| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
ipvlan: Make the addrs_lock be per port
Make the addrs_lock be per port, not per ipvlan dev.
Initial code seems to be written in the assumption,
that any address change must occur under RTNL.
But it is not so for the case of IPv6. So
1) Introduce per-port addrs_lock.
2) It was needed to fix places where it was forgotten
to take lock (ipvlan_open/ipvlan_close)
This appears to be a very minor problem though.
Since it's highly unlikely that ipvlan_add_addr() will
be called on 2 CPU simultaneously. But nevertheless,
this could cause:
1) False-negative of ipvlan_addr_busy(): one interface
iterated through all port->ipvlans + ipvlan->addrs
under some ipvlan spinlock, and another added IP
under its own lock. Though this is only possible
for IPv6, since looks like only ipvlan_addr6_event() can be
called without rtnl_lock.
2) Race since ipvlan_ht_addr_add(port) is called under
different ipvlan->addrs_lock locks
This should not affect performance, since add/remove IP
is a rare situation and spinlock is not taken on fast
paths. |
| A memory corruption issue was addressed with improved lock state checking. This issue is fixed in watchOS 26.1, iOS 18.7.2 and iPadOS 18.7.2, macOS Tahoe 26.1, visionOS 26.1, tvOS 26.1, macOS Sonoma 14.8.2, macOS Sequoia 15.7.2, iOS 26.1 and iPadOS 26.1. A malicious application may cause unexpected changes in memory shared between processes. |
| In the Linux kernel, the following vulnerability has been resolved:
net: usb: r8152: fix resume reset deadlock
rtl8152 can trigger device reset during reset which
potentially can result in a deadlock:
**** DPM device timeout after 10 seconds; 15 seconds until panic ****
Call Trace:
<TASK>
schedule+0x483/0x1370
schedule_preempt_disabled+0x15/0x30
__mutex_lock_common+0x1fd/0x470
__rtl8152_set_mac_address+0x80/0x1f0
dev_set_mac_address+0x7f/0x150
rtl8152_post_reset+0x72/0x150
usb_reset_device+0x1d0/0x220
rtl8152_resume+0x99/0xc0
usb_resume_interface+0x3e/0xc0
usb_resume_both+0x104/0x150
usb_resume+0x22/0x110
The problem is that rtl8152 resume calls reset under
tp->control mutex while reset basically re-enters rtl8152
and attempts to acquire the same tp->control lock once
again.
Reset INACCESSIBLE device outside of tp->control mutex
scope to avoid recursive mutex_lock() deadlock. |
| In the Linux kernel, the following vulnerability has been resolved:
procfs: avoid fetching build ID while holding VMA lock
Fix PROCMAP_QUERY to fetch optional build ID only after dropping mmap_lock
or per-VMA lock, whichever was used to lock VMA under question, to avoid
deadlock reported by syzbot:
-> #1 (&mm->mmap_lock){++++}-{4:4}:
__might_fault+0xed/0x170
_copy_to_iter+0x118/0x1720
copy_page_to_iter+0x12d/0x1e0
filemap_read+0x720/0x10a0
blkdev_read_iter+0x2b5/0x4e0
vfs_read+0x7f4/0xae0
ksys_read+0x12a/0x250
do_syscall_64+0xcb/0xf80
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&sb->s_type->i_mutex_key#8){++++}-{4:4}:
__lock_acquire+0x1509/0x26d0
lock_acquire+0x185/0x340
down_read+0x98/0x490
blkdev_read_iter+0x2a7/0x4e0
__kernel_read+0x39a/0xa90
freader_fetch+0x1d5/0xa80
__build_id_parse.isra.0+0xea/0x6a0
do_procmap_query+0xd75/0x1050
procfs_procmap_ioctl+0x7a/0xb0
__x64_sys_ioctl+0x18e/0x210
do_syscall_64+0xcb/0xf80
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
rlock(&mm->mmap_lock);
lock(&sb->s_type->i_mutex_key#8);
lock(&mm->mmap_lock);
rlock(&sb->s_type->i_mutex_key#8);
*** DEADLOCK ***
This seems to be exacerbated (as we haven't seen these syzbot reports
before that) by the recent:
777a8560fd29 ("lib/buildid: use __kernel_read() for sleepable context")
To make this safe, we need to grab file refcount while VMA is still locked, but
other than that everything is pretty straightforward. Internal build_id_parse()
API assumes VMA is passed, but it only needs the underlying file reference, so
just add another variant build_id_parse_file() that expects file passed
directly.
[akpm@linux-foundation.org: fix up kerneldoc] |
| In the Linux kernel, the following vulnerability has been resolved:
riscv: trace: fix snapshot deadlock with sbi ecall
If sbi_ecall.c's functions are traceable,
echo "__sbi_ecall:snapshot" > /sys/kernel/tracing/set_ftrace_filter
may get the kernel into a deadlock.
(Functions in sbi_ecall.c are excluded from tracing if
CONFIG_RISCV_ALTERNATIVE_EARLY is set.)
__sbi_ecall triggers a snapshot of the ringbuffer. The snapshot code
raises an IPI interrupt, which results in another call to __sbi_ecall
and another snapshot...
All it takes to get into this endless loop is one initial __sbi_ecall.
On RISC-V systems without SSTC extension, the clock events in
timer-riscv.c issue periodic sbi ecalls, making the problem easy to
trigger.
Always exclude the sbi_ecall.c functions from tracing to fix the
potential deadlock.
sbi ecalls can easiliy be logged via trace events, excluding ecall
functions from function tracing is not a big limitation. |
| In the Linux kernel, the following vulnerability has been resolved:
hwmon: (acpi_power_meter) Fix deadlocks related to acpi_power_meter_notify()
The acpi_power_meter driver's .notify() callback function,
acpi_power_meter_notify(), calls hwmon_device_unregister() under a lock
that is also acquired by callbacks in sysfs attributes of the device
being unregistered which is prone to deadlocks between sysfs access and
device removal.
Address this by moving the hwmon device removal in
acpi_power_meter_notify() outside the lock in question, but notice
that doing it alone is not sufficient because two concurrent
METER_NOTIFY_CONFIG notifications may be attempting to remove the
same device at the same time. To prevent that from happening, add a
new lock serializing the execution of the switch () statement in
acpi_power_meter_notify(). For simplicity, it is a static mutex
which should not be a problem from the performance perspective.
The new lock also allows the hwmon_device_register_with_info()
in acpi_power_meter_notify() to be called outside the inner lock
because it prevents the other notifications handled by that function
from manipulating the "resource" object while the hwmon device based
on it is being registered. The sending of ACPI netlink messages from
acpi_power_meter_notify() is serialized by the new lock too which
generally helps to ensure that the order of handling firmware
notifications is the same as the order of sending netlink messages
related to them.
In addition, notice that hwmon_device_register_with_info() may fail
in which case resource->hwmon_dev will become an error pointer,
so add checks to avoid attempting to unregister the hwmon device
pointer to by it in that case to acpi_power_meter_notify() and
acpi_power_meter_remove(). |
| In the Linux kernel, the following vulnerability has been resolved:
sfc: fix deadlock in RSS config read
Since cited commit, core locks the net_device's rss_lock when handling
ethtool -x command, so driver's implementation should not lock it
again. Remove the latter. |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: do not strictly require dirty metadata threshold for metadata writepages
[BUG]
There is an internal report that over 1000 processes are
waiting at the io_schedule_timeout() of balance_dirty_pages(), causing
a system hang and trigger a kernel coredump.
The kernel is v6.4 kernel based, but the root problem still applies to
any upstream kernel before v6.18.
[CAUSE]
From Jan Kara for his wisdom on the dirty page balance behavior first.
This cgroup dirty limit was what was actually playing the role here
because the cgroup had only a small amount of memory and so the dirty
limit for it was something like 16MB.
Dirty throttling is responsible for enforcing that nobody can dirty
(significantly) more dirty memory than there's dirty limit. Thus when
a task is dirtying pages it periodically enters into balance_dirty_pages()
and we let it sleep there to slow down the dirtying.
When the system is over dirty limit already (either globally or within
a cgroup of the running task), we will not let the task exit from
balance_dirty_pages() until the number of dirty pages drops below the
limit.
So in this particular case, as I already mentioned, there was a cgroup
with relatively small amount of memory and as a result with dirty limit
set at 16MB. A task from that cgroup has dirtied about 28MB worth of
pages in btrfs btree inode and these were practically the only dirty
pages in that cgroup.
So that means the only way to reduce the dirty pages of that cgroup is
to writeback the dirty pages of btrfs btree inode, and only after that
those processes can exit balance_dirty_pages().
Now back to the btrfs part, btree_writepages() is responsible for
writing back dirty btree inode pages.
The problem here is, there is a btrfs internal threshold that if the
btree inode's dirty bytes are below the 32M threshold, it will not
do any writeback.
This behavior is to batch as much metadata as possible so we won't write
back those tree blocks and then later re-COW them again for another
modification.
This internal 32MiB is higher than the existing dirty page size (28MiB),
meaning no writeback will happen, causing a deadlock between btrfs and
cgroup:
- Btrfs doesn't want to write back btree inode until more dirty pages
- Cgroup/MM doesn't want more dirty pages for btrfs btree inode
Thus any process touching that btree inode is put into sleep until
the number of dirty pages is reduced.
Thanks Jan Kara a lot for the analysis of the root cause.
[ENHANCEMENT]
Since kernel commit b55102826d7d ("btrfs: set AS_KERNEL_FILE on the
btree_inode"), btrfs btree inode pages will only be charged to the root
cgroup which should have a much larger limit than btrfs' 32MiB
threshold.
So it should not affect newer kernels.
But for all current LTS kernels, they are all affected by this problem,
and backporting the whole AS_KERNEL_FILE may not be a good idea.
Even for newer kernels I still think it's a good idea to get
rid of the internal threshold at btree_writepages(), since for most cases
cgroup/MM has a better view of full system memory usage than btrfs' fixed
threshold.
For internal callers using btrfs_btree_balance_dirty() since that
function is already doing internal threshold check, we don't need to
bother them.
But for external callers of btree_writepages(), just respect their
requests and write back whatever they want, ignoring the internal
btrfs threshold to avoid such deadlock on btree inode dirty page
balancing. |
| In the Linux kernel, the following vulnerability has been resolved:
Revert "f2fs: block cache/dio write during f2fs_enable_checkpoint()"
This reverts commit 196c81fdd438f7ac429d5639090a9816abb9760a.
Original patch may cause below deadlock, revert it.
write remount
- write_begin
- lock_page --- lock A
- prepare_write_begin
- f2fs_map_lock
- f2fs_enable_checkpoint
- down_write(cp_enable_rwsem) --- lock B
- sync_inode_sb
- writepages
- lock_page --- lock A
- down_read(cp_enable_rwsem) --- lock A |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: ath12k: fix dead lock while flushing management frames
Commit [1] converted the management transmission work item into a
wiphy work. Since a wiphy work can only run under wiphy lock
protection, a race condition happens in below scenario:
1. a management frame is queued for transmission.
2. ath12k_mac_op_flush() gets called to flush pending frames associated
with the hardware (i.e, vif being NULL). Then in ath12k_mac_flush()
the process waits for the transmission done.
3. Since wiphy lock has been taken by the flush process, the transmission
work item has no chance to run, hence the dead lock.
>From user view, this dead lock results in below issue:
wlp8s0: authenticate with xxxxxx (local address=xxxxxx)
wlp8s0: send auth to xxxxxx (try 1/3)
wlp8s0: authenticate with xxxxxx (local address=xxxxxx)
wlp8s0: send auth to xxxxxx (try 1/3)
wlp8s0: authenticated
wlp8s0: associate with xxxxxx (try 1/3)
wlp8s0: aborting association with xxxxxx by local choice (Reason: 3=DEAUTH_LEAVING)
ath12k_pci 0000:08:00.0: failed to flush mgmt transmit queue, mgmt pkts pending 1
The dead lock can be avoided by invoking wiphy_work_flush() to proactively
run the queued work item. Note actually it is already present in
ath12k_mac_op_flush(), however it does not protect the case where vif
being NULL. Hence move it ahead to cover this case as well.
Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c5-00302-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.115823.3 |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: cfg80211: Add missing lock in cfg80211_check_and_end_cac()
Callers of wdev_chandef() must hold the wiphy mutex.
But the worker cfg80211_propagate_cac_done_wk() never takes the lock.
Which triggers the warning below with the mesh_peer_connected_dfs
test from hostapd and not (yet) released mac80211 code changes:
WARNING: CPU: 0 PID: 495 at net/wireless/chan.c:1552 wdev_chandef+0x60/0x165
Modules linked in:
CPU: 0 UID: 0 PID: 495 Comm: kworker/u4:2 Not tainted 6.14.0-rc5-wt-g03960e6f9d47 #33 13c287eeabfe1efea01c0bcc863723ab082e17cf
Workqueue: cfg80211 cfg80211_propagate_cac_done_wk
Stack:
00000000 00000001 ffffff00 6093267c
00000000 6002ec30 6d577c50 60037608
00000000 67e8d108 6063717b 00000000
Call Trace:
[<6002ec30>] ? _printk+0x0/0x98
[<6003c2b3>] show_stack+0x10e/0x11a
[<6002ec30>] ? _printk+0x0/0x98
[<60037608>] dump_stack_lvl+0x71/0xb8
[<6063717b>] ? wdev_chandef+0x60/0x165
[<6003766d>] dump_stack+0x1e/0x20
[<6005d1b7>] __warn+0x101/0x20f
[<6005d3a8>] warn_slowpath_fmt+0xe3/0x15d
[<600b0c5c>] ? mark_lock.part.0+0x0/0x4ec
[<60751191>] ? __this_cpu_preempt_check+0x0/0x16
[<600b11a2>] ? mark_held_locks+0x5a/0x6e
[<6005d2c5>] ? warn_slowpath_fmt+0x0/0x15d
[<60052e53>] ? unblock_signals+0x3a/0xe7
[<60052f2d>] ? um_set_signals+0x2d/0x43
[<60751191>] ? __this_cpu_preempt_check+0x0/0x16
[<607508b2>] ? lock_is_held_type+0x207/0x21f
[<6063717b>] wdev_chandef+0x60/0x165
[<605f89b4>] regulatory_propagate_dfs_state+0x247/0x43f
[<60052f00>] ? um_set_signals+0x0/0x43
[<605e6bfd>] cfg80211_propagate_cac_done_wk+0x3a/0x4a
[<6007e460>] process_scheduled_works+0x3bc/0x60e
[<6007d0ec>] ? move_linked_works+0x4d/0x81
[<6007d120>] ? assign_work+0x0/0xaa
[<6007f81f>] worker_thread+0x220/0x2dc
[<600786ef>] ? set_pf_worker+0x0/0x57
[<60087c96>] ? to_kthread+0x0/0x43
[<6008ab3c>] kthread+0x2d3/0x2e2
[<6007f5ff>] ? worker_thread+0x0/0x2dc
[<6006c05b>] ? calculate_sigpending+0x0/0x56
[<6003b37d>] new_thread_handler+0x4a/0x64
irq event stamp: 614611
hardirqs last enabled at (614621): [<00000000600bc96b>] __up_console_sem+0x82/0xaf
hardirqs last disabled at (614630): [<00000000600bc92c>] __up_console_sem+0x43/0xaf
softirqs last enabled at (614268): [<00000000606c55c6>] __ieee80211_wake_queue+0x933/0x985
softirqs last disabled at (614266): [<00000000606c52d6>] __ieee80211_wake_queue+0x643/0x985 |
| In the Linux kernel, the following vulnerability has been resolved:
parisc: Fix locking in pdc_iodc_print() firmware call
Utilize pdc_lock spinlock to protect parallel modifications of the
iodc_dbuf[] buffer, check length to prevent buffer overflow of
iodc_dbuf[], drop the iodc_retbuf[] buffer and fix some wrong
indentings. |
| Multiple Cisco products are affected by a vulnerability in the Snort 3 Detection Engine that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart, resulting in an interruption of packet inspection.
This vulnerability is due to an error in the binder module initialization logic of the Snort Detection Engine. An attacker could exploit this vulnerability by sending certain packets through an established connection that is parsed by Snort 3. A successful exploit could allow the attacker to cause a DoS condition when the Snort 3 Detection Engine restarts unexpectedly. |
| ZwiiCMS versions prior to 13.7.00 contain a denial-of-service vulnerability in multiple administrative endpoints due to improper authorization checks combined with flawed resource state management. When an authenticated low-privilege user requests an administrative page, the application returns "404 Not Found" as expected, but incorrectly acquires and associates a temporary lock on the targeted resource with the attacker session prior to authorization. This lock prevents other users, including administrators, from accessing the affected functionality until the attacker navigates away or the session is terminated. |
| Improper Locking vulnerability (CWE-667) in Gallagher Morpho integration allows a privileged operator to cause a limited denial-of-service in the Command Centre Server.
This issue affects Command Centre Server:
9.40 prior to vEL9.40.1976(MR1), 9.30 prior to vEL9.30.3382 (MR4), 9.20 prior to vEL9.20.3783 (MR6), 9.10 prior to vEL9.10.4647 (MR9), all versions of 9.00 and prior. |
| 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--- |
| In the Linux kernel, the following vulnerability has been resolved:
ublk: fix deadlock when reading partition table
When one process(such as udev) opens ublk block device (e.g., to read
the partition table via bdev_open()), a deadlock[1] can occur:
1. bdev_open() grabs disk->open_mutex
2. The process issues read I/O to ublk backend to read partition table
3. In __ublk_complete_rq(), blk_update_request() or blk_mq_end_request()
runs bio->bi_end_io() callbacks
4. If this triggers fput() on file descriptor of ublk block device, the
work may be deferred to current task's task work (see fput() implementation)
5. This eventually calls blkdev_release() from the same context
6. blkdev_release() tries to grab disk->open_mutex again
7. Deadlock: same task waiting for a mutex it already holds
The fix is to run blk_update_request() and blk_mq_end_request() with bottom
halves disabled. This forces blkdev_release() to run in kernel work-queue
context instead of current task work context, and allows ublk server to make
forward progress, and avoids the deadlock.
[axboe: rewrite comment in ublk] |
| Improper locking for some Intel(R) TDX Module firmware before version 1.5.13 may allow a privileged user to potentially enable escalation of privilege via local access. |
| Under undisclosed traffic conditions along with conditions beyond the attacker's control, hardware systems with a High-Speed Bridge (HSB) may experience a lockup of the HSB.
Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated. |
| In the Linux kernel, the following vulnerability has been resolved:
sched_ext: Fix possible deadlock in the deferred_irq_workfn()
For PREEMPT_RT=y kernels, the deferred_irq_workfn() is executed in
the per-cpu irq_work/* task context and not disable-irq, if the rq
returned by container_of() is current CPU's rq, the following scenarios
may occur:
lock(&rq->__lock);
<Interrupt>
lock(&rq->__lock);
This commit use IRQ_WORK_INIT_HARD() to replace init_irq_work() to
initialize rq->scx.deferred_irq_work, make the deferred_irq_workfn()
is always invoked in hard-irq context. |