pecl / PEAR network commands segfault on php:8.3-alpine for linux/riscv64

[thecaliskan]

Description

On linux/riscv64, the official php:8.3-alpine image crashes with exit code 139 (SIGSEGV) when running PECL/PEAR commands that contact remote channels (e.g. pecl install, pear list-channels, pecl list-channels).

Local-only PEAR commands such as pear version and pear list work fine.

This blocks the documented workflow of installing PHP extensions via pecl install on riscv64, including multi-arch image builds that use docker buildx with QEMU emulation for linux/riscv64.

Environment

Image	php:8.3-alpine3.24
PHP	8.3.33 (cli) NTS
PEAR	1.10.18
Platform	linux/riscv64 (also reproduced under QEMU via Docker Desktop on macOS)
OpenSSL	3.5.7

Steps to reproduce

docker run --rm --platform linux/riscv64 php:8.3-alpine3.24 sh -euxc '
  apk add --no-cache $PHPIZE_DEPS
  pecl install igbinary
'

Also fails without any build deps:

docker run --rm --platform linux/riscv64 php:8.3-alpine3.24 pear list-channels

Actual result

Segmentation fault

Exit code: 139

Expected result

pecl install should download and build the extension, as it does on other PHP versions and architectures.

Scope (tested)

PHP version	linux/riscv64 pecl install igbinary
8.2-alpine3.24	works
8.3-alpine3.24	segfault
8.4-alpine3.24	works
8.5-alpine3.24	works

Platform	php:8.3-alpine3.24 pecl install igbinary
linux/amd64	works
linux/arm64	works
linux/ppc64le	works
linux/s390x	works
linux/riscv64	segfault

Commands that work on php:8.3-alpine / riscv64:

• pear version
• pear list
• php /usr/local/lib/php/pearcmd.php (help output)

Commands that segfault:

• pecl install <package>
• pear list-channels
• pecl list-channels
• pecl search <package>

The crash appears tied to PEAR network/channel operations, not extension compilation.

Real-world impact

Any Dockerfile using pecl install fails when building for linux/riscv64 with PHP 8.3:

FROM php:8.3-alpine
RUN apk add --no-cache $PHPIZE_DEPS \
    && pecl install igbinary redis swoole \
    && docker-php-ext-enable igbinary redis swoole

Example from a multi-arch base image build:

+ LDFLAGS=-lucontext pecl install igbinary redis swoole ssh2
Segmentation fault
ERROR: exit code: 139

Additional context

• register_argc_argv=On and other flags from the pecl wrapper script do not change the outcome.
• Adding libucontext / LDFLAGS="-lucontext" does not fix the segfault (that is a separate build concern on some architectures for extensions like swoole).
• PHP 8.3 on riscv64 is otherwise functional (php -v, php -m, docker-php-ext-install from local source work).

[tianon]

I'm able to reproduce, but only on QEMU -- on native hardware, this works fine, so this is probably a classic QEMU emulation quirk.