kernel/linux.git/scripts/faddr2line, branch v6.19.11

scripts/faddr2line: Fix "Argument list too long" error

2025-10-14T21:45:20+00:00

The run_readelf() function reads the entire output of readelf into a single shell variable. For large object files with extensive debug information, the size of this variable can exceed the system's command-line argument length limit. When this variable is subsequently passed to sed via `echo "${out}"`, it triggers an "Argument list too long" error, causing the script to fail. Fix this by redirecting the output of readelf to a temporary file instead of a variable. The sed commands are then modified to read from this file, avoiding the argument length limitation entirely. Signed-off-by: Pankaj Raghav Signed-off-by: Josh Poimboeuf

scripts/faddr2line: Use /usr/bin/env bash for portability

2025-10-14T21:45:20+00:00

The shebang `#!/bin/bash` assumes a fixed path for the bash interpreter. This path does not exist on some systems, such as NixOS, causing the script to fail. Replace `/bin/bash` with the more portable `#!/usr/bin/env bash`. Signed-off-by: Pankaj Raghav Signed-off-by: Josh Poimboeuf

scripts/faddr2line: Set LANG=C to enforce ASCII output

2025-10-14T21:45:20+00:00

Force tools like readelf to use the POSIX/C locale by exporting LANG=C This ensures ASCII-only output and avoids locale-specific characters(e.g., UTF-8 symbols or translated strings), which could break text processing utilities like sed in the script Signed-off-by: John Wang Signed-off-by: Josh Poimboeuf

Revert "scripts/faddr2line: Check only two symbols when calculating symbol size"

2024-10-17T22:16:04+00:00

This reverts commit c02904f05ff805d6c0631634d5751ebd338f75ec. Such commit assumed that only two symbols are relevant for the symbol size calculation. However, this can lead to an incorrect symbol size calculation when there are mapping symbols emitted by readelf. For instance, when feeding 'update_irq_load_avg+0x1c/0x1c4', faddr2line might need to process the following readelf lines: 784284: ffffffc0081cca30 428 FUNC GLOBAL DEFAULT 2 update_irq_load_avg 87319: ffffffc0081ccb0c 0 NOTYPE LOCAL DEFAULT 2 $x.62522 87321: ffffffc0081ccbdc 0 NOTYPE LOCAL DEFAULT 2 $x.62524 87323: ffffffc0081ccbe0 0 NOTYPE LOCAL DEFAULT 2 $x.62526 87325: ffffffc0081ccbe4 0 NOTYPE LOCAL DEFAULT 2 $x.62528 87327: ffffffc0081ccbe8 0 NOTYPE LOCAL DEFAULT 2 $x.62530 87329: ffffffc0081ccbec 0 NOTYPE LOCAL DEFAULT 2 $x.62532 87331: ffffffc0081ccbf0 0 NOTYPE LOCAL DEFAULT 2 $x.62534 87332: ffffffc0081ccbf4 0 NOTYPE LOCAL DEFAULT 2 $x.62535 783403: ffffffc0081ccbf4 424 FUNC GLOBAL DEFAULT 2 sched_pelt_multiplier The symbol size of 'update_irq_load_avg' should be calculated with the address of 'sched_pelt_multiplier', after skipping the mapping symbols seen in between. However, the offending commit cuts the list short and faddr2line incorrectly assumes 'update_irq_load_avg' is the last symbol in the section, resulting in: $ scripts/faddr2line vmlinux update_irq_load_avg+0x1c/0x1c4 skipping update_irq_load_avg address at 0xffffffc0081cca4c due to size mismatch (0x1c4 != 0x3ff9a59988) no match for update_irq_load_avg+0x1c/0x1c4 After reverting the commit the issue is resolved: $ scripts/faddr2line vmlinux update_irq_load_avg+0x1c/0x1c4 update_irq_load_avg+0x1c/0x1c4: cpu_of at kernel/sched/sched.h:1109 (inlined by) update_irq_load_avg at kernel/sched/pelt.c:481 Fixes: c02904f05ff8 ("scripts/faddr2line: Check only two symbols when calculating symbol size") Signed-off-by: Carlos Llamas Acked-by: Will Deacon Acked-by: Brian Johannesmeyer Signed-off-by: Josh Poimboeuf

scripts/faddr2line: Check only two symbols when calculating symbol size

2024-07-03T06:38:37+00:00

Rather than looping through each symbol in a particular section to calculate a symbol's size, grep for the symbol and its immediate successor, and only use those two symbols. Signed-off-by: Brian Johannesmeyer Link: https://lore.kernel.org/r/20240415145538.1938745-8-bjohannesmeyer@gmail.com Signed-off-by: Josh Poimboeuf

scripts/faddr2line: Remove call to addr2line from find_dir_prefix()

2024-07-03T06:38:37+00:00

Use the single long-running faddr2line process from find_dir_prefix(). Signed-off-by: Brian Johannesmeyer Link: https://lore.kernel.org/r/20240415145538.1938745-7-bjohannesmeyer@gmail.com Signed-off-by: Josh Poimboeuf

scripts/faddr2line: Invoke addr2line as a single long-running process

2024-07-03T06:38:36+00:00

Rather than invoking a separate addr2line process for each address, invoke a single addr2line coprocess, and pass each address to its stdin. Previous work [0] applied a similar change to perf, leading to a ~60x speed-up [1]. If using an object file that is _not_ vmlinux, faddr2line passes a section name argument to addr2line. Because we do not know until runtime which section names will be passed to addr2line, we cannot apply this change to non-vmlinux object files. Hence, it only applies to vmlinux. [0] commit be8ecc57f180 ("perf srcline: Use long-running addr2line per DSO") [1] Link: https://eighty-twenty.org/2021/09/09/perf-addr2line-speed-improvement Signed-off-by: Brian Johannesmeyer Link: https://lore.kernel.org/r/20240415145538.1938745-6-bjohannesmeyer@gmail.com Signed-off-by: Josh Poimboeuf

scripts/faddr2line: Pass --addresses argument to addr2line

2024-07-03T06:38:36+00:00

In preparation for identifying an addr2line sentinel. See previous work [0], which applies a similar change to perf. [0] commit 8dc26b6f718a ("perf srcline: Make sentinel reading for binutils addr2line more robust") Signed-off-by: Brian Johannesmeyer Link: https://lore.kernel.org/r/20240415145538.1938745-5-bjohannesmeyer@gmail.com Signed-off-by: Josh Poimboeuf

scripts/faddr2line: Check vmlinux only once

2024-07-03T06:38:36+00:00

Rather than checking whether the object file is vmlinux for each invocation of __faddr2line, check it only once beforehand. Signed-off-by: Brian Johannesmeyer Link: https://lore.kernel.org/r/20240415145538.1938745-4-bjohannesmeyer@gmail.com Signed-off-by: Josh Poimboeuf

scripts/faddr2line: Combine three readelf calls into one

2024-07-03T06:38:36+00:00

Rather than calling readelf three separate times to collect three different types of info, call it only once, and parse out the different types of info from its output. Signed-off-by: Brian Johannesmeyer Link: https://lore.kernel.org/r/20240415145538.1938745-3-bjohannesmeyer@gmail.com Signed-off-by: Josh Poimboeuf