| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
misc: fastrpc: fix possible map leak in fastrpc_put_args
copy_to_user() failure would cause an early return without cleaning up
the fdlist, which has been updated by the DSP. This could lead to map
leak. Fix this by redirecting to a cleanup path on failure, ensuring
that all mapped buffers are properly released before returning. |
| In the Linux kernel, the following vulnerability has been resolved:
PCI/AER: Avoid NULL pointer dereference in aer_ratelimit()
When platform firmware supplies error information to the OS, e.g., via the
ACPI APEI GHES mechanism, it may identify an error source device that
doesn't advertise an AER Capability and therefore dev->aer_info, which
contains AER stats and ratelimiting data, is NULL.
pci_dev_aer_stats_incr() already checks dev->aer_info for NULL, but
aer_ratelimit() did not, leading to NULL pointer dereferences like this one
from the URL below:
{1}[Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 0
{1}[Hardware Error]: event severity: corrected
{1}[Hardware Error]: device_id: 0000:00:00.0
{1}[Hardware Error]: vendor_id: 0x8086, device_id: 0x2020
{1}[Hardware Error]: aer_cor_status: 0x00001000, aer_cor_mask: 0x00002000
BUG: kernel NULL pointer dereference, address: 0000000000000264
RIP: 0010:___ratelimit+0xc/0x1b0
pci_print_aer+0x141/0x360
aer_recover_work_func+0xb5/0x130
[8086:2020] is an Intel "Sky Lake-E DMI3 Registers" device that claims to
be a Root Port but does not advertise an AER Capability.
Add a NULL check in aer_ratelimit() to avoid the NULL pointer dereference.
Note that this also prevents ratelimiting these events from GHES.
[bhelgaas: add crash details to commit log] |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: rtw89: free unused skb to prevent memory leak
This avoid potential memory leak under power saving mode. |
| In the Linux kernel, the following vulnerability has been resolved:
perf/x86/intel: Fix IA32_PMC_x_CFG_B MSRs access error
When running perf_fuzzer on PTL, sometimes the below "unchecked MSR
access error" is seen when accessing IA32_PMC_x_CFG_B MSRs.
[ 55.611268] unchecked MSR access error: WRMSR to 0x1986 (tried to write 0x0000000200000001) at rIP: 0xffffffffac564b28 (native_write_msr+0x8/0x30)
[ 55.611280] Call Trace:
[ 55.611282] <TASK>
[ 55.611284] ? intel_pmu_config_acr+0x87/0x160
[ 55.611289] intel_pmu_enable_acr+0x6d/0x80
[ 55.611291] intel_pmu_enable_event+0xce/0x460
[ 55.611293] x86_pmu_start+0x78/0xb0
[ 55.611297] x86_pmu_enable+0x218/0x3a0
[ 55.611300] ? x86_pmu_enable+0x121/0x3a0
[ 55.611302] perf_pmu_enable+0x40/0x50
[ 55.611307] ctx_resched+0x19d/0x220
[ 55.611309] __perf_install_in_context+0x284/0x2f0
[ 55.611311] ? __pfx_remote_function+0x10/0x10
[ 55.611314] remote_function+0x52/0x70
[ 55.611317] ? __pfx_remote_function+0x10/0x10
[ 55.611319] generic_exec_single+0x84/0x150
[ 55.611323] smp_call_function_single+0xc5/0x1a0
[ 55.611326] ? __pfx_remote_function+0x10/0x10
[ 55.611329] perf_install_in_context+0xd1/0x1e0
[ 55.611331] ? __pfx___perf_install_in_context+0x10/0x10
[ 55.611333] __do_sys_perf_event_open+0xa76/0x1040
[ 55.611336] __x64_sys_perf_event_open+0x26/0x30
[ 55.611337] x64_sys_call+0x1d8e/0x20c0
[ 55.611339] do_syscall_64+0x4f/0x120
[ 55.611343] entry_SYSCALL_64_after_hwframe+0x76/0x7e
On PTL, GP counter 0 and 1 doesn't support auto counter reload feature,
thus it would trigger a #GP when trying to write 1 on bit 0 of CFG_B MSR
which requires to enable auto counter reload on GP counter 0.
The root cause of causing this issue is the check for auto counter
reload (ACR) counter mask from user space is incorrect in
intel_pmu_acr_late_setup() helper. It leads to an invalid ACR counter
mask from user space could be set into hw.config1 and then written into
CFG_B MSRs and trigger the MSR access warning.
e.g., User may create a perf event with ACR counter mask (config2=0xcb),
and there is only 1 event created, so "cpuc->n_events" is 1.
The correct check condition should be "i + idx >= cpuc->n_events"
instead of "i + idx > cpuc->n_events" (it looks a typo). Otherwise,
the counter mask would traverse twice and an invalid "cpuc->assign[1]"
bit (bit 0) is set into hw.config1 and cause MSR accessing error.
Besides, also check if the ACR counter mask corresponding events are
ACR events. If not, filter out these counter mask. If a event is not a
ACR event, it could be scheduled to an HW counter which doesn't support
ACR. It's invalid to add their counter index in ACR counter mask.
Furthermore, remove the WARN_ON_ONCE() since it's easily triggered as
user could set any invalid ACR counter mask and the warning message
could mislead users. |
| In the Linux kernel, the following vulnerability has been resolved:
tls: wait for pending async decryptions if tls_strp_msg_hold fails
Async decryption calls tls_strp_msg_hold to create a clone of the
input skb to hold references to the memory it uses. If we fail to
allocate that clone, proceeding with async decryption can lead to
various issues (UAF on the skb, writing into userspace memory after
the recv() call has returned).
In this case, wait for all pending decryption requests. |
| In the Linux kernel, the following vulnerability has been resolved:
ext4: avoid potential buffer over-read in parse_apply_sb_mount_options()
Unlike other strings in the ext4 superblock, we rely on tune2fs to
make sure s_mount_opts is NUL terminated. Harden
parse_apply_sb_mount_options() by treating s_mount_opts as a potential
__nonstring. |
| In the Linux kernel, the following vulnerability has been resolved:
tee: fix register_shm_helper()
In register_shm_helper(), fix incorrect error handling for a call to
iov_iter_extract_pages(). A case is missing for when
iov_iter_extract_pages() only got some pages and return a number larger
than 0, but not the requested amount.
This fixes a possible NULL pointer dereference following a bad input from
ioctl(TEE_IOC_SHM_REGISTER) where parts of the buffer isn't mapped. |
| In the Linux kernel, the following vulnerability has been resolved:
ARM: zynq: Fix refcount leak in zynq_early_slcr_init
of_find_compatible_node() returns a node pointer with refcount incremented,
we should use of_node_put() on error path.
Add missing of_node_put() to avoid refcount leak. |
| In the Linux kernel, the following vulnerability has been resolved:
sctp: Fix MAC comparison to be constant-time
To prevent timing attacks, MACs need to be compared in constant time.
Use the appropriate helper function for this. |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: usb-mixer: us16x08: validate meter packet indices
get_meter_levels_from_urb() parses the 64-byte meter packets sent by
the device and fills the per-channel arrays meter_level[],
comp_level[] and master_level[] in struct snd_us16x08_meter_store.
Currently the function derives the channel index directly from the
meter packet (MUB2(meter_urb, s) - 1) and uses it to index those
arrays without validating the range. If the packet contains a
negative or out-of-range channel number, the driver may write past
the end of these arrays.
Introduce a local channel variable and validate it before updating the
arrays. We reject negative indices, limit meter_level[] and
comp_level[] to SND_US16X08_MAX_CHANNELS, and guard master_level[]
updates with ARRAY_SIZE(master_level). |
| In the Linux kernel, the following vulnerability has been resolved:
x86/CPU/AMD: Add missing terminator for zen5_rdseed_microcode
Running x86_match_min_microcode_rev() on a Zen5 CPU trips up KASAN for an out
of bounds access. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: ath9k: hif_usb: Fix use-after-free in ath9k_hif_usb_reg_in_cb()
It is possible that skb is freed in ath9k_htc_rx_msg(), then
usb_submit_urb() fails and we try to free skb again. It causes
use-after-free bug. Moreover, if alloc_skb() fails, urb->context becomes
NULL but rx_buf is not freed and there can be a memory leak.
The patch removes unnecessary nskb and makes skb processing more clear: it
is supposed that ath9k_htc_rx_msg() either frees old skb or passes its
managing to another callback function.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Check the helper function is valid in get_helper_proto
kernel test robot reported verifier bug [1] where the helper func
pointer could be NULL due to disabled config option.
As Alexei suggested we could check on that in get_helper_proto
directly. Marking tail_call helper func with BPF_PTR_POISON,
because it is unused by design.
[1] https://lore.kernel.org/oe-lkp/202507160818.68358831-lkp@intel.com |
| In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: f_acm: Refactor bind path to use __free()
After an bind/unbind cycle, the acm->notify_req is left stale. If a
subsequent bind fails, the unified error label attempts to free this
stale request, leading to a NULL pointer dereference when accessing
ep->ops->free_request.
Refactor the error handling in the bind path to use the __free()
automatic cleanup mechanism.
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020
Call trace:
usb_ep_free_request+0x2c/0xec
gs_free_req+0x30/0x44
acm_bind+0x1b8/0x1f4
usb_add_function+0xcc/0x1f0
configfs_composite_bind+0x468/0x588
gadget_bind_driver+0x104/0x270
really_probe+0x190/0x374
__driver_probe_device+0xa0/0x12c
driver_probe_device+0x3c/0x218
__device_attach_driver+0x14c/0x188
bus_for_each_drv+0x10c/0x168
__device_attach+0xfc/0x198
device_initial_probe+0x14/0x24
bus_probe_device+0x94/0x11c
device_add+0x268/0x48c
usb_add_gadget+0x198/0x28c
dwc3_gadget_init+0x700/0x858
__dwc3_set_mode+0x3cc/0x664
process_scheduled_works+0x1d8/0x488
worker_thread+0x244/0x334
kthread+0x114/0x1bc
ret_from_fork+0x10/0x20 |
| In the Linux kernel, the following vulnerability has been resolved:
cifs: fix session state check in reconnect to avoid use-after-free issue
Don't collect exiting session in smb2_reconnect_server(), because it
will be released soon.
Note that the exiting session will stay in server->smb_ses_list until
it complete the cifs_free_ipc() and logoff() and then delete itself
from the list. |
| In the Linux kernel, the following vulnerability has been resolved:
NFSD: Define a proc_layoutcommit for the FlexFiles layout type
Avoid a crash if a pNFS client should happen to send a LAYOUTCOMMIT
operation on a FlexFiles layout. |
| ntfs3 in the Linux kernel through 6.8.0 allows a physically proximate attacker to read kernel memory by mounting a filesystem (e.g., if a Linux distribution is configured to allow unprivileged mounts of removable media) and then leveraging local access to trigger an out-of-bounds read. A length value can be larger than the amount of memory allocated. NOTE: the supplier's perspective is that there is no vulnerability when an attack requires an attacker-modified filesystem image. |
| In the Linux kernel, the following vulnerability has been resolved:
media: b2c2: Fix use-after-free causing by irq_check_work in flexcop_pci_remove
The original code uses cancel_delayed_work() in flexcop_pci_remove(), which
does not guarantee that the delayed work item irq_check_work has fully
completed if it was already running. This leads to use-after-free scenarios
where flexcop_pci_remove() may free the flexcop_device while irq_check_work
is still active and attempts to dereference the device.
A typical race condition is illustrated below:
CPU 0 (remove) | CPU 1 (delayed work callback)
flexcop_pci_remove() | flexcop_pci_irq_check_work()
cancel_delayed_work() |
flexcop_device_kfree(fc_pci->fc_dev) |
| fc = fc_pci->fc_dev; // UAF
This is confirmed by a KASAN report:
==================================================================
BUG: KASAN: slab-use-after-free in __run_timer_base.part.0+0x7d7/0x8c0
Write of size 8 at addr ffff8880093aa8c8 by task bash/135
...
Call Trace:
<IRQ>
dump_stack_lvl+0x55/0x70
print_report+0xcf/0x610
? __run_timer_base.part.0+0x7d7/0x8c0
kasan_report+0xb8/0xf0
? __run_timer_base.part.0+0x7d7/0x8c0
__run_timer_base.part.0+0x7d7/0x8c0
? __pfx___run_timer_base.part.0+0x10/0x10
? __pfx_read_tsc+0x10/0x10
? ktime_get+0x60/0x140
? lapic_next_event+0x11/0x20
? clockevents_program_event+0x1d4/0x2a0
run_timer_softirq+0xd1/0x190
handle_softirqs+0x16a/0x550
irq_exit_rcu+0xaf/0xe0
sysvec_apic_timer_interrupt+0x70/0x80
</IRQ>
...
Allocated by task 1:
kasan_save_stack+0x24/0x50
kasan_save_track+0x14/0x30
__kasan_kmalloc+0x7f/0x90
__kmalloc_noprof+0x1be/0x460
flexcop_device_kmalloc+0x54/0xe0
flexcop_pci_probe+0x1f/0x9d0
local_pci_probe+0xdc/0x190
pci_device_probe+0x2fe/0x470
really_probe+0x1ca/0x5c0
__driver_probe_device+0x248/0x310
driver_probe_device+0x44/0x120
__driver_attach+0xd2/0x310
bus_for_each_dev+0xed/0x170
bus_add_driver+0x208/0x500
driver_register+0x132/0x460
do_one_initcall+0x89/0x300
kernel_init_freeable+0x40d/0x720
kernel_init+0x1a/0x150
ret_from_fork+0x10c/0x1a0
ret_from_fork_asm+0x1a/0x30
Freed by task 135:
kasan_save_stack+0x24/0x50
kasan_save_track+0x14/0x30
kasan_save_free_info+0x3a/0x60
__kasan_slab_free+0x3f/0x50
kfree+0x137/0x370
flexcop_device_kfree+0x32/0x50
pci_device_remove+0xa6/0x1d0
device_release_driver_internal+0xf8/0x210
pci_stop_bus_device+0x105/0x150
pci_stop_and_remove_bus_device_locked+0x15/0x30
remove_store+0xcc/0xe0
kernfs_fop_write_iter+0x2c3/0x440
vfs_write+0x871/0xd70
ksys_write+0xee/0x1c0
do_syscall_64+0xac/0x280
entry_SYSCALL_64_after_hwframe+0x77/0x7f
...
Replace cancel_delayed_work() with cancel_delayed_work_sync() to ensure
that the delayed work item is properly canceled and any executing delayed
work has finished before the device memory is deallocated.
This bug was initially identified through static analysis. To reproduce
and test it, I simulated the B2C2 FlexCop PCI device in QEMU and introduced
artificial delays within the flexcop_pci_irq_check_work() function to
increase the likelihood of triggering the bug. |
| In the Linux kernel, the following vulnerability has been resolved:
s390/fpu: Fix false-positive kmsan report in fpu_vstl()
A false-positive kmsan report is detected when running ping command.
An inline assembly instruction 'vstl' can write varied amount of bytes
depending on value of 'index' argument. If 'index' > 0, 'vstl' writes
at least 2 bytes.
clang generates kmsan write helper call depending on inline assembly
constraints. Constraints are evaluated compile-time, but value of
'index' argument is known only at runtime.
clang currently generates call to __msan_instrument_asm_store with 1 byte
as size. Manually call kmsan function to indicate correct amount of bytes
written and fix false-positive report.
This change fixes following kmsan reports:
[ 36.563119] =====================================================
[ 36.563594] BUG: KMSAN: uninit-value in virtqueue_add+0x35c6/0x7c70
[ 36.563852] virtqueue_add+0x35c6/0x7c70
[ 36.564016] virtqueue_add_outbuf+0xa0/0xb0
[ 36.564266] start_xmit+0x288c/0x4a20
[ 36.564460] dev_hard_start_xmit+0x302/0x900
[ 36.564649] sch_direct_xmit+0x340/0xea0
[ 36.564894] __dev_queue_xmit+0x2e94/0x59b0
[ 36.565058] neigh_resolve_output+0x936/0xb40
[ 36.565278] __neigh_update+0x2f66/0x3a60
[ 36.565499] neigh_update+0x52/0x60
[ 36.565683] arp_process+0x1588/0x2de0
[ 36.565916] NF_HOOK+0x1da/0x240
[ 36.566087] arp_rcv+0x3e4/0x6e0
[ 36.566306] __netif_receive_skb_list_core+0x1374/0x15a0
[ 36.566527] netif_receive_skb_list_internal+0x1116/0x17d0
[ 36.566710] napi_complete_done+0x376/0x740
[ 36.566918] virtnet_poll+0x1bae/0x2910
[ 36.567130] __napi_poll+0xf4/0x830
[ 36.567294] net_rx_action+0x97c/0x1ed0
[ 36.567556] handle_softirqs+0x306/0xe10
[ 36.567731] irq_exit_rcu+0x14c/0x2e0
[ 36.567910] do_io_irq+0xd4/0x120
[ 36.568139] io_int_handler+0xc2/0xe8
[ 36.568299] arch_cpu_idle+0xb0/0xc0
[ 36.568540] arch_cpu_idle+0x76/0xc0
[ 36.568726] default_idle_call+0x40/0x70
[ 36.568953] do_idle+0x1d6/0x390
[ 36.569486] cpu_startup_entry+0x9a/0xb0
[ 36.569745] rest_init+0x1ea/0x290
[ 36.570029] start_kernel+0x95e/0xb90
[ 36.570348] startup_continue+0x2e/0x40
[ 36.570703]
[ 36.570798] Uninit was created at:
[ 36.571002] kmem_cache_alloc_node_noprof+0x9e8/0x10e0
[ 36.571261] kmalloc_reserve+0x12a/0x470
[ 36.571553] __alloc_skb+0x310/0x860
[ 36.571844] __ip_append_data+0x483e/0x6a30
[ 36.572170] ip_append_data+0x11c/0x1e0
[ 36.572477] raw_sendmsg+0x1c8c/0x2180
[ 36.572818] inet_sendmsg+0xe6/0x190
[ 36.573142] __sys_sendto+0x55e/0x8e0
[ 36.573392] __s390x_sys_socketcall+0x19ae/0x2ba0
[ 36.573571] __do_syscall+0x12e/0x240
[ 36.573823] system_call+0x6e/0x90
[ 36.573976]
[ 36.574017] Byte 35 of 98 is uninitialized
[ 36.574082] Memory access of size 98 starts at 0000000007aa0012
[ 36.574218]
[ 36.574325] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G B N 6.17.0-dirty #16 NONE
[ 36.574541] Tainted: [B]=BAD_PAGE, [N]=TEST
[ 36.574617] Hardware name: IBM 3931 A01 703 (KVM/Linux)
[ 36.574755] =====================================================
[ 63.532541] =====================================================
[ 63.533639] BUG: KMSAN: uninit-value in virtqueue_add+0x35c6/0x7c70
[ 63.533989] virtqueue_add+0x35c6/0x7c70
[ 63.534940] virtqueue_add_outbuf+0xa0/0xb0
[ 63.535861] start_xmit+0x288c/0x4a20
[ 63.536708] dev_hard_start_xmit+0x302/0x900
[ 63.537020] sch_direct_xmit+0x340/0xea0
[ 63.537997] __dev_queue_xmit+0x2e94/0x59b0
[ 63.538819] neigh_resolve_output+0x936/0xb40
[ 63.539793] ip_finish_output2+0x1ee2/0x2200
[ 63.540784] __ip_finish_output+0x272/0x7a0
[ 63.541765] ip_finish_output+0x4e/0x5e0
[ 63.542791] ip_output+0x166/0x410
[ 63.543771] ip_push_pending_frames+0x1a2/0x470
[ 63.544753] raw_sendmsg+0x1f06/0x2180
[ 63.545033] inet_sendmsg+0xe6/0x190
[ 63.546006] __sys_sendto+0x55e/0x8e0
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
blk-cgroup: fix possible deadlock while configuring policy
Following deadlock can be triggered easily by lockdep:
WARNING: possible circular locking dependency detected
6.17.0-rc3-00124-ga12c2658ced0 #1665 Not tainted
------------------------------------------------------
check/1334 is trying to acquire lock:
ff1100011d9d0678 (&q->sysfs_lock){+.+.}-{4:4}, at: blk_unregister_queue+0x53/0x180
but task is already holding lock:
ff1100011d9d00e0 (&q->q_usage_counter(queue)#3){++++}-{0:0}, at: del_gendisk+0xba/0x110
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&q->q_usage_counter(queue)#3){++++}-{0:0}:
blk_queue_enter+0x40b/0x470
blkg_conf_prep+0x7b/0x3c0
tg_set_limit+0x10a/0x3e0
cgroup_file_write+0xc6/0x420
kernfs_fop_write_iter+0x189/0x280
vfs_write+0x256/0x490
ksys_write+0x83/0x190
__x64_sys_write+0x21/0x30
x64_sys_call+0x4608/0x4630
do_syscall_64+0xdb/0x6b0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
-> #1 (&q->rq_qos_mutex){+.+.}-{4:4}:
__mutex_lock+0xd8/0xf50
mutex_lock_nested+0x2b/0x40
wbt_init+0x17e/0x280
wbt_enable_default+0xe9/0x140
blk_register_queue+0x1da/0x2e0
__add_disk+0x38c/0x5d0
add_disk_fwnode+0x89/0x250
device_add_disk+0x18/0x30
virtblk_probe+0x13a3/0x1800
virtio_dev_probe+0x389/0x610
really_probe+0x136/0x620
__driver_probe_device+0xb3/0x230
driver_probe_device+0x2f/0xe0
__driver_attach+0x158/0x250
bus_for_each_dev+0xa9/0x130
driver_attach+0x26/0x40
bus_add_driver+0x178/0x3d0
driver_register+0x7d/0x1c0
__register_virtio_driver+0x2c/0x60
virtio_blk_init+0x6f/0xe0
do_one_initcall+0x94/0x540
kernel_init_freeable+0x56a/0x7b0
kernel_init+0x2b/0x270
ret_from_fork+0x268/0x4c0
ret_from_fork_asm+0x1a/0x30
-> #0 (&q->sysfs_lock){+.+.}-{4:4}:
__lock_acquire+0x1835/0x2940
lock_acquire+0xf9/0x450
__mutex_lock+0xd8/0xf50
mutex_lock_nested+0x2b/0x40
blk_unregister_queue+0x53/0x180
__del_gendisk+0x226/0x690
del_gendisk+0xba/0x110
sd_remove+0x49/0xb0 [sd_mod]
device_remove+0x87/0xb0
device_release_driver_internal+0x11e/0x230
device_release_driver+0x1a/0x30
bus_remove_device+0x14d/0x220
device_del+0x1e1/0x5a0
__scsi_remove_device+0x1ff/0x2f0
scsi_remove_device+0x37/0x60
sdev_store_delete+0x77/0x100
dev_attr_store+0x1f/0x40
sysfs_kf_write+0x65/0x90
kernfs_fop_write_iter+0x189/0x280
vfs_write+0x256/0x490
ksys_write+0x83/0x190
__x64_sys_write+0x21/0x30
x64_sys_call+0x4608/0x4630
do_syscall_64+0xdb/0x6b0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
other info that might help us debug this:
Chain exists of:
&q->sysfs_lock --> &q->rq_qos_mutex --> &q->q_usage_counter(queue)#3
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&q->q_usage_counter(queue)#3);
lock(&q->rq_qos_mutex);
lock(&q->q_usage_counter(queue)#3);
lock(&q->sysfs_lock);
Root cause is that queue_usage_counter is grabbed with rq_qos_mutex
held in blkg_conf_prep(), while queue should be freezed before
rq_qos_mutex from other context.
The blk_queue_enter() from blkg_conf_prep() is used to protect against
policy deactivation, which is already protected with blkcg_mutex, hence
convert blk_queue_enter() to blkcg_mutex to fix this problem. Meanwhile,
consider that blkcg_mutex is held after queue is freezed from policy
deactivation, also convert blkg_alloc() to use GFP_NOIO. |