<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/kernel/trace/bpf_trace.c, branch v6.0-rc1</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net</title>
<updated>2022-06-23T19:33:24+00:00</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2022-06-23T19:33:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=93817be8b62c7fa1f1bdc3e8c037a73a60026be9'/>
<id>93817be8b62c7fa1f1bdc3e8c037a73a60026be9</id>
<content type='text'>
No conflicts.

Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
No conflicts.

Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next</title>
<updated>2022-06-18T02:35:19+00:00</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2022-06-18T02:35:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=9fb424c4c29df0d7f39b686d4037cbc7e06ed7b5'/>
<id>9fb424c4c29df0d7f39b686d4037cbc7e06ed7b5</id>
<content type='text'>
Daniel Borkmann says:

====================
pull-request: bpf-next 2022-06-17

We've added 72 non-merge commits during the last 15 day(s) which contain
a total of 92 files changed, 4582 insertions(+), 834 deletions(-).

The main changes are:

1) Add 64 bit enum value support to BTF, from Yonghong Song.

2) Implement support for sleepable BPF uprobe programs, from Delyan Kratunov.

3) Add new BPF helpers to issue and check TCP SYN cookies without binding to a
   socket especially useful in synproxy scenarios, from Maxim Mikityanskiy.

4) Fix libbpf's internal USDT address translation logic for shared libraries as
   well as uprobe's symbol file offset calculation, from Andrii Nakryiko.

5) Extend libbpf to provide an API for textual representation of the various
   map/prog/attach/link types and use it in bpftool, from Daniel Müller.

6) Provide BTF line info for RV64 and RV32 JITs, and fix a put_user bug in the
   core seen in 32 bit when storing BPF function addresses, from Pu Lehui.

7) Fix libbpf's BTF pointer size guessing by adding a list of various aliases
   for 'long' types, from Douglas Raillard.

8) Fix bpftool to readd setting rlimit since probing for memcg-based accounting
   has been unreliable and caused a regression on COS, from Quentin Monnet.

9) Fix UAF in BPF cgroup's effective program computation triggered upon BPF link
   detachment, from Tadeusz Struk.

10) Fix bpftool build bootstrapping during cross compilation which was pointing
    to the wrong AR process, from Shahab Vahedi.

11) Fix logic bug in libbpf's is_pow_of_2 implementation, from Yuze Chi.

12) BPF hash map optimization to avoid grabbing spinlocks of all CPUs when there
    is no free element. Also add a benchmark as reproducer, from Feng Zhou.

13) Fix bpftool's codegen to bail out when there's no BTF, from Michael Mullin.

14) Various minor cleanup and improvements all over the place.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (72 commits)
  bpf: Fix bpf_skc_lookup comment wrt. return type
  bpf: Fix non-static bpf_func_proto struct definitions
  selftests/bpf: Don't force lld on non-x86 architectures
  selftests/bpf: Add selftests for raw syncookie helpers in TC mode
  bpf: Allow the new syncookie helpers to work with SKBs
  selftests/bpf: Add selftests for raw syncookie helpers
  bpf: Add helpers to issue and check SYN cookies in XDP
  bpf: Allow helpers to accept pointers with a fixed size
  bpf: Fix documentation of th_len in bpf_tcp_{gen,check}_syncookie
  selftests/bpf: add tests for sleepable (uk)probes
  libbpf: add support for sleepable uprobe programs
  bpf: allow sleepable uprobe programs to attach
  bpf: implement sleepable uprobes by chaining gps
  bpf: move bpf_prog to bpf.h
  libbpf: Fix internal USDT address translation logic for shared libraries
  samples/bpf: Check detach prog exist or not in xdp_fwd
  selftests/bpf: Avoid skipping certain subtests
  selftests/bpf: Fix test_varlen verification failure with latest llvm
  bpftool: Do not check return value from libbpf_set_strict_mode()
  Revert "bpftool: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK"
  ...
====================

Link: https://lore.kernel.org/r/20220617220836.7373-1-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>
Daniel Borkmann says:

====================
pull-request: bpf-next 2022-06-17

We've added 72 non-merge commits during the last 15 day(s) which contain
a total of 92 files changed, 4582 insertions(+), 834 deletions(-).

The main changes are:

1) Add 64 bit enum value support to BTF, from Yonghong Song.

2) Implement support for sleepable BPF uprobe programs, from Delyan Kratunov.

3) Add new BPF helpers to issue and check TCP SYN cookies without binding to a
   socket especially useful in synproxy scenarios, from Maxim Mikityanskiy.

4) Fix libbpf's internal USDT address translation logic for shared libraries as
   well as uprobe's symbol file offset calculation, from Andrii Nakryiko.

5) Extend libbpf to provide an API for textual representation of the various
   map/prog/attach/link types and use it in bpftool, from Daniel Müller.

6) Provide BTF line info for RV64 and RV32 JITs, and fix a put_user bug in the
   core seen in 32 bit when storing BPF function addresses, from Pu Lehui.

7) Fix libbpf's BTF pointer size guessing by adding a list of various aliases
   for 'long' types, from Douglas Raillard.

8) Fix bpftool to readd setting rlimit since probing for memcg-based accounting
   has been unreliable and caused a regression on COS, from Quentin Monnet.

9) Fix UAF in BPF cgroup's effective program computation triggered upon BPF link
   detachment, from Tadeusz Struk.

10) Fix bpftool build bootstrapping during cross compilation which was pointing
    to the wrong AR process, from Shahab Vahedi.

11) Fix logic bug in libbpf's is_pow_of_2 implementation, from Yuze Chi.

12) BPF hash map optimization to avoid grabbing spinlocks of all CPUs when there
    is no free element. Also add a benchmark as reproducer, from Feng Zhou.

13) Fix bpftool's codegen to bail out when there's no BTF, from Michael Mullin.

14) Various minor cleanup and improvements all over the place.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (72 commits)
  bpf: Fix bpf_skc_lookup comment wrt. return type
  bpf: Fix non-static bpf_func_proto struct definitions
  selftests/bpf: Don't force lld on non-x86 architectures
  selftests/bpf: Add selftests for raw syncookie helpers in TC mode
  bpf: Allow the new syncookie helpers to work with SKBs
  selftests/bpf: Add selftests for raw syncookie helpers
  bpf: Add helpers to issue and check SYN cookies in XDP
  bpf: Allow helpers to accept pointers with a fixed size
  bpf: Fix documentation of th_len in bpf_tcp_{gen,check}_syncookie
  selftests/bpf: add tests for sleepable (uk)probes
  libbpf: add support for sleepable uprobe programs
  bpf: allow sleepable uprobe programs to attach
  bpf: implement sleepable uprobes by chaining gps
  bpf: move bpf_prog to bpf.h
  libbpf: Fix internal USDT address translation logic for shared libraries
  samples/bpf: Check detach prog exist or not in xdp_fwd
  selftests/bpf: Avoid skipping certain subtests
  selftests/bpf: Fix test_varlen verification failure with latest llvm
  bpftool: Do not check return value from libbpf_set_strict_mode()
  Revert "bpftool: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK"
  ...
====================

Link: https://lore.kernel.org/r/20220617220836.7373-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Force cookies array to follow symbols sorting</title>
<updated>2022-06-17T02:42:21+00:00</updated>
<author>
<name>Jiri Olsa</name>
<email>jolsa@kernel.org</email>
</author>
<published>2022-06-15T11:21:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=eb5fb0325698d05f0bf78d322de82c451a3685a2'/>
<id>eb5fb0325698d05f0bf78d322de82c451a3685a2</id>
<content type='text'>
When user specifies symbols and cookies for kprobe_multi link
interface it's very likely the cookies will be misplaced and
returned to wrong functions (via get_attach_cookie helper).

The reason is that to resolve the provided functions we sort
them before passing them to ftrace_lookup_symbols, but we do
not do the same sort on the cookie values.

Fixing this by using sort_r function with custom swap callback
that swaps cookie values as well.

Fixes: 0236fec57a15 ("bpf: Resolve symbols with ftrace_lookup_symbols for kprobe multi link")
Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Link: https://lore.kernel.org/r/20220615112118.497303-4-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>
When user specifies symbols and cookies for kprobe_multi link
interface it's very likely the cookies will be misplaced and
returned to wrong functions (via get_attach_cookie helper).

The reason is that to resolve the provided functions we sort
them before passing them to ftrace_lookup_symbols, but we do
not do the same sort on the cookie values.

Fixing this by using sort_r function with custom swap callback
that swaps cookie values as well.

Fixes: 0236fec57a15 ("bpf: Resolve symbols with ftrace_lookup_symbols for kprobe multi link")
Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Link: https://lore.kernel.org/r/20220615112118.497303-4-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: implement sleepable uprobes by chaining gps</title>
<updated>2022-06-17T02:27:29+00:00</updated>
<author>
<name>Delyan Kratunov</name>
<email>delyank@fb.com</email>
</author>
<published>2022-06-14T23:10:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=8c7dcb84e3b744b2b70baa7a44a9b1881c33a9c9'/>
<id>8c7dcb84e3b744b2b70baa7a44a9b1881c33a9c9</id>
<content type='text'>
uprobes work by raising a trap, setting a task flag from within the
interrupt handler, and processing the actual work for the uprobe on the
way back to userspace. As a result, uprobe handlers already execute in a
might_fault/_sleep context. The primary obstacle to sleepable bpf uprobe
programs is therefore on the bpf side.

Namely, the bpf_prog_array attached to the uprobe is protected by normal
rcu. In order for uprobe bpf programs to become sleepable, it has to be
protected by the tasks_trace rcu flavor instead (and kfree() called after
a corresponding grace period).

Therefore, the free path for bpf_prog_array now chains a tasks_trace and
normal grace periods one after the other.

Users who iterate under tasks_trace read section would
be safe, as would users who iterate under normal read sections (from
non-sleepable locations).

The downside is that the tasks_trace latency affects all perf_event-attached
bpf programs (and not just uprobe ones). This is deemed safe given the
possible attach rates for kprobe/uprobe/tp programs.

Separately, non-sleepable programs need access to dynamically sized
rcu-protected maps, so bpf_run_prog_array_sleepables now conditionally takes
an rcu read section, in addition to the overarching tasks_trace section.

Signed-off-by: Delyan Kratunov &lt;delyank@fb.com&gt;
Link: https://lore.kernel.org/r/ce844d62a2fd0443b08c5ab02e95bc7149f9aeb1.1655248076.git.delyank@fb.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
uprobes work by raising a trap, setting a task flag from within the
interrupt handler, and processing the actual work for the uprobe on the
way back to userspace. As a result, uprobe handlers already execute in a
might_fault/_sleep context. The primary obstacle to sleepable bpf uprobe
programs is therefore on the bpf side.

Namely, the bpf_prog_array attached to the uprobe is protected by normal
rcu. In order for uprobe bpf programs to become sleepable, it has to be
protected by the tasks_trace rcu flavor instead (and kfree() called after
a corresponding grace period).

Therefore, the free path for bpf_prog_array now chains a tasks_trace and
normal grace periods one after the other.

Users who iterate under tasks_trace read section would
be safe, as would users who iterate under normal read sections (from
non-sleepable locations).

The downside is that the tasks_trace latency affects all perf_event-attached
bpf programs (and not just uprobe ones). This is deemed safe given the
possible attach rates for kprobe/uprobe/tp programs.

Separately, non-sleepable programs need access to dynamically sized
rcu-protected maps, so bpf_run_prog_array_sleepables now conditionally takes
an rcu read section, in addition to the overarching tasks_trace section.

Signed-off-by: Delyan Kratunov &lt;delyank@fb.com&gt;
Link: https://lore.kernel.org/r/ce844d62a2fd0443b08c5ab02e95bc7149f9aeb1.1655248076.git.delyank@fb.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Use safer kvmalloc_array() where possible</title>
<updated>2022-06-07T17:40:53+00:00</updated>
<author>
<name>Dan Carpenter</name>
<email>dan.carpenter@oracle.com</email>
</author>
<published>2022-05-26T10:24:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=fd58f7df2415ef747782e01f94880fefad1247cf'/>
<id>fd58f7df2415ef747782e01f94880fefad1247cf</id>
<content type='text'>
The kvmalloc_array() function is safer because it has a check for
integer overflows.  These sizes come from the user and I was not
able to see any bounds checking so an integer overflow seems like a
realistic concern.

Fixes: 0dcac2725406 ("bpf: Add multi kprobe link")
Signed-off-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Link: https://lore.kernel.org/bpf/Yo9VRVMeHbALyjUH@kili
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The kvmalloc_array() function is safer because it has a check for
integer overflows.  These sizes come from the user and I was not
able to see any bounds checking so an integer overflow seems like a
realistic concern.

Fixes: 0dcac2725406 ("bpf: Add multi kprobe link")
Signed-off-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Link: https://lore.kernel.org/bpf/Yo9VRVMeHbALyjUH@kili
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Add bpf_skc_to_mptcp_sock_proto</title>
<updated>2022-05-20T22:29:00+00:00</updated>
<author>
<name>Geliang Tang</name>
<email>geliang.tang@suse.com</email>
</author>
<published>2022-05-19T23:30:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=3bc253c2e652cf5f12cd8c00d80d8ec55d67d1a7'/>
<id>3bc253c2e652cf5f12cd8c00d80d8ec55d67d1a7</id>
<content type='text'>
This patch implements a new struct bpf_func_proto, named
bpf_skc_to_mptcp_sock_proto. Define a new bpf_id BTF_SOCK_TYPE_MPTCP,
and a new helper bpf_skc_to_mptcp_sock(), which invokes another new
helper bpf_mptcp_sock_from_subflow() in net/mptcp/bpf.c to get struct
mptcp_sock from a given subflow socket.

v2: Emit BTF type, add func_id checks in verifier.c and bpf_trace.c,
remove build check for CONFIG_BPF_JIT
v5: Drop EXPORT_SYMBOL (Martin)

Co-developed-by: Nicolas Rybowski &lt;nicolas.rybowski@tessares.net&gt;
Co-developed-by: Matthieu Baerts &lt;matthieu.baerts@tessares.net&gt;
Signed-off-by: Nicolas Rybowski &lt;nicolas.rybowski@tessares.net&gt;
Signed-off-by: Matthieu Baerts &lt;matthieu.baerts@tessares.net&gt;
Signed-off-by: Geliang Tang &lt;geliang.tang@suse.com&gt;
Signed-off-by: Mat Martineau &lt;mathew.j.martineau@linux.intel.com&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20220519233016.105670-2-mathew.j.martineau@linux.intel.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patch implements a new struct bpf_func_proto, named
bpf_skc_to_mptcp_sock_proto. Define a new bpf_id BTF_SOCK_TYPE_MPTCP,
and a new helper bpf_skc_to_mptcp_sock(), which invokes another new
helper bpf_mptcp_sock_from_subflow() in net/mptcp/bpf.c to get struct
mptcp_sock from a given subflow socket.

v2: Emit BTF type, add func_id checks in verifier.c and bpf_trace.c,
remove build check for CONFIG_BPF_JIT
v5: Drop EXPORT_SYMBOL (Martin)

Co-developed-by: Nicolas Rybowski &lt;nicolas.rybowski@tessares.net&gt;
Co-developed-by: Matthieu Baerts &lt;matthieu.baerts@tessares.net&gt;
Signed-off-by: Nicolas Rybowski &lt;nicolas.rybowski@tessares.net&gt;
Signed-off-by: Matthieu Baerts &lt;matthieu.baerts@tessares.net&gt;
Signed-off-by: Geliang Tang &lt;geliang.tang@suse.com&gt;
Signed-off-by: Mat Martineau &lt;mathew.j.martineau@linux.intel.com&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20220519233016.105670-2-mathew.j.martineau@linux.intel.com
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: add bpf_map_lookup_percpu_elem for percpu map</title>
<updated>2022-05-12T01:16:54+00:00</updated>
<author>
<name>Feng Zhou</name>
<email>zhoufeng.zf@bytedance.com</email>
</author>
<published>2022-05-11T09:38:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=07343110b293456d30393e89b86c4dee1ac051c8'/>
<id>07343110b293456d30393e89b86c4dee1ac051c8</id>
<content type='text'>
Add new ebpf helpers bpf_map_lookup_percpu_elem.

The implementation method is relatively simple, refer to the implementation
method of map_lookup_elem of percpu map, increase the parameters of cpu, and
obtain it according to the specified cpu.

Signed-off-by: Feng Zhou &lt;zhoufeng.zf@bytedance.com&gt;
Link: https://lore.kernel.org/r/20220511093854.411-2-zhoufeng.zf@bytedance.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add new ebpf helpers bpf_map_lookup_percpu_elem.

The implementation method is relatively simple, refer to the implementation
method of map_lookup_elem of percpu map, increase the parameters of cpu, and
obtain it according to the specified cpu.

Signed-off-by: Feng Zhou &lt;zhoufeng.zf@bytedance.com&gt;
Link: https://lore.kernel.org/r/20220511093854.411-2-zhoufeng.zf@bytedance.com
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf, x86: Attach a cookie to fentry/fexit/fmod_ret/lsm.</title>
<updated>2022-05-11T04:58:31+00:00</updated>
<author>
<name>Kui-Feng Lee</name>
<email>kuifeng@fb.com</email>
</author>
<published>2022-05-10T20:59:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2fcc82411e74e5e6aba336561cf56fb899bfae4e'/>
<id>2fcc82411e74e5e6aba336561cf56fb899bfae4e</id>
<content type='text'>
Pass a cookie along with BPF_LINK_CREATE requests.

Add a bpf_cookie field to struct bpf_tracing_link to attach a cookie.
The cookie of a bpf_tracing_link is available by calling
bpf_get_attach_cookie when running the BPF program of the attached
link.

The value of a cookie will be set at bpf_tramp_run_ctx by the
trampoline of the link.

Signed-off-by: Kui-Feng Lee &lt;kuifeng@fb.com&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Acked-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20220510205923.3206889-4-kuifeng@fb.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pass a cookie along with BPF_LINK_CREATE requests.

Add a bpf_cookie field to struct bpf_tracing_link to attach a cookie.
The cookie of a bpf_tracing_link is available by calling
bpf_get_attach_cookie when running the BPF program of the attached
link.

The value of a cookie will be set at bpf_tramp_run_ctx by the
trampoline of the link.

Signed-off-by: Kui-Feng Lee &lt;kuifeng@fb.com&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Acked-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20220510205923.3206889-4-kuifeng@fb.com
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Resolve symbols with ftrace_lookup_symbols for kprobe multi link</title>
<updated>2022-05-10T21:42:06+00:00</updated>
<author>
<name>Jiri Olsa</name>
<email>jolsa@kernel.org</email>
</author>
<published>2022-05-10T12:26:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=0236fec57a15dc2a068dfe4488e0c2ab4559b1ec'/>
<id>0236fec57a15dc2a068dfe4488e0c2ab4559b1ec</id>
<content type='text'>
Using kallsyms_lookup_names function to speed up symbols lookup in
kprobe multi link attachment and replacing with it the current
kprobe_multi_resolve_syms function.

This speeds up bpftrace kprobe attachment:

  # perf stat -r 5 -e cycles ./src/bpftrace -e 'kprobe:x* {  } i:ms:1 { exit(); }'
  ...
  6.5681 +- 0.0225 seconds time elapsed  ( +-  0.34% )

After:

  # perf stat -r 5 -e cycles ./src/bpftrace -e 'kprobe:x* {  } i:ms:1 { exit(); }'
  ...
  0.5661 +- 0.0275 seconds time elapsed  ( +-  4.85% )

Acked-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Link: https://lore.kernel.org/r/20220510122616.2652285-5-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>
Using kallsyms_lookup_names function to speed up symbols lookup in
kprobe multi link attachment and replacing with it the current
kprobe_multi_resolve_syms function.

This speeds up bpftrace kprobe attachment:

  # perf stat -r 5 -e cycles ./src/bpftrace -e 'kprobe:x* {  } i:ms:1 { exit(); }'
  ...
  6.5681 +- 0.0225 seconds time elapsed  ( +-  0.34% )

After:

  # perf stat -r 5 -e cycles ./src/bpftrace -e 'kprobe:x* {  } i:ms:1 { exit(); }'
  ...
  0.5661 +- 0.0275 seconds time elapsed  ( +-  4.85% )

Acked-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Link: https://lore.kernel.org/r/20220510122616.2652285-5-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Move rcu lock management out of BPF_PROG_RUN routines</title>
<updated>2022-04-19T16:45:47+00:00</updated>
<author>
<name>Stanislav Fomichev</name>
<email>sdf@google.com</email>
</author>
<published>2022-04-14T16:12:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=055eb95533273bc334794dbc598400d10800528f'/>
<id>055eb95533273bc334794dbc598400d10800528f</id>
<content type='text'>
Commit 7d08c2c91171 ("bpf: Refactor BPF_PROG_RUN_ARRAY family of macros
into functions") switched a bunch of BPF_PROG_RUN macros to inline
routines. This changed the semantic a bit. Due to arguments expansion
of macros, it used to be:

	rcu_read_lock();
	array = rcu_dereference(cgrp-&gt;bpf.effective[atype]);
	...

Now, with with inline routines, we have:
	array_rcu = rcu_dereference(cgrp-&gt;bpf.effective[atype]);
	/* array_rcu can be kfree'd here */
	rcu_read_lock();
	array = rcu_dereference(array_rcu);

I'm assuming in practice rcu subsystem isn't fast enough to trigger
this but let's use rcu API properly.

Also, rename to lower caps to not confuse with macros. Additionally,
drop and expand BPF_PROG_CGROUP_INET_EGRESS_RUN_ARRAY.

See [1] for more context.

  [1] https://lore.kernel.org/bpf/CAKH8qBs60fOinFdxiiQikK_q0EcVxGvNTQoWvHLEUGbgcj1UYg@mail.gmail.com/T/#u

v2
- keep rcu locks inside by passing cgroup_bpf

Fixes: 7d08c2c91171 ("bpf: Refactor BPF_PROG_RUN_ARRAY family of macros into functions")
Signed-off-by: Stanislav Fomichev &lt;sdf@google.com&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Acked-by: Martin KaFai Lau &lt;kafai@fb.com&gt;
Link: https://lore.kernel.org/bpf/20220414161233.170780-1-sdf@google.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit 7d08c2c91171 ("bpf: Refactor BPF_PROG_RUN_ARRAY family of macros
into functions") switched a bunch of BPF_PROG_RUN macros to inline
routines. This changed the semantic a bit. Due to arguments expansion
of macros, it used to be:

	rcu_read_lock();
	array = rcu_dereference(cgrp-&gt;bpf.effective[atype]);
	...

Now, with with inline routines, we have:
	array_rcu = rcu_dereference(cgrp-&gt;bpf.effective[atype]);
	/* array_rcu can be kfree'd here */
	rcu_read_lock();
	array = rcu_dereference(array_rcu);

I'm assuming in practice rcu subsystem isn't fast enough to trigger
this but let's use rcu API properly.

Also, rename to lower caps to not confuse with macros. Additionally,
drop and expand BPF_PROG_CGROUP_INET_EGRESS_RUN_ARRAY.

See [1] for more context.

  [1] https://lore.kernel.org/bpf/CAKH8qBs60fOinFdxiiQikK_q0EcVxGvNTQoWvHLEUGbgcj1UYg@mail.gmail.com/T/#u

v2
- keep rcu locks inside by passing cgroup_bpf

Fixes: 7d08c2c91171 ("bpf: Refactor BPF_PROG_RUN_ARRAY family of macros into functions")
Signed-off-by: Stanislav Fomichev &lt;sdf@google.com&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Acked-by: Martin KaFai Lau &lt;kafai@fb.com&gt;
Link: https://lore.kernel.org/bpf/20220414161233.170780-1-sdf@google.com
</pre>
</div>
</content>
</entry>
</feed>
