linux-stable/kernel/events
Hou Tao 0be9ae5486 bpf, events: Use prog to emit ksymbol event for main program
Since commit 0108a4e9f3 ("bpf: ensure main program has an extable"),
prog->aux->func[0]->kallsyms is left as uninitialized. For BPF programs
with subprogs, the symbol for the main program is missing just as shown
in the output of perf script below:

 ffffffff81284b69 qp_trie_lookup_elem+0xb9 ([kernel.kallsyms])
 ffffffffc0011125 bpf_prog_a4a0eb0651e6af8b_lookup_qp_trie+0x5d (bpf...)
 ffffffff8127bc2b bpf_for_each_array_elem+0x7b ([kernel.kallsyms])
 ffffffffc00110a1 +0x25 ()
 ffffffff8121a89a trace_call_bpf+0xca ([kernel.kallsyms])

Fix it by always using prog instead prog->aux->func[0] to emit ksymbol
event for the main program. After the fix, the output of perf script
will be correct:

 ffffffff81284b96 qp_trie_lookup_elem+0xe6 ([kernel.kallsyms])
 ffffffffc001382d bpf_prog_a4a0eb0651e6af8b_lookup_qp_trie+0x5d (bpf...)
 ffffffff8127bc2b bpf_for_each_array_elem+0x7b ([kernel.kallsyms])
 ffffffffc0013779 bpf_prog_245c55ab25cfcf40_qp_trie_lookup+0x25 (bpf...)
 ffffffff8121a89a trace_call_bpf+0xca ([kernel.kallsyms])

Fixes: 0108a4e9f3 ("bpf: ensure main program has an extable")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Yonghong Song <yonghong.song@linux.dev>
Reviewed-by: Krister Johansen <kjlx@templeofstupid.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20240714065533.1112616-1-houtao@huaweicloud.com
2024-07-19 17:26:36 +02:00
..
callchain.c perf: Shrink the size of the recursion counter. 2024-07-09 13:26:35 +02:00
core.c bpf, events: Use prog to emit ksymbol event for main program 2024-07-19 17:26:36 +02:00
hw_breakpoint_test.c perf/hw_breakpoint: remove MODULE_LICENSE in non-modules 2023-04-13 13:13:52 -07:00
hw_breakpoint.c perf/hw_breakpoint: Remove arch breakpoint hooks 2023-08-16 23:54:50 +10:00
internal.h perf: Move swevent_htable::recursion into task_struct. 2024-07-09 13:26:36 +02:00
Makefile perf/hw_breakpoint: Add KUnit test for constraints accounting 2022-08-30 10:56:20 +02:00
ring_buffer.c perf: Make rb_alloc_aux() return an error immediately if nr_pages <= 0 2024-07-04 16:00:23 +02:00
uprobes.c Probes updates for v6.10: 2024-05-17 18:29:30 -07:00