Bpftool sync 2023-07-12 #110
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When building bpftool with !CONFIG_PERF_EVENTS:
skeleton/pid_iter.bpf.c:47:14: error: incomplete definition of type 'struct bpf_perf_link'
perf_link = container_of(link, struct bpf_perf_link, link);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helpers.h:74:22: note: expanded from macro 'container_of'
((type *)(__mptr - offsetof(type, member))); \
^~~~~~~~~~~~~~~~~~~~~~
tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helpers.h:68:60: note: expanded from macro 'offsetof'
#define offsetof(TYPE, MEMBER) ((unsigned long)&((TYPE *)0)->MEMBER)
~~~~~~~~~~~^
skeleton/pid_iter.bpf.c:44:9: note: forward declaration of 'struct bpf_perf_link'
struct bpf_perf_link *perf_link;
^
&bpf_perf_link is being defined and used only under the ifdef.
Define struct bpf_perf_link___local with the `preserve_access_index`
attribute inside the pid_iter BPF prog to allow compiling on any
configs. CO-RE will substitute it with the real struct bpf_perf_link
accesses later on.
container_of() uses offsetof(), which does the necessary CO-RE
relocation if the field is specified with `preserve_access_index` - as
is the case for struct bpf_perf_link___local.
Fixes: cbdaf71f7e65 ("bpftool: Add bpf_cookie to link output")
Suggested-by: Andrii Nakryiko <[email protected]>
Signed-off-by: Alexander Lobakin <[email protected]>
Signed-off-by: Quentin Monnet <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
In order to allow the BPF program in bpftool's pid_iter.bpf.c to compile
correctly on hosts where vmlinux.h does not define
BPF_LINK_TYPE_PERF_EVENT (running kernel versions lower than 5.15, for
example), define and use a local copy of the enum value. This requires
LLVM 12 or newer to build the BPF program.
Fixes: cbdaf71f7e65 ("bpftool: Add bpf_cookie to link output")
Signed-off-by: Quentin Monnet <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
Fix the following error when building bpftool:
CLANG profiler.bpf.o
CLANG pid_iter.bpf.o
skeleton/profiler.bpf.c:18:21: error: invalid application of 'sizeof' to an incomplete type 'struct bpf_perf_event_value'
__uint(value_size, sizeof(struct bpf_perf_event_value));
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helpers.h:13:39: note: expanded from macro '__uint'
tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helper_defs.h:7:8: note: forward declaration of 'struct bpf_perf_event_value'
struct bpf_perf_event_value;
^
struct bpf_perf_event_value is being used in the kernel only when
CONFIG_BPF_EVENTS is enabled, so it misses a BTF entry then.
Define struct bpf_perf_event_value___local with the
`preserve_access_index` attribute inside the pid_iter BPF prog to
allow compiling on any configs. It is a full mirror of a UAPI
structure, so is compatible both with and w/o CO-RE.
bpf_perf_event_read_value() requires a pointer of the original type,
so a cast is needed.
Fixes: 47c09d6a9f67 ("bpftool: Introduce "prog profile" command")
Suggested-by: Andrii Nakryiko <[email protected]>
Signed-off-by: Alexander Lobakin <[email protected]>
Signed-off-by: Quentin Monnet <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
Pull latest libbpf from mirror. Libbpf version: 1.3.0 Libbpf commit: 05f94ddbb837f5f4b3161e341eed21be307eaa04 Signed-off-by: Quentin Monnet <[email protected]>
When CONFIG_PERF_EVENTS is not set, struct perf_event remains empty.
However, the structure is being used by bpftool indirectly via BTF.
This leads to:
skeleton/pid_iter.bpf.c:49:30: error: no member named 'bpf_cookie' in 'struct perf_event'
return BPF_CORE_READ(event, bpf_cookie);
~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~
...
skeleton/pid_iter.bpf.c:49:9: error: returning 'void' from a function with incompatible result type '__u64' (aka 'unsigned long long')
return BPF_CORE_READ(event, bpf_cookie);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Tools and samples can't use any CONFIG_ definitions, so the fields
used there should always be present.
Define struct perf_event___local with the `preserve_access_index`
attribute inside the pid_iter BPF prog to allow compiling on any
configs. CO-RE will substitute it with the real struct perf_event
accesses later on.
Fixes: cbdaf71f7e65 ("bpftool: Add bpf_cookie to link output")
Suggested-by: Andrii Nakryiko <[email protected]>
Signed-off-by: Alexander Lobakin <[email protected]>
Signed-off-by: Quentin Monnet <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
Syncing latest bpftool commits from kernel repository.
Baseline bpf-next commit: 856fe03d929205b4c8c8fa51296342cd85592e3f
Checkpoint bpf-next commit: a3e7e6b17946f48badce98d7ac360678a0ea7393
Baseline bpf commit: 496720b7cfb6574a8f6f4d434f23e3d1e6cfaeb9
Checkpoint bpf commit: 496720b7cfb6574a8f6f4d434f23e3d1e6cfaeb9
Alexander Lobakin (3):
bpftool: use a local copy of perf_event to fix accessing :: Bpf_cookie
bpftool: Define a local bpf_perf_link to fix accessing its fields
bpftool: Use a local bpf_perf_event_value to fix accessing its fields
Quentin Monnet (1):
bpftool: Use a local copy of BPF_LINK_TYPE_PERF_EVENT in
pid_iter.bpf.c
src/skeleton/pid_iter.bpf.c | 26 +++++++++++++++++++++-----
src/skeleton/profiler.bpf.c | 27 +++++++++++++++++----------
2 files changed, 38 insertions(+), 15 deletions(-)
Signed-off-by: Quentin Monnet <[email protected]>
qmonnet
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|
I'll need to bump the LLVM version on the Ubuntu 20.04 workflow for this to pass. |
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Due to recent changes in pid_iter.bpf.c, we need support for the __builtin_preserve_enum_value build-in, which is not available in the version that ships on Ubuntu 20.04 runners (clang 11). Let's use clang-12, which is also installed. Signed-off-by: Quentin Monnet <[email protected]>
qmonnet
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Pull latest libbpf from mirror and sync bpftool repo with kernel, up to the commits used for libbpf sync. This is an automatic update performed by calling the sync script from this repo:
Fixes: #17