Patch "bpf, perf: Use subprog name when reporting subprog ksymbol" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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 5.10-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-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit bd643f8b1d8962cb417ca693c5618ca3504c82ed
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 0e01216f4e5a..e9b354d521a3 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -8740,7 +8740,7 @@ 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);
 		}
 	}
 }