Wind River Support Network

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.