2.2.9: zfs share -a segfaults on musl if /etc/exports.d is missing. #17967
Description
System information
| Type | Version/Name |
|---|---|
| Distribution Name | Gentoo |
| Distribution Version | rolling/latest |
| Kernel Version | 6.17.8-gentoo-dist |
| Architecture | Aarch64 |
| OpenZFS Version | 2.2.9 |
Describe the problem you're observing
Running zfs share -a results in a segmentation fault when /etc/exports.d does not exist on musl-based systems.
Describe how to reproduce the problem
# Ensure /etc/exports.d does not exist.
rm -rf /etc/exports.d
# Trigger the crash.
zfs share -aExpected: Command completes successfully or prints a warning
Actual: Segmentation fault
Include any warning/errors/backtraces from the system logs
strace output:
openat(AT_FDCWD, "/etc/exports.d/zfs.exports.lock", O_RDWR|O_CREAT|O_LARGEFILE|O_CLOEXEC, 0600) = -1 ENOENT (No such file or directory)
--- SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_MAPERR, si_addr=0x27} ---
+++ killed by SIGSEGV +++
LLDB backtrace:
(lldb) bt all
* thread #1, name = 'zfs', stop reason = signal SIGSEGV: address not mapped to object (fault address=0x27)
* frame #0: 0x0000fffff7f7bbe4 libc.so`__strerror_l + 16
frame #1: 0x0000fffff7eddd84 libzfs.so.4`___lldb_unnamed_symbol_6fcac + 216
frame #2: 0x0000fffff7eddea0 libzfs.so.4`___lldb_unnamed_symbol_6fe70 + 48
frame #3: 0x0000fffff7ebb550 libzfs.so.4`zfs_truncate_shares + 48
frame #4: 0x0000aaaaaaac7348 zfs`___lldb_unnamed_symbol_26f58 + 1008
frame #5: 0x0000aaaaaaabdaa4 zfs`___lldb_unnamed_symbol_1d7f4 + 688
Root Cause
This issue was introduced in commit ede037c and fixed in commit 41e55b4.
The fix exists in master but was not backported to the 2.2.x stable branch.
Request
Please backport commit 41e55b4 to the zfs-2.2-release branch for inclusion in 2.2.10.
The patch applies cleanly to 2.2.9 and resolves the segfault.
Workaround
mkdir -p /etc/exports.d/
touch /etc/exports.d/zfs.exports.lock