Linux: >> Linux Kernel >> 3.8.1 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
ring-buffer: Fix deadloop issue on reading trace_pipe
Soft lockup occurs when reading file 'trace_pipe':
watchdog: BUG: soft lockup - CPU#6 stuck for 22s! [cat:4488]
[...]
RIP: 0010:ring_buffer_empty_cpu+0xed/0x170
RSP: 0018:ffff88810dd6fc48 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000246 RCX: ffffffff93d1aaeb
RDX: ffff88810a280040 RSI: 0000000000000008 RDI: ffff88811164b218
RBP: ffff88811164b218 R08: 0000000000000000 R09: ffff88815156600f
R10: ffffed102a2acc01 R11: 0000000000000001 R12: 0000000051651901
R13: 0000000000000000 R14: ffff888115e49500 R15: 0000000000000000
[...]
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8d853c2000 CR3: 000000010dcd8000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__find_next_entry+0x1a8/0x4b0
? peek_next_entry+0x250/0x250
? down_write+0xa5/0x120
? down_write_killable+0x130/0x130
trace_find_next_entry_inc+0x3b/0x1d0
tracing_read_pipe+0x423/0xae0
? tracing_splice_read_pipe+0xcb0/0xcb0
vfs_read+0x16b/0x490
ksys_read+0x105/0x210
? __ia32_sys_pwrite64+0x200/0x200
? switch_fpu_return+0x108/0x220
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x61/0xc6
Through the vmcore, I found it's because in tracing_read_pipe(),
ring_buffer_empty_cpu() found some buffer is not empty but then it
cannot read anything due to "rb_num_of_entries() == 0" always true,
Then it infinitely loop the procedure due to user buffer not been
filled, see following code path:
tracing_read_pipe() {
... ...
waitagain:
tracing_wait_pipe() // 1. find non-empty buffer here
trace_find_next_entry_inc() // 2. loop here try to find an entry
__find_next_entry()
ring_buffer_empty_cpu(); // 3. find non-empty buffer
peek_next_entry() // 4. but peek always return NULL
ring_buffer_peek()
rb_buffer_peek()
rb_get_reader_page()
// 5. because rb_num_of_entries() == 0 always true here
// then return NULL
// 6. user buffer not been filled so goto 'waitgain'
// and eventually leads to an deadloop in kernel!!!
}
By some analyzing, I found that when resetting ringbuffer, the 'entries'
of its pages are not all cleared (see rb_reset_cpu()). Then when reducing
the ringbuffer, and if some reduced pages exist dirty 'entries' data, they
will be added into 'cpu_buffer->overrun' (see rb_remove_pages()), which
cause wrong 'overrun' count and eventually cause the deadloop issue.
To fix it, we need to clear every pages in rb_reset_cpu().
CVSS Score
7.1
EPSS Score
0.001
Published
2025-10-07
In the Linux kernel, the following vulnerability has been resolved:
ALSA: ac97: Fix possible NULL dereference in snd_ac97_mixer
smatch error:
sound/pci/ac97/ac97_codec.c:2354 snd_ac97_mixer() error:
we previously assumed 'rac97' could be null (see line 2072)
remove redundant assignment, return error if rac97 is NULL.
CVSS Score
5.5
EPSS Score
0.002
Published
2025-10-07
In the Linux kernel, the following vulnerability has been resolved:
fbdev: omapfb: lcd_mipid: Fix an error handling path in mipid_spi_probe()
If 'mipid_detect()' fails, we must free 'md' to avoid a memory leak.
CVSS Score
5.5
EPSS Score
0.002
Published
2025-10-07
In the Linux kernel, the following vulnerability has been resolved:
wifi: ath9k: hif_usb: fix memory leak of remain_skbs
hif_dev->remain_skb is allocated and used exclusively in
ath9k_hif_usb_rx_stream(). It is implied that an allocated remain_skb is
processed and subsequently freed (in error paths) only during the next
call of ath9k_hif_usb_rx_stream().
So, if the urbs are deallocated between those two calls due to the device
deinitialization or suspend, it is possible that ath9k_hif_usb_rx_stream()
is not called next time and the allocated remain_skb is leaked. Our local
Syzkaller instance was able to trigger that.
remain_skb makes sense when receiving two consecutive urbs which are
logically linked together, i.e. a specific data field from the first skb
indicates a cached skb to be allocated, memcpy'd with some data and
subsequently processed in the next call to ath9k_hif_usb_rx_stream(). Urbs
deallocation supposedly makes that link irrelevant so we need to free the
cached skb in those cases.
Fix the leak by introducing a function to explicitly free remain_skb (if
it is not NULL) when the rx urbs have been deallocated. remain_skb is NULL
when it has not been allocated at all (hif_dev struct is kzalloced) or
when it has been processed in next call to ath9k_hif_usb_rx_stream().
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
CVSS Score
5.5
EPSS Score
0.001
Published
2025-10-07
In the Linux kernel, the following vulnerability has been resolved:
media: radio-shark: Add endpoint checks
The syzbot fuzzer was able to provoke a WARNING from the radio-shark2
driver:
------------[ cut here ]------------
usb 1-1: BOGUS urb xfer, pipe 1 != type 3
WARNING: CPU: 0 PID: 3271 at drivers/usb/core/urb.c:504 usb_submit_urb+0xed2/0x1880 drivers/usb/core/urb.c:504
Modules linked in:
CPU: 0 PID: 3271 Comm: kworker/0:3 Not tainted 6.1.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Workqueue: usb_hub_wq hub_event
RIP: 0010:usb_submit_urb+0xed2/0x1880 drivers/usb/core/urb.c:504
Code: 7c 24 18 e8 00 36 ea fb 48 8b 7c 24 18 e8 36 1c 02 ff 41 89 d8 44 89 e1 4c 89 ea 48 89 c6 48 c7 c7 a0 b6 90 8a e8 9a 29 b8 03 <0f> 0b e9 58 f8 ff ff e8 d2 35 ea fb 48 81 c5 c0 05 00 00 e9 84 f7
RSP: 0018:ffffc90003876dd0 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000
RDX: ffff8880750b0040 RSI: ffffffff816152b8 RDI: fffff5200070edac
RBP: ffff8880172d81e0 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000000 R12: 0000000000000001
R13: ffff8880285c5040 R14: 0000000000000002 R15: ffff888017158200
FS: 0000000000000000(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe03235b90 CR3: 000000000bc8e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
usb_start_wait_urb+0x101/0x4b0 drivers/usb/core/message.c:58
usb_bulk_msg+0x226/0x550 drivers/usb/core/message.c:387
shark_write_reg+0x1ff/0x2e0 drivers/media/radio/radio-shark2.c:88
...
The problem was caused by the fact that the driver does not check
whether the endpoints it uses are actually present and have the
appropriate types. This can be fixed by adding a simple check of
these endpoints (and similarly for the radio-shark driver).
CVSS Score
5.5
EPSS Score
0.001
Published
2025-10-07
In the Linux kernel, the following vulnerability has been resolved:
netfilter: conntrack: Avoid nf_ct_helper_hash uses after free
If nf_conntrack_init_start() fails (for example due to a
register_nf_conntrack_bpf() failure), the nf_conntrack_helper_fini()
clean-up path frees the nf_ct_helper_hash map.
When built with NF_CONNTRACK=y, further netfilter modules (e.g:
netfilter_conntrack_ftp) can still be loaded and call
nf_conntrack_helpers_register(), independently of whether nf_conntrack
initialized correctly. This accesses the nf_ct_helper_hash dangling
pointer and causes a uaf, possibly leading to random memory corruption.
This patch guards nf_conntrack_helper_register() from accessing a freed
or uninitialized nf_ct_helper_hash pointer and fixes possible
uses-after-free when loading a conntrack module.
CVSS Score
7.8
EPSS Score
0.002
Published
2025-10-07
In the Linux kernel, the following vulnerability has been resolved:
md: fix soft lockup in status_resync
status_resync() will calculate 'curr_resync - recovery_active' to show
user a progress bar like following:
[============>........] resync = 61.4%
'curr_resync' and 'recovery_active' is updated in md_do_sync(), and
status_resync() can read them concurrently, hence it's possible that
'curr_resync - recovery_active' can overflow to a huge number. In this
case status_resync() will be stuck in the loop to print a large amount
of '=', which will end up soft lockup.
Fix the problem by setting 'resync' to MD_RESYNC_ACTIVE in this case,
this way resync in progress will be reported to user.
CVSS Score
5.5
EPSS Score
0.001
Published
2025-10-07
In the Linux kernel, the following vulnerability has been resolved:
gfs2: Fix possible data races in gfs2_show_options()
Some fields such as gt_logd_secs of the struct gfs2_tune are accessed
without holding the lock gt_spin in gfs2_show_options():
val = sdp->sd_tune.gt_logd_secs;
if (val != 30)
seq_printf(s, ",commit=%d", val);
And thus can cause data races when gfs2_show_options() and other functions
such as gfs2_reconfigure() are concurrently executed:
spin_lock(>->gt_spin);
gt->gt_logd_secs = newargs->ar_commit;
To fix these possible data races, the lock sdp->sd_tune.gt_spin is
acquired before accessing the fields of gfs2_tune and released after these
accesses.
Further changes by Andreas:
- Don't hold the spin lock over the seq_printf operations.
CVSS Score
7.0
EPSS Score
0.001
Published
2025-10-07
In the Linux kernel, the following vulnerability has been resolved:
dm thin: Fix ABBA deadlock between shrink_slab and dm_pool_abort_metadata
Following concurrent processes:
P1(drop cache) P2(kworker)
drop_caches_sysctl_handler
drop_slab
shrink_slab
down_read(&shrinker_rwsem) - LOCK A
do_shrink_slab
super_cache_scan
prune_icache_sb
dispose_list
evict
ext4_evict_inode
ext4_clear_inode
ext4_discard_preallocations
ext4_mb_load_buddy_gfp
ext4_mb_init_cache
ext4_read_block_bitmap_nowait
ext4_read_bh_nowait
submit_bh
dm_submit_bio
do_worker
process_deferred_bios
commit
metadata_operation_failed
dm_pool_abort_metadata
down_write(&pmd->root_lock) - LOCK B
__destroy_persistent_data_objects
dm_block_manager_destroy
dm_bufio_client_destroy
unregister_shrinker
down_write(&shrinker_rwsem)
thin_map |
dm_thin_find_block ↓
down_read(&pmd->root_lock) --> ABBA deadlock
, which triggers hung task:
[ 76.974820] INFO: task kworker/u4:3:63 blocked for more than 15 seconds.
[ 76.976019] Not tainted 6.1.0-rc4-00011-g8f17dd350364-dirty #910
[ 76.978521] task:kworker/u4:3 state:D stack:0 pid:63 ppid:2
[ 76.978534] Workqueue: dm-thin do_worker
[ 76.978552] Call Trace:
[ 76.978564] __schedule+0x6ba/0x10f0
[ 76.978582] schedule+0x9d/0x1e0
[ 76.978588] rwsem_down_write_slowpath+0x587/0xdf0
[ 76.978600] down_write+0xec/0x110
[ 76.978607] unregister_shrinker+0x2c/0xf0
[ 76.978616] dm_bufio_client_destroy+0x116/0x3d0
[ 76.978625] dm_block_manager_destroy+0x19/0x40
[ 76.978629] __destroy_persistent_data_objects+0x5e/0x70
[ 76.978636] dm_pool_abort_metadata+0x8e/0x100
[ 76.978643] metadata_operation_failed+0x86/0x110
[ 76.978649] commit+0x6a/0x230
[ 76.978655] do_worker+0xc6e/0xd90
[ 76.978702] process_one_work+0x269/0x630
[ 76.978714] worker_thread+0x266/0x630
[ 76.978730] kthread+0x151/0x1b0
[ 76.978772] INFO: task test.sh:2646 blocked for more than 15 seconds.
[ 76.979756] Not tainted 6.1.0-rc4-00011-g8f17dd350364-dirty #910
[ 76.982111] task:test.sh state:D stack:0 pid:2646 ppid:2459
[ 76.982128] Call Trace:
[ 76.982139] __schedule+0x6ba/0x10f0
[ 76.982155] schedule+0x9d/0x1e0
[ 76.982159] rwsem_down_read_slowpath+0x4f4/0x910
[ 76.982173] down_read+0x84/0x170
[ 76.982177] dm_thin_find_block+0x4c/0xd0
[ 76.982183] thin_map+0x201/0x3d0
[ 76.982188] __map_bio+0x5b/0x350
[ 76.982195] dm_submit_bio+0x2b6/0x930
[ 76.982202] __submit_bio+0x123/0x2d0
[ 76.982209] submit_bio_noacct_nocheck+0x101/0x3e0
[ 76.982222] submit_bio_noacct+0x389/0x770
[ 76.982227] submit_bio+0x50/0xc0
[ 76.982232] submit_bh_wbc+0x15e/0x230
[ 76.982238] submit_bh+0x14/0x20
[ 76.982241] ext4_read_bh_nowait+0xc5/0x130
[ 76.982247] ext4_read_block_bitmap_nowait+0x340/0xc60
[ 76.982254] ext4_mb_init_cache+0x1ce/0xdc0
[ 76.982259] ext4_mb_load_buddy_gfp+0x987/0xfa0
[ 76.982263] ext4_discard_preallocations+0x45d/0x830
[ 76.982274] ext4_clear_inode+0x48/0xf0
[ 76.982280] ext4_evict_inode+0xcf/0xc70
[ 76.982285] evict+0x119/0x2b0
[ 76.982290] dispose_list+0x43/0xa0
[ 76.982294] prune_icache_sb+0x64/0x90
[ 76.982298] super_cache_scan+0x155/0x210
[ 76.982303] do_shrink_slab+0x19e/0x4e0
[ 76.982310] shrink_slab+0x2bd/0x450
[ 76.982317] drop_slab+0xcc/0x1a0
[ 76.982323] drop_caches_sysctl_handler+0xb7/0xe0
[ 76.982327] proc_sys_call_handler+0x1bc/0x300
[ 76.982331] proc_sys_write+0x17/0x20
[ 76.982334] vfs_write+0x3d3/0x570
[ 76.982342] ksys_write+0x73/0x160
[ 76.982347] __x64_sys_write+0x1e/0x30
[ 76.982352] do_syscall_64+0x35/0x80
[ 76.982357] entry_SYSCALL_64_after_hwframe+0x63/0xcd
Funct
---truncated---
CVSS Score
5.5
EPSS Score
0.001
Published
2025-10-07
In the Linux kernel, the following vulnerability has been resolved:
media: si470x: Fix use-after-free in si470x_int_in_callback()
syzbot reported use-after-free in si470x_int_in_callback() [1]. This
indicates that urb->context, which contains struct si470x_device
object, is freed when si470x_int_in_callback() is called.
The cause of this issue is that si470x_int_in_callback() is called for
freed urb.
si470x_usb_driver_probe() calls si470x_start_usb(), which then calls
usb_submit_urb() and si470x_start(). If si470x_start_usb() fails,
si470x_usb_driver_probe() doesn't kill urb, but it just frees struct
si470x_device object, as depicted below:
si470x_usb_driver_probe()
...
si470x_start_usb()
...
usb_submit_urb()
retval = si470x_start()
return retval
if (retval < 0)
free struct si470x_device object, but don't kill urb
This patch fixes this issue by killing urb when si470x_start_usb()
fails and urb is submitted. If si470x_start_usb() fails and urb is
not submitted, i.e. submitting usb fails, it just frees struct
si470x_device object.
CVSS Score
7.8
EPSS Score
0.002
Published
2025-10-07