RE: [PATCH 0/4] reftable: fix out-of-memory errors on NonStop

From: Randall Becker <randall.becker@nexbridge.ca>
Date: Dec 21, 2024, 15:05 UTC
Message-ID: <BL3PR17MB6020D6CB8712F2C6F36FC8CFF4002@BL3PR17MB6020.namprd17.prod.outlook.com>
In-Reply-To: <20241221-b4-pks-reftable-oom-fix-without-readers-v1-0-12db83a3267c@pks.im>

On December 21, 2024 6:50 AM, Patrick Steinhardt wrote:

Show 24 quoted lines

>this small patch series fixes out-of-memory errors on NonStop with the reftable
>backend. These errors are caused by zero-sized allocations, which return `NULL`
>pointers on NonStop.
>
>Thanks!
>
>Patrick
>
>---
>Patrick Steinhardt (4):
>      reftable/stack: don't perform auto-compaction with less than two tables
>      reftable/merged: fix zero-sized allocation when there are no readers
>      reftable/stack: fix zero-sized allocation when there are no readers
>      reftable/basics: return NULL on zero-sized allocations
>
> reftable/basics.c |  7 +++++++
> reftable/merged.c | 12 +++++++-----
> reftable/stack.c  | 47 ++++++++++++++++++++++++++---------------------
> 3 files changed, 40 insertions(+), 26 deletions(-)
>
>
>---
>base-commit: ff795a5c5ed2e2d07c688c217a615d89e3f5733b
>change-id: 20241220-b4-pks-reftable-oom-fix-without-readers-c7d8fda0694d

From the malloc man page: "If size is 0, then malloc() returns either NULL, or a unique pointer value that can later be successfully passed to free()."

Thank you for this series. I think the problem may not be limited only to NonStop based on the documented ambiguous behaviour of malloc.

--Randall