Linux: >> Linux Kernel >> 5.4.276 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
f2fs: don't reset unchangable mount option in f2fs_remount()
syzbot reports a bug as below:
general protection fault, probably for non-canonical address 0xdffffc0000000009: 0000 [#1] PREEMPT SMP KASAN
RIP: 0010:__lock_acquire+0x69/0x2000 kernel/locking/lockdep.c:4942
Call Trace:
lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5691
__raw_write_lock include/linux/rwlock_api_smp.h:209 [inline]
_raw_write_lock+0x2e/0x40 kernel/locking/spinlock.c:300
__drop_extent_tree+0x3ac/0x660 fs/f2fs/extent_cache.c:1100
f2fs_drop_extent_tree+0x17/0x30 fs/f2fs/extent_cache.c:1116
f2fs_insert_range+0x2d5/0x3c0 fs/f2fs/file.c:1664
f2fs_fallocate+0x4e4/0x6d0 fs/f2fs/file.c:1838
vfs_fallocate+0x54b/0x6b0 fs/open.c:324
ksys_fallocate fs/open.c:347 [inline]
__do_sys_fallocate fs/open.c:355 [inline]
__se_sys_fallocate fs/open.c:353 [inline]
__x64_sys_fallocate+0xbd/0x100 fs/open.c:353
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
The root cause is race condition as below:
- since it tries to remount rw filesystem, so that do_remount won't
call sb_prepare_remount_readonly to block fallocate, there may be race
condition in between remount and fallocate.
- in f2fs_remount(), default_options() will reset mount option to default
one, and then update it based on result of parse_options(), so there is
a hole which race condition can happen.
Thread A Thread B
- f2fs_fill_super
- parse_options
- clear_opt(READ_EXTENT_CACHE)
- f2fs_remount
- default_options
- set_opt(READ_EXTENT_CACHE)
- f2fs_fallocate
- f2fs_insert_range
- f2fs_drop_extent_tree
- __drop_extent_tree
- __may_extent_tree
- test_opt(READ_EXTENT_CACHE) return true
- write_lock(&et->lock) access NULL pointer
- parse_options
- clear_opt(READ_EXTENT_CACHE)
CVSS Score
4.7
EPSS Score
0.0
Published
2025-09-18
In the Linux kernel, the following vulnerability has been resolved:
bpf: cpumap: Fix memory leak in cpu_map_update_elem
Syzkaller reported a memory leak as follows:
BUG: memory leak
unreferenced object 0xff110001198ef748 (size 192):
comm "syz-executor.3", pid 17672, jiffies 4298118891 (age 9.906s)
hex dump (first 32 bytes):
00 00 00 00 4a 19 00 00 80 ad e3 e4 fe ff c0 00 ....J...........
00 b2 d3 0c 01 00 11 ff 28 f5 8e 19 01 00 11 ff ........(.......
backtrace:
[<ffffffffadd28087>] __cpu_map_entry_alloc+0xf7/0xb00
[<ffffffffadd28d8e>] cpu_map_update_elem+0x2fe/0x3d0
[<ffffffffadc6d0fd>] bpf_map_update_value.isra.0+0x2bd/0x520
[<ffffffffadc7349b>] map_update_elem+0x4cb/0x720
[<ffffffffadc7d983>] __se_sys_bpf+0x8c3/0xb90
[<ffffffffb029cc80>] do_syscall_64+0x30/0x40
[<ffffffffb0400099>] entry_SYSCALL_64_after_hwframe+0x61/0xc6
BUG: memory leak
unreferenced object 0xff110001198ef528 (size 192):
comm "syz-executor.3", pid 17672, jiffies 4298118891 (age 9.906s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffffadd281f0>] __cpu_map_entry_alloc+0x260/0xb00
[<ffffffffadd28d8e>] cpu_map_update_elem+0x2fe/0x3d0
[<ffffffffadc6d0fd>] bpf_map_update_value.isra.0+0x2bd/0x520
[<ffffffffadc7349b>] map_update_elem+0x4cb/0x720
[<ffffffffadc7d983>] __se_sys_bpf+0x8c3/0xb90
[<ffffffffb029cc80>] do_syscall_64+0x30/0x40
[<ffffffffb0400099>] entry_SYSCALL_64_after_hwframe+0x61/0xc6
BUG: memory leak
unreferenced object 0xff1100010fd93d68 (size 8):
comm "syz-executor.3", pid 17672, jiffies 4298118891 (age 9.906s)
hex dump (first 8 bytes):
00 00 00 00 00 00 00 00 ........
backtrace:
[<ffffffffade5db3e>] kvmalloc_node+0x11e/0x170
[<ffffffffadd28280>] __cpu_map_entry_alloc+0x2f0/0xb00
[<ffffffffadd28d8e>] cpu_map_update_elem+0x2fe/0x3d0
[<ffffffffadc6d0fd>] bpf_map_update_value.isra.0+0x2bd/0x520
[<ffffffffadc7349b>] map_update_elem+0x4cb/0x720
[<ffffffffadc7d983>] __se_sys_bpf+0x8c3/0xb90
[<ffffffffb029cc80>] do_syscall_64+0x30/0x40
[<ffffffffb0400099>] entry_SYSCALL_64_after_hwframe+0x61/0xc6
In the cpu_map_update_elem flow, when kthread_stop is called before
calling the threadfn of rcpu->kthread, since the KTHREAD_SHOULD_STOP bit
of kthread has been set by kthread_stop, the threadfn of rcpu->kthread
will never be executed, and rcpu->refcnt will never be 0, which will
lead to the allocated rcpu, rcpu->queue and rcpu->queue->queue cannot be
released.
Calling kthread_stop before executing kthread's threadfn will return
-EINTR. We can complete the release of memory resources in this state.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-18
In the Linux kernel, the following vulnerability has been resolved:
firewire: net: fix use after free in fwnet_finish_incoming_packet()
The netif_rx() function frees the skb so we can't dereference it to
save the skb->len.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-18
In the Linux kernel, the following vulnerability has been resolved:
x86/MCE: Always save CS register on AMD Zen IF Poison errors
The Instruction Fetch (IF) units on current AMD Zen-based systems do not
guarantee a synchronous #MC is delivered for poison consumption errors.
Therefore, MCG_STATUS[EIPV|RIPV] will not be set. However, the
microarchitecture does guarantee that the exception is delivered within
the same context. In other words, the exact rIP is not known, but the
context is known to not have changed.
There is no architecturally-defined method to determine this behavior.
The Code Segment (CS) register is always valid on such IF unit poison
errors regardless of the value of MCG_STATUS[EIPV|RIPV].
Add a quirk to save the CS register for poison consumption from the IF
unit banks.
This is needed to properly determine the context of the error.
Otherwise, the severity grading function will assume the context is
IN_KERNEL due to the m->cs value being 0 (the initialized value). This
leads to unnecessary kernel panics on data poison errors due to the
kernel believing the poison consumption occurred in kernel context.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-18
In the Linux kernel, the following vulnerability has been resolved:
btrfs: don't check PageError in __extent_writepage
__extent_writepage currenly sets PageError whenever any error happens,
and the also checks for PageError to decide if to call error handling.
This leads to very unclear responsibility for cleaning up on errors.
In the VM and generic writeback helpers the basic idea is that once
I/O is fired off all error handling responsibility is delegated to the
end I/O handler. But if that end I/O handler sets the PageError bit,
and the submitter checks it, the bit could in some cases leak into the
submission context for fast enough I/O.
Fix this by simply not checking PageError and just using the local
ret variable to check for submission errors. This also fundamentally
solves the long problem documented in a comment in __extent_writepage
by never leaking the error bit into the submission context.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-18
In the Linux kernel, the following vulnerability has been resolved:
drm/panfrost: Fix GEM handle creation ref-counting
panfrost_gem_create_with_handle() previously returned a BO but with the
only reference being from the handle, which user space could in theory
guess and release, causing a use-after-free. Additionally if the call to
panfrost_gem_mapping_get() in panfrost_ioctl_create_bo() failed then
a(nother) reference on the BO was dropped.
The _create_with_handle() is a problematic pattern, so ditch it and
instead create the handle in panfrost_ioctl_create_bo(). If the call to
panfrost_gem_mapping_get() fails then this means that user space has
indeed gone behind our back and freed the handle. In which case just
return an error code.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-18
In the Linux kernel, the following vulnerability has been resolved:
rcu: Protect rcu_print_task_exp_stall() ->exp_tasks access
For kernels built with CONFIG_PREEMPT_RCU=y, the following scenario can
result in a NULL-pointer dereference:
CPU1 CPU2
rcu_preempt_deferred_qs_irqrestore rcu_print_task_exp_stall
if (special.b.blocked) READ_ONCE(rnp->exp_tasks) != NULL
raw_spin_lock_rcu_node
np = rcu_next_node_entry(t, rnp)
if (&t->rcu_node_entry == rnp->exp_tasks)
WRITE_ONCE(rnp->exp_tasks, np)
....
raw_spin_unlock_irqrestore_rcu_node
raw_spin_lock_irqsave_rcu_node
t = list_entry(rnp->exp_tasks->prev,
struct task_struct, rcu_node_entry)
(if rnp->exp_tasks is NULL, this
will dereference a NULL pointer)
The problem is that CPU2 accesses the rcu_node structure's->exp_tasks
field without holding the rcu_node structure's ->lock and CPU2 did
not observe CPU1's change to rcu_node structure's ->exp_tasks in time.
Therefore, if CPU1 sets rcu_node structure's->exp_tasks pointer to NULL,
then CPU2 might dereference that NULL pointer.
This commit therefore holds the rcu_node structure's ->lock while
accessing that structure's->exp_tasks field.
[ paulmck: Apply Frederic Weisbecker feedback. ]
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-18
In the Linux kernel, the following vulnerability has been resolved:
NFSD: Protect against send buffer overflow in NFSv2 READ
Since before the git era, NFSD has conserved the number of pages
held by each nfsd thread by combining the RPC receive and send
buffers into a single array of pages. This works because there are
no cases where an operation needs a large RPC Call message and a
large RPC Reply at the same time.
Once an RPC Call has been received, svc_process() updates
svc_rqst::rq_res to describe the part of rq_pages that can be
used for constructing the Reply. This means that the send buffer
(rq_res) shrinks when the received RPC record containing the RPC
Call is large.
A client can force this shrinkage on TCP by sending a correctly-
formed RPC Call header contained in an RPC record that is
excessively large. The full maximum payload size cannot be
constructed in that case.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-18
In the Linux kernel, the following vulnerability has been resolved:
drm: bridge: adv7511: unregister cec i2c device after cec adapter
cec_unregister_adapter() assumes that the underlying adapter ops are
callable. For example, if the CEC adapter currently has a valid physical
address, then the unregistration procedure will invalidate the physical
address by setting it to f.f.f.f. Whence the following kernel oops
observed after removing the adv7511 module:
Unable to handle kernel execution of user memory at virtual address 0000000000000000
Internal error: Oops: 86000004 [#1] PREEMPT_RT SMP
Call trace:
0x0
adv7511_cec_adap_log_addr+0x1ac/0x1c8 [adv7511]
cec_adap_unconfigure+0x44/0x90 [cec]
__cec_s_phys_addr.part.0+0x68/0x230 [cec]
__cec_s_phys_addr+0x40/0x50 [cec]
cec_unregister_adapter+0xb4/0x118 [cec]
adv7511_remove+0x60/0x90 [adv7511]
i2c_device_remove+0x34/0xe0
device_release_driver_internal+0x114/0x1f0
driver_detach+0x54/0xe0
bus_remove_driver+0x60/0xd8
driver_unregister+0x34/0x60
i2c_del_driver+0x2c/0x68
adv7511_exit+0x1c/0x67c [adv7511]
__arm64_sys_delete_module+0x154/0x288
invoke_syscall+0x48/0x100
el0_svc_common.constprop.0+0x48/0xe8
do_el0_svc+0x28/0x88
el0_svc+0x1c/0x50
el0t_64_sync_handler+0xa8/0xb0
el0t_64_sync+0x15c/0x160
Code: bad PC value
---[ end trace 0000000000000000 ]---
Protect against this scenario by unregistering i2c_cec after
unregistering the CEC adapter. Duly disable the CEC clock afterwards
too.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-18
In the Linux kernel, the following vulnerability has been resolved:
iomap: iomap: fix memory corruption when recording errors during writeback
Every now and then I see this crash on arm64:
Unable to handle kernel NULL pointer dereference at virtual address 00000000000000f8
Buffer I/O error on dev dm-0, logical block 8733687, async page read
Mem abort info:
ESR = 0x0000000096000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x06: level 2 translation fault
Data abort info:
ISV = 0, ISS = 0x00000006
CM = 0, WnR = 0
user pgtable: 64k pages, 42-bit VAs, pgdp=0000000139750000
[00000000000000f8] pgd=0000000000000000, p4d=0000000000000000, pud=0000000000000000, pmd=0000000000000000
Internal error: Oops: 96000006 [#1] PREEMPT SMP
Buffer I/O error on dev dm-0, logical block 8733688, async page read
Dumping ftrace buffer:
Buffer I/O error on dev dm-0, logical block 8733689, async page read
(ftrace buffer empty)
XFS (dm-0): log I/O error -5
Modules linked in: dm_thin_pool dm_persistent_data
XFS (dm-0): Metadata I/O Error (0x1) detected at xfs_trans_read_buf_map+0x1ec/0x590 [xfs] (fs/xfs/xfs_trans_buf.c:296).
dm_bio_prison
XFS (dm-0): Please unmount the filesystem and rectify the problem(s)
XFS (dm-0): xfs_imap_lookup: xfs_ialloc_read_agi() returned error -5, agno 0
dm_bufio dm_log_writes xfs nft_chain_nat xt_REDIRECT nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip6t_REJECT
potentially unexpected fatal signal 6.
nf_reject_ipv6
potentially unexpected fatal signal 6.
ipt_REJECT nf_reject_ipv4
CPU: 1 PID: 122166 Comm: fsstress Tainted: G W 6.0.0-rc5-djwa #rc5 3004c9f1de887ebae86015f2677638ce51ee7
rpcsec_gss_krb5 auth_rpcgss xt_tcpudp ip_set_hash_ip ip_set_hash_net xt_set nft_compat ip_set_hash_mac ip_set nf_tables
Hardware name: QEMU KVM Virtual Machine, BIOS 1.5.1 06/16/2021
pstate: 60001000 (nZCv daif -PAN -UAO -TCO -DIT +SSBS BTYPE=--)
ip_tables
pc : 000003fd6d7df200
x_tables
lr : 000003fd6d7df1ec
overlay nfsv4
CPU: 0 PID: 54031 Comm: u4:3 Tainted: G W 6.0.0-rc5-djwa #rc5 3004c9f1de887ebae86015f2677638ce51ee7405
Hardware name: QEMU KVM Virtual Machine, BIOS 1.5.1 06/16/2021
Workqueue: writeback wb_workfn
sp : 000003ffd9522fd0
(flush-253:0)
pstate: 60401005 (nZCv daif +PAN -UAO -TCO -DIT +SSBS BTYPE=--)
pc : errseq_set+0x1c/0x100
x29: 000003ffd9522fd0 x28: 0000000000000023 x27: 000002acefeb6780
x26: 0000000000000005 x25: 0000000000000001 x24: 0000000000000000
x23: 00000000ffffffff x22: 0000000000000005
lr : __filemap_set_wb_err+0x24/0xe0
x21: 0000000000000006
sp : fffffe000f80f760
x29: fffffe000f80f760 x28: 0000000000000003 x27: fffffe000f80f9f8
x26: 0000000002523000 x25: 00000000fffffffb x24: fffffe000f80f868
x23: fffffe000f80fbb0 x22: fffffc0180c26a78 x21: 0000000002530000
x20: 0000000000000000 x19: 0000000000000000 x18: 0000000000000000
x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
x14: 0000000000000001 x13: 0000000000470af3 x12: fffffc0058f70000
x11: 0000000000000040 x10: 0000000000001b20 x9 : fffffe000836b288
x8 : fffffc00eb9fd480 x7 : 0000000000f83659 x6 : 0000000000000000
x5 : 0000000000000869 x4 : 0000000000000005 x3 : 00000000000000f8
x20: 000003fd6d740020 x19: 000000000001dd36 x18: 0000000000000001
x17: 000003fd6d78704c x16: 0000000000000001 x15: 000002acfac87668
x2 : 0000000000000ffa x1 : 00000000fffffffb x0 : 00000000000000f8
Call trace:
errseq_set+0x1c/0x100
__filemap_set_wb_err+0x24/0xe0
iomap_do_writepage+0x5e4/0xd5c
write_cache_pages+0x208/0x674
iomap_writepages+0x34/0x60
xfs_vm_writepages+0x8c/0xcc [xfs 7a861f39c43631f15d3a5884246ba5035d4ca78b]
x14: 0000000000000000 x13: 2064656e72757465 x12: 0000000000002180
x11: 000003fd6d8a82d0 x10: 0000000000000000 x9 : 000003fd6d8ae288
x8 : 0000000000000083 x7 : 00000000ffffffff x6 : 00000000ffffffee
x5 : 00000000fbad2887 x4 : 000003fd6d9abb58 x3 : 000003fd6d740020
x2 : 0000000000000006 x1 : 000000000001dd36 x0 : 0000000000000000
CPU:
---truncated---
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-18