This is a note to let you know that I've just added the patch titled bpf, perf: Use subprog name when reporting subprog ksymbol to the 6.0-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: bpf-perf-use-subprog-name-when-reporting-subprog-ksy.patch and it can be found in the queue-6.0 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit de6b38b4fd0db753eab4292567d9bfeda4647032 Author: Hou Tao <houtao1@xxxxxxxxxx> Date: Mon Nov 14 17:57:33 2022 +0800 bpf, perf: Use subprog name when reporting subprog ksymbol [ Upstream commit 47df8a2f78bc34ff170d147d05b121f84e252b85 ] Since commit bfea9a8574f3 ("bpf: Add name to struct bpf_ksym"), when reporting subprog ksymbol to perf, prog name instead of subprog name is used. The backtrace of bpf program with subprogs will be incorrect as shown below: ffffffffc02deace bpf_prog_e44a3057dcb151f8_overwrite+0x66 ffffffffc02de9f7 bpf_prog_e44a3057dcb151f8_overwrite+0x9f ffffffffa71d8d4e trace_call_bpf+0xce ffffffffa71c2938 perf_call_bpf_enter.isra.0+0x48 overwrite is the entry program and it invokes the overwrite_htab subprog through bpf_loop, but in above backtrace, overwrite program just jumps inside itself. Fixing it by using subprog name when reporting subprog ksymbol. After the fix, the output of perf script will be correct as shown below: ffffffffc031aad2 bpf_prog_37c0bec7d7c764a4_overwrite_htab+0x66 ffffffffc031a9e7 bpf_prog_c7eb827ef4f23e71_overwrite+0x9f ffffffffa3dd8d4e trace_call_bpf+0xce ffffffffa3dc2938 perf_call_bpf_enter.isra.0+0x48 Fixes: bfea9a8574f3 ("bpf: Add name to struct bpf_ksym") Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx> Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx> Link: https://lore.kernel.org/bpf/20221114095733.158588-1-houtao@xxxxxxxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/kernel/events/core.c b/kernel/events/core.c index bec18d81b116..8dcbefd90b7f 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -9006,7 +9006,7 @@ static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog, PERF_RECORD_KSYMBOL_TYPE_BPF, (u64)(unsigned long)subprog->bpf_func, subprog->jited_len, unregister, - prog->aux->ksym.name); + subprog->aux->ksym.name); } } }