Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
gfs2: Validate i_depth for exhash directories
A fuzzer test introduced corruption that ends up with a depth of 0 in
dir_e_read(), causing an undefined shift by 32 at:
index = hash >> (32 - dip->i_depth);
As calculated in an open-coded way in dir_make_exhash(), the minimum
depth for an exhash directory is ilog2(sdp->sd_hash_ptrs) and 0 is
invalid as sdp->sd_hash_ptrs is fixed as sdp->bsize / 16 at mount time.
So we can avoid the undefined behaviour by checking for depth values
lower than the minimum in gfs2_dinode_in(). Values greater than the
maximum are already being checked for there.
Also switch the calculation in dir_make_exhash() to use ilog2() to
clarify how the depth is calculated.
Tested with the syzkaller repro.c and xfstests '-g quick'.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-04
In the Linux kernel, the following vulnerability has been resolved:
drm/xe: Make dma-fences compliant with the safe access rules
Xe can free some of the data pointed to by the dma-fences it exports. Most
notably the timeline name can get freed if userspace closes the associated
submit queue. At the same time the fence could have been exported to a
third party (for example a sync_fence fd) which will then cause an use-
after-free on subsequent access.
To make this safe we need to make the driver compliant with the newly
documented dma-fence rules. Driver has to ensure a RCU grace period
between signalling a fence and freeing any data pointed to by said fence.
For the timeline name we simply make the queue be freed via kfree_rcu and
for the shared lock associated with multiple queues we add a RCU grace
period before freeing the per GT structure holding the lock.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-04
In the Linux kernel, the following vulnerability has been resolved:
rcu/nocb: Fix possible invalid rdp's->nocb_cb_kthread pointer access
In the preparation stage of CPU online, if the corresponding
the rdp's->nocb_cb_kthread does not exist, will be created,
there is a situation where the rdp's rcuop kthreads creation fails,
and then de-offload this CPU's rdp, does not assign this CPU's
rdp->nocb_cb_kthread pointer, but this rdp's->nocb_gp_rdp and
rdp's->rdp_gp->nocb_gp_kthread is still valid.
This will cause the subsequent re-offload operation of this offline
CPU, which will pass the conditional check and the kthread_unpark()
will access invalid rdp's->nocb_cb_kthread pointer.
This commit therefore use rdp's->nocb_gp_kthread instead of
rdp_gp's->nocb_gp_kthread for safety check.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-04
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/pm: fix null pointer access
Writing a string without delimiters (' ', '\n', '\0') to the under
gpu_od/fan_ctrl sysfs or pp_power_profile_mode for the CUSTOM profile
will result in a null pointer dereference.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-04
In the Linux kernel, the following vulnerability has been resolved:
x86/fpu: Fix NULL dereference in avx512_status()
Problem
-------
With CONFIG_X86_DEBUG_FPU enabled, reading /proc/[kthread]/arch_status
causes a warning and a NULL pointer dereference.
This is because the AVX-512 timestamp code uses x86_task_fpu() but
doesn't check it for NULL. CONFIG_X86_DEBUG_FPU addles that function
for kernel threads (PF_KTHREAD specifically), making it return NULL.
The point of the warning was to ensure that kernel threads only access
task->fpu after going through kernel_fpu_begin()/_end(). Note: all
kernel tasks exposed in /proc have a valid task->fpu.
Solution
--------
One option is to silence the warning and check for NULL from
x86_task_fpu(). However, that warning is fairly fresh and seems like a
defense against misuse of the FPU state in kernel threads.
Instead, stop outputting AVX-512_elapsed_ms for kernel threads
altogether. The data was garbage anyway because avx512_timestamp is
only updated for user threads, not kernel threads.
If anyone ever wants to track kernel thread AVX-512 use, they can come
back later and do it properly, separate from this bug fix.
[ dhansen: mostly rewrite changelog ]
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-04
In the Linux kernel, the following vulnerability has been resolved:
drm/xe/migrate: prevent infinite recursion
If the buf + offset is not aligned to XE_CAHELINE_BYTES we fallback to
using a bounce buffer. However the bounce buffer here is allocated on
the stack, and the only alignment requirement here is that it's
naturally aligned to u8, and not XE_CACHELINE_BYTES. If the bounce
buffer is also misaligned we then recurse back into the function again,
however the new bounce buffer might also not be aligned, and might never
be until we eventually blow through the stack, as we keep recursing.
Instead of using the stack use kmalloc, which should respect the
power-of-two alignment request here. Fixes a kernel panic when
triggering this path through eudebug.
v2 (Stuart):
- Add build bug check for power-of-two restriction
- s/EINVAL/ENOMEM/
(cherry picked from commit 38b34e928a08ba594c4bbf7118aa3aadacd62fff)
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-04
In the Linux kernel, the following vulnerability has been resolved:
exfat: add cluster chain loop check for dir
An infinite loop may occur if the following conditions occur due to
file system corruption.
(1) Condition for exfat_count_dir_entries() to loop infinitely.
- The cluster chain includes a loop.
- There is no UNUSED entry in the cluster chain.
(2) Condition for exfat_create_upcase_table() to loop infinitely.
- The cluster chain of the root directory includes a loop.
- There are no UNUSED entry and up-case table entry in the cluster
chain of the root directory.
(3) Condition for exfat_load_bitmap() to loop infinitely.
- The cluster chain of the root directory includes a loop.
- There are no UNUSED entry and bitmap entry in the cluster chain
of the root directory.
(4) Condition for exfat_find_dir_entry() to loop infinitely.
- The cluster chain includes a loop.
- The unused directory entries were exhausted by some operation.
(5) Condition for exfat_check_dir_empty() to loop infinitely.
- The cluster chain includes a loop.
- The unused directory entries were exhausted by some operation.
- All files and sub-directories under the directory are deleted.
This commit adds checks to break the above infinite loop.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-04
In the Linux kernel, the following vulnerability has been resolved:
userfaultfd: fix a crash in UFFDIO_MOVE when PMD is a migration entry
When UFFDIO_MOVE encounters a migration PMD entry, it proceeds with
obtaining a folio and accessing it even though the entry is swp_entry_t.
Add the missing check and let split_huge_pmd() handle migration entries.
While at it also remove unnecessary folio check.
[surenb@google.com: remove extra folio check, per David]
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-04
In the Linux kernel, the following vulnerability has been resolved:
iommufd: Prevent ALIGN() overflow
When allocating IOVA the candidate range gets aligned to the target
alignment. If the range is close to ULONG_MAX then the ALIGN() can
wrap resulting in a corrupted iova.
Open code the ALIGN() using get_add_overflow() to prevent this.
This simplifies the checks as we don't need to check for length earlier
either.
Consolidate the two copies of this code under a single helper.
This bug would allow userspace to create a mapping that overlaps with some
other mapping or a reserved range.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-04
In the Linux kernel, the following vulnerability has been resolved:
i2c: core: Fix double-free of fwnode in i2c_unregister_device()
Before commit df6d7277e552 ("i2c: core: Do not dereference fwnode in struct
device"), i2c_unregister_device() only called fwnode_handle_put() on
of_node-s in the form of calling of_node_put(client->dev.of_node).
But after this commit the i2c_client's fwnode now unconditionally gets
fwnode_handle_put() on it.
When the i2c_client has no primary (ACPI / OF) fwnode but it does have
a software fwnode, the software-node will be the primary node and
fwnode_handle_put() will put() it.
But for the software fwnode device_remove_software_node() will also put()
it leading to a double free:
[ 82.665598] ------------[ cut here ]------------
[ 82.665609] refcount_t: underflow; use-after-free.
[ 82.665808] WARNING: CPU: 3 PID: 1502 at lib/refcount.c:28 refcount_warn_saturate+0xba/0x11
...
[ 82.666830] RIP: 0010:refcount_warn_saturate+0xba/0x110
...
[ 82.666962] <TASK>
[ 82.666971] i2c_unregister_device+0x60/0x90
Fix this by not calling fwnode_handle_put() when the primary fwnode is
a software-node.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-04