Executive brief
The Linux kernel's network filesystem (netfs) layer handles file write operations for remote filesystems. A bug in the writethrough write path prevented asynchronous collection of write requests, potentially causing incomplete O_SYNC writes and delayed completion signaling. This fix ensures write collection is processed asynchronously as intended.
Technical details
This is a bug fix rather than a vulnerability in the traditional sense. The issue involves the netfs writethrough write path failing to set the NETFS_RREQ_OFFLOAD_COLLECTION flag on write requests, causing collection to occur only at the end of the operation rather than asynchronously. The root cause lies in the netfs_begin_writethrough() function in fs/netfs/write_issue.c, which was missing a __set_bit() call. The fix adds one line to set the flag, ensuring asynchronous O_SYNC writes are properly collected. This affects the Linux kernel's network filesystem implementation and is addressed by a single-line patch addition.
Affected products
- Linux Linux kernel Multiple versions across 2.6.11 through 7.2 series
Timeline
- 2026-06-25: disclosed: Upstream commit ba6a9f6533c77c628eef0c0c5c19cd316e2be1b4 authored
- 2026-07-24: patched: Backported to stable kernels