<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/kernel/bpf/helpers.c, branch v7.2-rc2</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge tag 'mm-nonmm-stable-2026-06-21-10-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm</title>
<updated>2026-06-21T20:20:19+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2026-06-21T20:20:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=2e05544060b9fef5d4d0e0172944e6956c55080f'/>
<id>2e05544060b9fef5d4d0e0172944e6956c55080f</id>
<content type='text'>
Pull non-MM updates from Andrew Morton:

 - "taskstats: fix TGID dead-thread stat retention" (Yiyang Chen)

   Fix a taskstats TGID aggregation bug where fields added in the TGID
   query path were not preserved after thread exit, and adds a kselftest
   covering the regression.

 - "lib/tests: string_helpers: Slight improvements" (Andy Shevchenko)

   Improve lib/tests/string_helpers_kunit.c a little

 - "lib/base64: decode fixes" (Josh Law)

   Address minor issues in lib/base64.c

 - "selftests/filelock: Make output more kselftestish" (Mark Brown)

   Make the output from the ofdlocks test a bit easier for tooling to
   work with. Also ignore the generated file

 - "uaccess: unify inline vs outline copy_{from,to}_user() selection"
   (Yury Norov)

   Simplify the usercopy code by removing the selectability of inlining
   copy_{from,to}_user().

 - "ocfs2: validate inline xattr header consumers" (ZhengYuan Huang)

   Fix a number of possible issues in the ocfs2 xattr code

 - "lib and lib/cmdline enhancements" (Dmitry Antipov)

   Provide additional robustness checking in the cmdline handling code
   and its in-kernel testing and selftests

 - "cleanup the RAID6 P/Q library" (Christoph Hellwig)

   Clean up the RAID6 P/Q library to match the recent updates to the
   RAID 5 XOR library and other CRC/crypto libraries

 - "ocfs2: harden inode validators against forged metadata" (Michael
   Bommarito)

   Add three structural checks to OCFS2 dinode validation so malformed
   on-disk fields are rejected before ocfs2_populate_inode() copies them
   into the in-core inode

 - "lib/raid: replace __get_free_pages() call with kmalloc()" (Mike
   Rapoport)

   Clean up the lib/raid code by using kmalloc() in more places

* tag 'mm-nonmm-stable-2026-06-21-10-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (108 commits)
  ocfs2: fix circular locking dependency in ocfs2_dio_end_io_write
  ocfs2: fix NULL h_transaction deref in ocfs2_assure_trans_credits
  lib: interval_tree_test: validate benchmark parameters
  ocfs2: avoid moving extents to occupied clusters
  treewide: fix transposed "sign" typos and update spelling.txt
  ocfs2: fix UBSAN array-index-out-of-bounds in ocfs2_sum_rightmost_rec
  fat: reject BPB volumes whose data area starts beyond total sectors
  selftests/uevent: increase __UEVENT_BUFFER_SIZE to avoid ENOBUFS on busy systems
  lib/test_firmware: allocate the configured into_buf size
  fs: efs: remove unneeded debug prints
  checkpatch: cuppress warnings when Reported-by: is followed by Link:
  MAINTAINERS: add Alexander as a kcov reviewer
  mailmap: update Alexander Sverdlin's Email addresses
  fs: fat: inode: replace sprintf() with scnprintf()
  ocfs2: fix out-of-bounds write in ocfs2_remove_refcount_extent
  ocfs2: fix race between ocfs2_control_install_private() and ocfs2_control_release()
  ocfs2/dlm: require a ref for locking_state debugfs open
  ocfs2: reject FITRIM ranges shorter than a cluster
  ocfs2: validate fast symlink target during inode read
  ocfs2: add journal NULL check in ocfs2_checkpoint_inode()
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull non-MM updates from Andrew Morton:

 - "taskstats: fix TGID dead-thread stat retention" (Yiyang Chen)

   Fix a taskstats TGID aggregation bug where fields added in the TGID
   query path were not preserved after thread exit, and adds a kselftest
   covering the regression.

 - "lib/tests: string_helpers: Slight improvements" (Andy Shevchenko)

   Improve lib/tests/string_helpers_kunit.c a little

 - "lib/base64: decode fixes" (Josh Law)

   Address minor issues in lib/base64.c

 - "selftests/filelock: Make output more kselftestish" (Mark Brown)

   Make the output from the ofdlocks test a bit easier for tooling to
   work with. Also ignore the generated file

 - "uaccess: unify inline vs outline copy_{from,to}_user() selection"
   (Yury Norov)

   Simplify the usercopy code by removing the selectability of inlining
   copy_{from,to}_user().

 - "ocfs2: validate inline xattr header consumers" (ZhengYuan Huang)

   Fix a number of possible issues in the ocfs2 xattr code

 - "lib and lib/cmdline enhancements" (Dmitry Antipov)

   Provide additional robustness checking in the cmdline handling code
   and its in-kernel testing and selftests

 - "cleanup the RAID6 P/Q library" (Christoph Hellwig)

   Clean up the RAID6 P/Q library to match the recent updates to the
   RAID 5 XOR library and other CRC/crypto libraries

 - "ocfs2: harden inode validators against forged metadata" (Michael
   Bommarito)

   Add three structural checks to OCFS2 dinode validation so malformed
   on-disk fields are rejected before ocfs2_populate_inode() copies them
   into the in-core inode

 - "lib/raid: replace __get_free_pages() call with kmalloc()" (Mike
   Rapoport)

   Clean up the lib/raid code by using kmalloc() in more places

* tag 'mm-nonmm-stable-2026-06-21-10-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (108 commits)
  ocfs2: fix circular locking dependency in ocfs2_dio_end_io_write
  ocfs2: fix NULL h_transaction deref in ocfs2_assure_trans_credits
  lib: interval_tree_test: validate benchmark parameters
  ocfs2: avoid moving extents to occupied clusters
  treewide: fix transposed "sign" typos and update spelling.txt
  ocfs2: fix UBSAN array-index-out-of-bounds in ocfs2_sum_rightmost_rec
  fat: reject BPB volumes whose data area starts beyond total sectors
  selftests/uevent: increase __UEVENT_BUFFER_SIZE to avoid ENOBUFS on busy systems
  lib/test_firmware: allocate the configured into_buf size
  fs: efs: remove unneeded debug prints
  checkpatch: cuppress warnings when Reported-by: is followed by Link:
  MAINTAINERS: add Alexander as a kcov reviewer
  mailmap: update Alexander Sverdlin's Email addresses
  fs: fat: inode: replace sprintf() with scnprintf()
  ocfs2: fix out-of-bounds write in ocfs2_remove_refcount_extent
  ocfs2: fix race between ocfs2_control_install_private() and ocfs2_control_release()
  ocfs2/dlm: require a ref for locking_state debugfs open
  ocfs2: reject FITRIM ranges shorter than a cluster
  ocfs2: validate fast symlink target during inode read
  ocfs2: add journal NULL check in ocfs2_checkpoint_inode()
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>treewide: fix transposed "sign" typos and update spelling.txt</title>
<updated>2026-06-17T22:37:47+00:00</updated>
<author>
<name>Shardul Deshpande</name>
<email>iamsharduld@gmail.com</email>
</author>
<published>2026-06-12T18:16:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=07669b0abe4ce76c716e8437e198e1337cf43d1f'/>
<id>07669b0abe4ce76c716e8437e198e1337cf43d1f</id>
<content type='text'>
Several comments transpose the letters in "assigned" and "unsigned",
spelling them with "sing" instead of "sign".  Correct all of them.

Of these, the misspelling of "assigned" is not yet flagged by checkpatch,
so also add it to scripts/spelling.txt.

The remaining matches of `grep -ri singed` are RISINGEDGE register and
enum names, not typos.

Link: https://lore.kernel.org/20260612181633.734458-1-iamsharduld@gmail.com
Signed-off-by: Shardul Deshpande &lt;iamsharduld@gmail.com&gt;
Suggested-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Reviewed-by: SeongJae Park &lt;sj@kernel.org&gt;
Cc: Joe Perches &lt;joe@perches.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Several comments transpose the letters in "assigned" and "unsigned",
spelling them with "sing" instead of "sign".  Correct all of them.

Of these, the misspelling of "assigned" is not yet flagged by checkpatch,
so also add it to scripts/spelling.txt.

The remaining matches of `grep -ri singed` are RISINGEDGE register and
enum names, not typos.

Link: https://lore.kernel.org/20260612181633.734458-1-iamsharduld@gmail.com
Signed-off-by: Shardul Deshpande &lt;iamsharduld@gmail.com&gt;
Suggested-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Reviewed-by: SeongJae Park &lt;sj@kernel.org&gt;
Cc: Joe Perches &lt;joe@perches.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Fix NULL pointer dereference in bpf_task_from_vpid()</title>
<updated>2026-06-08T11:33:55+00:00</updated>
<author>
<name>Sechang Lim</name>
<email>rhkrqnwk98@gmail.com</email>
</author>
<published>2026-06-08T05:00:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=50dff00615522f3ec03449680ca23beb4cfc549c'/>
<id>50dff00615522f3ec03449680ca23beb4cfc549c</id>
<content type='text'>
bpf_task_from_vpid() looks up a task in the pid namespace of the
current task, via find_task_by_vpid():

  find_task_by_vpid(vpid)
    find_task_by_pid_ns(vpid, task_active_pid_ns(current))
      find_pid_ns(nr, ns) -&gt; idr_find(&amp;ns-&gt;idr, nr)

cgroup_skb programs run in softirq, which may interrupt a task that is
itself in do_exit(). Once that task has passed
exit_notify() -&gt; release_task() -&gt; __unhash_process(), its thread_pid is
cleared, so task_active_pid_ns(current) returns NULL and find_pid_ns()
dereferences &amp;NULL-&gt;idr:

  BUG: kernel NULL pointer dereference, address: 0000000000000050
  RIP: 0010:idr_find+0x11/0x30 lib/idr.c:176
  Call Trace:
   &lt;IRQ&gt;
   find_pid_ns kernel/pid.c:370 [inline]
   find_task_by_pid_ns+0x3b/0xe0 kernel/pid.c:485
   bpf_task_from_vpid+0x5b/0x200 kernel/bpf/helpers.c:2916
   bpf_prog_run_array_cg+0x17e/0x530 kernel/bpf/cgroup.c:81
   __cgroup_bpf_run_filter_skb+0x12b/0x250 kernel/bpf/cgroup.c:1612
   sk_filter_trim_cap+0x1dc/0x4c0 net/core/filter.c:148
   tcp_v4_rcv+0x18d1/0x2200 net/ipv4/tcp_ipv4.c:2223
   &lt;/IRQ&gt;
   &lt;TASK&gt;
   do_exit+0xa63/0x1270 kernel/exit.c:1010
   get_signal+0x141c/0x1530 kernel/signal.c:3037

Bail out when current has no pid namespace.

Fixes: 675c3596ff32 ("bpf: Add bpf_task_from_vpid() kfunc")
Signed-off-by: Sechang Lim &lt;rhkrqnwk98@gmail.com&gt;
Acked-by: Leon Hwang &lt;leon.hwang@linux.dev&gt;
Link: https://lore.kernel.org/bpf/20260608050001.2545245-1-rhkrqnwk98@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi &lt;memxor@gmail.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
bpf_task_from_vpid() looks up a task in the pid namespace of the
current task, via find_task_by_vpid():

  find_task_by_vpid(vpid)
    find_task_by_pid_ns(vpid, task_active_pid_ns(current))
      find_pid_ns(nr, ns) -&gt; idr_find(&amp;ns-&gt;idr, nr)

cgroup_skb programs run in softirq, which may interrupt a task that is
itself in do_exit(). Once that task has passed
exit_notify() -&gt; release_task() -&gt; __unhash_process(), its thread_pid is
cleared, so task_active_pid_ns(current) returns NULL and find_pid_ns()
dereferences &amp;NULL-&gt;idr:

  BUG: kernel NULL pointer dereference, address: 0000000000000050
  RIP: 0010:idr_find+0x11/0x30 lib/idr.c:176
  Call Trace:
   &lt;IRQ&gt;
   find_pid_ns kernel/pid.c:370 [inline]
   find_task_by_pid_ns+0x3b/0xe0 kernel/pid.c:485
   bpf_task_from_vpid+0x5b/0x200 kernel/bpf/helpers.c:2916
   bpf_prog_run_array_cg+0x17e/0x530 kernel/bpf/cgroup.c:81
   __cgroup_bpf_run_filter_skb+0x12b/0x250 kernel/bpf/cgroup.c:1612
   sk_filter_trim_cap+0x1dc/0x4c0 net/core/filter.c:148
   tcp_v4_rcv+0x18d1/0x2200 net/ipv4/tcp_ipv4.c:2223
   &lt;/IRQ&gt;
   &lt;TASK&gt;
   do_exit+0xa63/0x1270 kernel/exit.c:1010
   get_signal+0x141c/0x1530 kernel/signal.c:3037

Bail out when current has no pid namespace.

Fixes: 675c3596ff32 ("bpf: Add bpf_task_from_vpid() kfunc")
Signed-off-by: Sechang Lim &lt;rhkrqnwk98@gmail.com&gt;
Acked-by: Leon Hwang &lt;leon.hwang@linux.dev&gt;
Link: https://lore.kernel.org/bpf/20260608050001.2545245-1-rhkrqnwk98@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi &lt;memxor@gmail.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Clear rb node linkage when freeing bpf_rb_root</title>
<updated>2026-06-05T21:19:19+00:00</updated>
<author>
<name>Kaitao Cheng</name>
<email>chengkaitao@kylinos.cn</email>
</author>
<published>2026-06-05T09:41:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=4a7910ee060d8ce55612f5b3cc267f3a265a3cec'/>
<id>4a7910ee060d8ce55612f5b3cc267f3a265a3cec</id>
<content type='text'>
bpf_rb_root_free() detaches the root by copying the current rb_root_cached
and then replacing the live root with RB_ROOT_CACHED. It then walks the
copied root and drops each object contained in the tree.

This leaves the rb node state intact while dropping the object. If the
object is refcounted and survives the drop, its bpf_rb_node_kern still
contains an owner pointer to the freed root and stale rb tree linkage. If
a later bpf_rb_root allocation reuses the same address, bpf_rbtree_remove()
can incorrectly pass the owner check and call rb_erase_cached() on a node
whose rb pointers belong to the old tree.

Mirror the list draining behavior by marking nodes as busy while the root
is being detached, then clear the rb node and release the owner before
dropping the containing object. This makes surviving nodes unowned and
safe to reject from remove or accept for a later add.

Fixes: 9c395c1b99bd ("bpf: Add basic bpf_rb_{root,node} support")
Signed-off-by: Kaitao Cheng &lt;chengkaitao@kylinos.cn&gt;
Acked-by: Yonghong Song &lt;yonghong.song@linux.dev&gt;
Link: https://lore.kernel.org/r/20260605094143.5509-1-kaitao.cheng@linux.dev
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
bpf_rb_root_free() detaches the root by copying the current rb_root_cached
and then replacing the live root with RB_ROOT_CACHED. It then walks the
copied root and drops each object contained in the tree.

This leaves the rb node state intact while dropping the object. If the
object is refcounted and survives the drop, its bpf_rb_node_kern still
contains an owner pointer to the freed root and stale rb tree linkage. If
a later bpf_rb_root allocation reuses the same address, bpf_rbtree_remove()
can incorrectly pass the owner check and call rb_erase_cached() on a node
whose rb pointers belong to the old tree.

Mirror the list draining behavior by marking nodes as busy while the root
is being detached, then clear the rb node and release the owner before
dropping the containing object. This makes surviving nodes unowned and
safe to reject from remove or accept for a later add.

Fixes: 9c395c1b99bd ("bpf: Add basic bpf_rb_{root,node} support")
Signed-off-by: Kaitao Cheng &lt;chengkaitao@kylinos.cn&gt;
Acked-by: Yonghong Song &lt;yonghong.song@linux.dev&gt;
Link: https://lore.kernel.org/r/20260605094143.5509-1-kaitao.cheng@linux.dev
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Unify release handling for helpers and kfuncs</title>
<updated>2026-06-02T01:31:41+00:00</updated>
<author>
<name>Amery Hung</name>
<email>ameryhung@gmail.com</email>
</author>
<published>2026-05-29T01:49:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=bcfcb15fde94ed39068eb1d6e4b9b37d27111965'/>
<id>bcfcb15fde94ed39068eb1d6e4b9b37d27111965</id>
<content type='text'>
Introduce release_reg() to consolidate the release logic shared by both
helpers and kfuncs: dynptr release, kptr_xchg percpu-to-RCU conversion,
regular reference release, and NULL pass-through. NULL pass-through is
only allowed if the prototype indicates the argument may be null.

Determine release_regno from the function prototype/metadata before
argument checking, rather than discovering it dynamically during
argument processing. For helpers, scan the arg_type array in
check_func_proto() via check_proto_release_reg(). For kfuncs, set
release_regno to BPF_REG_1 in bpf_fetch_kfunc_arg_meta() when
KF_RELEASE is set. In the future when we start adding decl_tag to
kfunc arguments, we can just look at the function prototype instead
of a release_regno.

Extract ref_convert_alloc_rcu_protected() and
invalidate_rcu_protected_refs() to make it more clear what the code is
doing. For ref_convert_alloc_rcu_protected(), it pre-converts
MEM_ALLOC | MEM_PERCPU registers to MEM_RCU (clearing id so they
survive), then calls release_reference() to invalidate the remaining
registers and release the reference state.

Add KF_RELEASE to bpf_dynptr_file_discard() so its release_regno is set
via fetch_kfunc_meta rather than being assigned manually in the dynptr
argument processing. Set arg_type to ARG_PTR_TO_DYNPTR for
KF_ARG_PTR_TO_DYNPTR so that check_func_arg_reg_off() correctly allows
non-zero stack offsets for dynptr release arguments same as helper.

Acked-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Signed-off-by: Amery Hung &lt;ameryhung@gmail.com&gt;
Link: https://lore.kernel.org/r/20260529014936.2811085-9-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Introduce release_reg() to consolidate the release logic shared by both
helpers and kfuncs: dynptr release, kptr_xchg percpu-to-RCU conversion,
regular reference release, and NULL pass-through. NULL pass-through is
only allowed if the prototype indicates the argument may be null.

Determine release_regno from the function prototype/metadata before
argument checking, rather than discovering it dynamically during
argument processing. For helpers, scan the arg_type array in
check_func_proto() via check_proto_release_reg(). For kfuncs, set
release_regno to BPF_REG_1 in bpf_fetch_kfunc_arg_meta() when
KF_RELEASE is set. In the future when we start adding decl_tag to
kfunc arguments, we can just look at the function prototype instead
of a release_regno.

Extract ref_convert_alloc_rcu_protected() and
invalidate_rcu_protected_refs() to make it more clear what the code is
doing. For ref_convert_alloc_rcu_protected(), it pre-converts
MEM_ALLOC | MEM_PERCPU registers to MEM_RCU (clearing id so they
survive), then calls release_reference() to invalidate the remaining
registers and release the reference state.

Add KF_RELEASE to bpf_dynptr_file_discard() so its release_regno is set
via fetch_kfunc_meta rather than being assigned manually in the dynptr
argument processing. Set arg_type to ARG_PTR_TO_DYNPTR for
KF_ARG_PTR_TO_DYNPTR so that check_func_arg_reg_off() correctly allows
non-zero stack offsets for dynptr release arguments same as helper.

Acked-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Signed-off-by: Amery Hung &lt;ameryhung@gmail.com&gt;
Link: https://lore.kernel.org/r/20260529014936.2811085-9-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 7.1-rc5</title>
<updated>2026-05-25T13:33:30+00:00</updated>
<author>
<name>Alexei Starovoitov</name>
<email>ast@kernel.org</email>
</author>
<published>2026-05-25T13:33:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=eb19eead368bb0f0ef06a4125d03ed661cd23d36'/>
<id>eb19eead368bb0f0ef06a4125d03ed661cd23d36</id>
<content type='text'>
Cross-merge BPF and other fixes after downstream PR.

Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Cross-merge BPF and other fixes after downstream PR.

Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: add bpf_list_is_first/last/empty kfuncs</title>
<updated>2026-05-21T09:47:46+00:00</updated>
<author>
<name>Kaitao Cheng</name>
<email>chengkaitao@kylinos.cn</email>
</author>
<published>2026-05-21T03:23:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=745515d386eb5e6891d9f91a92ad15dace3a33ef'/>
<id>745515d386eb5e6891d9f91a92ad15dace3a33ef</id>
<content type='text'>
Add three kfuncs for BPF linked list queries:
- bpf_list_is_first(head, node): true if node is the first in the list.
- bpf_list_is_last(head, node): true if node is the last in the list.
- bpf_list_empty(head): true if the list has no entries.

Currently, without these kfuncs, to implement the above functionality
it is necessary to first call bpf_list_pop_front/back to retrieve the
first or last node before checking whether the passed-in node was the
first or last one. After the check, the node had to be pushed back into
the list using bpf_list_push_front/back, which was very inefficient.

Now, with the bpf_list_is_first/last/empty kfuncs, we can directly
check whether a node is the first, last, or whether the list is empty,
without having to first retrieve the node.

Signed-off-by: Kaitao Cheng &lt;chengkaitao@kylinos.cn&gt;
Reviewed-by: Emil Tsalapatis &lt;emil@etsalapatis.com&gt;
Link: https://lore.kernel.org/r/20260521032306.97118-8-kaitao.cheng@linux.dev
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</content>
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<pre>
Add three kfuncs for BPF linked list queries:
- bpf_list_is_first(head, node): true if node is the first in the list.
- bpf_list_is_last(head, node): true if node is the last in the list.
- bpf_list_empty(head): true if the list has no entries.

Currently, without these kfuncs, to implement the above functionality
it is necessary to first call bpf_list_pop_front/back to retrieve the
first or last node before checking whether the passed-in node was the
first or last one. After the check, the node had to be pushed back into
the list using bpf_list_push_front/back, which was very inefficient.

Now, with the bpf_list_is_first/last/empty kfuncs, we can directly
check whether a node is the first, last, or whether the list is empty,
without having to first retrieve the node.

Signed-off-by: Kaitao Cheng &lt;chengkaitao@kylinos.cn&gt;
Reviewed-by: Emil Tsalapatis &lt;emil@etsalapatis.com&gt;
Link: https://lore.kernel.org/r/20260521032306.97118-8-kaitao.cheng@linux.dev
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Add bpf_list_add to insert node after a given list node</title>
<updated>2026-05-21T09:47:46+00:00</updated>
<author>
<name>Kaitao Cheng</name>
<email>chengkaitao@kylinos.cn</email>
</author>
<published>2026-05-21T03:23:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=a3493ca504f16877bf29a123f27835c3f841a05f'/>
<id>a3493ca504f16877bf29a123f27835c3f841a05f</id>
<content type='text'>
Add a new kfunc bpf_list_add(head, new, prev, meta, off) that
inserts 'new' after 'prev' in the BPF linked list. Both must be in
the same list; 'prev' must already be in the list. The new node must
be an owning reference (e.g. from bpf_obj_new); the kfunc consumes
that reference and the node becomes non-owning once inserted.

We have added an additional parameter bpf_list_head *head to
bpf_list_add, as the verifier requires the head parameter to
check whether the lock is being held.

Returns 0 on success, -EINVAL if 'prev' is not in a list or 'new'
is already in a list (or duplicate insertion). On failure, the
kernel drops the passed-in node.

Signed-off-by: Kaitao Cheng &lt;chengkaitao@kylinos.cn&gt;
Reviewed-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Link: https://lore.kernel.org/r/20260521032306.97118-7-kaitao.cheng@linux.dev
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add a new kfunc bpf_list_add(head, new, prev, meta, off) that
inserts 'new' after 'prev' in the BPF linked list. Both must be in
the same list; 'prev' must already be in the list. The new node must
be an owning reference (e.g. from bpf_obj_new); the kfunc consumes
that reference and the node becomes non-owning once inserted.

We have added an additional parameter bpf_list_head *head to
bpf_list_add, as the verifier requires the head parameter to
check whether the lock is being held.

Returns 0 on success, -EINVAL if 'prev' is not in a list or 'new'
is already in a list (or duplicate insertion). On failure, the
kernel drops the passed-in node.

Signed-off-by: Kaitao Cheng &lt;chengkaitao@kylinos.cn&gt;
Reviewed-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Link: https://lore.kernel.org/r/20260521032306.97118-7-kaitao.cheng@linux.dev
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: refactor __bpf_list_add to take insertion point via **prev_ptr</title>
<updated>2026-05-21T09:47:45+00:00</updated>
<author>
<name>Kaitao Cheng</name>
<email>chengkaitao@kylinos.cn</email>
</author>
<published>2026-05-21T03:23:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=e6919ff67c1e612ec1ce3be51dba6e7ffc47997a'/>
<id>e6919ff67c1e612ec1ce3be51dba6e7ffc47997a</id>
<content type='text'>
Refactor __bpf_list_add to accept (node, head, struct list_head **prev_ptr,
..) instead of (node, head, bool tail, ..). Load prev from *prev_ptr after
INIT_LIST_HEAD(h), so we never dereference an uninitialized h-&gt;prev when
head was 0-initialized (e.g. push_back passes &amp;h-&gt;prev).

When prev is not the list head, validate that prev is in the list via
its owner.

Prepares for bpf_list_add(head, new, prev, ..) to insert after a given
list node.

Signed-off-by: Kaitao Cheng &lt;chengkaitao@kylinos.cn&gt;
Reviewed-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Link: https://lore.kernel.org/r/20260521032306.97118-6-kaitao.cheng@linux.dev
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Refactor __bpf_list_add to accept (node, head, struct list_head **prev_ptr,
..) instead of (node, head, bool tail, ..). Load prev from *prev_ptr after
INIT_LIST_HEAD(h), so we never dereference an uninitialized h-&gt;prev when
head was 0-initialized (e.g. push_back passes &amp;h-&gt;prev).

When prev is not the list head, validate that prev is in the list via
its owner.

Prepares for bpf_list_add(head, new, prev, ..) to insert after a given
list node.

Signed-off-by: Kaitao Cheng &lt;chengkaitao@kylinos.cn&gt;
Reviewed-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Link: https://lore.kernel.org/r/20260521032306.97118-6-kaitao.cheng@linux.dev
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Introduce the bpf_list_del kfunc.</title>
<updated>2026-05-21T09:47:45+00:00</updated>
<author>
<name>Kaitao Cheng</name>
<email>chengkaitao@kylinos.cn</email>
</author>
<published>2026-05-21T03:23:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=187baa10963ac9f1db5123fa2ab761ab34ea06b9'/>
<id>187baa10963ac9f1db5123fa2ab761ab34ea06b9</id>
<content type='text'>
Allow users to remove any node from a linked list.

We have added an additional parameter bpf_list_head *head to
bpf_list_del, as the verifier requires the head parameter to
check whether the lock is being held.

Signed-off-by: Kaitao Cheng &lt;chengkaitao@kylinos.cn&gt;
Reviewed-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Link: https://lore.kernel.org/r/20260521032306.97118-5-kaitao.cheng@linux.dev
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Allow users to remove any node from a linked list.

We have added an additional parameter bpf_list_head *head to
bpf_list_del, as the verifier requires the head parameter to
check whether the lock is being held.

Signed-off-by: Kaitao Cheng &lt;chengkaitao@kylinos.cn&gt;
Reviewed-by: Eduard Zingerman &lt;eddyz87@gmail.com&gt;
Link: https://lore.kernel.org/r/20260521032306.97118-5-kaitao.cheng@linux.dev
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
