On 9/22/22 23:03, Jiri Olsa wrote:
Changing return value of kprobe's version of bpf_get_func_ip
to return zero if the attach address is not on the function's
entry point.
For kprobes attached in the middle of the function we can't easily
get to the function address especially now with the CONFIG_X86_KERNEL_IBT
support.
If user cares about current IP for kprobes attached within the
function body, they can get it with PT_REGS_IP(ctx).
Suggested-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Tested the patches with "pwru --filter-func='.*skb.*'
--filter-dst-ip=1.1.1.1" from [1] - the symbol name resolution works,
thanks!
Without your patches:
SKB CPU PROCESS FUNC
0xffff8989c159b4e8 0 [curl] 0xffffffffbbb06164
0xffff8989c223f000 0 [curl] 0xffffffffbbb07534
0xffff8989c223f000 0 [curl] 0xffffffffbbb04934
0xffff8989c223f000 0 [curl] skb_release_data
0xffff8989c223f000 0 [curl] kfree_skbmem
0xffff8989c159b4e8 0 [curl] 0xffffffffbbb00db4
[..]
With patches:
SKB CPU PROCESS FUNC
0xffffa4564159b4e8 0 [curl] validate_xmit_skb_list
0xffffa4564159b4e8 0 [curl] netif_skb_features
0xffffa4564159b4e8 0 [curl] skb_network_protocol
0xffffa4564159b4e8 0 [curl] skb_csum_hwoffload_help
0xffffa4564159b4e8 0 [curl] skb_checksum_help
0xffffa4564159b4e8 0 [curl] skb_ensure_writable
0xffffa4564159b4e8 0 [curl] skb_to_sgvec
[..]
[1]: https://github.com/cilium/pwru/tree/test-ibt-kernel-fix
Acked-by: Martynas Pumputis <m@xxxxxxxxx>
---
kernel/trace/bpf_trace.c | 5 ++++-
tools/testing/selftests/bpf/progs/get_func_ip_test.c | 4 ++--
2 files changed, 6 insertions(+), 3 deletions(-)
[..]
