Currently, stackmap and bpf_get_stackid helper are provided
for bpf program to get the stack trace. This approach has
a limitation though. If two stack traces have the same hash,
only one will get stored in the stackmap table regardless of
whether BPF_F_REUSE_STACKID is specified or not,
so some stack traces may be missing from user perspective.
This patch implements a new helper, bpf_get_stack, will
send stack traces directly to bpf program. The bpf program
is able to see all stack traces, and then can do in-kernel
processing or send stack traces to user space through
shared map or bpf_perf_event_output.
Patches #1 and #2 implemented the core kernel support.
Patches #3 and #4 are two verifier improves to make
bpf programming easier. Patch #5 synced the new helper
to tools headers. Patch #6 moved perf_event polling code
and ksym lookup code from samples/bpf to
tools/testing/selftests/bpf. Patch #7 added a verifier
test in tools/bpf for new verifier change.
Patches #8 and #9 added tests for raw tracepoint prog
and tracepoint prog respectively.
Changelogs:
v2 -> v3:
. use meta to track helper memory size argument
. implement range checking for ARSH in verifier
. move perf event polling and ksym related functions
from samples/bpf to tools/bpf
. added test to compare build id's between bpf_get_stackid
and bpf_get_stack
v1 -> v2:
. fix compilation error when CONFIG_PERF_EVENTS is not enabled
Yonghong Song (9):
bpf: change prototype for stack_map_get_build_id_offset
bpf: add bpf_get_stack helper
bpf/verifier: refine retval R0 state for bpf_get_stack helper
bpf/verifier: improve register value range tracking with ARSH
tools/bpf: add bpf_get_stack helper to tools headers
samples/bpf: move common-purpose trace functions to selftests
tools/bpf: add a verifier test case for bpf_get_stack helper and ARSH
tools/bpf: add a test for bpf_get_stack with raw tracepoint prog
tools/bpf: add a test for bpf_get_stack with tracepoint prog
include/linux/bpf.h | 1 +
include/linux/filter.h | 3 +-
include/uapi/linux/bpf.h | 19 ++-
kernel/bpf/core.c | 5 +
kernel/bpf/stackmap.c | 80 ++++++++-
kernel/bpf/syscall.c | 10 ++
kernel/bpf/verifier.c | 56 +++++++
kernel/trace/bpf_trace.c | 50 +++++-
samples/bpf/Makefile | 11 +-
samples/bpf/bpf_load.c | 63 -------
samples/bpf/bpf_load.h | 7 -
samples/bpf/offwaketime_user.c | 1 +
samples/bpf/sampleip_user.c | 1 +
samples/bpf/spintest_user.c | 1 +
samples/bpf/trace_event_user.c | 1 +
samples/bpf/trace_output_user.c | 125 ++------------
tools/include/uapi/linux/bpf.h | 19 ++-
tools/testing/selftests/bpf/Makefile | 3 +-
tools/testing/selftests/bpf/bpf_helpers.h | 3 +-
tools/testing/selftests/bpf/test_get_stack_rawtp.c | 102 +++++++++++
tools/testing/selftests/bpf/test_progs.c | 178 +++++++++++++++++++-
.../selftests/bpf/test_stacktrace_build_id.c | 20 ++-
tools/testing/selftests/bpf/test_stacktrace_map.c | 20 ++-
tools/testing/selftests/bpf/test_verifier.c | 45 +++++
tools/testing/selftests/bpf/trace_helpers.c | 186 +++++++++++++++++++++
tools/testing/selftests/bpf/trace_helpers.h | 24 +++
26 files changed, 825 insertions(+), 209 deletions(-)
create mode 100644 tools/testing/selftests/bpf/test_get_stack_rawtp.c
create mode 100644 tools/testing/selftests/bpf/trace_helpers.c
create mode 100644 tools/testing/selftests/bpf/trace_helpers.h
--
2.9.5
