| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
pstore/ram: Add check for kstrdup
Add check for the return value of kstrdup() and return the error
if it fails in order to avoid NULL pointer dereference. |
| In the Linux kernel, the following vulnerability has been resolved:
dmaengine: apple-admac: Fix 'current_tx' not getting freed
In terminate_all we should queue up all submitted descriptors to be
freed. We do that for the content of the 'issued' and 'submitted' lists,
but the 'current_tx' descriptor falls through the cracks as it's
removed from the 'issued' list once it gets assigned to be the current
descriptor. Explicitly queue up freeing of the 'current_tx' descriptor
to address a memory leak that is otherwise present. |
| In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix potential corruption when moving a directory
F2FS has the same issue in ext4_rename causing crash revealed by
xfstests/generic/707.
See also commit 0813299c586b ("ext4: Fix possible corruption when moving a directory") |
| In the Linux kernel, the following vulnerability has been resolved:
usb: typec: altmodes/displayport: fix pin_assignment_show
This patch fixes negative indexing of buf array in pin_assignment_show
when get_current_pin_assignments returns 0 i.e. no compatible pin
assignments are found.
BUG: KASAN: use-after-free in pin_assignment_show+0x26c/0x33c
...
Call trace:
dump_backtrace+0x110/0x204
dump_stack_lvl+0x84/0xbc
print_report+0x358/0x974
kasan_report+0x9c/0xfc
__do_kernel_fault+0xd4/0x2d4
do_bad_area+0x48/0x168
do_tag_check_fault+0x24/0x38
do_mem_abort+0x6c/0x14c
el1_abort+0x44/0x68
el1h_64_sync_handler+0x64/0xa4
el1h_64_sync+0x78/0x7c
pin_assignment_show+0x26c/0x33c
dev_attr_show+0x50/0xc0 |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: remove BUG_ON()'s in add_new_free_space()
At add_new_free_space() we have these BUG_ON()'s that are there to deal
with any failure to add free space to the in memory free space cache.
Such failures are mostly -ENOMEM that should be very rare. However there's
no need to have these BUG_ON()'s, we can just return any error to the
caller and all callers and their upper call chain are already dealing with
errors.
So just make add_new_free_space() return any errors, while removing the
BUG_ON()'s, and returning the total amount of added free space to an
optional u64 pointer argument. |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: target: iscsit: Free cmds before session free
Commands from recovery entries are freed after session has been closed.
That leads to use-after-free at command free or NPE with such call trace:
Time2Retain timer expired for SID: 1, cleaning up iSCSI session.
BUG: kernel NULL pointer dereference, address: 0000000000000140
RIP: 0010:sbitmap_queue_clear+0x3a/0xa0
Call Trace:
target_release_cmd_kref+0xd1/0x1f0 [target_core_mod]
transport_generic_free_cmd+0xd1/0x180 [target_core_mod]
iscsit_free_cmd+0x53/0xd0 [iscsi_target_mod]
iscsit_free_connection_recovery_entries+0x29d/0x320 [iscsi_target_mod]
iscsit_close_session+0x13a/0x140 [iscsi_target_mod]
iscsit_check_post_dataout+0x440/0x440 [iscsi_target_mod]
call_timer_fn+0x24/0x140
Move cleanup of recovery enrties to before session freeing. |
| In the Linux kernel, the following vulnerability has been resolved:
media: v4l2-core: Fix a potential resource leak in v4l2_fwnode_parse_link()
If fwnode_graph_get_remote_endpoint() fails, 'fwnode' is known to be NULL,
so fwnode_handle_put() is a no-op.
Release the reference taken from a previous fwnode_graph_get_port_parent()
call instead.
Also handle fwnode_graph_get_port_parent() failures.
In order to fix these issues, add an error handling path to the function
and the needed gotos. |
| In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to check readonly condition correctly
With below case, it can mount multi-device image w/ rw option, however
one of secondary device is set as ro, later update will cause panic, so
let's introduce f2fs_dev_is_readonly(), and check multi-devices rw status
in f2fs_remount() w/ it in order to avoid such inconsistent mount status.
mkfs.f2fs -c /dev/zram1 /dev/zram0 -f
blockdev --setro /dev/zram1
mount -t f2fs dev/zram0 /mnt/f2fs
mount: /mnt/f2fs: WARNING: source write-protected, mounted read-only.
mount -t f2fs -o remount,rw mnt/f2fs
dd if=/dev/zero of=/mnt/f2fs/file bs=1M count=8192
kernel BUG at fs/f2fs/inline.c:258!
RIP: 0010:f2fs_write_inline_data+0x23e/0x2d0 [f2fs]
Call Trace:
f2fs_write_single_data_page+0x26b/0x9f0 [f2fs]
f2fs_write_cache_pages+0x389/0xa60 [f2fs]
__f2fs_write_data_pages+0x26b/0x2d0 [f2fs]
f2fs_write_data_pages+0x2e/0x40 [f2fs]
do_writepages+0xd3/0x1b0
__writeback_single_inode+0x5b/0x420
writeback_sb_inodes+0x236/0x5a0
__writeback_inodes_wb+0x56/0xf0
wb_writeback+0x2a3/0x490
wb_do_writeback+0x2b2/0x330
wb_workfn+0x6a/0x260
process_one_work+0x270/0x5e0
worker_thread+0x52/0x3e0
kthread+0xf4/0x120
ret_from_fork+0x29/0x50 |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix issue in verifying allow_ptr_leaks
After we converted the capabilities of our networking-bpf program from
cap_sys_admin to cap_net_admin+cap_bpf, our networking-bpf program
failed to start. Because it failed the bpf verifier, and the error log
is "R3 pointer comparison prohibited".
A simple reproducer as follows,
SEC("cls-ingress")
int ingress(struct __sk_buff *skb)
{
struct iphdr *iph = (void *)(long)skb->data + sizeof(struct ethhdr);
if ((long)(iph + 1) > (long)skb->data_end)
return TC_ACT_STOLEN;
return TC_ACT_OK;
}
Per discussion with Yonghong and Alexei [1], comparison of two packet
pointers is not a pointer leak. This patch fixes it.
Our local kernel is 6.1.y and we expect this fix to be backported to
6.1.y, so stable is CCed.
[1]. https://lore.kernel.org/bpf/CAADnVQ+Nmspr7Si+pxWn8zkE7hX-7s93ugwC+94aXSy4uQ9vBg@mail.gmail.com/ |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: handle case when repair happens with dev-replace
[BUG]
There is a bug report that a BUG_ON() in btrfs_repair_io_failure()
(originally repair_io_failure() in v6.0 kernel) got triggered when
replacing a unreliable disk:
BTRFS warning (device sda1): csum failed root 257 ino 2397453 off 39624704 csum 0xb0d18c75 expected csum 0x4dae9c5e mirror 3
kernel BUG at fs/btrfs/extent_io.c:2380!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 9 PID: 3614331 Comm: kworker/u257:2 Tainted: G OE 6.0.0-5-amd64 #1 Debian 6.0.10-2
Hardware name: Micro-Star International Co., Ltd. MS-7C60/TRX40 PRO WIFI (MS-7C60), BIOS 2.70 07/01/2021
Workqueue: btrfs-endio btrfs_end_bio_work [btrfs]
RIP: 0010:repair_io_failure+0x24a/0x260 [btrfs]
Call Trace:
<TASK>
clean_io_failure+0x14d/0x180 [btrfs]
end_bio_extent_readpage+0x412/0x6e0 [btrfs]
? __switch_to+0x106/0x420
process_one_work+0x1c7/0x380
worker_thread+0x4d/0x380
? rescuer_thread+0x3a0/0x3a0
kthread+0xe9/0x110
? kthread_complete_and_exit+0x20/0x20
ret_from_fork+0x22/0x30
[CAUSE]
Before the BUG_ON(), we got some read errors from the replace target
first, note the mirror number (3, which is beyond RAID1 duplication,
thus it's read from the replace target device).
Then at the BUG_ON() location, we are trying to writeback the repaired
sectors back the failed device.
The check looks like this:
ret = btrfs_map_block(fs_info, BTRFS_MAP_WRITE, logical,
&map_length, &bioc, mirror_num);
if (ret)
goto out_counter_dec;
BUG_ON(mirror_num != bioc->mirror_num);
But inside btrfs_map_block(), we can modify bioc->mirror_num especially
for dev-replace:
if (dev_replace_is_ongoing && mirror_num == map->num_stripes + 1 &&
!need_full_stripe(op) && dev_replace->tgtdev != NULL) {
ret = get_extra_mirror_from_replace(fs_info, logical, *length,
dev_replace->srcdev->devid,
&mirror_num,
&physical_to_patch_in_first_stripe);
patch_the_first_stripe_for_dev_replace = 1;
}
Thus if we're repairing the replace target device, we're going to
trigger that BUG_ON().
But in reality, the read failure from the replace target device may be
that, our replace hasn't reached the range we're reading, thus we're
reading garbage, but with replace running, the range would be properly
filled later.
Thus in that case, we don't need to do anything but let the replace
routine to handle it.
[FIX]
Instead of a BUG_ON(), just skip the repair if we're repairing the
device replace target device. |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: qla2xxx: Array index may go out of bound
Klocwork reports array 'vha->host_str' of size 16 may use index value(s)
16..19. Use snprintf() instead of sprintf(). |
| In the Linux kernel, the following vulnerability has been resolved:
of: unittest: fix null pointer dereferencing in of_unittest_find_node_by_name()
when kmalloc() fail to allocate memory in kasprintf(), name
or full_name will be NULL, strcmp() will cause
null pointer dereference. |
| In the Linux kernel, the following vulnerability has been resolved:
quota: fix warning in dqgrab()
There's issue as follows when do fault injection:
WARNING: CPU: 1 PID: 14870 at include/linux/quotaops.h:51 dquot_disable+0x13b7/0x18c0
Modules linked in:
CPU: 1 PID: 14870 Comm: fsconfig Not tainted 6.3.0-next-20230505-00006-g5107a9c821af-dirty #541
RIP: 0010:dquot_disable+0x13b7/0x18c0
RSP: 0018:ffffc9000acc79e0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88825e41b980
RDX: 0000000000000000 RSI: ffff88825e41b980 RDI: 0000000000000002
RBP: ffff888179f68000 R08: ffffffff82087ca7 R09: 0000000000000000
R10: 0000000000000001 R11: ffffed102f3ed026 R12: ffff888179f68130
R13: ffff888179f68110 R14: dffffc0000000000 R15: ffff888179f68118
FS: 00007f450a073740(0000) GS:ffff88882fc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe96f2efd8 CR3: 000000025c8ad000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
dquot_load_quota_sb+0xd53/0x1060
dquot_resume+0x172/0x230
ext4_reconfigure+0x1dc6/0x27b0
reconfigure_super+0x515/0xa90
__x64_sys_fsconfig+0xb19/0xd20
do_syscall_64+0x39/0xb0
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Above issue may happens as follows:
ProcessA ProcessB ProcessC
sys_fsconfig
vfs_fsconfig_locked
reconfigure_super
ext4_remount
dquot_suspend -> suspend all type quota
sys_fsconfig
vfs_fsconfig_locked
reconfigure_super
ext4_remount
dquot_resume
ret = dquot_load_quota_sb
add_dquot_ref
do_open -> open file O_RDWR
vfs_open
do_dentry_open
get_write_access
atomic_inc_unless_negative(&inode->i_writecount)
ext4_file_open
dquot_file_open
dquot_initialize
__dquot_initialize
dqget
atomic_inc(&dquot->dq_count);
__dquot_initialize
__dquot_initialize
dqget
if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
ext4_acquire_dquot
-> Return error DQ_ACTIVE_B flag isn't set
dquot_disable
invalidate_dquots
if (atomic_read(&dquot->dq_count))
dqgrab
WARN_ON_ONCE(!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
-> Trigger warning
In the above scenario, 'dquot->dq_flags' has no DQ_ACTIVE_B is normal when
dqgrab().
To solve above issue just replace the dqgrab() use in invalidate_dquots() with
atomic_inc(&dquot->dq_count). |
| In the Linux kernel, the following vulnerability has been resolved:
mptcp: stricter state check in mptcp_worker
As reported by Christoph, the mptcp protocol can run the
worker when the relevant msk socket is in an unexpected state:
connect()
// incoming reset + fastclose
// the mptcp worker is scheduled
mptcp_disconnect()
// msk is now CLOSED
listen()
mptcp_worker()
Leading to the following splat:
divide error: 0000 [#1] PREEMPT SMP
CPU: 1 PID: 21 Comm: kworker/1:0 Not tainted 6.3.0-rc1-gde5e8fd0123c #11
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014
Workqueue: events mptcp_worker
RIP: 0010:__tcp_select_window+0x22c/0x4b0 net/ipv4/tcp_output.c:3018
RSP: 0018:ffffc900000b3c98 EFLAGS: 00010293
RAX: 000000000000ffd7 RBX: 000000000000ffd7 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8214ce97 RDI: 0000000000000004
RBP: 000000000000ffd7 R08: 0000000000000004 R09: 0000000000010000
R10: 000000000000ffd7 R11: ffff888005afa148 R12: 000000000000ffd7
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88803ed00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000405270 CR3: 000000003011e006 CR4: 0000000000370ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
tcp_select_window net/ipv4/tcp_output.c:262 [inline]
__tcp_transmit_skb+0x356/0x1280 net/ipv4/tcp_output.c:1345
tcp_transmit_skb net/ipv4/tcp_output.c:1417 [inline]
tcp_send_active_reset+0x13e/0x320 net/ipv4/tcp_output.c:3459
mptcp_check_fastclose net/mptcp/protocol.c:2530 [inline]
mptcp_worker+0x6c7/0x800 net/mptcp/protocol.c:2705
process_one_work+0x3bd/0x950 kernel/workqueue.c:2390
worker_thread+0x5b/0x610 kernel/workqueue.c:2537
kthread+0x138/0x170 kernel/kthread.c:376
ret_from_fork+0x2c/0x50 arch/x86/entry/entry_64.S:308
</TASK>
This change addresses the issue explicitly checking for bad states
before running the mptcp worker. |
| In the Linux kernel, the following vulnerability has been resolved:
i2c: xiic: xiic_xfer(): Fix runtime PM leak on error path
The xiic_xfer() function gets a runtime PM reference when the function is
entered. This reference is released when the function is exited. There is
currently one error path where the function exits directly, which leads to
a leak of the runtime PM reference.
Make sure that this error path also releases the runtime PM reference. |
| In the Linux kernel, the following vulnerability has been resolved:
vfio: Fix NULL pointer dereference caused by uninitialized group->iommufd
group->iommufd is not initialized for the iommufd_ctx_put()
[20018.331541] BUG: kernel NULL pointer dereference, address: 0000000000000000
[20018.377508] RIP: 0010:iommufd_ctx_put+0x5/0x10 [iommufd]
...
[20018.476483] Call Trace:
[20018.479214] <TASK>
[20018.481555] vfio_group_fops_unl_ioctl+0x506/0x690 [vfio]
[20018.487586] __x64_sys_ioctl+0x6a/0xb0
[20018.491773] ? trace_hardirqs_on+0xc5/0xe0
[20018.496347] do_syscall_64+0x67/0x90
[20018.500340] entry_SYSCALL_64_after_hwframe+0x4b/0xb5 |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Disable preemption in bpf_event_output
We received report [1] of kernel crash, which is caused by
using nesting protection without disabled preemption.
The bpf_event_output can be called by programs executed by
bpf_prog_run_array_cg function that disabled migration but
keeps preemption enabled.
This can cause task to be preempted by another one inside the
nesting protection and lead eventually to two tasks using same
perf_sample_data buffer and cause crashes like:
BUG: kernel NULL pointer dereference, address: 0000000000000001
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
...
? perf_output_sample+0x12a/0x9a0
? finish_task_switch.isra.0+0x81/0x280
? perf_event_output+0x66/0xa0
? bpf_event_output+0x13a/0x190
? bpf_event_output_data+0x22/0x40
? bpf_prog_dfc84bbde731b257_cil_sock4_connect+0x40a/0xacb
? xa_load+0x87/0xe0
? __cgroup_bpf_run_filter_sock_addr+0xc1/0x1a0
? release_sock+0x3e/0x90
? sk_setsockopt+0x1a1/0x12f0
? udp_pre_connect+0x36/0x50
? inet_dgram_connect+0x93/0xa0
? __sys_connect+0xb4/0xe0
? udp_setsockopt+0x27/0x40
? __pfx_udp_push_pending_frames+0x10/0x10
? __sys_setsockopt+0xdf/0x1a0
? __x64_sys_connect+0xf/0x20
? do_syscall_64+0x3a/0x90
? entry_SYSCALL_64_after_hwframe+0x72/0xdc
Fixing this by disabling preemption in bpf_event_output.
[1] https://github.com/cilium/cilium/issues/26756 |
| In the Linux kernel, the following vulnerability has been resolved:
x86/hyperv: Disable IBT when hypercall page lacks ENDBR instruction
On hardware that supports Indirect Branch Tracking (IBT), Hyper-V VMs
with ConfigVersion 9.3 or later support IBT in the guest. However,
current versions of Hyper-V have a bug in that there's not an ENDBR64
instruction at the beginning of the hypercall page. Since hypercalls are
made with an indirect call to the hypercall page, all hypercall attempts
fail with an exception and Linux panics.
A Hyper-V fix is in progress to add ENDBR64. But guard against the Linux
panic by clearing X86_FEATURE_IBT if the hypercall page doesn't start
with ENDBR. The VM will boot and run without IBT.
If future Linux 32-bit kernels were to support IBT, additional hypercall
page hackery would be needed to make IBT work for such kernels in a
Hyper-V VM. |
| In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix memory leak of iter->temp when reading trace_pipe
kmemleak reports:
unreferenced object 0xffff88814d14e200 (size 256):
comm "cat", pid 336, jiffies 4294871818 (age 779.490s)
hex dump (first 32 bytes):
04 00 01 03 00 00 00 00 08 00 00 00 00 00 00 00 ................
0c d8 c8 9b ff ff ff ff 04 5a ca 9b ff ff ff ff .........Z......
backtrace:
[<ffffffff9bdff18f>] __kmalloc+0x4f/0x140
[<ffffffff9bc9238b>] trace_find_next_entry+0xbb/0x1d0
[<ffffffff9bc9caef>] trace_print_lat_context+0xaf/0x4e0
[<ffffffff9bc94490>] print_trace_line+0x3e0/0x950
[<ffffffff9bc95499>] tracing_read_pipe+0x2d9/0x5a0
[<ffffffff9bf03a43>] vfs_read+0x143/0x520
[<ffffffff9bf04c2d>] ksys_read+0xbd/0x160
[<ffffffff9d0f0edf>] do_syscall_64+0x3f/0x90
[<ffffffff9d2000aa>] entry_SYSCALL_64_after_hwframe+0x6e/0xd8
when reading file 'trace_pipe', 'iter->temp' is allocated or relocated
in trace_find_next_entry() but not freed before 'trace_pipe' is closed.
To fix it, free 'iter->temp' in tracing_release_pipe(). |
| In the Linux kernel, the following vulnerability has been resolved:
keys: Fix linking a duplicate key to a keyring's assoc_array
When making a DNS query inside the kernel using dns_query(), the request
code can in rare cases end up creating a duplicate index key in the
assoc_array of the destination keyring. It is eventually found by
a BUG_ON() check in the assoc_array implementation and results in
a crash.
Example report:
[2158499.700025] kernel BUG at ../lib/assoc_array.c:652!
[2158499.700039] invalid opcode: 0000 [#1] SMP PTI
[2158499.700065] CPU: 3 PID: 31985 Comm: kworker/3:1 Kdump: loaded Not tainted 5.3.18-150300.59.90-default #1 SLE15-SP3
[2158499.700096] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020
[2158499.700351] Workqueue: cifsiod cifs_resolve_server [cifs]
[2158499.700380] RIP: 0010:assoc_array_insert+0x85f/0xa40
[2158499.700401] Code: ff 74 2b 48 8b 3b 49 8b 45 18 4c 89 e6 48 83 e7 fe e8 95 ec 74 00 3b 45 88 7d db 85 c0 79 d4 0f 0b 0f 0b 0f 0b e8 41 f2 be ff <0f> 0b 0f 0b 81 7d 88 ff ff ff 7f 4c 89 eb 4c 8b ad 58 ff ff ff 0f
[2158499.700448] RSP: 0018:ffffc0bd6187faf0 EFLAGS: 00010282
[2158499.700470] RAX: ffff9f1ea7da2fe8 RBX: ffff9f1ea7da2fc1 RCX: 0000000000000005
[2158499.700492] RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000000
[2158499.700515] RBP: ffffc0bd6187fbb0 R08: ffff9f185faf1100 R09: 0000000000000000
[2158499.700538] R10: ffff9f1ea7da2cc0 R11: 000000005ed8cec8 R12: ffffc0bd6187fc28
[2158499.700561] R13: ffff9f15feb8d000 R14: ffff9f1ea7da2fc0 R15: ffff9f168dc0d740
[2158499.700585] FS: 0000000000000000(0000) GS:ffff9f185fac0000(0000) knlGS:0000000000000000
[2158499.700610] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[2158499.700630] CR2: 00007fdd94fca238 CR3: 0000000809d8c006 CR4: 00000000003706e0
[2158499.700702] Call Trace:
[2158499.700741] ? key_alloc+0x447/0x4b0
[2158499.700768] ? __key_link_begin+0x43/0xa0
[2158499.700790] __key_link_begin+0x43/0xa0
[2158499.700814] request_key_and_link+0x2c7/0x730
[2158499.700847] ? dns_resolver_read+0x20/0x20 [dns_resolver]
[2158499.700873] ? key_default_cmp+0x20/0x20
[2158499.700898] request_key_tag+0x43/0xa0
[2158499.700926] dns_query+0x114/0x2ca [dns_resolver]
[2158499.701127] dns_resolve_server_name_to_ip+0x194/0x310 [cifs]
[2158499.701164] ? scnprintf+0x49/0x90
[2158499.701190] ? __switch_to_asm+0x40/0x70
[2158499.701211] ? __switch_to_asm+0x34/0x70
[2158499.701405] reconn_set_ipaddr_from_hostname+0x81/0x2a0 [cifs]
[2158499.701603] cifs_resolve_server+0x4b/0xd0 [cifs]
[2158499.701632] process_one_work+0x1f8/0x3e0
[2158499.701658] worker_thread+0x2d/0x3f0
[2158499.701682] ? process_one_work+0x3e0/0x3e0
[2158499.701703] kthread+0x10d/0x130
[2158499.701723] ? kthread_park+0xb0/0xb0
[2158499.701746] ret_from_fork+0x1f/0x40
The situation occurs as follows:
* Some kernel facility invokes dns_query() to resolve a hostname, for
example, "abcdef". The function registers its global DNS resolver
cache as current->cred.thread_keyring and passes the query to
request_key_net() -> request_key_tag() -> request_key_and_link().
* Function request_key_and_link() creates a keyring_search_context
object. Its match_data.cmp method gets set via a call to
type->match_preparse() (resolves to dns_resolver_match_preparse()) to
dns_resolver_cmp().
* Function request_key_and_link() continues and invokes
search_process_keyrings_rcu() which returns that a given key was not
found. The control is then passed to request_key_and_link() ->
construct_alloc_key().
* Concurrently to that, a second task similarly makes a DNS query for
"abcdef." and its result gets inserted into the DNS resolver cache.
* Back on the first task, function construct_alloc_key() first runs
__key_link_begin() to determine an assoc_array_edit operation to
insert a new key. Index keys in the array are compared exactly as-is,
using keyring_compare_object(). The operation
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