* [PATCH v5 1/3] scripts/faddr2line: Don't filter out non-function symbols from readelf
2023-10-02 16:57 [PATCH v5 0/3] Fix 'faddr2line' for LLVM arm64 builds Will Deacon
@ 2023-10-02 16:57 ` Will Deacon
2023-10-02 16:57 ` [PATCH v5 2/3] scripts/faddr2line: Use LLVM addr2line and readelf if LLVM=1 Will Deacon
` (2 subsequent siblings)
3 siblings, 0 replies; 10+ messages in thread
From: Will Deacon @ 2023-10-02 16:57 UTC (permalink / raw)
To: linux-kernel
Cc: kernel-team, Will Deacon, Masahiro Yamada, Nathan Chancellor,
Nick Desaulniers, Nicolas Schier, Josh Poimboeuf, John Stultz,
linux-kbuild
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.
Cc: John Stultz <jstultz@google.com>
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>
---
scripts/faddr2line | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/scripts/faddr2line b/scripts/faddr2line
index 0e73aca4f908..a35a420d0f26 100755
--- a/scripts/faddr2line
+++ b/scripts/faddr2line
@@ -260,7 +260,7 @@ __faddr2line() {
DONE=1
- done < <(${READELF} --symbols --wide $objfile | sed 's/\[.*\]//' | ${AWK} -v fn=$sym_name '$4 == "FUNC" && $8 == fn')
+ done < <(${READELF} --symbols --wide $objfile | sed 's/\[.*\]//' | ${AWK} -v fn=$sym_name '$8 == fn')
}
[[ $# -lt 2 ]] && usage
--
2.42.0.582.g8ccd20d70d-goog
^ permalink raw reply related [flat|nested] 10+ messages in thread* [PATCH v5 2/3] scripts/faddr2line: Use LLVM addr2line and readelf if LLVM=1
2023-10-02 16:57 [PATCH v5 0/3] Fix 'faddr2line' for LLVM arm64 builds Will Deacon
2023-10-02 16:57 ` [PATCH v5 1/3] scripts/faddr2line: Don't filter out non-function symbols from readelf Will Deacon
@ 2023-10-02 16:57 ` Will Deacon
2023-10-02 17:00 ` Nick Desaulniers
2023-10-24 8:52 ` [tip: objtool/core] " tip-bot2 for Will Deacon
2023-10-02 16:57 ` [PATCH v5 3/3] scripts/faddr2line: Skip over mapping symbols in output from readelf Will Deacon
2023-10-23 13:42 ` [PATCH v5 0/3] Fix 'faddr2line' for LLVM arm64 builds Will Deacon
3 siblings, 2 replies; 10+ messages in thread
From: Will Deacon @ 2023-10-02 16:57 UTC (permalink / raw)
To: linux-kernel
Cc: kernel-team, Will Deacon, Masahiro Yamada, Nathan Chancellor,
Nick Desaulniers, Nicolas Schier, Josh Poimboeuf, John Stultz,
linux-kbuild
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
$x.73 at main.c:?
Although this can be worked around by setting CROSS_COMPILE to "llvm=-",
it's cleaner to follow the same syntax as the top-level Makefile and
accept LLVM= as an indication to use the llvm- tools, optionally
specifying their location or specific version number.
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: John Stultz <jstultz@google.com>
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
---
scripts/faddr2line | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/scripts/faddr2line b/scripts/faddr2line
index a35a420d0f26..6b8206802157 100755
--- a/scripts/faddr2line
+++ b/scripts/faddr2line
@@ -58,8 +58,21 @@ die() {
exit 1
}
-READELF="${CROSS_COMPILE:-}readelf"
-ADDR2LINE="${CROSS_COMPILE:-}addr2line"
+UTIL_SUFFIX=""
+if [[ "${LLVM:-}" == "" ]]; then
+ UTIL_PREFIX=${CROSS_COMPILE:-}
+else
+ UTIL_PREFIX=llvm-
+
+ if [[ "${LLVM}" == *"/" ]]; then
+ UTIL_PREFIX=${LLVM}${UTIL_PREFIX}
+ elif [[ "${LLVM}" == "-"* ]]; then
+ UTIL_SUFFIX=${LLVM}
+ fi
+fi
+
+READELF="${UTIL_PREFIX}readelf${UTIL_SUFFIX}"
+ADDR2LINE="${UTIL_PREFIX}addr2line${UTIL_SUFFIX}"
AWK="awk"
GREP="grep"
--
2.42.0.582.g8ccd20d70d-goog
^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [PATCH v5 2/3] scripts/faddr2line: Use LLVM addr2line and readelf if LLVM=1
2023-10-02 16:57 ` [PATCH v5 2/3] scripts/faddr2line: Use LLVM addr2line and readelf if LLVM=1 Will Deacon
@ 2023-10-02 17:00 ` Nick Desaulniers
2023-10-24 8:52 ` [tip: objtool/core] " tip-bot2 for Will Deacon
1 sibling, 0 replies; 10+ messages in thread
From: Nick Desaulniers @ 2023-10-02 17:00 UTC (permalink / raw)
To: Will Deacon
Cc: linux-kernel, kernel-team, Masahiro Yamada, Nathan Chancellor,
Nicolas Schier, Josh Poimboeuf, John Stultz, linux-kbuild
On Mon, Oct 2, 2023 at 9:58 AM Will Deacon <will@kernel.org> wrote:
>
> 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
> $x.73 at main.c:?
>
> Although this can be worked around by setting CROSS_COMPILE to "llvm=-",
> it's cleaner to follow the same syntax as the top-level Makefile and
> accept LLVM= as an indication to use the llvm- tools, optionally
> specifying their location or specific version number.
>
> Cc: Josh Poimboeuf <jpoimboe@kernel.org>
> Cc: John Stultz <jstultz@google.com>
> Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
> Signed-off-by: Will Deacon <will@kernel.org>
Thanks for the patch!
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> ---
> scripts/faddr2line | 17 +++++++++++++++--
> 1 file changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/scripts/faddr2line b/scripts/faddr2line
> index a35a420d0f26..6b8206802157 100755
> --- a/scripts/faddr2line
> +++ b/scripts/faddr2line
> @@ -58,8 +58,21 @@ die() {
> exit 1
> }
>
> -READELF="${CROSS_COMPILE:-}readelf"
> -ADDR2LINE="${CROSS_COMPILE:-}addr2line"
> +UTIL_SUFFIX=""
> +if [[ "${LLVM:-}" == "" ]]; then
> + UTIL_PREFIX=${CROSS_COMPILE:-}
> +else
> + UTIL_PREFIX=llvm-
> +
> + if [[ "${LLVM}" == *"/" ]]; then
> + UTIL_PREFIX=${LLVM}${UTIL_PREFIX}
> + elif [[ "${LLVM}" == "-"* ]]; then
> + UTIL_SUFFIX=${LLVM}
> + fi
> +fi
> +
> +READELF="${UTIL_PREFIX}readelf${UTIL_SUFFIX}"
> +ADDR2LINE="${UTIL_PREFIX}addr2line${UTIL_SUFFIX}"
> AWK="awk"
> GREP="grep"
>
> --
> 2.42.0.582.g8ccd20d70d-goog
>
--
Thanks,
~Nick Desaulniers
^ permalink raw reply [flat|nested] 10+ messages in thread* [tip: objtool/core] scripts/faddr2line: Use LLVM addr2line and readelf if LLVM=1
2023-10-02 16:57 ` [PATCH v5 2/3] scripts/faddr2line: Use LLVM addr2line and readelf if LLVM=1 Will Deacon
2023-10-02 17:00 ` Nick Desaulniers
@ 2023-10-24 8:52 ` tip-bot2 for Will Deacon
1 sibling, 0 replies; 10+ messages in thread
From: tip-bot2 for Will Deacon @ 2023-10-24 8:52 UTC (permalink / raw)
To: linux-tip-commits
Cc: Masahiro Yamada, Will Deacon, Nick Desaulniers, Josh Poimboeuf,
x86, linux-kernel
The following commit has been merged into the objtool/core branch of tip:
Commit-ID: 86bf86e19d308a1dba41e5f1f7e8cc105a5efa49
Gitweb: https://git.kernel.org/tip/86bf86e19d308a1dba41e5f1f7e8cc105a5efa49
Author: Will Deacon <will@kernel.org>
AuthorDate: Mon, 02 Oct 2023 17:57:48 +01:00
Committer: Josh Poimboeuf <jpoimboe@kernel.org>
CommitterDate: Mon, 23 Oct 2023 08:36:33 -07:00
scripts/faddr2line: Use LLVM addr2line and readelf if LLVM=1
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
$x.73 at main.c:?
Although this can be worked around by setting CROSS_COMPILE to "llvm=-",
it's cleaner to follow the same syntax as the top-level Makefile and
accept LLVM= as an indication to use the llvm- tools, optionally
specifying their location or specific version number.
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20231002165750.1661-3-will@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
scripts/faddr2line | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/scripts/faddr2line b/scripts/faddr2line
index a35a420..6b82068 100755
--- a/scripts/faddr2line
+++ b/scripts/faddr2line
@@ -58,8 +58,21 @@ die() {
exit 1
}
-READELF="${CROSS_COMPILE:-}readelf"
-ADDR2LINE="${CROSS_COMPILE:-}addr2line"
+UTIL_SUFFIX=""
+if [[ "${LLVM:-}" == "" ]]; then
+ UTIL_PREFIX=${CROSS_COMPILE:-}
+else
+ UTIL_PREFIX=llvm-
+
+ if [[ "${LLVM}" == *"/" ]]; then
+ UTIL_PREFIX=${LLVM}${UTIL_PREFIX}
+ elif [[ "${LLVM}" == "-"* ]]; then
+ UTIL_SUFFIX=${LLVM}
+ fi
+fi
+
+READELF="${UTIL_PREFIX}readelf${UTIL_SUFFIX}"
+ADDR2LINE="${UTIL_PREFIX}addr2line${UTIL_SUFFIX}"
AWK="awk"
GREP="grep"
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH v5 3/3] scripts/faddr2line: Skip over mapping symbols in output from readelf
2023-10-02 16:57 [PATCH v5 0/3] Fix 'faddr2line' for LLVM arm64 builds Will Deacon
2023-10-02 16:57 ` [PATCH v5 1/3] scripts/faddr2line: Don't filter out non-function symbols from readelf Will Deacon
2023-10-02 16:57 ` [PATCH v5 2/3] scripts/faddr2line: Use LLVM addr2line and readelf if LLVM=1 Will Deacon
@ 2023-10-02 16:57 ` Will Deacon
2023-10-02 17:02 ` Nick Desaulniers
` (2 more replies)
2023-10-23 13:42 ` [PATCH v5 0/3] Fix 'faddr2line' for LLVM arm64 builds Will Deacon
3 siblings, 3 replies; 10+ messages in thread
From: Will Deacon @ 2023-10-02 16:57 UTC (permalink / raw)
To: linux-kernel
Cc: kernel-team, Will Deacon, Masahiro Yamada, Nathan Chancellor,
Nick Desaulniers, Nicolas Schier, Josh Poimboeuf, John Stultz,
linux-kbuild
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.
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: John Stultz <jstultz@google.com>
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
---
scripts/faddr2line | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/scripts/faddr2line b/scripts/faddr2line
index 6b8206802157..587415a52b6f 100755
--- a/scripts/faddr2line
+++ b/scripts/faddr2line
@@ -179,6 +179,11 @@ __faddr2line() {
local cur_sym_elf_size=${fields[2]}
local cur_sym_name=${fields[7]:-}
+ # is_mapping_symbol(cur_sym_name)
+ if [[ ${cur_sym_name} =~ ^(\.L|L0|\$) ]]; then
+ continue
+ fi
+
if [[ $cur_sym_addr = $sym_addr ]] &&
[[ $cur_sym_elf_size = $sym_elf_size ]] &&
[[ $cur_sym_name = $sym_name ]]; then
--
2.42.0.582.g8ccd20d70d-goog
^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [PATCH v5 3/3] scripts/faddr2line: Skip over mapping symbols in output from readelf
2023-10-02 16:57 ` [PATCH v5 3/3] scripts/faddr2line: Skip over mapping symbols in output from readelf Will Deacon
@ 2023-10-02 17:02 ` Nick Desaulniers
2023-10-24 0:17 ` Masahiro Yamada
2023-10-24 8:52 ` [tip: objtool/core] " tip-bot2 for Will Deacon
2 siblings, 0 replies; 10+ messages in thread
From: Nick Desaulniers @ 2023-10-02 17:02 UTC (permalink / raw)
To: Will Deacon
Cc: linux-kernel, kernel-team, Masahiro Yamada, Nathan Chancellor,
Nicolas Schier, Josh Poimboeuf, John Stultz, linux-kbuild
On Mon, Oct 2, 2023 at 9:58 AM Will Deacon <will@kernel.org> wrote:
>
> Mapping symbols emitted in the readelf output can confuse the
> 'faddr2line' symbol size calculation, resulting in the erroneous
> rejection of valid offsets. This is especially prevalent when building
> an arm64 kernel with CONFIG_CFI_CLANG=y, where most functions are
> prefixed with a 32-bit data value in a '$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.
>
> Cc: Josh Poimboeuf <jpoimboe@kernel.org>
> Cc: John Stultz <jstultz@google.com>
> Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
> Signed-off-by: Will Deacon <will@kernel.org>
Thanks for the patch!
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> ---
> scripts/faddr2line | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/scripts/faddr2line b/scripts/faddr2line
> index 6b8206802157..587415a52b6f 100755
> --- a/scripts/faddr2line
> +++ b/scripts/faddr2line
> @@ -179,6 +179,11 @@ __faddr2line() {
> local cur_sym_elf_size=${fields[2]}
> local cur_sym_name=${fields[7]:-}
>
> + # is_mapping_symbol(cur_sym_name)
> + if [[ ${cur_sym_name} =~ ^(\.L|L0|\$) ]]; then
> + continue
> + fi
> +
> if [[ $cur_sym_addr = $sym_addr ]] &&
> [[ $cur_sym_elf_size = $sym_elf_size ]] &&
> [[ $cur_sym_name = $sym_name ]]; then
> --
> 2.42.0.582.g8ccd20d70d-goog
>
--
Thanks,
~Nick Desaulniers
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [PATCH v5 3/3] scripts/faddr2line: Skip over mapping symbols in output from readelf
2023-10-02 16:57 ` [PATCH v5 3/3] scripts/faddr2line: Skip over mapping symbols in output from readelf Will Deacon
2023-10-02 17:02 ` Nick Desaulniers
@ 2023-10-24 0:17 ` Masahiro Yamada
2023-10-24 8:52 ` [tip: objtool/core] " tip-bot2 for Will Deacon
2 siblings, 0 replies; 10+ messages in thread
From: Masahiro Yamada @ 2023-10-24 0:17 UTC (permalink / raw)
To: Will Deacon
Cc: linux-kernel, kernel-team, Nathan Chancellor, Nick Desaulniers,
Nicolas Schier, Josh Poimboeuf, John Stultz, linux-kbuild
On Tue, Oct 3, 2023 at 1:58 AM Will Deacon <will@kernel.org> wrote:
>
> Mapping symbols emitted in the readelf output can confuse the
> 'faddr2line' symbol size calculation, resulting in the erroneous
> rejection of valid offsets. This is especially prevalent when building
> an arm64 kernel with CONFIG_CFI_CLANG=y, where most functions are
> prefixed with a 32-bit data value in a '$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.
>
> Cc: Josh Poimboeuf <jpoimboe@kernel.org>
> Cc: John Stultz <jstultz@google.com>
> Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
> Signed-off-by: Will Deacon <will@kernel.org>
> ---
> scripts/faddr2line | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/scripts/faddr2line b/scripts/faddr2line
> index 6b8206802157..587415a52b6f 100755
> --- a/scripts/faddr2line
> +++ b/scripts/faddr2line
> @@ -179,6 +179,11 @@ __faddr2line() {
> local cur_sym_elf_size=${fields[2]}
> local cur_sym_name=${fields[7]:-}
>
> + # is_mapping_symbol(cur_sym_name)
> + if [[ ${cur_sym_name} =~ ^(\.L|L0|\$) ]]; then
> + continue
> + fi
> +
> if [[ $cur_sym_addr = $sym_addr ]] &&
> [[ $cur_sym_elf_size = $sym_elf_size ]] &&
> [[ $cur_sym_name = $sym_name ]]; then
> --
> 2.42.0.582.g8ccd20d70d-goog
>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
--
Best Regards
Masahiro Yamada
^ permalink raw reply [flat|nested] 10+ messages in thread* [tip: objtool/core] scripts/faddr2line: Skip over mapping symbols in output from readelf
2023-10-02 16:57 ` [PATCH v5 3/3] scripts/faddr2line: Skip over mapping symbols in output from readelf Will Deacon
2023-10-02 17:02 ` Nick Desaulniers
2023-10-24 0:17 ` Masahiro Yamada
@ 2023-10-24 8:52 ` tip-bot2 for Will Deacon
2 siblings, 0 replies; 10+ messages in thread
From: tip-bot2 for Will Deacon @ 2023-10-24 8:52 UTC (permalink / raw)
To: linux-tip-commits
Cc: Masahiro Yamada, Will Deacon, Nick Desaulniers, Josh Poimboeuf,
x86, linux-kernel
The following commit has been merged into the objtool/core branch of tip:
Commit-ID: 60fd39af33d3f63c4c94bd06784ebdf0d883f5c9
Gitweb: https://git.kernel.org/tip/60fd39af33d3f63c4c94bd06784ebdf0d883f5c9
Author: Will Deacon <will@kernel.org>
AuthorDate: Mon, 02 Oct 2023 17:57:49 +01:00
Committer: Josh Poimboeuf <jpoimboe@kernel.org>
CommitterDate: Mon, 23 Oct 2023 08:36:46 -07:00
scripts/faddr2line: Skip over mapping symbols in output from readelf
Mapping symbols emitted in the readelf output can confuse the
'faddr2line' symbol size calculation, resulting in the erroneous
rejection of valid offsets. This is especially prevalent when building
an arm64 kernel with CONFIG_CFI_CLANG=y, where most functions are
prefixed with a 32-bit data value in a '$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 | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/scripts/faddr2line b/scripts/faddr2line
index 6b82068..587415a 100755
--- a/scripts/faddr2line
+++ b/scripts/faddr2line
@@ -179,6 +179,11 @@ __faddr2line() {
local cur_sym_elf_size=${fields[2]}
local cur_sym_name=${fields[7]:-}
+ # is_mapping_symbol(cur_sym_name)
+ if [[ ${cur_sym_name} =~ ^(\.L|L0|\$) ]]; then
+ continue
+ fi
+
if [[ $cur_sym_addr = $sym_addr ]] &&
[[ $cur_sym_elf_size = $sym_elf_size ]] &&
[[ $cur_sym_name = $sym_name ]]; then
^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH v5 0/3] Fix 'faddr2line' for LLVM arm64 builds
2023-10-02 16:57 [PATCH v5 0/3] Fix 'faddr2line' for LLVM arm64 builds Will Deacon
` (2 preceding siblings ...)
2023-10-02 16:57 ` [PATCH v5 3/3] scripts/faddr2line: Skip over mapping symbols in output from readelf Will Deacon
@ 2023-10-23 13:42 ` Will Deacon
3 siblings, 0 replies; 10+ messages in thread
From: Will Deacon @ 2023-10-23 13:42 UTC (permalink / raw)
To: linux-kernel, jpoimboe
Cc: kernel-team, Masahiro Yamada, Nathan Chancellor, Nick Desaulniers,
Nicolas Schier, John Stultz, linux-kbuild
Josh,
On Mon, Oct 02, 2023 at 05:57:46PM +0100, Will Deacon wrote:
> Hello again.
>
> This is version five of the fadd2line fixes that I previously posted at:
>
> v1: https://lore.kernel.org/r/20230724174517.15736-1-will@kernel.org
> v2: https://lore.kernel.org/r/20230725211157.17031-1-will@kernel.org
> v3: https://lore.kernel.org/r/20230728113415.21067-1-will@kernel.org
> v4: https://lore.kernel.org/r/20230914131225.13415-1-will@kernel.org
>
> Changes since v4 include:
> * Simplify the is_mapping_symbol() regex to reflect the latest version
> of the C code.
> * Add Suggested-by and Reviewed-by tags to patch 1.
Please can you pick this up for 6.7?
Will
^ permalink raw reply [flat|nested] 10+ messages in thread