<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/net/bpf, branch v6.5.2</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>bpf: Move kernel test kfuncs to bpf_testmod</title>
<updated>2023-05-17T05:09:24+00:00</updated>
<author>
<name>Jiri Olsa</name>
<email>jolsa@kernel.org</email>
</author>
<published>2023-05-15T13:37:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=65eb006d85a2ac0b23464808099726bd826e9877'/>
<id>65eb006d85a2ac0b23464808099726bd826e9877</id>
<content type='text'>
Moving kernel test kfuncs into bpf_testmod kernel module, and adding
necessary init calls and BTF IDs records.

We need to keep following structs in kernel:
  struct prog_test_ref_kfunc
  struct prog_test_member (embedded in prog_test_ref_kfunc)

The reason is because they need to be marked as rcu safe (check test
prog mark_ref_as_untrusted_or_null) and such objects are being required
to be defined only in kernel at the moment (see rcu_safe_kptr check
in kernel).

We need to keep also dtor functions for both objects in kernel:
  bpf_kfunc_call_test_release
  bpf_kfunc_call_memb_release

We also keep the copy of these struct in bpf_testmod_kfunc.h, because
other test functions use them. This is unfortunate, but this is just
temporary solution until we are able to these structs them to bpf_testmod
completely.

As suggested by David adding bpf_testmod.ko make dependency for
bpf programs, so they are rebuilt if we change the bpf_testmod.ko
module.

Also adding missing __bpf_kfunc to bpf_kfunc_call_test4 functions.

Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Acked-by: David Vernet &lt;void@manifault.com&gt;
Link: https://lore.kernel.org/r/20230515133756.1658301-11-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Moving kernel test kfuncs into bpf_testmod kernel module, and adding
necessary init calls and BTF IDs records.

We need to keep following structs in kernel:
  struct prog_test_ref_kfunc
  struct prog_test_member (embedded in prog_test_ref_kfunc)

The reason is because they need to be marked as rcu safe (check test
prog mark_ref_as_untrusted_or_null) and such objects are being required
to be defined only in kernel at the moment (see rcu_safe_kptr check
in kernel).

We need to keep also dtor functions for both objects in kernel:
  bpf_kfunc_call_test_release
  bpf_kfunc_call_memb_release

We also keep the copy of these struct in bpf_testmod_kfunc.h, because
other test functions use them. This is unfortunate, but this is just
temporary solution until we are able to these structs them to bpf_testmod
completely.

As suggested by David adding bpf_testmod.ko make dependency for
bpf programs, so they are rebuilt if we change the bpf_testmod.ko
module.

Also adding missing __bpf_kfunc to bpf_kfunc_call_test4 functions.

Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Acked-by: David Vernet &lt;void@manifault.com&gt;
Link: https://lore.kernel.org/r/20230515133756.1658301-11-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: introduce and use skb_frag_fill_page_desc()</title>
<updated>2023-05-13T18:47:56+00:00</updated>
<author>
<name>Yunsheng Lin</name>
<email>linyunsheng@huawei.com</email>
</author>
<published>2023-05-11T01:12:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b51f4113ebb02011f0ca86abc3134b28d2071b6a'/>
<id>b51f4113ebb02011f0ca86abc3134b28d2071b6a</id>
<content type='text'>
Most users use __skb_frag_set_page()/skb_frag_off_set()/
skb_frag_size_set() to fill the page desc for a skb frag.

Introduce skb_frag_fill_page_desc() to do that.

net/bpf/test_run.c does not call skb_frag_off_set() to
set the offset, "copy_from_user(page_address(page), ...)"
and 'shinfo' being part of the 'data' kzalloced in
bpf_test_init() suggest that it is assuming offset to be
initialized as zero, so call skb_frag_fill_page_desc()
with offset being zero for this case.

Also, skb_frag_set_page() is not used anymore, so remove
it.

Signed-off-by: Yunsheng Lin &lt;linyunsheng@huawei.com&gt;
Reviewed-by: Leon Romanovsky &lt;leonro@nvidia.com&gt;
Reviewed-by: Simon Horman &lt;simon.horman@corigine.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Most users use __skb_frag_set_page()/skb_frag_off_set()/
skb_frag_size_set() to fill the page desc for a skb frag.

Introduce skb_frag_fill_page_desc() to do that.

net/bpf/test_run.c does not call skb_frag_off_set() to
set the offset, "copy_from_user(page_address(page), ...)"
and 'shinfo' being part of the 'data' kzalloced in
bpf_test_init() suggest that it is assuming offset to be
initialized as zero, so call skb_frag_fill_page_desc()
with offset being zero for this case.

Also, skb_frag_set_page() is not used anymore, so remove
it.

Signed-off-by: Yunsheng Lin &lt;linyunsheng@huawei.com&gt;
Reviewed-by: Leon Romanovsky &lt;leonro@nvidia.com&gt;
Reviewed-by: Simon Horman &lt;simon.horman@corigine.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: add test_run support for netfilter program type</title>
<updated>2023-04-21T18:34:50+00:00</updated>
<author>
<name>Florian Westphal</name>
<email>fw@strlen.de</email>
</author>
<published>2023-04-21T17:02:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2b99ef22e0d237e08bfc437e7d051f78f352aeb2'/>
<id>2b99ef22e0d237e08bfc437e7d051f78f352aeb2</id>
<content type='text'>
add glue code so a bpf program can be run using userspace-provided
netfilter state and packet/skb.

Default is to use ipv4:output hook point, but this can be overridden by
userspace.  Userspace provided netfilter state is restricted, only hook and
protocol families can be overridden and only to ipv4/ipv6.

Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Link: https://lore.kernel.org/r/20230421170300.24115-7-fw@strlen.de
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
add glue code so a bpf program can be run using userspace-provided
netfilter state and packet/skb.

Default is to use ipv4:output hook point, but this can be overridden by
userspace.  Userspace provided netfilter state is restricted, only hook and
protocol families can be overridden and only to ipv4/ipv6.

Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Link: https://lore.kernel.org/r/20230421170300.24115-7-fw@strlen.de
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Remove bpf_kfunc_call_test_kptr_get() test kfunc</title>
<updated>2023-04-16T15:51:24+00:00</updated>
<author>
<name>David Vernet</name>
<email>void@manifault.com</email>
</author>
<published>2023-04-16T08:49:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=09b501d905217a38f03c0f07d5a66e0b5c8c1644'/>
<id>09b501d905217a38f03c0f07d5a66e0b5c8c1644</id>
<content type='text'>
We've managed to improve the UX for kptrs significantly over the last 9
months. All of the prior main use cases, struct bpf_cpumask *, struct
task_struct *, and struct cgroup *, have all been updated to be
synchronized mainly using RCU. In other words, their KF_ACQUIRE kfunc
calls are all KF_RCU, and the pointers themselves are MEM_RCU and can be
accessed in an RCU read region in BPF.

In a follow-on change, we'll be removing the KF_KPTR_GET kfunc flag.
This patch prepares for that by removing the
bpf_kfunc_call_test_kptr_get() kfunc, and all associated selftests.

Signed-off-by: David Vernet &lt;void@manifault.com&gt;
Link: https://lore.kernel.org/r/20230416084928.326135-2-void@manifault.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
We've managed to improve the UX for kptrs significantly over the last 9
months. All of the prior main use cases, struct bpf_cpumask *, struct
task_struct *, and struct cgroup *, have all been updated to be
synchronized mainly using RCU. In other words, their KF_ACQUIRE kfunc
calls are all KF_RCU, and the pointers themselves are MEM_RCU and can be
accessed in an RCU read region in BPF.

In a follow-on change, we'll be removing the KF_KPTR_GET kfunc flag.
This patch prepares for that by removing the
bpf_kfunc_call_test_kptr_get() kfunc, and all associated selftests.

Signed-off-by: David Vernet &lt;void@manifault.com&gt;
Link: https://lore.kernel.org/r/20230416084928.326135-2-void@manifault.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Daniel Borkmann says:</title>
<updated>2023-04-13T23:43:38+00:00</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2023-04-13T23:11:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c2865b1122595e69e7df52d01f7f02338b8babca'/>
<id>c2865b1122595e69e7df52d01f7f02338b8babca</id>
<content type='text'>
====================
pull-request: bpf-next 2023-04-13

We've added 260 non-merge commits during the last 36 day(s) which contain
a total of 356 files changed, 21786 insertions(+), 11275 deletions(-).

The main changes are:

1) Rework BPF verifier log behavior and implement it as a rotating log
   by default with the option to retain old-style fixed log behavior,
   from Andrii Nakryiko.

2) Adds support for using {FOU,GUE} encap with an ipip device operating
   in collect_md mode and add a set of BPF kfuncs for controlling encap
   params, from Christian Ehrig.

3) Allow BPF programs to detect at load time whether a particular kfunc
   exists or not, and also add support for this in light skeleton,
   from Alexei Starovoitov.

4) Optimize hashmap lookups when key size is multiple of 4,
   from Anton Protopopov.

5) Enable RCU semantics for task BPF kptrs and allow referenced kptr
   tasks to be stored in BPF maps, from David Vernet.

6) Add support for stashing local BPF kptr into a map value via
   bpf_kptr_xchg(). This is useful e.g. for rbtree node creation
   for new cgroups, from Dave Marchevsky.

7) Fix BTF handling of is_int_ptr to skip modifiers to work around
   tracing issues where a program cannot be attached, from Feng Zhou.

8) Migrate a big portion of test_verifier unit tests over to
   test_progs -a verifier_* via inline asm to ease {read,debug}ability,
   from Eduard Zingerman.

9) Several updates to the instruction-set.rst documentation
   which is subject to future IETF standardization
   (https://lwn.net/Articles/926882/), from Dave Thaler.

10) Fix BPF verifier in the __reg_bound_offset's 64-&gt;32 tnum sub-register
    known bits information propagation, from Daniel Borkmann.

11) Add skb bitfield compaction work related to BPF with the overall goal
    to make more of the sk_buff bits optional, from Jakub Kicinski.

12) BPF selftest cleanups for build id extraction which stand on its own
    from the upcoming integration work of build id into struct file object,
    from Jiri Olsa.

13) Add fixes and optimizations for xsk descriptor validation and several
    selftest improvements for xsk sockets, from Kal Conley.

14) Add BPF links for struct_ops and enable switching implementations
    of BPF TCP cong-ctls under a given name by replacing backing
    struct_ops map, from Kui-Feng Lee.

15) Remove a misleading BPF verifier env-&gt;bypass_spec_v1 check on variable
    offset stack read as earlier Spectre checks cover this,
    from Luis Gerhorst.

16) Fix issues in copy_from_user_nofault() for BPF and other tracers
    to resemble copy_from_user_nmi() from safety PoV, from Florian Lehner
    and Alexei Starovoitov.

17) Add --json-summary option to test_progs in order for CI tooling to
    ease parsing of test results, from Manu Bretelle.

18) Batch of improvements and refactoring to prep for upcoming
    bpf_local_storage conversion to bpf_mem_cache_{alloc,free} allocator,
    from Martin KaFai Lau.

19) Improve bpftool's visual program dump which produces the control
    flow graph in a DOT format by adding C source inline annotations,
    from Quentin Monnet.

20) Fix attaching fentry/fexit/fmod_ret/lsm to modules by extracting
    the module name from BTF of the target and searching kallsyms of
    the correct module, from Viktor Malik.

21) Improve BPF verifier handling of '&lt;const&gt; &lt;cond&gt; &lt;non_const&gt;'
    to better detect whether in particular jmp32 branches are taken,
    from Yonghong Song.

22) Allow BPF TCP cong-ctls to write app_limited of struct tcp_sock.
    A built-in cc or one from a kernel module is already able to write
    to app_limited, from Yixin Shen.

Conflicts:

Documentation/bpf/bpf_devel_QA.rst
  b7abcd9c656b ("bpf, doc: Link to submitting-patches.rst for general patch submission info")
  0f10f647f455 ("bpf, docs: Use internal linking for link to netdev subsystem doc")
https://lore.kernel.org/all/20230307095812.236eb1be@canb.auug.org.au/

include/net/ip_tunnels.h
  bc9d003dc48c3 ("ip_tunnel: Preserve pointer const in ip_tunnel_info_opts")
  ac931d4cdec3d ("ipip,ip_tunnel,sit: Add FOU support for externally controlled ipip devices")
https://lore.kernel.org/all/20230413161235.4093777-1-broonie@kernel.org/

net/bpf/test_run.c
  e5995bc7e2ba ("bpf, test_run: fix crashes due to XDP frame overwriting/corruption")
  294635a8165a ("bpf, test_run: fix &amp;xdp_frame misplacement for LIVE_FRAMES")
https://lore.kernel.org/all/20230320102619.05b80a98@canb.auug.org.au/
====================

Link: https://lore.kernel.org/r/20230413191525.7295-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
====================
pull-request: bpf-next 2023-04-13

We've added 260 non-merge commits during the last 36 day(s) which contain
a total of 356 files changed, 21786 insertions(+), 11275 deletions(-).

The main changes are:

1) Rework BPF verifier log behavior and implement it as a rotating log
   by default with the option to retain old-style fixed log behavior,
   from Andrii Nakryiko.

2) Adds support for using {FOU,GUE} encap with an ipip device operating
   in collect_md mode and add a set of BPF kfuncs for controlling encap
   params, from Christian Ehrig.

3) Allow BPF programs to detect at load time whether a particular kfunc
   exists or not, and also add support for this in light skeleton,
   from Alexei Starovoitov.

4) Optimize hashmap lookups when key size is multiple of 4,
   from Anton Protopopov.

5) Enable RCU semantics for task BPF kptrs and allow referenced kptr
   tasks to be stored in BPF maps, from David Vernet.

6) Add support for stashing local BPF kptr into a map value via
   bpf_kptr_xchg(). This is useful e.g. for rbtree node creation
   for new cgroups, from Dave Marchevsky.

7) Fix BTF handling of is_int_ptr to skip modifiers to work around
   tracing issues where a program cannot be attached, from Feng Zhou.

8) Migrate a big portion of test_verifier unit tests over to
   test_progs -a verifier_* via inline asm to ease {read,debug}ability,
   from Eduard Zingerman.

9) Several updates to the instruction-set.rst documentation
   which is subject to future IETF standardization
   (https://lwn.net/Articles/926882/), from Dave Thaler.

10) Fix BPF verifier in the __reg_bound_offset's 64-&gt;32 tnum sub-register
    known bits information propagation, from Daniel Borkmann.

11) Add skb bitfield compaction work related to BPF with the overall goal
    to make more of the sk_buff bits optional, from Jakub Kicinski.

12) BPF selftest cleanups for build id extraction which stand on its own
    from the upcoming integration work of build id into struct file object,
    from Jiri Olsa.

13) Add fixes and optimizations for xsk descriptor validation and several
    selftest improvements for xsk sockets, from Kal Conley.

14) Add BPF links for struct_ops and enable switching implementations
    of BPF TCP cong-ctls under a given name by replacing backing
    struct_ops map, from Kui-Feng Lee.

15) Remove a misleading BPF verifier env-&gt;bypass_spec_v1 check on variable
    offset stack read as earlier Spectre checks cover this,
    from Luis Gerhorst.

16) Fix issues in copy_from_user_nofault() for BPF and other tracers
    to resemble copy_from_user_nmi() from safety PoV, from Florian Lehner
    and Alexei Starovoitov.

17) Add --json-summary option to test_progs in order for CI tooling to
    ease parsing of test results, from Manu Bretelle.

18) Batch of improvements and refactoring to prep for upcoming
    bpf_local_storage conversion to bpf_mem_cache_{alloc,free} allocator,
    from Martin KaFai Lau.

19) Improve bpftool's visual program dump which produces the control
    flow graph in a DOT format by adding C source inline annotations,
    from Quentin Monnet.

20) Fix attaching fentry/fexit/fmod_ret/lsm to modules by extracting
    the module name from BTF of the target and searching kallsyms of
    the correct module, from Viktor Malik.

21) Improve BPF verifier handling of '&lt;const&gt; &lt;cond&gt; &lt;non_const&gt;'
    to better detect whether in particular jmp32 branches are taken,
    from Yonghong Song.

22) Allow BPF TCP cong-ctls to write app_limited of struct tcp_sock.
    A built-in cc or one from a kernel module is already able to write
    to app_limited, from Yixin Shen.

Conflicts:

Documentation/bpf/bpf_devel_QA.rst
  b7abcd9c656b ("bpf, doc: Link to submitting-patches.rst for general patch submission info")
  0f10f647f455 ("bpf, docs: Use internal linking for link to netdev subsystem doc")
https://lore.kernel.org/all/20230307095812.236eb1be@canb.auug.org.au/

include/net/ip_tunnels.h
  bc9d003dc48c3 ("ip_tunnel: Preserve pointer const in ip_tunnel_info_opts")
  ac931d4cdec3d ("ipip,ip_tunnel,sit: Add FOU support for externally controlled ipip devices")
https://lore.kernel.org/all/20230413161235.4093777-1-broonie@kernel.org/

net/bpf/test_run.c
  e5995bc7e2ba ("bpf, test_run: fix crashes due to XDP frame overwriting/corruption")
  294635a8165a ("bpf, test_run: fix &amp;xdp_frame misplacement for LIVE_FRAMES")
https://lore.kernel.org/all/20230320102619.05b80a98@canb.auug.org.au/
====================

Link: https://lore.kernel.org/r/20230413191525.7295-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>selftests/bpf: Add test to access u32 ptr argument in tracing program</title>
<updated>2023-04-11T18:29:49+00:00</updated>
<author>
<name>Feng Zhou</name>
<email>zhoufeng.zf@bytedance.com</email>
</author>
<published>2023-04-10T08:59:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=75dcef8d3609d0b1d3497d6ed4809096513e0b83'/>
<id>75dcef8d3609d0b1d3497d6ed4809096513e0b83</id>
<content type='text'>
Adding verifier test for accessing u32 pointer argument in
tracing programs.

The test program loads 1nd argument of bpf_fentry_test9 function
which is u32 pointer and checks that verifier allows that.

Co-developed-by: Chengming Zhou &lt;zhouchengming@bytedance.com&gt;
Signed-off-by: Chengming Zhou &lt;zhouchengming@bytedance.com&gt;
Signed-off-by: Feng Zhou &lt;zhoufeng.zf@bytedance.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20230410085908.98493-3-zhoufeng.zf@bytedance.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Adding verifier test for accessing u32 pointer argument in
tracing programs.

The test program loads 1nd argument of bpf_fentry_test9 function
which is u32 pointer and checks that verifier allows that.

Co-developed-by: Chengming Zhou &lt;zhouchengming@bytedance.com&gt;
Signed-off-by: Chengming Zhou &lt;zhouchengming@bytedance.com&gt;
Signed-off-by: Feng Zhou &lt;zhoufeng.zf@bytedance.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20230410085908.98493-3-zhoufeng.zf@bytedance.com
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Remove unused arguments from btf_struct_access().</title>
<updated>2023-04-04T23:57:10+00:00</updated>
<author>
<name>Alexei Starovoitov</name>
<email>ast@kernel.org</email>
</author>
<published>2023-04-04T04:50:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b7e852a9ec96635168c04204fb7cf1f7390b9a8c'/>
<id>b7e852a9ec96635168c04204fb7cf1f7390b9a8c</id>
<content type='text'>
Remove unused arguments from btf_struct_access() callback.

Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Acked-by: David Vernet &lt;void@manifault.com&gt;
Link: https://lore.kernel.org/bpf/20230404045029.82870-3-alexei.starovoitov@gmail.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Remove unused arguments from btf_struct_access() callback.

Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Acked-by: David Vernet &lt;void@manifault.com&gt;
Link: https://lore.kernel.org/bpf/20230404045029.82870-3-alexei.starovoitov@gmail.com
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Invoke btf_struct_access() callback only for writes.</title>
<updated>2023-04-04T23:57:03+00:00</updated>
<author>
<name>Alexei Starovoitov</name>
<email>ast@kernel.org</email>
</author>
<published>2023-04-04T04:50:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7d64c513284408fee5178a0953a686e9410f2399'/>
<id>7d64c513284408fee5178a0953a686e9410f2399</id>
<content type='text'>
Remove duplicated if (atype == BPF_READ) btf_struct_access() from
btf_struct_access() callback and invoke it only for writes. This is
possible to do because currently btf_struct_access() custom callback
always delegates to generic btf_struct_access() helper for BPF_READ
accesses.

Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Acked-by: David Vernet &lt;void@manifault.com&gt;
Link: https://lore.kernel.org/bpf/20230404045029.82870-2-alexei.starovoitov@gmail.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Remove duplicated if (atype == BPF_READ) btf_struct_access() from
btf_struct_access() callback and invoke it only for writes. This is
possible to do because currently btf_struct_access() custom callback
always delegates to generic btf_struct_access() helper for BPF_READ
accesses.

Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Acked-by: David Vernet &lt;void@manifault.com&gt;
Link: https://lore.kernel.org/bpf/20230404045029.82870-2-alexei.starovoitov@gmail.com
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Treat KF_RELEASE kfuncs as KF_TRUSTED_ARGS</title>
<updated>2023-03-25T23:56:22+00:00</updated>
<author>
<name>David Vernet</name>
<email>void@manifault.com</email>
</author>
<published>2023-03-25T21:31:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6c831c4684124a544f73f7c9b83bc7b2eb0b23d3'/>
<id>6c831c4684124a544f73f7c9b83bc7b2eb0b23d3</id>
<content type='text'>
KF_RELEASE kfuncs are not currently treated as having KF_TRUSTED_ARGS,
even though they have a superset of the requirements of KF_TRUSTED_ARGS.
Like KF_TRUSTED_ARGS, KF_RELEASE kfuncs require a 0-offset argument, and
don't allow NULL-able arguments. Unlike KF_TRUSTED_ARGS which require
_either_ an argument with ref_obj_id &gt; 0, _or_ (ref-&gt;type &amp;
BPF_REG_TRUSTED_MODIFIERS) (and no unsafe modifiers allowed), KF_RELEASE
only allows for ref_obj_id &gt; 0.  Because KF_RELEASE today doesn't
automatically imply KF_TRUSTED_ARGS, some of these requirements are
enforced in different ways that can make the behavior of the verifier
feel unpredictable. For example, a KF_RELEASE kfunc with a NULL-able
argument will currently fail in the verifier with a message like, "arg#0
is ptr_or_null_ expected ptr_ or socket" rather than "Possibly NULL
pointer passed to trusted arg0". Our intention is the same, but the
semantics are different due to implemenetation details that kfunc authors
and BPF program writers should not need to care about.

Let's make the behavior of the verifier more consistent and intuitive by
having KF_RELEASE kfuncs imply the presence of KF_TRUSTED_ARGS. Our
eventual goal is to have all kfuncs assume KF_TRUSTED_ARGS by default
anyways, so this takes us a step in that direction.

Note that it does not make sense to assume KF_TRUSTED_ARGS for all
KF_ACQUIRE kfuncs. KF_ACQUIRE kfuncs can have looser semantics than
KF_RELEASE, with e.g. KF_RCU | KF_RET_NULL. We may want to have
KF_ACQUIRE imply KF_TRUSTED_ARGS _unless_ KF_RCU is specified, but that
can be left to another patch set, and there are no such subtleties to
address for KF_RELEASE.

Signed-off-by: David Vernet &lt;void@manifault.com&gt;
Link: https://lore.kernel.org/r/20230325213144.486885-4-void@manifault.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
KF_RELEASE kfuncs are not currently treated as having KF_TRUSTED_ARGS,
even though they have a superset of the requirements of KF_TRUSTED_ARGS.
Like KF_TRUSTED_ARGS, KF_RELEASE kfuncs require a 0-offset argument, and
don't allow NULL-able arguments. Unlike KF_TRUSTED_ARGS which require
_either_ an argument with ref_obj_id &gt; 0, _or_ (ref-&gt;type &amp;
BPF_REG_TRUSTED_MODIFIERS) (and no unsafe modifiers allowed), KF_RELEASE
only allows for ref_obj_id &gt; 0.  Because KF_RELEASE today doesn't
automatically imply KF_TRUSTED_ARGS, some of these requirements are
enforced in different ways that can make the behavior of the verifier
feel unpredictable. For example, a KF_RELEASE kfunc with a NULL-able
argument will currently fail in the verifier with a message like, "arg#0
is ptr_or_null_ expected ptr_ or socket" rather than "Possibly NULL
pointer passed to trusted arg0". Our intention is the same, but the
semantics are different due to implemenetation details that kfunc authors
and BPF program writers should not need to care about.

Let's make the behavior of the verifier more consistent and intuitive by
having KF_RELEASE kfuncs imply the presence of KF_TRUSTED_ARGS. Our
eventual goal is to have all kfuncs assume KF_TRUSTED_ARGS by default
anyways, so this takes us a step in that direction.

Note that it does not make sense to assume KF_TRUSTED_ARGS for all
KF_ACQUIRE kfuncs. KF_ACQUIRE kfuncs can have looser semantics than
KF_RELEASE, with e.g. KF_RCU | KF_RET_NULL. We may want to have
KF_ACQUIRE imply KF_TRUSTED_ARGS _unless_ KF_RCU is specified, but that
can be left to another patch set, and there are no such subtleties to
address for KF_RELEASE.

Signed-off-by: David Vernet &lt;void@manifault.com&gt;
Link: https://lore.kernel.org/r/20230325213144.486885-4-void@manifault.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Remove now-unnecessary NULL checks for KF_RELEASE kfuncs</title>
<updated>2023-03-25T23:56:22+00:00</updated>
<author>
<name>David Vernet</name>
<email>void@manifault.com</email>
</author>
<published>2023-03-25T21:31:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fb2211a57c110b4ced3cb7f8570bd7246acf2d04'/>
<id>fb2211a57c110b4ced3cb7f8570bd7246acf2d04</id>
<content type='text'>
Now that we're not invoking kfunc destructors when the kptr in a map was
NULL, we no longer require NULL checks in many of our KF_RELEASE kfuncs.
This patch removes those NULL checks.

Signed-off-by: David Vernet &lt;void@manifault.com&gt;
Link: https://lore.kernel.org/r/20230325213144.486885-3-void@manifault.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Now that we're not invoking kfunc destructors when the kptr in a map was
NULL, we no longer require NULL checks in many of our KF_RELEASE kfuncs.
This patch removes those NULL checks.

Signed-off-by: David Vernet &lt;void@manifault.com&gt;
Link: https://lore.kernel.org/r/20230325213144.486885-3-void@manifault.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
