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>
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>
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>
Commit 1d1a0e7c51 ("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:
1fd6cee127 ("libbpf: Fix VERSIONED_SYM_COUNT number parsing")
aa915931ac ("libbpf: Fix readelf output parsing for Fedora")
[jpoimboe: rework commit log]
Fixes: 1d1a0e7c51 ("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>
Since commit dcea997bee ("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: dcea997bee ("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
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: 1d1a0e7c51 ("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
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: 67326666e2 ("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
Commit 6870c0165f ("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: 6870c0165f ("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>
When addr2line output contains discriminator, the current awk script
cannot parse it. This patch fixes it by extracting key words using
regex which is more reliable.
$ scripts/faddr2line vmlinux tlb_flush_mmu_free+0x26
tlb_flush_mmu_free+0x26/0x50:
tlb_flush_mmu_free at mm/memory.c:258 (discriminator 3)
scripts/faddr2line: eval: line 173: unexpected EOF while looking for matching `)'
Link: http://lkml.kernel.org/r/1525323379-25193-1-git-send-email-changbin.du@intel.com
Fixes: 6870c0165f ("scripts/faddr2line: show the code context")
Signed-off-by: Changbin Du <changbin.du@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: NeilBrown <neilb@suse.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
faddr2line hit var unbound error when CROSS_COMPILE isn't set since
nounset option is set in bash script.
Link: http://lkml.kernel.org/r/20171206013022.GA83929@sofia
Fixes: 95a8798254 ("scripts/faddr2line: extend usage on generic arch")
Signed-off-by: Liu Changcheng <changcheng.liu@intel.com>
Reported-by: Richard Weinberger <richard.weinberger@gmail.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: NeilBrown <neilb@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When cross-compiling, fadd2line should use the binary tool used for the
target system, rather than that of the host.
Link: http://lkml.kernel.org/r/20171121092911.GA150711@sofia
Signed-off-by: Liu Changcheng <changcheng.liu@intel.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: NeilBrown <neilb@suse.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If faddr2line is given a function name which is the last one listed by
"nm -n", it will fail because it never finds the next symbol.
So teach the awk script to catch that possibility, and use 'size' to
provide the end point of the last function.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I'm not sure how we missed this problem before. When I take a function
address and size from an oops and give it to faddr2line, it usually
complains about a size mismatch:
$ scripts/faddr2line ~/k/vmlinux write_sysrq_trigger+0x51/0x60
skipping write_sysrq_trigger address at 0xffffffff815731a1 due to size mismatch (0x60 != 83)
no match for write_sysrq_trigger+0x51/0x60
The problem is caused by differences in how kallsyms and faddr2line
determine a function's size.
kallsyms calculates a function's size by parsing the output of 'nm -n'
and subtracting the next function's address from the current function's
address. This means that nop instructions after the end of the function
are included in the size.
In contrast, faddr2line reads the size from the symbol table, which does
*not* include the ending nops in the function's size.
Change faddr2line to calculate the size from the output of 'nm -n' to be
consistent with kallsyms and oops outputs.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/bd313ed7c4003f6b1fda63e825325c44a9d837de.1477405374.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Due to our compiler include directives, the build pathnames for header
files often end up being of the form "$srcdir/./include/linux/xyz.h",
which ends up having that extra "." path component after the build base
in it.
Teach faddr2line to skip that too, to make code generated in inline
functions in header files match the filename for the regular C files.
Rabin Vincent pointed out that I can't make a stricter regexp match by
using the " at " prefix for the pathname, because that ends up being
locale-dependent. But this does require that the path match be preceded
by a space, to make it a bit more strict (that matters mainly if we
didn't find any base_dir at all, and we only end up with the "./" part
of the match)
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Rabin Vincent <rabin@rab.in>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
addr2line doesn't work with KASLR addresses. Add a basic addr2line
wrapper script which takes the 'func+offset/size' format as input.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Will Deacon