Linux: >> Linux Kernel >> 2.0 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
md/raid10: prevent soft lockup while flush writes
Currently, there is no limit for raid1/raid10 plugged bio. While flushing
writes, raid1 has cond_resched() while raid10 doesn't, and too many
writes can cause soft lockup.
Follow up soft lockup can be triggered easily with writeback test for
raid10 with ramdisks:
watchdog: BUG: soft lockup - CPU#10 stuck for 27s! [md0_raid10:1293]
Call Trace:
<TASK>
call_rcu+0x16/0x20
put_object+0x41/0x80
__delete_object+0x50/0x90
delete_object_full+0x2b/0x40
kmemleak_free+0x46/0xa0
slab_free_freelist_hook.constprop.0+0xed/0x1a0
kmem_cache_free+0xfd/0x300
mempool_free_slab+0x1f/0x30
mempool_free+0x3a/0x100
bio_free+0x59/0x80
bio_put+0xcf/0x2c0
free_r10bio+0xbf/0xf0
raid_end_bio_io+0x78/0xb0
one_write_done+0x8a/0xa0
raid10_end_write_request+0x1b4/0x430
bio_endio+0x175/0x320
brd_submit_bio+0x3b9/0x9b7 [brd]
__submit_bio+0x69/0xe0
submit_bio_noacct_nocheck+0x1e6/0x5a0
submit_bio_noacct+0x38c/0x7e0
flush_pending_writes+0xf0/0x240
raid10d+0xac/0x1ed0
Fix the problem by adding cond_resched() to raid10 like what raid1 did.
Note that unlimited plugged bio still need to be optimized, for example,
in the case of lots of dirty pages writeback, this will take lots of
memory and io will spend a long time in plug, hence io latency is bad.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
xfrm: Duplicate SPI Handling
The issue originates when Strongswan initiates an XFRM_MSG_ALLOCSPI
Netlink message, which triggers the kernel function xfrm_alloc_spi().
This function is expected to ensure uniqueness of the Security Parameter
Index (SPI) for inbound Security Associations (SAs). However, it can
return success even when the requested SPI is already in use, leading
to duplicate SPIs assigned to multiple inbound SAs, differentiated
only by their destination addresses.
This behavior causes inconsistencies during SPI lookups for inbound packets.
Since the lookup may return an arbitrary SA among those with the same SPI,
packet processing can fail, resulting in packet drops.
According to RFC 4301 section 4.4.2 , for inbound processing a unicast SA
is uniquely identified by the SPI and optionally protocol.
Reproducing the Issue Reliably:
To consistently reproduce the problem, restrict the available SPI range in
charon.conf : spi_min = 0x10000000 spi_max = 0x10000002
This limits the system to only 2 usable SPI values.
Next, create more than 2 Child SA. each using unique pair of src/dst address.
As soon as the 3rd Child SA is initiated, it will be assigned a duplicate
SPI, since the SPI pool is already exhausted.
With a narrow SPI range, the issue is consistently reproducible.
With a broader/default range, it becomes rare and unpredictable.
Current implementation:
xfrm_spi_hash() lookup function computes hash using daddr, proto, and family.
So if two SAs have the same SPI but different destination addresses, then
they will:
a. Hash into different buckets
b. Be stored in different linked lists (byspi + h)
c. Not be seen in the same hlist_for_each_entry_rcu() iteration.
As a result, the lookup will result in NULL and kernel allows that Duplicate SPI
Proposed Change:
xfrm_state_lookup_spi_proto() does a truly global search - across all states,
regardless of hash bucket and matches SPI and proto.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-12
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:
iio: common: st_sensors: Fix use of uninitialize device structs
Throughout the various probe functions &indio_dev->dev is used before it
is initialized. This caused a kernel panic in st_sensors_power_enable()
when the call to devm_regulator_bulk_get_enable() fails and then calls
dev_err_probe() with the uninitialized device.
This seems to only cause a panic with dev_err_probe(), dev_err(),
dev_warn() and dev_info() don't seem to cause a panic, but are fixed
as well.
The issue is reported and traced here: [1]
CVSS Score
5.5
EPSS Score
0.0
Published
2025-08-16
In the Linux kernel, the following vulnerability has been resolved:
drm/gem: Acquire references on GEM handles for framebuffers
A GEM handle can be released while the GEM buffer object is attached
to a DRM framebuffer. This leads to the release of the dma-buf backing
the buffer object, if any. [1] Trying to use the framebuffer in further
mode-setting operations leads to a segmentation fault. Most easily
happens with driver that use shadow planes for vmap-ing the dma-buf
during a page flip. An example is shown below.
[ 156.791968] ------------[ cut here ]------------
[ 156.796830] WARNING: CPU: 2 PID: 2255 at drivers/dma-buf/dma-buf.c:1527 dma_buf_vmap+0x224/0x430
[...]
[ 156.942028] RIP: 0010:dma_buf_vmap+0x224/0x430
[ 157.043420] Call Trace:
[ 157.045898] <TASK>
[ 157.048030] ? show_trace_log_lvl+0x1af/0x2c0
[ 157.052436] ? show_trace_log_lvl+0x1af/0x2c0
[ 157.056836] ? show_trace_log_lvl+0x1af/0x2c0
[ 157.061253] ? drm_gem_shmem_vmap+0x74/0x710
[ 157.065567] ? dma_buf_vmap+0x224/0x430
[ 157.069446] ? __warn.cold+0x58/0xe4
[ 157.073061] ? dma_buf_vmap+0x224/0x430
[ 157.077111] ? report_bug+0x1dd/0x390
[ 157.080842] ? handle_bug+0x5e/0xa0
[ 157.084389] ? exc_invalid_op+0x14/0x50
[ 157.088291] ? asm_exc_invalid_op+0x16/0x20
[ 157.092548] ? dma_buf_vmap+0x224/0x430
[ 157.096663] ? dma_resv_get_singleton+0x6d/0x230
[ 157.101341] ? __pfx_dma_buf_vmap+0x10/0x10
[ 157.105588] ? __pfx_dma_resv_get_singleton+0x10/0x10
[ 157.110697] drm_gem_shmem_vmap+0x74/0x710
[ 157.114866] drm_gem_vmap+0xa9/0x1b0
[ 157.118763] drm_gem_vmap_unlocked+0x46/0xa0
[ 157.123086] drm_gem_fb_vmap+0xab/0x300
[ 157.126979] drm_atomic_helper_prepare_planes.part.0+0x487/0xb10
[ 157.133032] ? lockdep_init_map_type+0x19d/0x880
[ 157.137701] drm_atomic_helper_commit+0x13d/0x2e0
[ 157.142671] ? drm_atomic_nonblocking_commit+0xa0/0x180
[ 157.147988] drm_mode_atomic_ioctl+0x766/0xe40
[...]
[ 157.346424] ---[ end trace 0000000000000000 ]---
Acquiring GEM handles for the framebuffer's GEM buffer objects prevents
this from happening. The framebuffer's cleanup later puts the handle
references.
Commit 1a148af06000 ("drm/gem-shmem: Use dma_buf from GEM object
instance") triggers the segmentation fault easily by using the dma-buf
field more widely. The underlying issue with reference counting has
been present before.
v2:
- acquire the handle instead of the BO (Christian)
- fix comment style (Christian)
- drop the Fixes tag (Christian)
- rename err_ gotos
- add missing Link tag
CVSS Score
5.5
EPSS Score
0.0
Published
2025-07-25
In the Linux kernel, the following vulnerability has been resolved:
s390/mm: Fix in_atomic() handling in do_secure_storage_access()
Kernel user spaces accesses to not exported pages in atomic context
incorrectly try to resolve the page fault.
With debug options enabled call traces like this can be seen:
BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1523
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 419074, name: qemu-system-s39
preempt_count: 1, expected: 0
RCU nest depth: 0, expected: 0
INFO: lockdep is turned off.
Preemption disabled at:
[<00000383ea47cfa2>] copy_page_from_iter_atomic+0xa2/0x8a0
CPU: 12 UID: 0 PID: 419074 Comm: qemu-system-s39
Tainted: G W 6.16.0-20250531.rc0.git0.69b3a602feac.63.fc42.s390x+debug #1 PREEMPT
Tainted: [W]=WARN
Hardware name: IBM 3931 A01 703 (LPAR)
Call Trace:
[<00000383e990d282>] dump_stack_lvl+0xa2/0xe8
[<00000383e99bf152>] __might_resched+0x292/0x2d0
[<00000383eaa7c374>] down_read+0x34/0x2d0
[<00000383e99432f8>] do_secure_storage_access+0x108/0x360
[<00000383eaa724b0>] __do_pgm_check+0x130/0x220
[<00000383eaa842e4>] pgm_check_handler+0x114/0x160
[<00000383ea47d028>] copy_page_from_iter_atomic+0x128/0x8a0
([<00000383ea47d016>] copy_page_from_iter_atomic+0x116/0x8a0)
[<00000383e9c45eae>] generic_perform_write+0x16e/0x310
[<00000383e9eb87f4>] ext4_buffered_write_iter+0x84/0x160
[<00000383e9da0de4>] vfs_write+0x1c4/0x460
[<00000383e9da123c>] ksys_write+0x7c/0x100
[<00000383eaa7284e>] __do_syscall+0x15e/0x280
[<00000383eaa8417e>] system_call+0x6e/0x90
INFO: lockdep is turned off.
It is not allowed to take the mmap_lock while in atomic context. Therefore
handle such a secure storage access fault as if the accessed page is not
mapped: the uaccess function will return -EFAULT, and the caller has to
deal with this. Usually this means that the access is retried in process
context, which allows to resolve the page fault (or in this case export the
page).
CVSS Score
5.5
EPSS Score
0.0
Published
2025-07-25
In the Linux kernel, the following vulnerability has been resolved:
smb: Log an error when close_all_cached_dirs fails
Under low-memory conditions, close_all_cached_dirs() can't move the
dentries to a separate list to dput() them once the locks are dropped.
This will result in a "Dentry still in use" error, so add an error
message that makes it clear this is what happened:
[ 495.281119] CIFS: VFS: \\otters.example.com\share Out of memory while dropping dentries
[ 495.281595] ------------[ cut here ]------------
[ 495.281887] BUG: Dentry ffff888115531138{i=78,n=/} still in use (2) [unmount of cifs cifs]
[ 495.282391] WARNING: CPU: 1 PID: 2329 at fs/dcache.c:1536 umount_check+0xc8/0xf0
Also, bail out of looping through all tcons as soon as a single
allocation fails, since we're already in trouble, and kmalloc() attempts
for subseqeuent tcons are likely to fail just like the first one did.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-07-10
In the Linux kernel, the following vulnerability has been resolved:
btrfs: exit after state insertion failure at btrfs_convert_extent_bit()
If insert_state() state failed it returns an error pointer and we call
extent_io_tree_panic() which will trigger a BUG() call. However if
CONFIG_BUG is disabled, which is an uncommon and exotic scenario, then
we fallthrough and call cache_state() which will dereference the error
pointer, resulting in an invalid memory access.
So jump to the 'out' label after calling extent_io_tree_panic(), it also
makes the code more clear besides dealing with the exotic scenario where
CONFIG_BUG is disabled.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-07-10
In the Linux kernel, the following vulnerability has been resolved:
sched/rt: Fix race in push_rt_task
Overview
========
When a CPU chooses to call push_rt_task and picks a task to push to
another CPU's runqueue then it will call find_lock_lowest_rq method
which would take a double lock on both CPUs' runqueues. If one of the
locks aren't readily available, it may lead to dropping the current
runqueue lock and reacquiring both the locks at once. During this window
it is possible that the task is already migrated and is running on some
other CPU. These cases are already handled. However, if the task is
migrated and has already been executed and another CPU is now trying to
wake it up (ttwu) such that it is queued again on the runqeue
(on_rq is 1) and also if the task was run by the same CPU, then the
current checks will pass even though the task was migrated out and is no
longer in the pushable tasks list.
Crashes
=======
This bug resulted in quite a few flavors of crashes triggering kernel
panics with various crash signatures such as assert failures, page
faults, null pointer dereferences, and queue corruption errors all
coming from scheduler itself.
Some of the crashes:
-> kernel BUG at kernel/sched/rt.c:1616! BUG_ON(idx >= MAX_RT_PRIO)
Call Trace:
? __die_body+0x1a/0x60
? die+0x2a/0x50
? do_trap+0x85/0x100
? pick_next_task_rt+0x6e/0x1d0
? do_error_trap+0x64/0xa0
? pick_next_task_rt+0x6e/0x1d0
? exc_invalid_op+0x4c/0x60
? pick_next_task_rt+0x6e/0x1d0
? asm_exc_invalid_op+0x12/0x20
? pick_next_task_rt+0x6e/0x1d0
__schedule+0x5cb/0x790
? update_ts_time_stats+0x55/0x70
schedule_idle+0x1e/0x40
do_idle+0x15e/0x200
cpu_startup_entry+0x19/0x20
start_secondary+0x117/0x160
secondary_startup_64_no_verify+0xb0/0xbb
-> BUG: kernel NULL pointer dereference, address: 00000000000000c0
Call Trace:
? __die_body+0x1a/0x60
? no_context+0x183/0x350
? __warn+0x8a/0xe0
? exc_page_fault+0x3d6/0x520
? asm_exc_page_fault+0x1e/0x30
? pick_next_task_rt+0xb5/0x1d0
? pick_next_task_rt+0x8c/0x1d0
__schedule+0x583/0x7e0
? update_ts_time_stats+0x55/0x70
schedule_idle+0x1e/0x40
do_idle+0x15e/0x200
cpu_startup_entry+0x19/0x20
start_secondary+0x117/0x160
secondary_startup_64_no_verify+0xb0/0xbb
-> BUG: unable to handle page fault for address: ffff9464daea5900
kernel BUG at kernel/sched/rt.c:1861! BUG_ON(rq->cpu != task_cpu(p))
-> kernel BUG at kernel/sched/rt.c:1055! BUG_ON(!rq->nr_running)
Call Trace:
? __die_body+0x1a/0x60
? die+0x2a/0x50
? do_trap+0x85/0x100
? dequeue_top_rt_rq+0xa2/0xb0
? do_error_trap+0x64/0xa0
? dequeue_top_rt_rq+0xa2/0xb0
? exc_invalid_op+0x4c/0x60
? dequeue_top_rt_rq+0xa2/0xb0
? asm_exc_invalid_op+0x12/0x20
? dequeue_top_rt_rq+0xa2/0xb0
dequeue_rt_entity+0x1f/0x70
dequeue_task_rt+0x2d/0x70
__schedule+0x1a8/0x7e0
? blk_finish_plug+0x25/0x40
schedule+0x3c/0xb0
futex_wait_queue_me+0xb6/0x120
futex_wait+0xd9/0x240
do_futex+0x344/0xa90
? get_mm_exe_file+0x30/0x60
? audit_exe_compare+0x58/0x70
? audit_filter_rules.constprop.26+0x65e/0x1220
__x64_sys_futex+0x148/0x1f0
do_syscall_64+0x30/0x80
entry_SYSCALL_64_after_hwframe+0x62/0xc7
-> BUG: unable to handle page fault for address: ffff8cf3608bc2c0
Call Trace:
? __die_body+0x1a/0x60
? no_context+0x183/0x350
? spurious_kernel_fault+0x171/0x1c0
? exc_page_fault+0x3b6/0x520
? plist_check_list+0x15/0x40
? plist_check_list+0x2e/0x40
? asm_exc_page_fault+0x1e/0x30
? _cond_resched+0x15/0x30
? futex_wait_queue_me+0xc8/0x120
? futex_wait+0xd9/0x240
? try_to_wake_up+0x1b8/0x490
? futex_wake+0x78/0x160
? do_futex+0xcd/0xa90
? plist_check_list+0x15/0x40
? plist_check_list+0x2e/0x40
? plist_del+0x6a/0xd0
? plist_check_list+0x15/0x40
? plist_check_list+0x2e/0x40
? dequeue_pushable_task+0x20/0x70
? __schedule+0x382/0x7e0
? asm_sysvec_reschedule_i
---truncated---
CVSS Score
4.7
EPSS Score
0.0
Published
2025-07-04
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