CVE-2026-89986

mm/mempolicy: fix sleeping allocation in alloc_pages_bulk_weighted_interleave()

HIGH
7.8
CVSS Score
Published: September 16, 2026 at 10:33 AM UTC
Updated: October 19, 2026 at 09:18 AM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
HIGH7.8
Exploit prediction
EPSS 0.2%

Description

In the Linux kernel, the following vulnerability has been resolved: mm/mempolicy: fix sleeping allocation in alloc_pages_bulk_weighted_interleave() syzbot reported a sleeping function called from invalid context splat in bucket_table_alloc(). When rhashtable_insert_slow() rehashes the table under rcu_read_lock(), it calls bucket_table_alloc(..., GFP_ATOMIC | __GFP_NOWARN). If the bucket table allocation uses vmalloc, __vmalloc_node_range_noprof() invokes vm_area_alloc_pages() -> alloc_pages_bulk_mempolicy_noprof() with the passed GFP_ATOMIC flags. If the current task has an MPOL_WEIGHTED_INTERLEAVE mempolicy, alloc_pages_bulk_weighted_interleave() is called and currently hardcodes GFP_KERNEL when allocating the temporary weights array, triggering a might_alloc() splat in atomic/RCU contexts. Pass the gfp flags (masked with GFP_RECLAIM_MASK to strip page-allocator zone modifiers like __GFP_HIGHMEM) received by alloc_pages_bulk_weighted_interleave() to kmalloc() instead of hardcoding GFP_KERNEL. Since the weights buffer is immediately initialized in full, kmalloc() is sufficient.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.9fa3bea4e1f8202d787709b7e3654eb0a99aed758
Vendor states this is fixed in 0ceda28f371df9e0bbdaa29214f71fe8298f23d8 (fixed)
Vendor states this is fixed in 2943f1f4b7f2816177060eb9f551f2e6d8b629ba (fixed)
Vendor states this is fixed in 540e583b66d6402bf556fde5e53c817a54c1afe5 (fixed)
Vendor states this is fixed in bcb3d0c867ee40dc48e9c085bf328fbc679b6656 (fixed)
Vendor states this is fixed in 6.12.110 (unaffected)
Vendor states this is fixed in 6.18.51 (unaffected)
Vendor states this is fixed in 6.9 (unaffected)
Vendor states this is fixed in 7.2.5 (unaffected)
Vendor states this is fixed in 7.3 (unaffected)
Vendor states this is fixed in 7.3-rc2 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

CVSS

7.8HIGHLinux
Vector?

Quick Info

StatusRECEIVED

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