Tracefs #3
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Tracefs #3
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michalgr
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michalgr
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Oct 27, 2022
…for -v option
Add additional information and change format of backtrace
- add symbol base offset, dso name, dso base offset
- symbol and dso info is included if it's available in target binary
- changed format:
INDEX ADDR [SYMBOL+OFFSET] (MODULE+OFFSET)
Print backtrace of ip if it failed to get syms.
Before:
# offcputime -v
psiginfo
vscanf
__snprintf_chk
[unknown]
[unknown]
[unknown]
[unknown]
[unknown]
sd_event_exit
sd_event_dispatch
sd_event_run
[unknown]
__libc_start_main
[unknown]
- systemd-journal (204)
1
xas_load
xas_find
filemap_map_pages
__handle_mm_fault
handle_mm_fault
do_page_fault
do_translation_fault
do_mem_abort
do_el0_ia_bp_hardening
el0_ia
xas_load
--
failed to get syms
- PmLogCtl (138757)
1
After:
# offcputime -v
#0 0xffffffc01018b7e8 __arm64_sys_clock_nanosleep+0x0
#1 0xffffffc01009a93c el0_svc_handler+0x34
#2 0xffffffc010084a08 el0_svc+0x8
#3 0xffffffc01018b7e8 __arm64_sys_clock_nanosleep+0x0
--
#4 0x0000007fa0bffd14 clock_nanosleep+0x94 (/usr/lib/libc-2.31.so+0x9ed14)
#5 0x0000007fa0c0530c nanosleep+0x1c (/usr/lib/libc-2.31.so+0xa430c)
#6 0x0000007fa0c051e4 sleep+0x34 (/usr/lib/libc-2.31.so+0xa41e4)
iovisor#7 0x000000558a5a9608 flb_loop+0x28 (/usr/bin/fluent-bit+0x52608)
iovisor#8 0x000000558a59f1c4 flb_main+0xa84 (/usr/bin/fluent-bit+0x481c4)
iovisor#9 0x0000007fa0b85124 __libc_start_main+0xe4 (/usr/lib/libc-2.31.so+0x24124)
iovisor#10 0x000000558a59d828 _start+0x34 (/usr/bin/fluent-bit+0x46828)
- fluent-bit (1238)
1
#0 0xffffffc01027daa4 generic_copy_file_checks+0x334
#1 0xffffffc0102ba634 __handle_mm_fault+0x8dc
#2 0xffffffc0102baa20 handle_mm_fault+0x168
#3 0xffffffc010ad23c0 do_page_fault+0x148
#4 0xffffffc010ad27c0 do_translation_fault+0xb0
#5 0xffffffc0100816b0 do_mem_abort+0x50
#6 0xffffffc0100843b0 el0_da+0x1c
iovisor#7 0xffffffc01027daa4 generic_copy_file_checks+0x334
--
iovisor#8 0x0000007f8dc12648 [unknown]
iovisor#9 0x0000007f8dc0aef8 [unknown]
iovisor#10 0x0000007f8dc1c990 [unknown]
iovisor#11 0x0000007f8dc08b0c [unknown]
iovisor#12 0x0000007f8dc08e48 [unknown]
iovisor#13 0x0000007f8dc081c8 [unknown]
- PmLogCtl (2412)
1
Fixed: iovisor#3884
Signed-off-by: Eunseon Lee <[email protected]>
jeez
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to jeez/bcc
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Oct 23, 2023
There are two pass managers in LLVM. Currently BCC uses the legacy one.
Switch to the new pass manager because the legacy one will be removed
in upcoming releases of LLVM.
Running the following script:
```
from bcc import BPF
bpf_text = '''
static int foobar()
{
bpf_trace_printk("enter vfs_read");
return 0;
}
KFUNC_PROBE(vfs_read)
{
return foobar();
}
'''
BPF(text=bpf_text, debug=1)
```
The IR output is the same with or without this change using LLVM 15:
; ModuleID = 'sscanf'
source_filename = "sscanf"
; ModuleID = '/virtual/main.c'
source_filename = "/virtual/main.c"
target datalayout = "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128"
target triple = "bpf-pc-linux"
@_version = dso_local global i32 332032, section "version", align 4, !dbg !0
@_license = dso_local global [4 x i8] c"GPL\00", section "license", align 1, !dbg !5
@__const.foobar._fmt = private unnamed_addr constant [15 x i8] c"enter vfs_read\00", align 1
@llvm.compiler.used = appending global [2 x ptr] [ptr @_license, ptr @_version], section "llvm.metadata"
; Function Attrs: alwaysinline nounwind
define dso_local i32 @kfunc__vfs_read(ptr nocapture noundef readnone %0) local_unnamed_addr #0 section ".bpf.fn.kfunc__vfs_read" !dbg !33 {
%2 = alloca [15 x i8], align 1
call void @llvm.dbg.value(metadata ptr %0, metadata !39, metadata !DIExpression()), !dbg !41
call void @llvm.dbg.value(metadata ptr undef, metadata !42, metadata !DIExpression()) michalgr#4, !dbg !45
call void @llvm.lifetime.start.p0(i64 15, ptr nonnull %2) michalgr#4, !dbg !47
call void @llvm.dbg.declare(metadata ptr %2, metadata !53, metadata !DIExpression()) michalgr#4, !dbg !58
call void @llvm.memcpy.p0.p0.i64(ptr noundef nonnull align 1 dereferenceable(15) %2, ptr noundef nonnull align 1 dereferenceable(15) @__const.foobar._fmt, i64 15, i1 false) michalgr#4, !dbg !58
%3 = call i32 (ptr, i64, ...) inttoptr (i64 6 to ptr)(ptr noundef nonnull %2, i64 noundef 15) michalgr#4, !dbg !59
call void @llvm.lifetime.end.p0(i64 15, ptr nonnull %2) michalgr#4, !dbg !60
call void @llvm.dbg.value(metadata i32 0, metadata !40, metadata !DIExpression()), !dbg !41
ret i32 0, !dbg !61
}
; Function Attrs: alwaysinline mustprogress nocallback nofree nosync nounwind readnone speculatable willreturn
declare void @llvm.dbg.declare(metadata, metadata, metadata) michalgr#1
; Function Attrs: alwaysinline argmemonly mustprogress nocallback nofree nosync nounwind willreturn
declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) michalgr#2
; Function Attrs: alwaysinline argmemonly mustprogress nocallback nofree nosync nounwind willreturn
declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) michalgr#2
; Function Attrs: alwaysinline argmemonly mustprogress nofree nounwind willreturn
declare void @llvm.memcpy.p0.p0.i64(ptr noalias nocapture writeonly, ptr noalias nocapture readonly, i64, i1 immarg) michalgr#3
; Function Attrs: alwaysinline mustprogress nocallback nofree nosync nounwind readnone speculatable willreturn
declare void @llvm.dbg.value(metadata, metadata, metadata) michalgr#1
attributes #0 = { alwaysinline nounwind "frame-pointer"="none" "min-legal-vector-width"="0" "no-jump-tables"="true" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
attributes michalgr#1 = { alwaysinline mustprogress nocallback nofree nosync nounwind readnone speculatable willreturn }
attributes michalgr#2 = { alwaysinline argmemonly mustprogress nocallback nofree nosync nounwind willreturn }
attributes michalgr#3 = { alwaysinline argmemonly mustprogress nofree nounwind willreturn }
attributes michalgr#4 = { nounwind }
!llvm.dbg.cu = !{!2}
!llvm.module.flags = !{!27, !28, !29, !30, !31}
!llvm.ident = !{!32}
!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
!1 = distinct !DIGlobalVariable(name: "_version", scope: !2, file: !14, line: 526, type: !26, isLocal: false, isDefinition: true)
!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "Ubuntu clang version 15.0.0-++20220426083628+d738d4717f6d-1~exp1~20220426203725.435", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, globals: !4, splitDebugInlining: false, nameTableKind: None)
!3 = !DIFile(filename: "/virtual/main.c", directory: "/home/ubuntu/sources/bpf-next")
!4 = !{!0, !5, !12}
!5 = !DIGlobalVariableExpression(var: !6, expr: !DIExpression())
!6 = distinct !DIGlobalVariable(name: "_license", scope: !2, file: !7, line: 26, type: !8, isLocal: false, isDefinition: true)
!7 = !DIFile(filename: "/virtual/include/bcc/footer.h", directory: "")
!8 = !DICompositeType(tag: DW_TAG_array_type, baseType: !9, size: 32, elements: !10)
!9 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
!10 = !{!11}
!11 = !DISubrange(count: 4)
!12 = !DIGlobalVariableExpression(var: !13, expr: !DIExpression())
!13 = distinct !DIGlobalVariable(name: "bpf_trace_printk_", scope: !2, file: !14, line: 542, type: !15, isLocal: true, isDefinition: true)
!14 = !DIFile(filename: "/virtual/include/bcc/helpers.h", directory: "")
!15 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !16, size: 64)
!16 = !DISubroutineType(types: !17)
!17 = !{!18, !19, !21, null}
!18 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!19 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !20, size: 64)
!20 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !9)
!21 = !DIDerivedType(tag: DW_TAG_typedef, name: "u64", file: !22, line: 23, baseType: !23)
!22 = !DIFile(filename: "include/asm-generic/int-ll64.h", directory: "/home/ubuntu/sources/bpf-next")
!23 = !DIDerivedType(tag: DW_TAG_typedef, name: "__u64", file: !24, line: 31, baseType: !25)
!24 = !DIFile(filename: "include/uapi/asm-generic/int-ll64.h", directory: "/home/ubuntu/sources/bpf-next")
!25 = !DIBasicType(name: "unsigned long long", size: 64, encoding: DW_ATE_unsigned)
!26 = !DIBasicType(name: "unsigned int", size: 32, encoding: DW_ATE_unsigned)
!27 = !{i32 7, !"Dwarf Version", i32 4}
!28 = !{i32 2, !"Debug Info Version", i32 3}
!29 = !{i32 1, !"wchar_size", i32 4}
!30 = !{i32 7, !"PIC Level", i32 2}
!31 = !{i32 7, !"PIE Level", i32 2}
!32 = !{!"Ubuntu clang version 15.0.0-++20220426083628+d738d4717f6d-1~exp1~20220426203725.435"}
!33 = distinct !DISubprogram(name: "kfunc__vfs_read", scope: !34, file: !34, line: 23, type: !35, scopeLine: 23, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !38)
!34 = !DIFile(filename: "/virtual/main.c", directory: "")
!35 = !DISubroutineType(types: !36)
!36 = !{!18, !37}
!37 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !25, size: 64)
!38 = !{!39, !40}
!39 = !DILocalVariable(name: "ctx", arg: 1, scope: !33, file: !34, line: 23, type: !37)
!40 = !DILocalVariable(name: "__ret", scope: !33, file: !34, line: 23, type: !18)
!41 = !DILocation(line: 0, scope: !33)
!42 = !DILocalVariable(name: "ctx", arg: 1, scope: !43, file: !34, line: 23, type: !37)
!43 = distinct !DISubprogram(name: "____kfunc__vfs_read", scope: !34, file: !34, line: 23, type: !35, scopeLine: 24, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !44)
!44 = !{!42}
!45 = !DILocation(line: 0, scope: !43, inlinedAt: !46)
!46 = distinct !DILocation(line: 23, column: 1, scope: !33)
!47 = !DILocation(line: 15, column: 5, scope: !48, inlinedAt: !57)
!48 = distinct !DILexicalBlock(scope: !49, file: !34, line: 15, column: 3)
!49 = distinct !DISubprogram(name: "foobar", scope: !34, file: !34, line: 13, type: !50, scopeLine: 14, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !52)
!50 = !DISubroutineType(types: !51)
!51 = !{!18}
!52 = !{!53}
!53 = !DILocalVariable(name: "_fmt", scope: !48, file: !34, line: 15, type: !54)
!54 = !DICompositeType(tag: DW_TAG_array_type, baseType: !9, size: 120, elements: !55)
!55 = !{!56}
!56 = !DISubrange(count: 15)
!57 = distinct !DILocation(line: 25, column: 9, scope: !43, inlinedAt: !46)
!58 = !DILocation(line: 15, column: 10, scope: !48, inlinedAt: !57)
!59 = !DILocation(line: 15, column: 37, scope: !48, inlinedAt: !57)
!60 = !DILocation(line: 15, column: 76, scope: !49, inlinedAt: !57)
!61 = !DILocation(line: 23, column: 1, scope: !33)
Closes iovisor#3947.
References:
[0]: https://llvm.org/docs/NewPassManager.html
[1]: https://blog.llvm.org/posts/2021-03-26-the-new-pass-manager/
Signed-off-by: Hengqi Chen <[email protected]>
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