Linux: >> Linux Kernel >> 4.19.307 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
kprobes: Fix check for probe enabled in kill_kprobe()
In kill_kprobe(), the check whether disarm_kprobe_ftrace() needs to be
called always fails. This is because before that we set the
KPROBE_FLAG_GONE flag for kprobe so that "!kprobe_disabled(p)" is always
false.
The disarm_kprobe_ftrace() call introduced by commit:
0cb2f1372baa ("kprobes: Fix NULL pointer dereference at kprobe_ftrace_handler")
to fix the NULL pointer reference problem. When the probe is enabled, if
we do not disarm it, this problem still exists.
Fix it by putting the probe enabled check before setting the
KPROBE_FLAG_GONE flag.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
mmc: rtsx_pci: fix return value check of mmc_add_host()
mmc_add_host() may return error, if we ignore its return value, the memory
that allocated in mmc_alloc_host() will be leaked and it will lead a kernel
crash because of deleting not added device in the remove path.
So fix this by checking the return value and calling mmc_free_host() in the
error path, beside, runtime PM also needs be disabled.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
USB: uhci: fix memory leak with using debugfs_lookup()
When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time. To make things simpler, just
call debugfs_lookup_and_remove() instead which handles all of the logic
at once.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
net: openvswitch: fix race on port output
assume the following setup on a single machine:
1. An openvswitch instance with one bridge and default flows
2. two network namespaces "server" and "client"
3. two ovs interfaces "server" and "client" on the bridge
4. for each ovs interface a veth pair with a matching name and 32 rx and
tx queues
5. move the ends of the veth pairs to the respective network namespaces
6. assign ip addresses to each of the veth ends in the namespaces (needs
to be the same subnet)
7. start some http server on the server network namespace
8. test if a client in the client namespace can reach the http server
when following the actions below the host has a chance of getting a cpu
stuck in a infinite loop:
1. send a large amount of parallel requests to the http server (around
3000 curls should work)
2. in parallel delete the network namespace (do not delete interfaces or
stop the server, just kill the namespace)
there is a low chance that this will cause the below kernel cpu stuck
message. If this does not happen just retry.
Below there is also the output of bpftrace for the functions mentioned
in the output.
The series of events happening here is:
1. the network namespace is deleted calling
`unregister_netdevice_many_notify` somewhere in the process
2. this sets first `NETREG_UNREGISTERING` on both ends of the veth and
then runs `synchronize_net`
3. it then calls `call_netdevice_notifiers` with `NETDEV_UNREGISTER`
4. this is then handled by `dp_device_event` which calls
`ovs_netdev_detach_dev` (if a vport is found, which is the case for
the veth interface attached to ovs)
5. this removes the rx_handlers of the device but does not prevent
packages to be sent to the device
6. `dp_device_event` then queues the vport deletion to work in
background as a ovs_lock is needed that we do not hold in the
unregistration path
7. `unregister_netdevice_many_notify` continues to call
`netdev_unregister_kobject` which sets `real_num_tx_queues` to 0
8. port deletion continues (but details are not relevant for this issue)
9. at some future point the background task deletes the vport
If after 7. but before 9. a packet is send to the ovs vport (which is
not deleted at this point in time) which forwards it to the
`dev_queue_xmit` flow even though the device is unregistering.
In `skb_tx_hash` (which is called in the `dev_queue_xmit`) path there is
a while loop (if the packet has a rx_queue recorded) that is infinite if
`dev->real_num_tx_queues` is zero.
To prevent this from happening we update `do_output` to handle devices
without carrier the same as if the device is not found (which would
be the code path after 9. is done).
Additionally we now produce a warning in `skb_tx_hash` if we will hit
the infinite loop.
bpftrace (first word is function name):
__dev_queue_xmit server: real_num_tx_queues: 1, cpu: 2, pid: 28024, tid: 28024, skb_addr: 0xffff9edb6f207000, reg_state: 1
netdev_core_pick_tx server: addr: 0xffff9f0a46d4a000 real_num_tx_queues: 1, cpu: 2, pid: 28024, tid: 28024, skb_addr: 0xffff9edb6f207000, reg_state: 1
dp_device_event server: real_num_tx_queues: 1 cpu 9, pid: 21024, tid: 21024, event 2, reg_state: 1
synchronize_rcu_expedited: cpu 9, pid: 21024, tid: 21024
synchronize_rcu_expedited: cpu 9, pid: 21024, tid: 21024
synchronize_rcu_expedited: cpu 9, pid: 21024, tid: 21024
synchronize_rcu_expedited: cpu 9, pid: 21024, tid: 21024
dp_device_event server: real_num_tx_queues: 1 cpu 9, pid: 21024, tid: 21024, event 6, reg_state: 2
ovs_netdev_detach_dev server: real_num_tx_queues: 1 cpu 9, pid: 21024, tid: 21024, reg_state: 2
netdev_rx_handler_unregister server: real_num_tx_queues: 1, cpu: 9, pid: 21024, tid: 21024, reg_state: 2
synchronize_rcu_expedited: cpu 9, pid: 21024, tid: 21024
netdev_rx_handler_unregister ret server: real_num_tx_queues: 1, cpu: 9, pid: 21024, tid: 21024, reg_state: 2
dp_
---truncated---
CVSS Score
4.7
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
tty: pcn_uart: fix memory leak with using debugfs_lookup()
When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time. To make things simpler, just
call debugfs_lookup_and_remove() instead which handles all of the logic
at once.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
mm: fix zswap writeback race condition
The zswap writeback mechanism can cause a race condition resulting in
memory corruption, where a swapped out page gets swapped in with data that
was written to a different page.
The race unfolds like this:
1. a page with data A and swap offset X is stored in zswap
2. page A is removed off the LRU by zpool driver for writeback in
zswap-shrink work, data for A is mapped by zpool driver
3. user space program faults and invalidates page entry A, offset X is
considered free
4. kswapd stores page B at offset X in zswap (zswap could also be
full, if so, page B would then be IOed to X, then skip step 5.)
5. entry A is replaced by B in tree->rbroot, this doesn't affect the
local reference held by zswap-shrink work
6. zswap-shrink work writes back A at X, and frees zswap entry A
7. swapin of slot X brings A in memory instead of B
The fix:
Once the swap page cache has been allocated (case ZSWAP_SWAPCACHE_NEW),
zswap-shrink work just checks that the local zswap_entry reference is
still the same as the one in the tree. If it's not the same it means that
it's either been invalidated or replaced, in both cases the writeback is
aborted because the local entry contains stale data.
Reproducer:
I originally found this by running `stress` overnight to validate my work
on the zswap writeback mechanism, it manifested after hours on my test
machine. The key to make it happen is having zswap writebacks, so
whatever setup pumps /sys/kernel/debug/zswap/written_back_pages should do
the trick.
In order to reproduce this faster on a vm, I setup a system with ~100M of
available memory and a 500M swap file, then running `stress --vm 1
--vm-bytes 300000000 --vm-stride 4000` makes it happen in matter of tens
of minutes. One can speed things up even more by swinging
/sys/module/zswap/parameters/max_pool_percent up and down between, say, 20
and 1; this makes it reproduce in tens of seconds. It's crucial to set
`--vm-stride` to something other than 4096 otherwise `stress` won't
realize that memory has been corrupted because all pages would have the
same data.
CVSS Score
4.7
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
vfio/type1: prevent underflow of locked_vm via exec()
When a vfio container is preserved across exec, the task does not change,
but it gets a new mm with locked_vm=0, and loses the count from existing
dma mappings. If the user later unmaps a dma mapping, locked_vm underflows
to a large unsigned value, and a subsequent dma map request fails with
ENOMEM in __account_locked_vm.
To avoid underflow, grab and save the mm at the time a dma is mapped.
Use that mm when adjusting locked_vm, rather than re-acquiring the saved
task's mm, which may have changed. If the saved mm is dead, do nothing.
locked_vm is incremented for existing mappings in a subsequent patch.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
ext4: avoid deadlock in fs reclaim with page writeback
Ext4 has a filesystem wide lock protecting ext4_writepages() calls to
avoid races with switching of journalled data flag or inode format. This
lock can however cause a deadlock like:
CPU0 CPU1
ext4_writepages()
percpu_down_read(sbi->s_writepages_rwsem);
ext4_change_inode_journal_flag()
percpu_down_write(sbi->s_writepages_rwsem);
- blocks, all readers block from now on
ext4_do_writepages()
ext4_init_io_end()
kmem_cache_zalloc(io_end_cachep, GFP_KERNEL)
fs_reclaim frees dentry...
dentry_unlink_inode()
iput() - last ref =>
iput_final() - inode dirty =>
write_inode_now()...
ext4_writepages() tries to acquire sbi->s_writepages_rwsem
and blocks forever
Make sure we cannot recurse into filesystem reclaim from writeback code
to avoid the deadlock.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: fix calltrace warning in amddrm_buddy_fini
The following call trace is observed when removing the amdgpu driver, which
is caused by that BOs allocated for psp are not freed until removing.
[61811.450562] RIP: 0010:amddrm_buddy_fini.cold+0x29/0x47 [amddrm_buddy]
[61811.450577] Call Trace:
[61811.450577] <TASK>
[61811.450579] amdgpu_vram_mgr_fini+0x135/0x1c0 [amdgpu]
[61811.450728] amdgpu_ttm_fini+0x207/0x290 [amdgpu]
[61811.450870] amdgpu_bo_fini+0x27/0xa0 [amdgpu]
[61811.451012] gmc_v9_0_sw_fini+0x4a/0x60 [amdgpu]
[61811.451166] amdgpu_device_fini_sw+0x117/0x520 [amdgpu]
[61811.451306] amdgpu_driver_release_kms+0x16/0x30 [amdgpu]
[61811.451447] devm_drm_dev_init_release+0x4d/0x80 [drm]
[61811.451466] devm_action_release+0x15/0x20
[61811.451469] release_nodes+0x40/0xb0
[61811.451471] devres_release_all+0x9b/0xd0
[61811.451473] __device_release_driver+0x1bb/0x2a0
[61811.451476] driver_detach+0xf3/0x140
[61811.451479] bus_remove_driver+0x6c/0xf0
[61811.451481] driver_unregister+0x31/0x60
[61811.451483] pci_unregister_driver+0x40/0x90
[61811.451486] amdgpu_exit+0x15/0x447 [amdgpu]
For smu v13_0_2, if the GPU supports xgmi, refer to
commit f5c7e7797060 ("drm/amdgpu: Adjust removal control flow for smu v13_0_2"),
it will run gpu recover in AMDGPU_RESET_FOR_DEVICE_REMOVE mode when removing,
which makes all devices in hive list have hw reset but no resume except the
basic ip blocks, then other ip blocks will not call .hw_fini according to
ip_block.status.hw.
Since psp_free_shared_bufs just includes some software operations, so move
it to psp_sw_fini.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-15
In the Linux kernel, the following vulnerability has been resolved:
drm/meson: remove drm bridges at aggregate driver unbind time
drm bridges added by meson_encoder_hdmi_init and meson_encoder_cvbs_init
were not manually removed at module unload time, which caused dangling
references to freed memory to remain linked in the global bridge_list.
When loading the driver modules back in, the same functions would again
call drm_bridge_add, and when traversing the global bridge_list, would
end up peeking into freed memory.
Once again KASAN revealed the problem:
[ +0.000095] =============================================================
[ +0.000008] BUG: KASAN: use-after-free in __list_add_valid+0x9c/0x120
[ +0.000018] Read of size 8 at addr ffff00003da291f0 by task modprobe/2483
[ +0.000018] CPU: 3 PID: 2483 Comm: modprobe Tainted: G C O 5.19.0-rc6-lrmbkasan+ #1
[ +0.000011] Hardware name: Hardkernel ODROID-N2Plus (DT)
[ +0.000008] Call trace:
[ +0.000006] dump_backtrace+0x1ec/0x280
[ +0.000012] show_stack+0x24/0x80
[ +0.000008] dump_stack_lvl+0x98/0xd4
[ +0.000011] print_address_description.constprop.0+0x80/0x520
[ +0.000011] print_report+0x128/0x260
[ +0.000008] kasan_report+0xb8/0xfc
[ +0.000008] __asan_report_load8_noabort+0x3c/0x50
[ +0.000009] __list_add_valid+0x9c/0x120
[ +0.000009] drm_bridge_add+0x6c/0x104 [drm]
[ +0.000165] dw_hdmi_probe+0x1900/0x2360 [dw_hdmi]
[ +0.000022] meson_dw_hdmi_bind+0x520/0x814 [meson_dw_hdmi]
[ +0.000014] component_bind+0x174/0x520
[ +0.000012] component_bind_all+0x1a8/0x38c
[ +0.000010] meson_drv_bind_master+0x5e8/0xb74 [meson_drm]
[ +0.000032] meson_drv_bind+0x20/0x2c [meson_drm]
[ +0.000027] try_to_bring_up_aggregate_device+0x19c/0x390
[ +0.000010] component_master_add_with_match+0x1c8/0x284
[ +0.000009] meson_drv_probe+0x274/0x280 [meson_drm]
[ +0.000026] platform_probe+0xd0/0x220
[ +0.000009] really_probe+0x3ac/0xa80
[ +0.000009] __driver_probe_device+0x1f8/0x400
[ +0.000009] driver_probe_device+0x68/0x1b0
[ +0.000009] __driver_attach+0x20c/0x480
[ +0.000008] bus_for_each_dev+0x114/0x1b0
[ +0.000009] driver_attach+0x48/0x64
[ +0.000008] bus_add_driver+0x390/0x564
[ +0.000009] driver_register+0x1a8/0x3e4
[ +0.000009] __platform_driver_register+0x6c/0x94
[ +0.000008] meson_drm_platform_driver_init+0x3c/0x1000 [meson_drm]
[ +0.000027] do_one_initcall+0xc4/0x2b0
[ +0.000011] do_init_module+0x154/0x570
[ +0.000011] load_module+0x1a78/0x1ea4
[ +0.000008] __do_sys_init_module+0x184/0x1cc
[ +0.000009] __arm64_sys_init_module+0x78/0xb0
[ +0.000009] invoke_syscall+0x74/0x260
[ +0.000009] el0_svc_common.constprop.0+0xcc/0x260
[ +0.000008] do_el0_svc+0x50/0x70
[ +0.000007] el0_svc+0x68/0x1a0
[ +0.000012] el0t_64_sync_handler+0x11c/0x150
[ +0.000008] el0t_64_sync+0x18c/0x190
[ +0.000016] Allocated by task 879:
[ +0.000008] kasan_save_stack+0x2c/0x5c
[ +0.000011] __kasan_kmalloc+0x90/0xd0
[ +0.000007] __kmalloc+0x278/0x4a0
[ +0.000011] mpi_resize+0x13c/0x1d0
[ +0.000011] mpi_powm+0xd24/0x1570
[ +0.000009] rsa_enc+0x1a4/0x30c
[ +0.000009] pkcs1pad_verify+0x3f0/0x580
[ +0.000009] public_key_verify_signature+0x7a8/0xba4
[ +0.000010] public_key_verify_signature_2+0x40/0x60
[ +0.000008] verify_signature+0xb4/0x114
[ +0.000008] pkcs7_validate_trust_one.constprop.0+0x3b8/0x574
[ +0.000009] pkcs7_validate_trust+0xb8/0x15c
[ +0.000008] verify_pkcs7_message_sig+0xec/0x1b0
[ +0.000012] verify_pkcs7_signature+0x78/0xac
[ +0.000007] mod_verify_sig+0x110/0x190
[ +0.000009] module_sig_check+0x114/0x1e0
[ +0.000009] load_module+0xa0/0x1ea4
[ +0.000008] __do_sys_init_module+0x184/0x1cc
[ +0.000008] __arm64_sys_init_module+0x78/0xb0
[ +0.000008] invoke_syscall+0x74/0x260
[ +0.000009] el0_svc_common.constprop.0+0x1a8/0x260
[ +0.000008] do_el0_svc+0x50/0x70
[ +0.000007] el0_svc+0x68/0x1a0
[ +0.000009] el0t_64_sync_handler+0x11c/0x150
[ +0.000009] el0t_64
---truncated---
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-15