linux-toradex.git/scripts/faddr2line, branch v6.9-rc5 Linux kernel for Apalis and Colibri modules scripts/faddr2line: Skip over mapping symbols in output from readelf 2023-10-23T15:36:46+00:00 Will Deacon will@kernel.org 2023-10-02T16:57:49+00:00 60fd39af33d3f63c4c94bd06784ebdf0d883f5c9 Mapping symbols emitted in the readelf output can confuse the 'faddr2line' symbol size calculation, resulting in the erroneous rejection of valid offsets. This is especially prevalent when building an arm64 kernel with CONFIG_CFI_CLANG=y, where most functions are prefixed with a 32-bit data value in a '$d.n' section. For example: 447538: ffff800080014b80 548 FUNC GLOBAL DEFAULT 2 do_one_initcall 104: ffff800080014c74 0 NOTYPE LOCAL DEFAULT 2 $x.73 106: ffff800080014d30 0 NOTYPE LOCAL DEFAULT 2 $x.75 111: ffff800080014da4 0 NOTYPE LOCAL DEFAULT 2 $d.78 112: ffff800080014da8 0 NOTYPE LOCAL DEFAULT 2 $x.79 36: ffff800080014de0 200 FUNC LOCAL DEFAULT 2 run_init_process Adding a warning to do_one_initcall() results in: | WARNING: CPU: 0 PID: 1 at init/main.c:1236 do_one_initcall+0xf4/0x260 Which 'faddr2line' refuses to accept: $ ./scripts/faddr2line vmlinux do_one_initcall+0xf4/0x260 skipping do_one_initcall address at 0xffff800080014c74 due to size mismatch (0x260 != 0x224) no match for do_one_initcall+0xf4/0x260 Filter out these entries from readelf using a shell reimplementation of is_mapping_symbol(), so that the size of a symbol is calculated as a delta to the next symbol present in ksymtab. Suggested-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Will Deacon <will@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://lore.kernel.org/r/20231002165750.1661-4-will@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> 
Mapping symbols emitted in the readelf output can confuse the
'faddr2line' symbol size calculation, resulting in the erroneous
rejection of valid offsets. This is especially prevalent when building
an arm64 kernel with CONFIG_CFI_CLANG=y, where most functions are
prefixed with a 32-bit data value in a '$d.n' section. For example:

447538: ffff800080014b80   548 FUNC    GLOBAL DEFAULT    2 do_one_initcall
   104: ffff800080014c74     0 NOTYPE  LOCAL  DEFAULT    2 $x.73
   106: ffff800080014d30     0 NOTYPE  LOCAL  DEFAULT    2 $x.75
   111: ffff800080014da4     0 NOTYPE  LOCAL  DEFAULT    2 $d.78
   112: ffff800080014da8     0 NOTYPE  LOCAL  DEFAULT    2 $x.79
    36: ffff800080014de0   200 FUNC    LOCAL  DEFAULT    2 run_init_process

Adding a warning to do_one_initcall() results in:

  | WARNING: CPU: 0 PID: 1 at init/main.c:1236 do_one_initcall+0xf4/0x260

Which 'faddr2line' refuses to accept:

$ ./scripts/faddr2line vmlinux do_one_initcall+0xf4/0x260
skipping do_one_initcall address at 0xffff800080014c74 due to size mismatch (0x260 != 0x224)
no match for do_one_initcall+0xf4/0x260

Filter out these entries from readelf using a shell reimplementation of
is_mapping_symbol(), so that the size of a symbol is calculated as a
delta to the next symbol present in ksymtab.

Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20231002165750.1661-4-will@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
scripts/faddr2line: Use LLVM addr2line and readelf if LLVM=1 2023-10-23T15:36:33+00:00 Will Deacon will@kernel.org 2023-10-02T16:57:48+00:00 86bf86e19d308a1dba41e5f1f7e8cc105a5efa49 GNU utilities cannot necessarily parse objects built by LLVM, which can result in confusing errors when using 'faddr2line': $ CROSS_COMPILE=aarch64-linux-gnu- ./scripts/faddr2line vmlinux do_one_initcall+0xf4/0x260 aarch64-linux-gnu-addr2line: vmlinux: unknown type [0x13] section `.relr.dyn' aarch64-linux-gnu-addr2line: DWARF error: invalid or unhandled FORM value: 0x25 do_one_initcall+0xf4/0x260: aarch64-linux-gnu-addr2line: vmlinux: unknown type [0x13] section `.relr.dyn' aarch64-linux-gnu-addr2line: DWARF error: invalid or unhandled FORM value: 0x25 $x.73 at main.c:? Although this can be worked around by setting CROSS_COMPILE to "llvm=-", it's cleaner to follow the same syntax as the top-level Makefile and accept LLVM= as an indication to use the llvm- tools, optionally specifying their location or specific version number. Suggested-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Will Deacon <will@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://lore.kernel.org/r/20231002165750.1661-3-will@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> 
GNU utilities cannot necessarily parse objects built by LLVM, which can
result in confusing errors when using 'faddr2line':

$ CROSS_COMPILE=aarch64-linux-gnu- ./scripts/faddr2line vmlinux do_one_initcall+0xf4/0x260
aarch64-linux-gnu-addr2line: vmlinux: unknown type [0x13] section `.relr.dyn'
aarch64-linux-gnu-addr2line: DWARF error: invalid or unhandled FORM value: 0x25
do_one_initcall+0xf4/0x260:
aarch64-linux-gnu-addr2line: vmlinux: unknown type [0x13] section `.relr.dyn'
aarch64-linux-gnu-addr2line: DWARF error: invalid or unhandled FORM value: 0x25
$x.73 at main.c:?

Although this can be worked around by setting CROSS_COMPILE to "llvm=-",
it's cleaner to follow the same syntax as the top-level Makefile and
accept LLVM= as an indication to use the llvm- tools, optionally
specifying their location or specific version number.

Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20231002165750.1661-3-will@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
scripts/faddr2line: Don't filter out non-function symbols from readelf 2023-10-23T15:35:01+00:00 Will Deacon will@kernel.org 2023-10-02T16:57:47+00:00 180af1a5bdaf8d4964837a46a9fce8c3a7fd2d97 As Josh points out in 20230724234734.zy67gm674vl3p3wv@treble: > Problem is, I think the kernel's symbol printing code prints the > nearest kallsyms symbol, and there are some valid non-FUNC code > symbols. For example, syscall_return_via_sysret. so we shouldn't be considering only 'FUNC'-type symbols in the output from readelf. Drop the function symbol type filtering from the faddr2line outer loop. Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://lore.kernel.org/r/20230724234734.zy67gm674vl3p3wv@treble Signed-off-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20231002165750.1661-2-will@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> 
As Josh points out in 20230724234734.zy67gm674vl3p3wv@treble:

> Problem is, I think the kernel's symbol printing code prints the
> nearest kallsyms symbol, and there are some valid non-FUNC code
> symbols.  For example, syscall_return_via_sysret.

so we shouldn't be considering only 'FUNC'-type symbols in the output
from readelf.

Drop the function symbol type filtering from the faddr2line outer loop.

Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20230724234734.zy67gm674vl3p3wv@treble
Signed-off-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20231002165750.1661-2-will@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
scripts/faddr2line: Fix regression in name resolution on ppc64le 2022-11-16T09:42:10+00:00 Srikar Dronamraju srikar@linux.vnet.ibm.com 2022-09-27T07:52:11+00:00 2d77de1581bb5b470486edaf17a7d70151131afd Commit 1d1a0e7c5100 ("scripts/faddr2line: Fix overlapping text section failures") can cause faddr2line to fail on ppc64le on some distributions, while it works fine on other distributions. The failure can be attributed to differences in the readelf output. $ ./scripts/faddr2line vmlinux find_busiest_group+0x00 no match for find_busiest_group+0x00 On ppc64le, readelf adds the localentry tag before the symbol name on some distributions, and adds the localentry tag after the symbol name on other distributions. This problem has been discussed previously: https://lore.kernel.org/bpf/20191211160133.GB4580@calabresa/ This problem can be overcome by filtering out the localentry tags in the readelf output. Similar fixes are already present in the kernel by way of the following commits: 1fd6cee127e2 ("libbpf: Fix VERSIONED_SYM_COUNT number parsing") aa915931ac3e ("libbpf: Fix readelf output parsing for Fedora") [jpoimboe: rework commit log] Fixes: 1d1a0e7c5100 ("scripts/faddr2line: Fix overlapping text section failures") Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Reviewed-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> Link: https://lore.kernel.org/r/20220927075211.897152-1-srikar@linux.vnet.ibm.com Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> 
Commit 1d1a0e7c5100 ("scripts/faddr2line: Fix overlapping text section
failures") can cause faddr2line to fail on ppc64le on some
distributions, while it works fine on other distributions. The failure
can be attributed to differences in the readelf output.

  $ ./scripts/faddr2line vmlinux find_busiest_group+0x00
  no match for find_busiest_group+0x00

On ppc64le, readelf adds the localentry tag before the symbol name on
some distributions, and adds the localentry tag after the symbol name on
other distributions. This problem has been discussed previously:

  https://lore.kernel.org/bpf/20191211160133.GB4580@calabresa/

This problem can be overcome by filtering out the localentry tags in the
readelf output. Similar fixes are already present in the kernel by way
of the following commits:

  1fd6cee127e2 ("libbpf: Fix VERSIONED_SYM_COUNT number parsing")
  aa915931ac3e ("libbpf: Fix readelf output parsing for Fedora")

[jpoimboe: rework commit log]

Fixes: 1d1a0e7c5100 ("scripts/faddr2line: Fix overlapping text section failures")
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Link: https://lore.kernel.org/r/20220927075211.897152-1-srikar@linux.vnet.ibm.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
scripts/faddr2line: Add CONFIG_DEBUG_INFO check 2022-08-02T20:08:17+00:00 Josh Poimboeuf jpoimboe@kernel.org 2022-07-21T18:01:24+00:00 a41a2e2e34a907bd8979a53c58f44287630616e8 Otherwise without DWARF it spits out gibberish and gives no indication of what the problem is. Suggested-by: John Garry <john.garry@huawei.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: John Garry <john.garry@huawei.com> Link: https://lore.kernel.org/r/ffa7734c929445caa374bf9e68078300174f09b4.1658426357.git.jpoimboe@kernel.org 
Otherwise without DWARF it spits out gibberish and gives no indication
of what the problem is.

Suggested-by: John Garry <john.garry@huawei.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/ffa7734c929445caa374bf9e68078300174f09b4.1658426357.git.jpoimboe@kernel.org
scripts/faddr2line: Fix vmlinux detection on arm64 2022-08-02T20:08:16+00:00 Josh Poimboeuf jpoimboe@kernel.org 2022-07-21T18:01:23+00:00 b6a5068854cfe372da7dee3224dcf023ed5b00cb Since commit dcea997beed6 ("faddr2line: Fix overlapping text section failures, the sequel"), faddr2line is completely broken on arm64. For some reason, on arm64, the vmlinux ELF object file type is ET_DYN rather than ET_EXEC. Check for both when determining whether the object is vmlinux. Modules and vmlinux.o have type ET_REL on all arches. Fixes: dcea997beed6 ("faddr2line: Fix overlapping text section failures, the sequel") Reported-by: John Garry <john.garry@huawei.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: John Garry <john.garry@huawei.com> Link: https://lore.kernel.org/r/dad1999737471b06d6188ce4cdb11329aa41682c.1658426357.git.jpoimboe@kernel.org 
Since commit dcea997beed6 ("faddr2line: Fix overlapping text section
failures, the sequel"), faddr2line is completely broken on arm64.

For some reason, on arm64, the vmlinux ELF object file type is ET_DYN
rather than ET_EXEC.  Check for both when determining whether the object
is vmlinux.

Modules and vmlinux.o have type ET_REL on all arches.

Fixes: dcea997beed6 ("faddr2line: Fix overlapping text section failures, the sequel")
Reported-by: John Garry <john.garry@huawei.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/dad1999737471b06d6188ce4cdb11329aa41682c.1658426357.git.jpoimboe@kernel.org
faddr2line: Fix overlapping text section failures, the sequel 2022-06-06T18:50:11+00:00 Josh Poimboeuf jpoimboe@kernel.org 2022-06-02T00:42:22+00:00 dcea997beed694cbd8705100ca1a6eb0d886de69 If a function lives in a section other than .text, but .text also exists in the object, faddr2line may wrongly assume .text. This can result in comically wrong output. For example: $ scripts/faddr2line vmlinux.o enter_from_user_mode+0x1c enter_from_user_mode+0x1c/0x30: find_next_bit at /home/jpoimboe/git/linux/./include/linux/find.h:40 (inlined by) perf_clear_dirty_counters at /home/jpoimboe/git/linux/arch/x86/events/core.c:2504 Fix it by passing the section name to addr2line, unless the object file is vmlinux, in which case the symbol table uses absolute addresses. Fixes: 1d1a0e7c5100 ("scripts/faddr2line: Fix overlapping text section failures") Reported-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lore.kernel.org/r/7d25bc1408bd3a750ac26e60d2f2815a5f4a8363.1654130536.git.jpoimboe@kernel.org 
If a function lives in a section other than .text, but .text also exists
in the object, faddr2line may wrongly assume .text.  This can result in
comically wrong output.  For example:

  $ scripts/faddr2line vmlinux.o enter_from_user_mode+0x1c
  enter_from_user_mode+0x1c/0x30:
  find_next_bit at /home/jpoimboe/git/linux/./include/linux/find.h:40
  (inlined by) perf_clear_dirty_counters at /home/jpoimboe/git/linux/arch/x86/events/core.c:2504

Fix it by passing the section name to addr2line, unless the object file
is vmlinux, in which case the symbol table uses absolute addresses.

Fixes: 1d1a0e7c5100 ("scripts/faddr2line: Fix overlapping text section failures")
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/7d25bc1408bd3a750ac26e60d2f2815a5f4a8363.1654130536.git.jpoimboe@kernel.org
scripts/faddr2line: Fix overlapping text section failures 2022-05-12T19:07:11+00:00 Josh Poimboeuf jpoimboe@kernel.org 2022-05-12T19:05:27+00:00 1d1a0e7c5100d332583e20b40aa8c0a8ed3d7849 There have been some recent reports of faddr2line failures: $ scripts/faddr2line sound/soundcore.ko sound_devnode+0x5/0x35 bad symbol size: base: 0x0000000000000000 end: 0x0000000000000000 $ ./scripts/faddr2line vmlinux.o enter_from_user_mode+0x24 bad symbol size: base: 0x0000000000005fe0 end: 0x0000000000005fe0 The problem is that faddr2line is based on 'nm', which has a major limitation: it doesn't know how to distinguish between different text sections. So if an offset exists in multiple text sections in the object, it may fail. Rewrite faddr2line to be section-aware, by basing it on readelf. Fixes: 67326666e2d4 ("scripts: add script for translating stack dump function offsets") Reported-by: Kaiwan N Billimoria <kaiwan.billimoria@gmail.com> Reported-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lore.kernel.org/r/29ff99f86e3da965b6e46c1cc2d72ce6528c17c3.1652382321.git.jpoimboe@kernel.org 
There have been some recent reports of faddr2line failures:

  $ scripts/faddr2line sound/soundcore.ko sound_devnode+0x5/0x35
  bad symbol size: base: 0x0000000000000000 end: 0x0000000000000000

  $ ./scripts/faddr2line vmlinux.o enter_from_user_mode+0x24
  bad symbol size: base: 0x0000000000005fe0 end: 0x0000000000005fe0

The problem is that faddr2line is based on 'nm', which has a major
limitation: it doesn't know how to distinguish between different text
sections.  So if an offset exists in multiple text sections in the
object, it may fail.

Rewrite faddr2line to be section-aware, by basing it on readelf.

Fixes: 67326666e2d4 ("scripts: add script for translating stack dump function offsets")
Reported-by: Kaiwan N Billimoria <kaiwan.billimoria@gmail.com>
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/29ff99f86e3da965b6e46c1cc2d72ce6528c17c3.1652382321.git.jpoimboe@kernel.org
scripts/faddr2line: fix location of start_kernel in comment 2018-11-18T18:15:09+00:00 Randy Dunlap rdunlap@infradead.org 2018-11-16T23:08:22+00:00 f5f67cc0e0d3d17ee046ba83f831f267767b8554 Fix a source file reference location to the correct path name. Link: http://lkml.kernel.org/r/1d50bd3d-178e-dcd8-779f-9711887440eb@infradead.org Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Fix a source file reference location to the correct path name.

Link: http://lkml.kernel.org/r/1d50bd3d-178e-dcd8-779f-9711887440eb@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
scripts/faddr2line: make the new code listing format optional 2018-06-05T16:04:37+00:00 Peter Zijlstra (Intel) peterz@infradead.org 2018-06-04T18:48:31+00:00 689135f0ed61b6bf3adc215d2ee70be747cf8f93 Commit 6870c0165feaa5 ("scripts/faddr2line: show the code context") radically altered the output format of the faddr2line tool. And while the new list output format might have merit it broke my vim usage and was hard to read. Make the new format optional; using a '--list' argument and attempt to make the output slightly easier to read by adding a little whitespace to separate the different files and explicitly mark the line in question. Cc: Changbin Du <changbin.du@intel.com> Fixes: 6870c0165feaa5 ("scripts/faddr2line: show the code context") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Commit 6870c0165feaa5 ("scripts/faddr2line: show the code context")
radically altered the output format of the faddr2line tool.  And while
the new list output format might have merit it broke my vim usage and
was hard to read.

Make the new format optional; using a '--list' argument and attempt to
make the output slightly easier to read by adding a little whitespace to
separate the different files and explicitly mark the line in question.

Cc: Changbin Du <changbin.du@intel.com>
Fixes: 6870c0165feaa5 ("scripts/faddr2line: show the code context")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>