtests.sh: fix destructive tests invocation</title>
<updated>2026-06-01T15:46:17+00:00</updated>
<author>
<name>Luiz Capitulino</name>
<email>luizcap@redhat.com</email>
</author>
<published>2026-04-27T16:03:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=898ea8abfa10d4f69c68ac57703d8240cd9b531d'/>
<id>urn:sha1:898ea8abfa10d4f69c68ac57703d8240cd9b531d</id>
<content type='text'>
commit 3432cbb291aabf85f8af4b9d1ec37179168ff999 upstream.

Destructive tests should be invoked with -d command-line option, but this
won't work today since 'd' is missing in getopts command-line.  This
commit fixes it.

Link: https://lore.kernel.org/214fd9e4-5398-4c26-859e-c982c2e277c3@redhat.com
Fixes: f16ff3b692ad ("selftests/mm: run_vmtests.sh: add missing tests")
Signed-off-by: Luiz Capitulino &lt;luizcap@redhat.com&gt;
Reviewed-by: Mike Rapoport (Microsoft) &lt;rppt@kernel.org&gt;
Reviewed-by: SeongJae Park &lt;sj@kernel.org&gt;
Cc: David Hildenbrand &lt;david@kernel.org&gt;
Cc: Liam R. Howlett &lt;liam@infradead.org&gt;
Cc: Lorenzo Stoakes &lt;ljs@kernel.org&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Shuah Khan &lt;shuah@kernel.org&gt;
Cc: Suren Baghdasaryan &lt;surenb@google.com&gt;
Cc: Vlastimil Babka &lt;vbabka@kernel.org&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>
</entry>
<entry>
<title>bpf: allow UTF-8 literals in bpf_bprintf_prepare()</title>
<updated>2026-05-23T11:04:42+00:00</updated>
<author>
<name>Yihan Ding</name>
<email>dingyihan@uniontech.com</email>
</author>
<published>2026-04-16T12:01:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=bf5c43e90b9276f07e371dcf43c2230a03899e1e'/>
<id>urn:sha1:bf5c43e90b9276f07e371dcf43c2230a03899e1e</id>
<content type='text'>
[ Upstream commit b960430ea8862ef37ce53c8bf74a8dc79d3f2404 ]

bpf_bprintf_prepare() only needs ASCII parsing for conversion
specifiers. Plain text can safely carry bytes &gt;= 0x80, so allow
UTF-8 literals outside '%' sequences while keeping ASCII control
bytes rejected and format specifiers ASCII-only.

This keeps existing parsing rules for format directives unchanged,
while allowing helpers such as bpf_trace_printk() to emit UTF-8
literal text.

Update test_snprintf_negative() in the same commit so selftests keep
matching the new plain-text vs format-specifier split during bisection.

Fixes: 48cac3f4a96d ("bpf: Implement formatted output helpers with bstr_printf")
Signed-off-by: Yihan Ding &lt;dingyihan@uniontech.com&gt;
Acked-by: Paul Chaignon &lt;paul.chaignon@gmail.com&gt;
Link: https://lore.kernel.org/r/20260416120142.1420646-2-dingyihan@uniontech.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>selftest: memcg: skip memcg_sock test if address family not supported</title>
<updated>2026-05-23T11:04:34+00:00</updated>
<author>
<name>Waiman Long</name>
<email>longman@redhat.com</email>
</author>
<published>2026-03-11T20:05:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=a52f3a289fdee070d4c6e2be82f32a5026547e10'/>
<id>urn:sha1:a52f3a289fdee070d4c6e2be82f32a5026547e10</id>
<content type='text'>
[ Upstream commit 2d028f3e4bbbfd448928a8d3d2814b0b04c214f4 ]

The test_memcg_sock test in memcontrol.c sets up an IPv6 socket and send
data over it to consume memory and verify that memory.stat.sock and
memory.current values are close.

On systems where IPv6 isn't enabled or not configured to support
SOCK_STREAM, the test_memcg_sock test always fails.  When the socket()
call fails, there is no way we can test the memory consumption and verify
the above claim.  I believe it is better to just skip the test in this
case instead of reporting a test failure hinting that there may be
something wrong with the memcg code.

Link: https://lkml.kernel.org/r/20260311200526.885899-1-longman@redhat.com
Fixes: 5f8f019380b8 ("selftests: cgroup/memcontrol: add basic test for socket accounting")
Signed-off-by: Waiman Long &lt;longman@redhat.com&gt;
Acked-by: Michal Koutný &lt;mkoutny@suse.com&gt;
Acked-by: Shakeel Butt &lt;shakeel.butt@linux.dev&gt;
Cc: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Michal Koutný &lt;mkoutny@suse.com&gt;
Cc: Mike Rapoport &lt;rppt@kernel.org&gt;
Cc: Muchun Song &lt;muchun.song@linux.dev&gt;
Cc: Roman Gushchin &lt;roman.gushchin@linux.dev&gt;
Cc: Shuah Khan &lt;shuah@kernel.org&gt;
Cc: Tejun Heo &lt;tj@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>selftests/mm: skip migration tests if NUMA is unavailable</title>
<updated>2026-05-23T11:04:34+00:00</updated>
<author>
<name>AnishMulay</name>
<email>anishm7030@gmail.com</email>
</author>
<published>2026-02-18T16:39:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=d0e8fde29012cb9b7e72a835a0094764992bd3a8'/>
<id>urn:sha1:d0e8fde29012cb9b7e72a835a0094764992bd3a8</id>
<content type='text'>
[ Upstream commit 54218f10dfbe88c8e41c744fd45a756cde60b8c4 ]

Currently, the migration test asserts that numa_available() returns 0.  On
systems where NUMA is not available (returning -1), such as certain ARM64
configurations or single-node systems, this assertion fails and crashes
the test.

Update the test to check the return value of numa_available().  If it is
less than 0, skip the test gracefully instead of failing.

This aligns the behavior with other MM selftests (like rmap) that skip
when NUMA support is missing.

Link: https://lkml.kernel.org/r/20260218163941.13499-1-anishm7030@gmail.com
Fixes: 0c2d08728470 ("mm: add selftests for migration entries")
Signed-off-by: AnishMulay &lt;anishm7030@gmail.com&gt;
Reviewed-by: SeongJae Park &lt;sj@kernel.org&gt;
Reviewed-by: Dev Jain &lt;dev.jain@arm.com&gt;
Reviewed-by: Anshuman Khandual &lt;anshuman.khandual@arm.com&gt;
Tested-by: Sayali Patil &lt;sayalip@linux.ibm.com&gt;
Acked-by: David Hildenbrand (Arm) &lt;david@kernel.org&gt;
Cc: Liam Howlett &lt;liam.howlett@oracle.com&gt;
Cc: Lorenzo Stoakes &lt;lorenzo.stoakes@oracle.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Mike Rapoport &lt;rppt@kernel.org&gt;
Cc: Shuah Khan &lt;shuah@kernel.org&gt;
Cc: Suren Baghdasaryan &lt;surenb@google.com&gt;
Cc: Vlastimil Babka &lt;vbabka@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>selftests/sched_ext: Add missing error check for exit__load()</title>
<updated>2026-05-23T11:04:28+00:00</updated>
<author>
<name>David Carlier</name>
<email>devnexen@gmail.com</email>
</author>
<published>2026-03-13T05:17:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=72d0233a814d4b25d9c50867bd772f7546f9c3ef'/>
<id>urn:sha1:72d0233a814d4b25d9c50867bd772f7546f9c3ef</id>
<content type='text'>
[ Upstream commit 1d02346fec8d13b05e54296ddc6ae29b7e1067df ]

exit__load(skel) was called without checking its return value.
Every other test in the suite wraps the load call with
SCX_FAIL_IF(). Add the missing check to be consistent with the
rest of the test suite.

Fixes: a5db7817af78 ("sched_ext: Add selftests")
Signed-off-by: David Carlier &lt;devnexen@gmail.com&gt;
Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>selftests: netfilter: nft_tproxy.sh: adjust to socat changes</title>
<updated>2026-05-23T11:04:25+00:00</updated>
<author>
<name>Florian Westphal</name>
<email>fw@strlen.de</email>
</author>
<published>2026-04-09T22:45:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=8b95b1d336344ccd1c6fb845e35bf019f950973a'/>
<id>urn:sha1:8b95b1d336344ccd1c6fb845e35bf019f950973a</id>
<content type='text'>
[ Upstream commit 61119542663cac70898aef532eb57ee41ea9b477 ]

Like e65d8b6f3092 ("selftests: drv-net: adjust to socat changes") we
need to add shut-none for this test too.

The extra 0-packet can trigger a second (unexpected) reply from the server.

Fixes: 7e37e0eacd22 ("selftests: netfilter: nft_tproxy.sh: add tcp tests")
Reported-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Closes: https://lore.kernel.org/netdev/20260408152432.24b8ad0d@kernel.org/
Suggested-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Link: https://patch.msgid.link/20260409224506.27072-1-fw@strlen.de
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>selftests/bpf: fix __jited_unpriv tag name</title>
<updated>2026-05-23T11:04:24+00:00</updated>
<author>
<name>Eduard Zingerman</name>
<email>eddyz87@gmail.com</email>
</author>
<published>2026-04-11T07:33:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=4a36fd0e2c9f5850ba95b4674d1c9d132c054d8d'/>
<id>urn:sha1:4a36fd0e2c9f5850ba95b4674d1c9d132c054d8d</id>
<content type='text'>
[ Upstream commit cdd54fe98c00549264a92613af6bb0e9a5fd0d1c ]

__jited_unpriv was using "test_jited=" as its tag name, same as the
priv variant __jited. Fix by using "test_jited_unpriv=".

Fixes: 7d743e4c759c ("selftests/bpf: __jited test tag to check disassembly after jit")
Acked-by: Ihor Solodrai &lt;ihor.solodrai@linux.dev&gt;
Reviewed-by: Puranjay Mohan &lt;puranjay@kernel.org&gt;
Signed-off-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Link: https://lore.kernel.org/r/20260410-selftests-global-tags-ordering-v2-1-c566ec9781bf@gmail.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
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</entry>
<entry>
<title>bpf: Relax scalar id equivalence for state pruning</title>
<updated>2026-05-23T11:04:24+00:00</updated>
<author>
<name>Puranjay Mohan</name>
<email>puranjay@kernel.org</email>
</author>
<published>2026-02-03T16:51:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=647585dcafd451a68bd315c325b3fd4219859e51'/>
<id>urn:sha1:647585dcafd451a68bd315c325b3fd4219859e51</id>
<content type='text'>
[ Upstream commit b0388bafa4949bd30af7b3be5ee415f2a25ac014 ]

Scalar register IDs are used by the verifier to track relationships
between registers and enable bounds propagation across those
relationships. Once an ID becomes singular (i.e. only a single
register/stack slot carries it), it can no longer contribute to bounds
propagation and effectively becomes stale. The previous commit makes the
verifier clear such ids before caching the state.

When comparing the current and cached states for pruning, these stale
IDs can cause technically equivalent states to be considered different
and thus prevent pruning.

For example, in the selftest added in the next commit, two registers -
r6 and r7 are not linked to any other registers and get cached with
id=0, in the current state, they are both linked to each other with
id=A.  Before this commit, check_scalar_ids would give temporary ids to
r6 and r7 (say tid1 and tid2) and then check_ids() would map tid1-&gt;A,
and when it would see tid2-&gt;A, it would not consider these state
equivalent.

Relax scalar ID equivalence by treating rold-&gt;id == 0 as "independent":
if the old state did not rely on any ID relationships for a register,
then any ID/linking present in the current state only adds constraints
and is always safe to accept for pruning. Implement this by returning
true immediately in check_scalar_ids() when old_id == 0.

Maintain correctness for the opposite direction (old_id != 0 &amp;&amp; cur_id
== 0) by still allocating a temporary ID for cur_id == 0. This avoids
incorrectly allowing multiple independent current registers (id==0) to
satisfy a single linked old ID during mapping.

Signed-off-by: Puranjay Mohan &lt;puranjay@kernel.org&gt;
Link: https://lore.kernel.org/r/20260203165102.2302462-5-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Stable-dep-of: 2f2ec8e7730e ("bpf: Enforce regsafe base id consistency for BPF_ADD_CONST scalars")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
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</entry>
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