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Shorten DEBUG_PRINT strings to pass BPF verifier on kernel 6.1.91 #225

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Shorten DEBUG_PRINT strings to pass BPF verifier on kernel 6.1.91 #225

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61 changes: 25 additions & 36 deletions support/ebpf/native_stack_trace.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -76,32 +76,24 @@ static EBPF_INLINE ErrorCode get_stack_delta(UnwindState *state, int *addrDiff,
key.fileID = state->text_section_id;
key.page = state->text_section_offset & ~STACK_DELTA_PAGE_MASK;
DEBUG_PRINT(
"Look up stack delta for %lx:%lx",
(unsigned long)state->text_section_id,
(unsigned long)state->text_section_offset);
"sd %lx:%lx", (unsigned long)state->text_section_id, (unsigned long)state->text_section_offset);
StackDeltaPageInfo *info = bpf_map_lookup_elem(&stack_delta_page_to_info, &key);
if (!info) {
DEBUG_PRINT(
"Failure to look up stack delta page fileID %lx, page %lx",
(unsigned long)key.fileID,
(unsigned long)key.page);
DEBUG_PRINT("ERR sdp %lx p=%lx", (unsigned long)key.fileID, (unsigned long)key.page);
state->error_metric = metricID_UnwindNativeErrLookupTextSection;
return ERR_NATIVE_LOOKUP_TEXT_SECTION;
}

void *outer_map = get_stack_delta_map(info->mapID);
if (!outer_map) {
DEBUG_PRINT(
"Failure to look up outer map for text section %lx in mapID %d",
(unsigned long)exe_id,
(int)info->mapID);
DEBUG_PRINT("ERR omap %lx m=%d", (unsigned long)exe_id, (int)info->mapID);
state->error_metric = metricID_UnwindNativeErrLookupStackDeltaOuterMap;
return ERR_NATIVE_LOOKUP_STACK_DELTA_OUTER_MAP;
}

void *inner_map = bpf_map_lookup_elem(outer_map, &exe_id);
if (!inner_map) {
DEBUG_PRINT("Failure to look up inner map for text section %lx", (unsigned long)exe_id);
DEBUG_PRINT("ERR imap %lx", (unsigned long)exe_id);
state->error_metric = metricID_UnwindNativeErrLookupStackDeltaInnerMap;
return ERR_NATIVE_LOOKUP_STACK_DELTA_INNER_MAP;
}
Expand All @@ -114,11 +106,7 @@ static EBPF_INLINE ErrorCode get_stack_delta(UnwindState *state, int *addrDiff,
u32 lo = info->firstDelta;
u32 hi = lo + info->numDeltas;

DEBUG_PRINT(
"Intervals should be from %lu to %lu (mapID %d)",
(unsigned long)lo,
(unsigned long)hi,
(int)info->mapID);
DEBUG_PRINT("bs %lu-%lu m=%d", (unsigned long)lo, (unsigned long)hi, (int)info->mapID);

// Do the binary search, up to 16 iterations. Deltas are paged to 64kB pages.
// They can contain at most 64kB deltas even if everything is single byte opcodes.
Expand All @@ -129,7 +117,7 @@ static EBPF_INLINE ErrorCode get_stack_delta(UnwindState *state, int *addrDiff,
}
}
if (i >= 16 || hi == 0) {
DEBUG_PRINT("Failed bsearch in 16 steps. Corrupt data?");
DEBUG_PRINT("ERR bs16");
state->error_metric = metricID_UnwindNativeErrLookupIterations;
return ERR_NATIVE_EXCEEDED_DELTA_LOOKUP_ITERATIONS;
}
Expand All @@ -149,8 +137,7 @@ static EBPF_INLINE ErrorCode get_stack_delta(UnwindState *state, int *addrDiff,
return ERR_NATIVE_LOOKUP_RANGE;
}

DEBUG_PRINT(
"delta index %d, addrLow 0x%x, unwindInfo %d", idx, delta->addrLow, delta->unwindInfo);
DEBUG_PRINT("d %d a=%x u=%d", idx, delta->addrLow, delta->unwindInfo);

// Calculate PC delta from stack delta for merged delta comparison
int deltaOffset = (int)page_offset - (int)delta->addrLow;
Expand All @@ -168,10 +155,6 @@ static EBPF_INLINE ErrorCode get_stack_delta(UnwindState *state, int *addrDiff,
state->error_metric = metricID_UnwindNativeErrStackDeltaInvalid;
return ERR_NATIVE_STACK_DELTA_INVALID;
}
if (delta->unwindInfo == STACK_DELTA_STOP) {
increment_metric(metricID_UnwindNativeStackDeltaStop);
}

return ERR_OK;
}

Expand Down Expand Up @@ -209,7 +192,7 @@ unwind_calc_register_with_deref(UnwindState *state, u8 baseReg, s32 param, bool
// Dereference, and add the postDereference adder.
unsigned long val;
if (bpf_probe_read_user(&val, sizeof(val), (void *)addr)) {
DEBUG_PRINT("unwind failed to dereference address 0x%lx", (unsigned long)addr);
DEBUG_PRINT("ERR deref %lx", (unsigned long)addr);
return 0;
}
// Return: "*(BASE + preDeref) + postDeref"
Expand Down Expand Up @@ -257,7 +240,7 @@ static EBPF_INLINE ErrorCode unwind_one_frame(PerCPURecord *record, bool *stop)
// This is the hard coded implementation of this expression. For further details,
// see https://hal.inria.fr/hal-02297690/document, page 4. (DOI: 10.1145/3360572)
cfa = state->sp + 8 + ((((state->pc & 15) >= 11) ? 1 : 0) << 3);
// DEBUG_PRINT("PLT, cfa=0x%lx", (unsigned long)cfa);
DEBUG_PRINT("PLT %lx", (unsigned long)cfa);
break;
case UNWIND_COMMAND_SIGNAL: {
// Use the PerCPURecord scratch union instead of a stack-local buffer to avoid
Expand All @@ -280,10 +263,13 @@ static EBPF_INLINE ErrorCode unwind_one_frame(PerCPURecord *record, bool *stop)
state->pc = rt_regs[16];

state->return_address = false;
// DEBUG_PRINT("signal frame");
DEBUG_PRINT("sigf");
goto frame_ok;
}
case UNWIND_COMMAND_STOP: *stop = true; return ERR_OK;
case UNWIND_COMMAND_STOP:
increment_metric(metricID_UnwindNativeStackDeltaStop);
*stop = true;
return ERR_OK;
case UNWIND_COMMAND_FRAME_POINTER:
if (!unwinder_unwind_frame_pointer(state)) {
goto err_native_pc_read;
Expand All @@ -305,10 +291,10 @@ static EBPF_INLINE ErrorCode unwind_one_frame(PerCPURecord *record, bool *stop)

s32 param = info->param;
if (info->mergeOpcode) {
// DEBUG_PRINT("AddrDiff %d, merged delta %#02x", addrDiff, info->mergeOpcode);
DEBUG_PRINT("ad=%d md=%x", addrDiff, info->mergeOpcode);
if (addrDiff >= (info->mergeOpcode & ~MERGEOPCODE_NEGATIVE)) {
param += (info->mergeOpcode & MERGEOPCODE_NEGATIVE) ? -8 : 8;
// DEBUG_PRINT("Merged delta match: cfaDelta=%d", unwindInfo);
DEBUG_PRINT("mdm cfa=%d", unwindInfo);
}
}

Expand Down Expand Up @@ -380,10 +366,13 @@ static EBPF_INLINE ErrorCode unwind_one_frame(struct PerCPURecord *record, bool

state->return_address = false;
state->lr_invalid = false;
DEBUG_PRINT("signal frame");
DEBUG_PRINT("sigf");
goto frame_ok;
}
case UNWIND_COMMAND_STOP: *stop = true; return ERR_OK;
case UNWIND_COMMAND_STOP:
increment_metric(metricID_UnwindNativeStackDeltaStop);
*stop = true;
return ERR_OK;
case UNWIND_COMMAND_FRAME_POINTER:
if (!unwinder_unwind_frame_pointer(state)) {
goto err_native_pc_read;
Expand All @@ -401,16 +390,16 @@ static EBPF_INLINE ErrorCode unwind_one_frame(struct PerCPURecord *record, bool
UnwindInfo *info = bpf_map_lookup_elem(&unwind_info_array, &unwindInfo);
if (!info) {
increment_metric(metricID_UnwindNativeErrBadUnwindInfoIndex);
DEBUG_PRINT("Giving up due to invalid unwind info array index");
DEBUG_PRINT("ERR uwi idx");
return ERR_NATIVE_BAD_UNWIND_INFO_INDEX;
}

s32 param = info->param;
if (info->mergeOpcode) {
DEBUG_PRINT("AddrDiff %d, merged delta %#02x", addrDiff, info->mergeOpcode);
DEBUG_PRINT("ad=%d md=%x", addrDiff, info->mergeOpcode);
if (addrDiff >= (info->mergeOpcode & ~MERGEOPCODE_NEGATIVE)) {
param += (info->mergeOpcode & MERGEOPCODE_NEGATIVE) ? -8 : 8;
DEBUG_PRINT("Merged delta match: cfaDelta=%d", unwindInfo);
DEBUG_PRINT("mdm cfa=%d", unwindInfo);
}
}

Expand All @@ -428,7 +417,7 @@ static EBPF_INLINE ErrorCode unwind_one_frame(struct PerCPURecord *record, bool
increment_metric(metricID_UnwindNativeErrPCRead);
}
// report failure to resolve RA and stop unwinding
DEBUG_PRINT("Giving up due to failure to resolve RA");
DEBUG_PRINT("ERR RA");
return ERR_NATIVE_PC_READ;
}

Expand Down
49 changes: 25 additions & 24 deletions support/ebpf/python_tracer.ebpf.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -64,7 +64,8 @@ static EBPF_INLINE ErrorCode process_python_frame(

// Read PyFrameObject
if (bpf_probe_read_user(pss->frame, sizeof(pss->frame), py_frameobject)) {
// DEBUG_PRINT("Failed to read PyFrameObject 0x%lx", (unsigned long)py_frameobject);
DEBUG_PRINT(
"E%d %lx", metricID_UnwindPythonErrBadFrameCodeObjectAddr, (unsigned long)py_frameobject);
increment_metric(metricID_UnwindPythonErrBadFrameCodeObjectAddr);
return ERR_PYTHON_BAD_FRAME_OBJECT_ADDR;
}
Expand Down Expand Up @@ -119,10 +120,10 @@ static EBPF_INLINE ErrorCode process_python_frame(
}

if (!py_codeobject) {
// DEBUG_PRINT(
// "Null codeobject for PyFrameObject 0x%lx 0x%lx",
// (unsigned long)py_frameobject,
// (unsigned long)(py_frameobject + pyinfo->PyFrameObject_f_code));
DEBUG_PRINT(
"E%d %lx",
metricID_UnwindPythonZeroFrameCodeObject,
(unsigned long)(py_frameobject + pyinfo->PyFrameObject_f_code));
increment_metric(metricID_UnwindPythonZeroFrameCodeObject);
goto push_frame;
}
Expand All @@ -139,9 +140,8 @@ static EBPF_INLINE ErrorCode process_python_frame(
// Read PyCodeObject
long pycode_err = bpf_probe_read_user(pss->code, sizeof(pss->code), py_codeobject);
if (pycode_err) {
// DEBUG_PRINT(
// "Failed to read PyCodeObject at 0x%lx err=%ld", (unsigned long)(py_codeobject),
// pycode_err);
DEBUG_PRINT(
"E%d %lx", metricID_UnwindPythonErrBadCodeObjectArgCountAddr, (unsigned long)(py_codeobject));
increment_metric(metricID_UnwindPythonErrBadCodeObjectArgCountAddr);
// Push the frame with the code object address so the agent can try to
// read it via /proc/pid/mem (which supports page faults unlike BPF).
Expand All @@ -163,10 +163,10 @@ static EBPF_INLINE ErrorCode process_python_frame(
lineno = py_encode_lineno(codeobject_id, (u32)py_f_lasti);

push_frame:
DEBUG_PRINT("Pushing Python %lx %lu", (unsigned long)file_id, (unsigned long)lineno);
DEBUG_PRINT("py+ %lx %lu", (unsigned long)file_id, (unsigned long)lineno);
ErrorCode error = push_python(&record->state, trace, file_id, lineno);
if (error) {
DEBUG_PRINT("failed to push python frame");
DEBUG_PRINT("ERR py+");
return error;
}
increment_metric(metricID_UnwindPythonFrames);
Expand All @@ -184,7 +184,8 @@ static EBPF_INLINE ErrorCode get_PyThreadState(
if (pyinfo->tls_offset != 0) {
if (bpf_probe_read_user(thread_state, sizeof(void *), tsd_base + pyinfo->tls_offset)) {
DEBUG_PRINT(
"Failed to read direct TLS at base 0x%lx offset %d",
"E%d %lx %d",
metricID_UnwindPythonErrReadThreadStateAddr,
(unsigned long)tsd_base,
pyinfo->tls_offset);
increment_metric(metricID_UnwindPythonErrReadThreadStateAddr);
Expand All @@ -196,7 +197,8 @@ static EBPF_INLINE ErrorCode get_PyThreadState(
// Python 3.12 and earlier: use pthread TLS
int key;
if (bpf_probe_read_user(&key, sizeof(key), autoTLSkeyAddr)) {
DEBUG_PRINT("Failed to read autoTLSkey from 0x%lx", (unsigned long)autoTLSkeyAddr);
DEBUG_PRINT(
"E%d %lx", metricID_UnwindPythonErrBadAutoTlsKeyAddr, (unsigned long)autoTLSkeyAddr);
increment_metric(metricID_UnwindPythonErrBadAutoTlsKeyAddr);
return ERR_PYTHON_BAD_AUTO_TLS_KEY_ADDR;
}
Expand All @@ -213,14 +215,11 @@ static EBPF_INLINE ErrorCode get_PyFrame(const PyProcInfo *pyinfo, void **frame)
{
void *tsd_base;
if (tsd_get_base(&tsd_base)) {
DEBUG_PRINT("Failed to get TSD base address");
DEBUG_PRINT("E%d", metricID_UnwindPythonErrReadTsdBase);
increment_metric(metricID_UnwindPythonErrReadTsdBase);
return ERR_PYTHON_READ_TSD_BASE;
}
DEBUG_PRINT(
"TSD Base 0x%lx, autoTLSKeyAddr 0x%lx",
(unsigned long)tsd_base,
(unsigned long)pyinfo->autoTLSKeyAddr);
DEBUG_PRINT("TSD %lx akey %lx", (unsigned long)tsd_base, (unsigned long)pyinfo->autoTLSKeyAddr);

// Get the PyThreadState from TSD
void *py_tsd_thread_state;
Expand All @@ -231,7 +230,7 @@ static EBPF_INLINE ErrorCode get_PyFrame(const PyProcInfo *pyinfo, void **frame)
}

if (!py_tsd_thread_state) {
DEBUG_PRINT("PyThreadState is 0x0");
DEBUG_PRINT("E%d", metricID_UnwindPythonErrZeroThreadState);
increment_metric(metricID_UnwindPythonErrZeroThreadState);
return ERR_PYTHON_ZERO_THREAD_STATE;
}
Expand All @@ -240,7 +239,8 @@ static EBPF_INLINE ErrorCode get_PyFrame(const PyProcInfo *pyinfo, void **frame)
if (bpf_probe_read_user(
frame, sizeof(void *), py_tsd_thread_state + pyinfo->PyThreadState_frame)) {
DEBUG_PRINT(
"Failed to read PyThreadState.frame at 0x%lx",
"E%d %lx",
metricID_UnwindPythonErrBadThreadStateFrameAddr,
(unsigned long)(py_tsd_thread_state + pyinfo->PyThreadState_frame));
increment_metric(metricID_UnwindPythonErrBadThreadStateFrameAddr);
return ERR_PYTHON_BAD_THREAD_STATE_FRAME_ADDR;
Expand All @@ -249,7 +249,8 @@ static EBPF_INLINE ErrorCode get_PyFrame(const PyProcInfo *pyinfo, void **frame)
if (pyinfo->frame_is_cframe) {
if (bpf_probe_read_user(frame, sizeof(void *), *frame + pyinfo->PyCFrame_current_frame)) {
DEBUG_PRINT(
"Failed to read _PyCFrame.current_frame at 0x%lx",
"E%d %lx",
metricID_UnwindPythonErrBadCFrameFrameAddr,
(unsigned long)(*frame + pyinfo->PyCFrame_current_frame));
increment_metric(metricID_UnwindPythonErrBadCFrameFrameAddr);
return ERR_PYTHON_BAD_CFRAME_CURRENT_FRAME_ADDR;
Expand Down Expand Up @@ -328,18 +329,18 @@ static EBPF_INLINE int unwind_python(struct pt_regs *ctx)
Trace *trace = &record->trace;
u32 pid = trace->pid;

DEBUG_PRINT("unwind_python()");
DEBUG_PRINT("upy");

const PyProcInfo *pyinfo = bpf_map_lookup_elem(&py_procs, &pid);
if (!pyinfo) {
// Not a Python process that we have info on
DEBUG_PRINT("Can't build Python stack, no address info");
DEBUG_PRINT("E%d", metricID_UnwindPythonErrNoProcInfo);
increment_metric(metricID_UnwindPythonErrNoProcInfo);
error = ERR_PYTHON_NO_PROC_INFO;
goto exit;
}

DEBUG_PRINT("Building Python stack for 0x%x", pyinfo->version);
DEBUG_PRINT("py v=%x", pyinfo->version);
if (!record->pythonUnwindState.py_frame) {
increment_metric(metricID_UnwindPythonAttempts);
error = get_PyFrame(pyinfo, &record->pythonUnwindState.py_frame);
Expand All @@ -348,7 +349,7 @@ static EBPF_INLINE int unwind_python(struct pt_regs *ctx)
}
}
if (!record->pythonUnwindState.py_frame) {
DEBUG_PRINT(" -> Python frames are handled");
DEBUG_PRINT("py done");
unwinder_mark_done(record, PROG_UNWIND_PYTHON);
goto exit;
}
Expand Down
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