Description
In the Linux kernel, the following vulnerability has been resolved: netfs: Fix missing alloc tagging of direct mempool allocations Commit 1d78d56c43ef ("netfs: Fix folio_queue ENOMEM in writeback by adding a mempool") added a mempool for the folio_queues and made the request, subrequest and folio_queue allocations distinguish between writeback and everything else. Writeback is part of memory reclaim and must not fail due to ENOMEM, so it allocates under GFP_NOFS through mempool_alloc(), which may dip into the pool's reserve and, if that runs empty, wait for elements to be returned. The GFP_KERNEL paths, which can return -ENOMEM to their callers, invoke the pool's ->alloc() callback directly instead. The direct call, however, skips the alloc_hooks() wrapper that the mempool_alloc() macro provides. The pool callbacks, mempool_alloc_slab() and mempool_kmalloc(), call kmem_cache_alloc_noprof() and kmalloc_noprof() and rely on current->alloc_tag having been set by the caller. With CONFIG_MEM_ALLOC_PROFILING_DEBUG=y this leads to current->alloc_tag not set WARNING: ./include/linux/alloc_tag.h:161 at __alloc_tagging_slab_alloc_hook alloc_tag was not set WARNING: ./include/linux/alloc_tag.h:166 at __alloc_tagging_slab_free_hook at allocation and free time respectively, as reported when reading files on a CIFS mount. The allocations are also missing from /proc/allocinfo. Wrap the direct ->alloc() invocations in alloc_hooks() with a new mempool_alloc_noreserve() helper in include/linux/mempool.h, next to the other alloc_hooks()-wrapped macros such as mempool_alloc(). The GFP_KERNEL paths keep their failable allocation semantics, they just get tagged now.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
15ed8a9b7c63e9171f5139a6aaa1ffb61809861f to < 5c03da745171485fd181f17b69213464f6d05f3daffected1d78d56c43ef3768183e8370e7367b162700e049 to < 37a2042748bc880df03ff8315db86ed82991fbb8affected1d78d56c43ef3768183e8370e7367b162700e049 to < b78b728e21c32ec4c330b299f657fb1eb02dffc2affectedb343252d6f536203dd0660f676190dcbf6d2ecdcaffected3f6d7f8a5416d852648d15a05e895f1195ee8a85affected6.12.114 to < 6.13affected7.1.8 to < 7.2affected
Linux Linux
Default version status: affected
7.2affected0 to < 7.2unaffected7.2.9 to ≤ 7.2.*unaffected7.3 to ≤ *unaffected