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7538d16397
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Arnaldo Carvalho de Melo 7538d16397 perf augmented_syscalls: Avoid optimization to pass older BPF validators 
See https://www.spinics.net/lists/netdev/msg480099.html for the whole
discussio, but to make the augmented_syscalls.c BPF program to get built
and loaded successfully in a greater range of kernels, add an extra
check.

Related patch:

  a60dd35d2e ("bpf: change bpf_perf_event_output arg5 type to ARG_CONST_SIZE_OR_ZERO")

That is in the kernel since v4.15, I couldn't figure why this is hitting
me with 4.17.17, but adding the workaround discussed there makes this
work with this fedora kernel and with 4.18.recent.

Before:

  # uname -a
  Linux seventh 4.17.17-100.fc27.x86_64 #1 SMP Mon Aug 20 15:53:11 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
  # perf trace -e tools/perf/examples/bpf/augmented_syscalls.c cat /etc/passwd > /dev/null
  libbpf: load bpf program failed: Permission denied
  libbpf: -- BEGIN DUMP LOG ---
  libbpf:
  0: (bf) r6 = r1
  1: (b7) r1 = 0
  2: (7b) *(u64 *)(r10 -8) = r1
  3: (7b) *(u64 *)(r10 -16) = r1
  4: (7b) *(u64 *)(r10 -24) = r1
  5: (7b) *(u64 *)(r10 -32) = r1
  6: (7b) *(u64 *)(r10 -40) = r1
  7: (7b) *(u64 *)(r10 -48) = r1
  8: (7b) *(u64 *)(r10 -56) = r1
  9: (7b) *(u64 *)(r10 -64) = r1
  10: (7b) *(u64 *)(r10 -72) = r1
  11: (7b) *(u64 *)(r10 -80) = r1
  12: (7b) *(u64 *)(r10 -88) = r1
  13: (7b) *(u64 *)(r10 -96) = r1
  14: (7b) *(u64 *)(r10 -104) = r1
  15: (7b) *(u64 *)(r10 -112) = r1
  16: (7b) *(u64 *)(r10 -120) = r1
  17: (7b) *(u64 *)(r10 -128) = r1
  18: (7b) *(u64 *)(r10 -136) = r1
  19: (7b) *(u64 *)(r10 -144) = r1
  20: (7b) *(u64 *)(r10 -152) = r1
  21: (7b) *(u64 *)(r10 -160) = r1
  22: (7b) *(u64 *)(r10 -168) = r1
  23: (7b) *(u64 *)(r10 -176) = r1
  24: (7b) *(u64 *)(r10 -184) = r1
  25: (7b) *(u64 *)(r10 -192) = r1
  26: (7b) *(u64 *)(r10 -200) = r1
  27: (7b) *(u64 *)(r10 -208) = r1
  28: (7b) *(u64 *)(r10 -216) = r1
  29: (7b) *(u64 *)(r10 -224) = r1
  30: (7b) *(u64 *)(r10 -232) = r1
  31: (7b) *(u64 *)(r10 -240) = r1
  32: (7b) *(u64 *)(r10 -248) = r1
  33: (7b) *(u64 *)(r10 -256) = r1
  34: (7b) *(u64 *)(r10 -264) = r1
  35: (7b) *(u64 *)(r10 -272) = r1
  36: (7b) *(u64 *)(r10 -280) = r1
  37: (7b) *(u64 *)(r10 -288) = r1
  38: (7b) *(u64 *)(r10 -296) = r1
  39: (7b) *(u64 *)(r10 -304) = r1
  40: (7b) *(u64 *)(r10 -312) = r1
  41: (bf) r7 = r10
  42: (07) r7 += -312
  43: (bf) r1 = r7
  44: (b7) r2 = 48
  45: (bf) r3 = r6
  46: (85) call bpf_probe_read#4
  47: (79) r3 = *(u64 *)(r6 +24)
  48: (bf) r1 = r10
  49: (07) r1 += -256
  50: (b7) r8 = 256
  51: (b7) r2 = 256
  52: (85) call bpf_probe_read_str#45
  53: (bf) r1 = r0
  54: (67) r1 <<= 32
  55: (77) r1 >>= 32
  56: (bf) r5 = r0
  57: (07) r5 += 56
  58: (2d) if r8 > r1 goto pc+1
   R0=inv(id=0) R1=inv(id=0,umin_value=256,umax_value=4294967295,var_off=(0x0; 0xffffffff)) R5=inv(id=0) R6=ctx(id=0,off=0,imm=0) R7=fp-312,call_-1 R8=inv256 R10=fp0,call_-1 fp-264=0
  59: (b7) r5 = 312
  60: (63) *(u32 *)(r10 -264) = r0
  61: (67) r5 <<= 32
  62: (77) r5 >>= 32
  63: (bf) r1 = r6
  64: (18) r2 = 0xffff8b9120cc8500
  66: (18) r3 = 0xffffffff
  68: (bf) r4 = r7
  69: (85) call bpf_perf_event_output#25
  70: (b7) r0 = 0
  71: (95) exit

  from 58 to 60: R0=inv(id=0) R1=inv(id=0,umax_value=255,var_off=(0x0; 0xff)) R5=inv(id=0) R6=ctx(id=0,off=0,imm=0) R7=fp-312,call_-1 R8=inv256 R10=fp0,call_-1 fp-264=0
  60: (63) *(u32 *)(r10 -264) = r0
  61: (67) r5 <<= 32
  62: (77) r5 >>= 32
  63: (bf) r1 = r6
  64: (18) r2 = 0xffff8b9120cc8500
  66: (18) r3 = 0xffffffff
  68: (bf) r4 = r7
  69: (85) call bpf_perf_event_output#25
  R5 unbounded memory access, use 'var &= const' or 'if (var < const)'

  libbpf: -- END LOG --
  libbpf: failed to load program 'syscalls:sys_enter_openat'
  libbpf: failed to load object 'tools/perf/examples/bpf/augmented_syscalls.c'
  bpf: load objects failed: err=-4007: (Kernel verifier blocks program loading)
  event syntax error: 'tools/perf/examples/bpf/augmented_syscalls.c'
                       \___ Kernel verifier blocks program loading

After:

  # perf trace -e tools/perf/examples/bpf/augmented_syscalls.c cat /etc/passwd > /dev/null
     0.000 cat/29249 openat(dfd: CWD, filename: /etc/ld.so.cache, flags: CLOEXEC)
     0.008 cat/29249 syscalls:sys_exit_openat:0x3
     0.021 cat/29249 openat(dfd: CWD, filename: /lib64/libc.so.6, flags: CLOEXEC)
     0.025 cat/29249 syscalls:sys_exit_openat:0x3
     0.180 cat/29249 open(filename: /usr/lib/locale/locale-archive, flags: CLOEXEC)
     0.185 cat/29249 syscalls:sys_exit_open:0x3
     0.242 cat/29249 openat(dfd: CWD, filename: /etc/passwd)
     0.245 cat/29249 syscalls:sys_exit_openat:0x3
  #

It also works with a more recent kernel:

  # uname -a
  Linux jouet 4.18.0-00014-g4e67b2a5df5d #6 SMP Thu Aug 30 17:34:17 -03 2018 x86_64 x86_64 x86_64 GNU/Linux
  # perf trace -e tools/perf/examples/bpf/augmented_syscalls.c cat /etc/passwd > /dev/null
     0.000 cat/26451 openat(dfd: CWD, filename: /etc/ld.so.cache, flags: CLOEXEC)
     0.020 cat/26451 syscalls:sys_exit_openat:0x3
     0.039 cat/26451 openat(dfd: CWD, filename: /lib64/libc.so.6, flags: CLOEXEC)
     0.044 cat/26451 syscalls:sys_exit_openat:0x3
     0.231 cat/26451 open(filename: /usr/lib/locale/locale-archive, flags: CLOEXEC)
     0.238 cat/26451 syscalls:sys_exit_open:0x3
     0.278 cat/26451 openat(dfd: CWD, filename: /etc/passwd)
     0.282 cat/26451 syscalls:sys_exit_openat:0x3
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: Gianluca Borello <g.borello@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Yonghong Song <yhs@fb.com>
Link: https://lkml.kernel.org/n/tip-wkpsivs1a9afwldbul46btbv@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-09-03 15:29:53 -03:00
..
arch perf annotate: Handle arm64 move instructions 2018-08-30 15:52:25 -03:00
bench tools arch: Update arch/x86/lib/memcpy_64.S copy used in 'perf bench mem memcpy' 2018-07-30 12:36:51 -03:00
Documentation perf report: Add --percent-type option 2018-08-08 15:55:54 -03:00
examples/bpf perf augmented_syscalls: Avoid optimization to pass older BPF validators 2018-09-03 15:29:53 -03:00
include/bpf perf bpf: Add syscall_exit() helper 2018-08-30 15:52:20 -03:00
jvmti perf tools: Fix compilation errors on gcc8 2018-07-11 09:39:57 -04:00
pmu-events perf vendor events arm64: Enable JSON events for eMAG 2018-08-08 15:55:43 -03:00
python perf python: Make twatch.py work with both python2 and python3 2018-02-19 12:28:08 -03:00
scripts perf scripts python: Add Python 3 support to EventClass.py 2018-07-11 10:01:50 -03:00
tests perf tools: Remove ext from struct kmod_path 2018-08-20 08:54:59 -03:00
trace perf trace beauty: Reorganize 'struct sockaddr *' beautifier 2018-08-30 15:52:20 -03:00
ui perf annotate: Add support to toggle percent type 2018-08-08 15:55:52 -03:00
util perf stat: Move the display functions to stat-display.c 2018-08-30 15:52:25 -03:00
.gitignore perf tools: Add trace/beauty/generated/ into .gitignore 2018-02-05 13:58:02 -03:00
Build perf trace: Remove audit-libs dependency if syscall tables are present 2018-01-23 09:51:38 -03:00
builtin-annotate.c perf annotate: Add --percent-type option 2018-08-08 15:55:53 -03:00
builtin-bench.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
builtin-buildid-cache.c perf buildid-cache: Warn --purge-all failures 2018-05-15 10:32:16 -03:00
builtin-buildid-list.c Merge branch 'linus' into perf/core, to fix conflicts 2017-11-07 10:30:18 +01:00
builtin-c2c.c perf c2c report: Fix crash for empty browser 2018-07-31 10:53:20 -03:00
builtin-config.c Merge branch 'linus' into perf/core, to fix conflicts 2017-11-07 10:30:18 +01:00
builtin-data.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
builtin-diff.c perf hists: Clarify callchain disabling when available 2018-07-24 14:37:33 -03:00
builtin-evlist.c Merge branch 'linus' into perf/core, to fix conflicts 2017-11-07 10:30:18 +01:00
builtin-ftrace.c perf ftrace: Append an EOL when write tracing files 2018-02-19 09:49:12 -03:00
builtin-help.c perf tools: Rename HAVE_SYSCALL_TABLE to HAVE_SYSCALL_TABLE_SUPPORT 2018-04-12 10:33:31 -03:00
builtin-inject.c perf thread: Make thread__find_map() return the map 2018-04-26 13:47:08 -03:00
builtin-kallsyms.c perf machine: Ditch find_kernel_function variants 2018-04-30 12:20:54 -03:00
builtin-kmem.c tools lib traceevent, perf tools: Rename 'enum pevent_flag' to 'enum tep_flag' 2018-08-13 15:22:18 -03:00
builtin-kvm.c perf tools: Ditch the symbol_conf.nr_events global 2018-06-04 10:28:52 -03:00
builtin-list.c Merge branch 'linus' into perf/core, to fix conflicts 2017-11-07 10:30:18 +01:00
builtin-lock.c Merge branch 'linus' into perf/core, to fix conflicts 2017-11-07 10:30:18 +01:00
builtin-mem.c perf mem: Allow all record/report options 2018-04-18 15:35:48 -03:00
builtin-probe.c perf tools: No need to check if the argument to __get() function is NULL 2018-06-04 10:28:50 -03:00
builtin-record.c perf tools: Switch 'session' argument to 'evlist' in perf_event__synthesize_attrs() 2018-08-30 15:52:21 -03:00
builtin-report.c tools lib traceevent, perf tools: Rename pevent_set_* APIs 2018-08-13 15:22:10 -03:00
builtin-sched.c perf sched: Use sched->show_callchain where appropriate 2018-06-05 10:09:54 -03:00
builtin-script.c perf stat: Pass a 'struct perf_stat_config' argument to global print functions 2018-08-30 15:52:23 -03:00
builtin-stat.c perf stat: Move the display functions to stat-display.c 2018-08-30 15:52:25 -03:00
builtin-timechart.c perf thread: Make thread__find_symbol() return the symbol searched 2018-04-26 13:47:09 -03:00
builtin-top.c perf hists: Clarify callchain disabling when available 2018-07-24 14:37:33 -03:00
builtin-trace.c perf trace beauty: Alias 'umount' to 'umount2' 2018-08-30 15:52:25 -03:00
builtin-version.c perf version: Print status for syscall_table 2018-04-12 10:33:34 -03:00
builtin.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
check-headers.sh perf tools: Move syscall_64.tbl check into check-headers.sh 2018-08-14 15:10:40 -03:00
command-list.txt perf tools: Missing c2c command in command-list 2017-03-13 10:59:31 -03:00
CREDITS
design.txt
Makefile perf tools: Disable parallelism for 'make clean' 2018-08-20 08:54:58 -03:00
Makefile.config perf build: Fix installation directory for eBPF 2018-07-31 10:54:50 -03:00
Makefile.perf perf bpf: Add linux/socket.h to the headers accessible to bpf proggies 2018-08-30 15:52:20 -03:00
MANIFEST perf tools: Get all of tools/{arch,include}/ in the MANIFEST 2017-09-25 10:39:43 -03:00
perf-archive.sh License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
perf-completion.sh perf tools: Auto-complete for events with ':' 2017-12-27 12:16:00 -03:00
perf-read-vdso.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
perf-sys.h Drop a bunch of metag references 2018-02-23 14:29:59 +00:00
perf-with-kcore.sh
perf.c perf tools: Remove dead quote.[ch] code 2018-06-04 10:28:50 -03:00
perf.h perf tools: Allow overriding MAX_NR_CPUS at compile time 2018-08-01 12:33:24 -03:00