Wind River Support Network

Description

In the Linux kernel, the following vulnerability has been resolved:  nfsd: add missing read barrier to rpc_status_get dumpit seqcount retry  The hand-rolled seqcount-like protocol in nfsd_nl_rpc_status_get_dumpit() is missing a read memory barrier (smp_rmb) before its second counter check.  The standard kernel read_seqcount_retry() includes smp_rmb() to ensure that all data reads complete before the counter is re-checked.  Without this barrier, on weakly-ordered architectures (ARM, POWER), the CPU may reorder field reads past the second counter check, making the retry logic ineffective: it could observe a consistent counter pair while reading fields that have been concurrently modified by the writer.  Add smp_rmb() before the second counter check to order the field reads ahead of it, matching the barrier semantics of the standard seqcount read-side.  The begin-side smp_load_acquire() already pairs with the smp_store_release() in nfsd_dispatch(); with the smp_rmb() now ordering the field reads, the retry check no longer needs acquire semantics and reads the counter with a plain READ_ONCE(), as read_seqcount_retry() does.  [ cel: Use READ_ONCE instead of smp_load_acquire() ]
Data source: kernel.org (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

CVEs

• CVE-2026-93229