CVE-2026-98524

In the Linux kernel, the following vulnerability has been resolved:

rds: ib: Clear the sg list when mapping an MR fails

rds_ib_map_frmr() stores the caller's scatterlist in the MR before DMA

mapping and registration can fail. On failure, __rds_rdma_map() unpins

the pages and frees the scatterlist, but rds_ib_free_frmr() can still

return the MR to the pool with the stale pointer set.

This leaves the pool with a dangling scatterlist and can lead to local

privilege escalation. KASAN detects the resulting use-after-free when the

MR is later torn down:

BUG: KASAN: slab-use-after-free in __rds_ib_teardown_mr

Read of size 8

Call Trace:

__rds_ib_teardown_mr

rds_ib_unreg_frmr

rds_ib_flush_mr_pool

rds_ib_flush_mrs

rds_free_mr

rds_setsockopt

Store the scatterlist in the MR only after DMA mapping succeeds. If DMA

mapping fails, return directly while the MR fields remain clear; the caller

keeps ownership of the scatterlist and its pinned pages. If a later

registration step fails, unmap the scatterlist and clear the MR fields

before returning.