Linux: >> Linux Kernel >> 6.6.63 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
mm/migrate: fix shmem xarray update during migration
A shmem folio can be either in page cache or in swap cache, but not at the
same time. Namely, once it is in swap cache, folio->mapping should be
NULL, and the folio is no longer in a shmem mapping.
In __folio_migrate_mapping(), to determine the number of xarray entries to
update, folio_test_swapbacked() is used, but that conflates shmem in page
cache case and shmem in swap cache case. It leads to xarray multi-index
entry corruption, since it turns a sibling entry to a normal entry during
xas_store() (see [1] for a userspace reproduction). Fix it by only using
folio_test_swapcache() to determine whether xarray is storing swap cache
entries or not to choose the right number of xarray entries to update.
[1] https://lore.kernel.org/linux-mm/Z8idPCkaJW1IChjT@casper.infradead.org/
Note:
In __split_huge_page(), folio_test_anon() && folio_test_swapcache() is
used to get swap_cache address space, but that ignores the shmem folio in
swap cache case. It could lead to NULL pointer dereferencing when a
in-swap-cache shmem folio is split at __xa_store(), since
!folio_test_anon() is true and folio->mapping is NULL. But fortunately,
its caller split_huge_page_to_list_to_order() bails out early with EBUSY
when folio->mapping is NULL. So no need to take care of it here.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-04-08
In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Unconditionally save+flush host FPSIMD/SVE/SME state
There are several problems with the way hyp code lazily saves the host's
FPSIMD/SVE state, including:
* Host SVE being discarded unexpectedly due to inconsistent
configuration of TIF_SVE and CPACR_ELx.ZEN. This has been seen to
result in QEMU crashes where SVE is used by memmove(), as reported by
Eric Auger:
https://issues.redhat.com/browse/RHEL-68997
* Host SVE state is discarded *after* modification by ptrace, which was an
unintentional ptrace ABI change introduced with lazy discarding of SVE state.
* The host FPMR value can be discarded when running a non-protected VM,
where FPMR support is not exposed to a VM, and that VM uses
FPSIMD/SVE. In these cases the hyp code does not save the host's FPMR
before unbinding the host's FPSIMD/SVE/SME state, leaving a stale
value in memory.
Avoid these by eagerly saving and "flushing" the host's FPSIMD/SVE/SME
state when loading a vCPU such that KVM does not need to save any of the
host's FPSIMD/SVE/SME state. For clarity, fpsimd_kvm_prepare() is
removed and the necessary call to fpsimd_save_and_flush_cpu_state() is
placed in kvm_arch_vcpu_load_fp(). As 'fpsimd_state' and 'fpmr_ptr'
should not be used, they are set to NULL; all uses of these will be
removed in subsequent patches.
Historical problems go back at least as far as v5.17, e.g. erroneous
assumptions about TIF_SVE being clear in commit:
8383741ab2e773a9 ("KVM: arm64: Get rid of host SVE tracking/saving")
... and so this eager save+flush probably needs to be backported to ALL
stable trees.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-04-08
In the Linux kernel, the following vulnerability has been resolved:
soc: qcom: pdr: Fix the potential deadlock
When some client process A call pdr_add_lookup() to add the look up for
the service and does schedule locator work, later a process B got a new
server packet indicating locator is up and call pdr_locator_new_server()
which eventually sets pdr->locator_init_complete to true which process A
sees and takes list lock and queries domain list but it will timeout due
to deadlock as the response will queued to the same qmi->wq and it is
ordered workqueue and process B is not able to complete new server
request work due to deadlock on list lock.
Fix it by removing the unnecessary list iteration as the list iteration
is already being done inside locator work, so avoid it here and just
call schedule_work() here.
Process A Process B
process_scheduled_works()
pdr_add_lookup() qmi_data_ready_work()
process_scheduled_works() pdr_locator_new_server()
pdr->locator_init_complete=true;
pdr_locator_work()
mutex_lock(&pdr->list_lock);
pdr_locate_service() mutex_lock(&pdr->list_lock);
pdr_get_domain_list()
pr_err("PDR: %s get domain list
txn wait failed: %d\n",
req->service_name,
ret);
Timeout error log due to deadlock:
"
PDR: tms/servreg get domain list txn wait failed: -110
PDR: service lookup for msm/adsp/sensor_pd:tms/servreg failed: -110
"
Thanks to Bjorn and Johan for letting me know that this commit also fixes
an audio regression when using the in-kernel pd-mapper as that makes it
easier to hit this race. [1]
CVSS Score
5.5
EPSS Score
0.0
Published
2025-04-08
In the Linux kernel, the following vulnerability has been resolved:
regulator: check that dummy regulator has been probed before using it
Due to asynchronous driver probing there is a chance that the dummy
regulator hasn't already been probed when first accessing it.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-04-08
In the Linux kernel, the following vulnerability has been resolved:
regulator: dummy: force synchronous probing
Sometimes I get a NULL pointer dereference at boot time in kobject_get()
with the following call stack:
anatop_regulator_probe()
devm_regulator_register()
regulator_register()
regulator_resolve_supply()
kobject_get()
By placing some extra BUG_ON() statements I could verify that this is
raised because probing of the 'dummy' regulator driver is not completed
('dummy_regulator_rdev' is still NULL).
In the JTAG debugger I can see that dummy_regulator_probe() and
anatop_regulator_probe() can be run by different kernel threads
(kworker/u4:*). I haven't further investigated whether this can be
changed or if there are other possibilities to force synchronization
between these two probe routines. On the other hand I don't expect much
boot time penalty by probing the 'dummy' regulator synchronously.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-04-08
In the Linux kernel, the following vulnerability has been resolved:
RDMA/hns: Fix soft lockup during bt pages loop
Driver runs a for-loop when allocating bt pages and mapping them with
buffer pages. When a large buffer (e.g. MR over 100GB) is being allocated,
it may require a considerable loop count. This will lead to soft lockup:
watchdog: BUG: soft lockup - CPU#27 stuck for 22s!
...
Call trace:
hem_list_alloc_mid_bt+0x124/0x394 [hns_roce_hw_v2]
hns_roce_hem_list_request+0xf8/0x160 [hns_roce_hw_v2]
hns_roce_mtr_create+0x2e4/0x360 [hns_roce_hw_v2]
alloc_mr_pbl+0xd4/0x17c [hns_roce_hw_v2]
hns_roce_reg_user_mr+0xf8/0x190 [hns_roce_hw_v2]
ib_uverbs_reg_mr+0x118/0x290
watchdog: BUG: soft lockup - CPU#35 stuck for 23s!
...
Call trace:
hns_roce_hem_list_find_mtt+0x7c/0xb0 [hns_roce_hw_v2]
mtr_map_bufs+0xc4/0x204 [hns_roce_hw_v2]
hns_roce_mtr_create+0x31c/0x3c4 [hns_roce_hw_v2]
alloc_mr_pbl+0xb0/0x160 [hns_roce_hw_v2]
hns_roce_reg_user_mr+0x108/0x1c0 [hns_roce_hw_v2]
ib_uverbs_reg_mr+0x120/0x2bc
Add a cond_resched() to fix soft lockup during these loops. In order not
to affect the allocation performance of normal-size buffer, set the loop
count of a 100GB MR as the threshold to call cond_resched().
CVSS Score
5.5
EPSS Score
0.0
Published
2025-04-08
In the Linux kernel, the following vulnerability has been resolved:
ipv6: Fix memleak of nhc_pcpu_rth_output in fib_check_nh_v6_gw().
fib_check_nh_v6_gw() expects that fib6_nh_init() cleans up everything
when it fails.
Commit 7dd73168e273 ("ipv6: Always allocate pcpu memory in a fib6_nh")
moved fib_nh_common_init() before alloc_percpu_gfp() within fib6_nh_init()
but forgot to add cleanup for fib6_nh->nh_common.nhc_pcpu_rth_output in
case it fails to allocate fib6_nh->rt6i_pcpu, resulting in memleak.
Let's call fib_nh_common_release() and clear nhc_pcpu_rth_output in the
error path.
Note that we can remove the fib6_nh_release() call in nh_create_ipv6()
later in net-next.git.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-04-03
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: Fix error code in chan_alloc_skb_cb()
The chan_alloc_skb_cb() function is supposed to return error pointers on
error. Returning NULL will lead to a NULL dereference.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-04-03
In the Linux kernel, the following vulnerability has been resolved:
drm/radeon: fix uninitialized size issue in radeon_vce_cs_parse()
On the off chance that command stream passed from userspace via
ioctl() call to radeon_vce_cs_parse() is weirdly crafted and
first command to execute is to encode (case 0x03000001), the function
in question will attempt to call radeon_vce_cs_reloc() with size
argument that has not been properly initialized. Specifically, 'size'
will point to 'tmp' variable before the latter had a chance to be
assigned any value.
Play it safe and init 'tmp' with 0, thus ensuring that
radeon_vce_cs_reloc() will catch an early error in cases like these.
Found by Linux Verification Center (linuxtesting.org) with static
analysis tool SVACE.
(cherry picked from commit 2d52de55f9ee7aaee0e09ac443f77855989c6b68)
CVSS Score
5.5
EPSS Score
0.0
Published
2025-04-03
In the Linux kernel, the following vulnerability has been resolved:
xsk: fix an integer overflow in xp_create_and_assign_umem()
Since the i and pool->chunk_size variables are of type 'u32',
their product can wrap around and then be cast to 'u64'.
This can lead to two different XDP buffers pointing to the same
memory area.
Found by InfoTeCS on behalf of Linux Verification Center
(linuxtesting.org) with SVACE.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-04-03