In the Linux kernel, the following vulnerability has been resolved:
mm: fix __vm_normal_page() to handle missing support for pmd_special()/pud_special()
On x86 32-bit with THP enabled, zap_huge_pmd() is seen to generate a
"WARNING: mm/memory.c:735 at __vm_normal_page+0x6a/0x7d", from the
VM_WARN_ON_ONCE(is_zero_pfn(pfn) || is_huge_zero_pfn(pfn)); followed by
"BUG: Bad rss-counter state"s, then later "BUG: Bad page state"s when
reclaim gets to call shrink_huge_zero_folio_scan().
It's as if the _PAGE_SPECIAL bit never got set in the huge_zero pmd: and
indeed, whereas pte_special() and pte_mkspecial() are subject to a
dedicated CONFIG_ARCH_HAS_PTE_SPECIAL, pmd_special() and pmd_mkspecial()
are subject to CONFIG_ARCH_SUPPORTS_PMD_PFNMAP, which is never enabled on
any 32-bit architecture.
While the problem was exposed through commit d80a9cb1a64a
("mm/huge_memory: add and use normal_or_softleaf_folio_pmd()"), it was an
oversight in commit af38538801c6 ("mm/memory: factor out common code from
vm_normal_page_*()") and would result in other problems:
* huge zero folio accounted in smaps, pagemap (PAGE_IS_FILE) and
numamaps as file-backed THP
* folio_walk_start() returning the folio even without FW_ZEROPAGE set.
Callers seem to tolerate that, though.
... and triggering the VM_WARN_ON_ONE(), although never reported so far.
To fix it, teach vm_normal_page_pmd()/vm_normal_page_pud() to consider
whether pmd_special/pud_special is actually implemented.
In the Linux kernel, the following vulnerability has been resolved:
drivers/base/memory: fix memory block reference leak in poison accounting
memblk_nr_poison_inc() and memblk_nr_poison_sub() look up a memory block
via find_memory_block_by_id(), which acquires a reference to the memory
block device.
Both helpers use the returned memory block without dropping that
reference, leaking the device reference on each successful lookup. Drop
the reference after updating nr_hwpoison.
In the Linux kernel, the following vulnerability has been resolved:
efi: Allocate runtime workqueue before ACPI init
Since commit
5894cf571e14 ("acpi/prmt: Use EFI runtime sandbox to invoke PRM handlers")
ACPI PRM calls are delegated to a workqueue which runs in a kernel
thread, making it easier to detect and mitigate faulting memory accesses
performed by the firmware.
Rafael reports that such PRM accesses may occur before efisubsys_init()
executes, which is where the workqueue is allocated, leading to NULL
pointer dereferences. Since acpi_init() [which triggers the early PRM
accesses] executes as a subsys_initcall() as well, and has its own
dependencies that may be sensitive to initcall ordering, deferring
acpi_init() is not an option.
So instead, split off the workqueue allocation into its own postcore
initcall, as this is the only missing piece to allow EFI runtime calls
to be made. This ensures that EFI runtime call (including PRM calls) are
accessible to all code running at subsys_initcall() level.
In the Linux kernel, the following vulnerability has been resolved:
mm/damon/sysfs-schemes: call missing mem_cgroup_iter_break()
damon_sysfs_memcg_path_to_id() breaks mem_cgroup_iter() loop without
calling mem_cgroup_iter_break(). This leaks the cgroup reference. Fix
the issue by calling mem_cgroup_iter_break() before the break.
The issue was discovered [1] by Sashiko.
In the Linux kernel, the following vulnerability has been resolved:
sysfs: don't remove existing directory on update failure
When sysfs_update_group() is called for a named group and create_files()
fails (e.g. -ENOMEM), internal_create_group() calls kernfs_remove(kn) on
the group directory. In the update path, kn was obtained via
kernfs_find_and_get() and refers to a directory that already existed
before this call. Removing it silently destroys a sysfs group that the
caller did not create.
Only remove the directory if we created it ourselves. On update failure
the directory remains as it is left empty by remove_files() inside
create_files(), but can be repopulated by a retry.
In the Linux kernel, the following vulnerability has been resolved:
spi: ep93xx: fix error pointer deref after DMA setup failure
The driver falls back to PIO mode if DMA setup fails during probe.
Make sure to the clear the DMA channel pointers on setup failure to
avoid dereferencing an error pointer on later probe errors or driver
unbind.
This issue was flagged by Sashiko when reviewing a devres allocation
conversion patch.
In the Linux kernel, the following vulnerability has been resolved:
spi: qup: fix error pointer deref after DMA setup failure
The driver falls back to PIO mode if DMA setup fails during probe.
Make sure to the clear the DMA channel pointers on setup failure to
avoid dereferencing an error pointer (or attempting to release a channel
a second time) on later probe errors or driver unbind.
This issue was flagged by Sashiko when reviewing a devres allocation
conversion patch.
In the Linux kernel, the following vulnerability has been resolved:
i2c: tegra: fix pm_runtime leak on mutex_lock failure
If tegra_i2c_mutex_lock() fails, the function returns without calling
pm_runtime_put(), leaking the runtime PM reference acquired by the
preceding pm_runtime_get_sync(). This prevents the device from ever
entering runtime suspend.
Add the missing pm_runtime_put() before returning on lock failure.
In the Linux kernel, the following vulnerability has been resolved:
KVM: SVM: Disable AVIC IPI virtualization on Hygon Family 18h (erratum #1235)
Hygon Family 18h CPUs are derived from AMD Family 17h (Zen1) silicon and
share the same erratum #1235: hardware may read a stale IsRunning=1 bit
during ICR write emulation and silently fail to generate an
AVIC_IPI_FAILURE_TARGET_NOT_RUNNING VM-Exit on the sending vCPU.
The absence of the VM-Exit causes KVM to miss the required wakeup of
blocking target vCPUs, leading to hung vCPUs and unbounded delays in
guest execution.
Extend the existing AMD Family 17h erratum #1235 workaround to also cover
Hygon Family 18h. With IPI virtualization disabled, KVM never sets
IsRunning=1 in the Physical ID table, so every non-self IPI generates a
VM-Exit and is correctly emulated.
In the Linux kernel, the following vulnerability has been resolved:
tracing: Do not call map->ops->elt_free() if elt_alloc() fails
In paths where tracing_map_elt_alloc() failed to allocate objects,
the map->ops->elt_alloc() call was never successful. In this case,
map->ops->elt_free() should not be called.