CVE-2024-42234 — mm: fix crashes from deferred split racing folio migration

Affected: Linux

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

mm: fix crashes from deferred split racing folio migration

Even on 6.10-rc6, I've been seeing elusive "Bad page state"s (often on flags when freeing, yet the flags shown are not bad: PG_locked had been set and cleared??), and VM_BUG_ON_PAGE(page_ref_count(page) == 0)s from deferred_split_scan()'s folio_put(), and a variety of other BUG and WARN symptoms implying double free by deferred split and large folio migration.

6.7 commit 9bcef5973e31 ("mm: memcg: fix split queue list crash when large folio migration") was right to fix the memcg-dependent locking broken in 85ce2c517ade ("memcontrol: only transfer the memcg data for migration"), but missed a subtlety of deferred_split_scan(): it moves folios to its own local list to work on them without split_queue_lock, during which time folio->_deferred_list is not empty, but even the "right" lock does nothing to secure the folio and the list it is on.

Fortunately, deferred_split_scan() is careful to use folio_try_get(): so folio_migrate_mapping() can avoid the race by folio_undo_large_rmappable() while the old folio's reference count is temporarily frozen to 0 - adding such a freeze in the !mapping case too (originally, folio lock and unmapping and no swap cache left an anon folio unreachable, so no freezing was needed there: but the deferred split queue offers a way to reach it).

USN-7089-1 — linux, linux-gcp-6.8, linux-hwe-6.8 vulnerabilities

Affected: Ubuntu:22.04:LTS: linux-gcp-6.8, Ubuntu:22.04:LTS: linux-hwe-6.8, Ubuntu:24.04:LTS: linux

Chenyuan Yang discovered that the USB Gadget subsystem in the Linux kernel did not properly check for the device to be enabled before writing. A local attacker could possibly use this to cause a denial of service. (CVE-2024-25741)

Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - ARM32 architecture; - MIPS architecture; - PA-RISC architecture; - PowerPC architecture; - RISC-V architecture; - S390 architecture; - x86 architecture; - Cryptographic API; - Serial ATA and Parallel ATA drivers; - Null block device driver; - Bluetooth drivers; - Cdrom driver; - Clock framework and drivers; - Hardware crypto device drivers; - CXL (Compute Express Link) drivers; - Cirrus firmware drivers; - GPIO subsystem; - GPU drivers; - I2C subsystem; - IIO subsystem; - InfiniBand drivers; - ISDN/mISDN subsystem; - LED subsystem; - Multiple devices driver; - Media drivers; - Fastrpc Driver; - Network drivers; - Microsoft Azure Network Adapter (MANA) driver; - Near Field Communication (NFC) drivers; - NVME drivers; - NVMEM (Non Volatile Memory) drivers; - PCI subsystem; - Pin controllers subsystem; - x86 platform drivers; - S/390 drivers; - SCSI drivers; - Thermal drivers; - TTY drivers; - UFS subsystem; - USB DSL drivers; - USB core drivers; - DesignWare USB3 driver; - USB Gadget dr…

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CVE-2024-42234 — mm: fix crashes from deferred split racing folio migration

USN-7089-1 — linux, linux-gcp-6.8, linux-hwe-6.8 vulnerabilities