clang-format-20 was terminated by OOM-killer while formatting large c-header

[FirelessWidelity]

system and version:

$ clang-format --version
Ubuntu clang-format version 20.1.8 (++20250708082409+6fb913d3e2ec-1~exp1~20250708202428.132)

$ uname -a
Linux tester 6.8.0-87-generic #88~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Tue Oct 14 14:03:14 UTC 2 x86_64 x86_64 x86_64 GNU/Linux

file size:

$ ls -lah ./drv_cfg.h
-rwxrwxr-x 1 tester tester 141K nov 17 12:43 ./drv_cfg.h

Memory usage increases every second until the system finally freezes/crashes:

$ while :; do ps -aux | rg clang-format ; sleep 1; clear; done
tester       6106  101 75.8 14380988 12239548 pts/0 R+ 12:46   0:20 clang-format-20 -verbose -i ./drv_cfg.h

The "-verbose" flag does not output errors to the console when formatting this file.

Can you make patch for 20th version of clang-format to fix this?

[llvmbot]

@llvm/issue-subscribers-clang-format

Author: None (FirelessWidelity)

system and version: ``` $ clang-format --version Ubuntu clang-format version 20.1.8 (++20250708082409+6fb913d3e2ec-1~exp1~20250708202428.132)

$ uname -a
Linux tester 6.8.0-87-generic #88~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Tue Oct 14 14:03:14 UTC 2 x86_64 x86_64 x86_64 GNU/Linux

file size:

$ ls -lah ./8192cd_cfg.h
-rwxrwxr-x 1 tester tester 141K nov 17 12:43 ./drv_cfg.h

Memory usage increases every second until the system finally freezes/crashes:

$ while :; do ps -aux | rg clang-format ; sleep 1; clear; done
tester 6106 101 75.8 14380988 12239548 pts/0 R+ 12:46 0:20 clang-format-20 -verbose -i ./drv_cfg.h

The "-verbose" flag does not output errors to the console when formatting this file.

Can you make patch for 20th version of clang-format to fix this?
</details>

[EugeneZelenko]

Could you please try 21 or main branch? Only most recent release is maintained.

[FirelessWidelity]

Could you please try 21 or main branch? Only most recent release is maintained.

I tried formatting on version 21.1.5, but it also didnt work

$ ./clang-format --version
clang-format version 21.1.5 (https://github.com/llvm/llvm-project 8e2cd28cd4ba46613a46467b0c91b1cabead26cd)

[EugeneZelenko]

Could you please provide reproducer?

[FirelessWidelity]

Could you please provide reproducer?

I cant show you the original file, but similar case is arch/arm/mach-davinci/da830.c from linux kernel:

da830.c

[FirelessWidelity]

The problem starts with this line:
static const struct mux_config da830_pins[]