| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
media: dvb-frontends: fix leak of memory fw |
| In the Linux kernel, the following vulnerability has been resolved:
RDMA/hns: fix memory leak in hns_roce_alloc_mr()
When hns_roce_mr_enable() failed in hns_roce_alloc_mr(), mr_key is not
released. Compiled test only. |
| In the Linux kernel, the following vulnerability has been resolved:
net: fix UAF issue in nfqnl_nf_hook_drop() when ops_init() failed
When the ops_init() interface is invoked to initialize the net, but
ops->init() fails, data is released. However, the ptr pointer in
net->gen is invalid. In this case, when nfqnl_nf_hook_drop() is invoked
to release the net, invalid address access occurs.
The process is as follows:
setup_net()
ops_init()
data = kzalloc(...) ---> alloc "data"
net_assign_generic() ---> assign "date" to ptr in net->gen
...
ops->init() ---> failed
...
kfree(data); ---> ptr in net->gen is invalid
...
ops_exit_list()
...
nfqnl_nf_hook_drop()
*q = nfnl_queue_pernet(net) ---> q is invalid
The following is the Call Trace information:
BUG: KASAN: use-after-free in nfqnl_nf_hook_drop+0x264/0x280
Read of size 8 at addr ffff88810396b240 by task ip/15855
Call Trace:
<TASK>
dump_stack_lvl+0x8e/0xd1
print_report+0x155/0x454
kasan_report+0xba/0x1f0
nfqnl_nf_hook_drop+0x264/0x280
nf_queue_nf_hook_drop+0x8b/0x1b0
__nf_unregister_net_hook+0x1ae/0x5a0
nf_unregister_net_hooks+0xde/0x130
ops_exit_list+0xb0/0x170
setup_net+0x7ac/0xbd0
copy_net_ns+0x2e6/0x6b0
create_new_namespaces+0x382/0xa50
unshare_nsproxy_namespaces+0xa6/0x1c0
ksys_unshare+0x3a4/0x7e0
__x64_sys_unshare+0x2d/0x40
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
</TASK>
Allocated by task 15855:
kasan_save_stack+0x1e/0x40
kasan_set_track+0x21/0x30
__kasan_kmalloc+0xa1/0xb0
__kmalloc+0x49/0xb0
ops_init+0xe7/0x410
setup_net+0x5aa/0xbd0
copy_net_ns+0x2e6/0x6b0
create_new_namespaces+0x382/0xa50
unshare_nsproxy_namespaces+0xa6/0x1c0
ksys_unshare+0x3a4/0x7e0
__x64_sys_unshare+0x2d/0x40
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
Freed by task 15855:
kasan_save_stack+0x1e/0x40
kasan_set_track+0x21/0x30
kasan_save_free_info+0x2a/0x40
____kasan_slab_free+0x155/0x1b0
slab_free_freelist_hook+0x11b/0x220
__kmem_cache_free+0xa4/0x360
ops_init+0xb9/0x410
setup_net+0x5aa/0xbd0
copy_net_ns+0x2e6/0x6b0
create_new_namespaces+0x382/0xa50
unshare_nsproxy_namespaces+0xa6/0x1c0
ksys_unshare+0x3a4/0x7e0
__x64_sys_unshare+0x2d/0x40
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0 |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: ipw2200: fix memory leak in ipw_wdev_init()
In the error path of ipw_wdev_init(), exception value is returned, and
the memory applied for in the function is not released. Also the memory
is not released in ipw_pci_probe(). As a result, memory leakage occurs.
So memory release needs to be added to the error path of ipw_wdev_init(). |
| In the Linux kernel, the following vulnerability has been resolved:
ppp: associate skb with a device at tx
Syzkaller triggered flow dissector warning with the following:
r0 = openat$ppp(0xffffffffffffff9c, &(0x7f0000000000), 0xc0802, 0x0)
ioctl$PPPIOCNEWUNIT(r0, 0xc004743e, &(0x7f00000000c0))
ioctl$PPPIOCSACTIVE(r0, 0x40107446, &(0x7f0000000240)={0x2, &(0x7f0000000180)=[{0x20, 0x0, 0x0, 0xfffff034}, {0x6}]})
pwritev(r0, &(0x7f0000000040)=[{&(0x7f0000000140)='\x00!', 0x2}], 0x1, 0x0, 0x0)
[ 9.485814] WARNING: CPU: 3 PID: 329 at net/core/flow_dissector.c:1016 __skb_flow_dissect+0x1ee0/0x1fa0
[ 9.485929] skb_get_poff+0x53/0xa0
[ 9.485937] bpf_skb_get_pay_offset+0xe/0x20
[ 9.485944] ? ppp_send_frame+0xc2/0x5b0
[ 9.485949] ? _raw_spin_unlock_irqrestore+0x40/0x60
[ 9.485958] ? __ppp_xmit_process+0x7a/0xe0
[ 9.485968] ? ppp_xmit_process+0x5b/0xb0
[ 9.485974] ? ppp_write+0x12a/0x190
[ 9.485981] ? do_iter_write+0x18e/0x2d0
[ 9.485987] ? __import_iovec+0x30/0x130
[ 9.485997] ? do_pwritev+0x1b6/0x240
[ 9.486016] ? trace_hardirqs_on+0x47/0x50
[ 9.486023] ? __x64_sys_pwritev+0x24/0x30
[ 9.486026] ? do_syscall_64+0x3d/0x80
[ 9.486031] ? entry_SYSCALL_64_after_hwframe+0x63/0xcd
Flow dissector tries to find skb net namespace either via device
or via socket. Neigher is set in ppp_send_frame, so let's manually
use ppp->dev. |
| In the Linux kernel, the following vulnerability has been resolved:
ext4: fix bug_on in __es_tree_search caused by bad quota inode
We got a issue as fllows:
==================================================================
kernel BUG at fs/ext4/extents_status.c:202!
invalid opcode: 0000 [#1] PREEMPT SMP
CPU: 1 PID: 810 Comm: mount Not tainted 6.1.0-rc1-next-g9631525255e3 #352
RIP: 0010:__es_tree_search.isra.0+0xb8/0xe0
RSP: 0018:ffffc90001227900 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 0000000077512a0f RCX: 0000000000000000
RDX: 0000000000000002 RSI: 0000000000002a10 RDI: ffff8881004cd0c8
RBP: ffff888177512ac8 R08: 47ffffffffffffff R09: 0000000000000001
R10: 0000000000000001 R11: 00000000000679af R12: 0000000000002a10
R13: ffff888177512d88 R14: 0000000077512a10 R15: 0000000000000000
FS: 00007f4bd76dbc40(0000)GS:ffff88842fd00000(0000)knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005653bf993cf8 CR3: 000000017bfdf000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
ext4_es_cache_extent+0xe2/0x210
ext4_cache_extents+0xd2/0x110
ext4_find_extent+0x5d5/0x8c0
ext4_ext_map_blocks+0x9c/0x1d30
ext4_map_blocks+0x431/0xa50
ext4_getblk+0x82/0x340
ext4_bread+0x14/0x110
ext4_quota_read+0xf0/0x180
v2_read_header+0x24/0x90
v2_check_quota_file+0x2f/0xa0
dquot_load_quota_sb+0x26c/0x760
dquot_load_quota_inode+0xa5/0x190
ext4_enable_quotas+0x14c/0x300
__ext4_fill_super+0x31cc/0x32c0
ext4_fill_super+0x115/0x2d0
get_tree_bdev+0x1d2/0x360
ext4_get_tree+0x19/0x30
vfs_get_tree+0x26/0xe0
path_mount+0x81d/0xfc0
do_mount+0x8d/0xc0
__x64_sys_mount+0xc0/0x160
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
</TASK>
==================================================================
Above issue may happen as follows:
-------------------------------------
ext4_fill_super
ext4_orphan_cleanup
ext4_enable_quotas
ext4_quota_enable
ext4_iget --> get error inode <5>
ext4_ext_check_inode --> Wrong imode makes it escape inspection
make_bad_inode(inode) --> EXT4_BOOT_LOADER_INO set imode
dquot_load_quota_inode
vfs_setup_quota_inode --> check pass
dquot_load_quota_sb
v2_check_quota_file
v2_read_header
ext4_quota_read
ext4_bread
ext4_getblk
ext4_map_blocks
ext4_ext_map_blocks
ext4_find_extent
ext4_cache_extents
ext4_es_cache_extent
__es_tree_search.isra.0
ext4_es_end --> Wrong extents trigger BUG_ON
In the above issue, s_usr_quota_inum is set to 5, but inode<5> contains
incorrect imode and disordered extents. Because 5 is EXT4_BOOT_LOADER_INO,
the ext4_ext_check_inode check in the ext4_iget function can be bypassed,
finally, the extents that are not checked trigger the BUG_ON in the
__es_tree_search function. To solve this issue, check whether the inode is
bad_inode in vfs_setup_quota_inode(). |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix panic due to wrong pageattr of im->image
In the scenario where livepatch and kretfunc coexist, the pageattr of
im->image is rox after arch_prepare_bpf_trampoline in
bpf_trampoline_update, and then modify_fentry or register_fentry returns
-EAGAIN from bpf_tramp_ftrace_ops_func, the BPF_TRAMP_F_ORIG_STACK flag
will be configured, and arch_prepare_bpf_trampoline will be re-executed.
At this time, because the pageattr of im->image is rox,
arch_prepare_bpf_trampoline will read and write im->image, which causes
a fault. as follows:
insmod livepatch-sample.ko # samples/livepatch/livepatch-sample.c
bpftrace -e 'kretfunc:cmdline_proc_show {}'
BUG: unable to handle page fault for address: ffffffffa0206000
PGD 322d067 P4D 322d067 PUD 322e063 PMD 1297e067 PTE d428061
Oops: 0003 [#1] PREEMPT SMP PTI
CPU: 2 PID: 270 Comm: bpftrace Tainted: G E K 6.1.0 #5
RIP: 0010:arch_prepare_bpf_trampoline+0xed/0x8c0
RSP: 0018:ffffc90001083ad8 EFLAGS: 00010202
RAX: ffffffffa0206000 RBX: 0000000000000020 RCX: 0000000000000000
RDX: ffffffffa0206001 RSI: ffffffffa0206000 RDI: 0000000000000030
RBP: ffffc90001083b70 R08: 0000000000000066 R09: ffff88800f51b400
R10: 000000002e72c6e5 R11: 00000000d0a15080 R12: ffff8880110a68c8
R13: 0000000000000000 R14: ffff88800f51b400 R15: ffffffff814fec10
FS: 00007f87bc0dc780(0000) GS:ffff88803e600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffa0206000 CR3: 0000000010b70000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
bpf_trampoline_update+0x25a/0x6b0
__bpf_trampoline_link_prog+0x101/0x240
bpf_trampoline_link_prog+0x2d/0x50
bpf_tracing_prog_attach+0x24c/0x530
bpf_raw_tp_link_attach+0x73/0x1d0
__sys_bpf+0x100e/0x2570
__x64_sys_bpf+0x1c/0x30
do_syscall_64+0x5b/0x80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
With this patch, when modify_fentry or register_fentry returns -EAGAIN
from bpf_tramp_ftrace_ops_func, the pageattr of im->image will be reset
to nx+rw. |
| In the Linux kernel, the following vulnerability has been resolved:
mmc: atmel-mci: fix return value check of mmc_add_host()
mmc_add_host() may return error, if we ignore its return value,
it will lead two issues:
1. The memory that allocated in mmc_alloc_host() is leaked.
2. In the remove() path, mmc_remove_host() will be called to
delete device, but it's not added yet, it will lead a kernel
crash because of null-ptr-deref in device_del().
So fix this by checking the return value and calling mmc_free_host()
in the error path. |
| In the Linux kernel, the following vulnerability has been resolved:
ethtool: eeprom: fix null-deref on genl_info in dump
The similar fix as commit 46cdedf2a0fa ("ethtool: pse-pd: fix null-deref on
genl_info in dump") is also needed for ethtool eeprom. |
| In the Linux kernel, the following vulnerability has been resolved:
ftrace: Fix recursive locking direct_mutex in ftrace_modify_direct_caller
Naveen reported recursive locking of direct_mutex with sample
ftrace-direct-modify.ko:
[ 74.762406] WARNING: possible recursive locking detected
[ 74.762887] 6.0.0-rc6+ #33 Not tainted
[ 74.763216] --------------------------------------------
[ 74.763672] event-sample-fn/1084 is trying to acquire lock:
[ 74.764152] ffffffff86c9d6b0 (direct_mutex){+.+.}-{3:3}, at: \
register_ftrace_function+0x1f/0x180
[ 74.764922]
[ 74.764922] but task is already holding lock:
[ 74.765421] ffffffff86c9d6b0 (direct_mutex){+.+.}-{3:3}, at: \
modify_ftrace_direct+0x34/0x1f0
[ 74.766142]
[ 74.766142] other info that might help us debug this:
[ 74.766701] Possible unsafe locking scenario:
[ 74.766701]
[ 74.767216] CPU0
[ 74.767437] ----
[ 74.767656] lock(direct_mutex);
[ 74.767952] lock(direct_mutex);
[ 74.768245]
[ 74.768245] *** DEADLOCK ***
[ 74.768245]
[ 74.768750] May be due to missing lock nesting notation
[ 74.768750]
[ 74.769332] 1 lock held by event-sample-fn/1084:
[ 74.769731] #0: ffffffff86c9d6b0 (direct_mutex){+.+.}-{3:3}, at: \
modify_ftrace_direct+0x34/0x1f0
[ 74.770496]
[ 74.770496] stack backtrace:
[ 74.770884] CPU: 4 PID: 1084 Comm: event-sample-fn Not tainted ...
[ 74.771498] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), ...
[ 74.772474] Call Trace:
[ 74.772696] <TASK>
[ 74.772896] dump_stack_lvl+0x44/0x5b
[ 74.773223] __lock_acquire.cold.74+0xac/0x2b7
[ 74.773616] lock_acquire+0xd2/0x310
[ 74.773936] ? register_ftrace_function+0x1f/0x180
[ 74.774357] ? lock_is_held_type+0xd8/0x130
[ 74.774744] ? my_tramp2+0x11/0x11 [ftrace_direct_modify]
[ 74.775213] __mutex_lock+0x99/0x1010
[ 74.775536] ? register_ftrace_function+0x1f/0x180
[ 74.775954] ? slab_free_freelist_hook.isra.43+0x115/0x160
[ 74.776424] ? ftrace_set_hash+0x195/0x220
[ 74.776779] ? register_ftrace_function+0x1f/0x180
[ 74.777194] ? kfree+0x3e1/0x440
[ 74.777482] ? my_tramp2+0x11/0x11 [ftrace_direct_modify]
[ 74.777941] ? __schedule+0xb40/0xb40
[ 74.778258] ? register_ftrace_function+0x1f/0x180
[ 74.778672] ? my_tramp1+0xf/0xf [ftrace_direct_modify]
[ 74.779128] register_ftrace_function+0x1f/0x180
[ 74.779527] ? ftrace_set_filter_ip+0x33/0x70
[ 74.779910] ? __schedule+0xb40/0xb40
[ 74.780231] ? my_tramp1+0xf/0xf [ftrace_direct_modify]
[ 74.780678] ? my_tramp2+0x11/0x11 [ftrace_direct_modify]
[ 74.781147] ftrace_modify_direct_caller+0x5b/0x90
[ 74.781563] ? 0xffffffffa0201000
[ 74.781859] ? my_tramp1+0xf/0xf [ftrace_direct_modify]
[ 74.782309] modify_ftrace_direct+0x1b2/0x1f0
[ 74.782690] ? __schedule+0xb40/0xb40
[ 74.783014] ? simple_thread+0x2a/0xb0 [ftrace_direct_modify]
[ 74.783508] ? __schedule+0xb40/0xb40
[ 74.783832] ? my_tramp2+0x11/0x11 [ftrace_direct_modify]
[ 74.784294] simple_thread+0x76/0xb0 [ftrace_direct_modify]
[ 74.784766] kthread+0xf5/0x120
[ 74.785052] ? kthread_complete_and_exit+0x20/0x20
[ 74.785464] ret_from_fork+0x22/0x30
[ 74.785781] </TASK>
Fix this by using register_ftrace_function_nolock in
ftrace_modify_direct_caller. |
| In the Linux kernel, the following vulnerability has been resolved:
EDAC/i10nm: fix refcount leak in pci_get_dev_wrapper()
As the comment of pci_get_domain_bus_and_slot() says, it returns
a PCI device with refcount incremented, so it doesn't need to
call an extra pci_dev_get() in pci_get_dev_wrapper(), and the PCI
device needs to be put in the error path. |
| In the Linux kernel, the following vulnerability has been resolved:
clk: ti: dra7-atl: Fix reference leak in of_dra7_atl_clk_probe
pm_runtime_get_sync() will increment pm usage counter.
Forgetting to putting operation will result in reference leak.
Add missing pm_runtime_put_sync in some error paths. |
| In the Linux kernel, the following vulnerability has been resolved:
HSI: omap_ssi: Fix refcount leak in ssi_probe
When returning or breaking early from a
for_each_available_child_of_node() loop, we need to explicitly call
of_node_put() on the child node to possibly release the node. |
| In the Linux kernel, the following vulnerability has been resolved:
mmc: core: Fix kernel panic when remove non-standard SDIO card
SDIO tuple is only allocated for standard SDIO card, especially it causes
memory corruption issues when the non-standard SDIO card has removed, which
is because the card device's reference counter does not increase for it at
sdio_init_func(), but all SDIO card device reference counter gets decreased
at sdio_release_func(). |
| In the Linux kernel, the following vulnerability has been resolved:
erofs: fix missing unmap if z_erofs_get_extent_compressedlen() fails
Otherwise, meta buffers could be leaked. |
| In the Linux kernel, the following vulnerability has been resolved:
io-wq: Fix memory leak in worker creation
If the CPU mask allocation for a node fails, then the memory allocated for
the 'io_wqe' struct of the current node doesn't get freed on the error
handling path, since it has not yet been added to the 'wqes' array.
This was spotted when fuzzing v6.1-rc1 with Syzkaller:
BUG: memory leak
unreferenced object 0xffff8880093d5000 (size 1024):
comm "syz-executor.2", pid 7701, jiffies 4295048595 (age 13.900s)
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:
[<00000000cb463369>] __kmem_cache_alloc_node+0x18e/0x720
[<00000000147a3f9c>] kmalloc_node_trace+0x2a/0x130
[<000000004e107011>] io_wq_create+0x7b9/0xdc0
[<00000000c38b2018>] io_uring_alloc_task_context+0x31e/0x59d
[<00000000867399da>] __io_uring_add_tctx_node.cold+0x19/0x1ba
[<000000007e0e7a79>] io_uring_setup.cold+0x1b80/0x1dce
[<00000000b545e9f6>] __x64_sys_io_uring_setup+0x5d/0x80
[<000000008a8a7508>] do_syscall_64+0x5d/0x90
[<000000004ac08bec>] entry_SYSCALL_64_after_hwframe+0x63/0xcd |
| In the Linux kernel, the following vulnerability has been resolved:
cpufreq: qcom-hw: Fix memory leak in qcom_cpufreq_hw_read_lut()
If "cpu_dev" fails to get opp table in qcom_cpufreq_hw_read_lut(),
the program will return, resulting in "table" resource is not released. |
| In the Linux kernel, the following vulnerability has been resolved:
PCI: Fix pci_device_is_present() for VFs by checking PF
pci_device_is_present() previously didn't work for VFs because it reads the
Vendor and Device ID, which are 0xffff for VFs, which looks like they
aren't present. Check the PF instead.
Wei Gong reported that if virtio I/O is in progress when the driver is
unbound or "0" is written to /sys/.../sriov_numvfs, the virtio I/O
operation hangs, which may result in output like this:
task:bash state:D stack: 0 pid: 1773 ppid: 1241 flags:0x00004002
Call Trace:
schedule+0x4f/0xc0
blk_mq_freeze_queue_wait+0x69/0xa0
blk_mq_freeze_queue+0x1b/0x20
blk_cleanup_queue+0x3d/0xd0
virtblk_remove+0x3c/0xb0 [virtio_blk]
virtio_dev_remove+0x4b/0x80
...
device_unregister+0x1b/0x60
unregister_virtio_device+0x18/0x30
virtio_pci_remove+0x41/0x80
pci_device_remove+0x3e/0xb0
This happened because pci_device_is_present(VF) returned "false" in
virtio_pci_remove(), so it called virtio_break_device(). The broken vq
meant that vring_interrupt() skipped the vq.callback() that would have
completed the virtio I/O operation via virtblk_done().
[bhelgaas: commit log, simplify to always use pci_physfn(), add stable tag] |
| In the Linux kernel, the following vulnerability has been resolved:
ext4: fix potential memory leak in ext4_fc_record_modified_inode()
As krealloc may return NULL, in this case 'state->fc_modified_inodes'
may not be freed by krealloc, but 'state->fc_modified_inodes' already
set NULL. Then will lead to 'state->fc_modified_inodes' memory leak. |
| In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to invalidate dcc->f2fs_issue_discard in error path
Syzbot reports a NULL pointer dereference issue as below:
__refcount_add include/linux/refcount.h:193 [inline]
__refcount_inc include/linux/refcount.h:250 [inline]
refcount_inc include/linux/refcount.h:267 [inline]
get_task_struct include/linux/sched/task.h:110 [inline]
kthread_stop+0x34/0x1c0 kernel/kthread.c:703
f2fs_stop_discard_thread+0x3c/0x5c fs/f2fs/segment.c:1638
kill_f2fs_super+0x5c/0x194 fs/f2fs/super.c:4522
deactivate_locked_super+0x70/0xe8 fs/super.c:332
deactivate_super+0xd0/0xd4 fs/super.c:363
cleanup_mnt+0x1f8/0x234 fs/namespace.c:1186
__cleanup_mnt+0x20/0x30 fs/namespace.c:1193
task_work_run+0xc4/0x14c kernel/task_work.c:177
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0x26c/0xbe0 kernel/exit.c:795
do_group_exit+0x60/0xe8 kernel/exit.c:925
__do_sys_exit_group kernel/exit.c:936 [inline]
__se_sys_exit_group kernel/exit.c:934 [inline]
__wake_up_parent+0x0/0x40 kernel/exit.c:934
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:636
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:654
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581
The root cause of this issue is in error path of f2fs_start_discard_thread(),
it missed to invalidate dcc->f2fs_issue_discard, later kthread_stop() may
access invalid pointer. |
