vdanen/rhvex-cve huggingface dataset:
CVE-2025-32444 (Critical severity, published 2025-04-29)
CVSS score: 10 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H)
CWE: CWE-502
Description: A flaw was found in the vllm component. The affected versions of vllm having vLLM integration with mooncake are vulnerable to remote code execution due to pickle-based serialization over unsecured ZeroMQ sockets. The vulnerable sockets were set to listen on all network interfaces, increasing the likelihood that an attacker could reach the vulnerable ZeroMQ sockets to carry out an attack. The vLLM instances that do not use the mooncake integration are not vulnerable.
Statement: RHEL-AI is not affected because it does not include Mooncake, which is required for the vLLM to be configured in a way that would expose this vulnerability.

In general this is a Critical vulnerability because it allows unauthenticated remote code execution via unsafe `pickle` deserialization over ZeroMQ sockets exposed to the network. Binding these sockets to all interfaces (`0.0.0.0`) significantly increases exposure, allowing attackers to execute arbitrary code remotely with minimal effort. The combination of insecure serialization and network-accessible endpoints makes the flaw easily exploitable and potentially system-compromising, far exceeding the risk level of a moderate issue.
Mitigation: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
CVE-2025-21792 (Moderate severity, published 2025-02-26)
CVSS score: 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
CWE: CWE-401
Description: In the Linux kernel, the following vulnerability has been resolved:

ax25: Fix refcount leak caused by setting SO_BINDTODEVICE sockopt

If an AX25 device is bound to a socket by setting the SO_BINDTODEVICE
socket option, a refcount leak will occur in ax25_release().

Commit 9fd75b66b8f6 ("ax25: Fix refcount leaks caused by ax25_cb_del()")
added decrement of device refcounts in ax25_release(). In order for that
to work correctly the refcounts must already be incremented when the
device is bound to the socket. An AX25 device can be bound to a socket
by either calling ax25_bind() or setting SO_BINDTODEVICE socket option.
In both cases the refcounts should be incremented, but in fact it is done
only in ax25_bind().

This bug leads to the following issue reported by Syzkaller:

================================================================
refcount_t: decrement hit 0; leaking memory.
WARNING: CPU: 1 PID: 5932 at lib/refcount.c:31 refcount_warn_saturate+0x1ed/0x210 lib/refcount.c:31
Modules linked in:
CPU: 1 UID: 0 PID: 5932 Comm: syz-executor424 Not tainted 6.13.0-rc4-syzkaller-00110-g4099a71718b0 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:refcount_warn_saturate+0x1ed/0x210 lib/refcount.c:31
Call Trace:
 <TASK>
 __refcount_dec include/linux/refcount.h:336 [inline]
 refcount_dec include/linux/refcount.h:351 [inline]
 ref_tracker_free+0x710/0x820 lib/ref_tracker.c:236
 netdev_tracker_free include/linux/netdevice.h:4156 [inline]
 netdev_put include/linux/netdevice.h:4173 [inline]
 netdev_put include/linux/netdevice.h:4169 [inline]
 ax25_release+0x33f/0xa10 net/ax25/af_ax25.c:1069
 __sock_release+0xb0/0x270 net/socket.c:640
 sock_close+0x1c/0x30 net/socket.c:1408
 ...
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
 ...
 </TASK>
================================================================

Fix the implementation of ax25_setsockopt() by adding increment of
refcounts for the new device bound, and decrement of refcounts for
the old unbound device.
CVE-2025-38049 (Low severity, published 2025-04-17)
CVSS score: 4.4 (CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H)
CWE: CWE-20
Description: In the Linux kernel, the following vulnerability has been resolved:

x86/resctrl: Fix allocation of cleanest CLOSID on platforms with no monitors

Commit

  6eac36bb9eb0 ("x86/resctrl: Allocate the cleanest CLOSID by searching closid_num_dirty_rmid")

added logic that causes resctrl to search for the CLOSID with the fewest dirty
cache lines when creating a new control group, if requested by the arch code.
This depends on the values read from the llc_occupancy counters. The logic is
applicable to architectures where the CLOSID effectively forms part of the
monitoring identifier and so do not allow complete freedom to choose an unused
monitoring identifier for a given CLOSID.

This support missed that some platforms may not have these counters.  This
causes a NULL pointer dereference when creating a new control group as the
array was not allocated by dom_data_init().

As this feature isn't necessary on platforms that don't have cache occupancy
monitors, add this to the check that occurs when a new control group is
allocated.
CVE-2025-7546 (Moderate severity, published 2025-07-13)
CVSS score: 5.3 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L)
CWE: CWE-787
Description: A flaw was found in gnu-binutils. The `bfd_elf_set_group_contents` function in `bfd/elf.c` contains an out-of-bounds write vulnerability triggered by manipulation of the ELF file contents. This flaw allows a local attacker to provide a crafted file. This manipulation can lead to memory corruption.
Statement: The Moderate severity rating is based on the requirement of local access for an attacker to exploit this vulnerability. Although a successful exploit could lead to out-of-bounds write, the prerequisite of having an established presence on the system lowers the risk compared to remotely exploitable vulnerabilities. Red Hat products widely use GNU Binutils, a fundamental set of programming tools for creating and managing binary files, which makes this a component of significant interest. However, the attack vector significantly mitigates the immediate risk to systems.
Mitigation: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
CVE-2025-22014 (Moderate severity, published 2025-04-07)
CVSS score: 4.4 (CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H)
CWE: CWE-833
Description: In the Linux kernel, the following vulnerability has been resolved:

soc: qcom: pdr: Fix the potential deadlock

When some client process A call pdr_add_lookup() to add the look up for
the service and does schedule locator work, later a process B got a new
server packet indicating locator is up and call pdr_locator_new_server()
which eventually sets pdr->locator_init_complete to true which process A
sees and takes list lock and queries domain list but it will timeout due
to deadlock as the response will queued to the same qmi->wq and it is
ordered workqueue and process B is not able to complete new server
request work due to deadlock on list lock.

Fix it by removing the unnecessary list iteration as the list iteration
is already being done inside locator work, so avoid it here and just
call schedule_work() here.

       Process A                        Process B

                                     process_scheduled_works()
pdr_add_lookup()                      qmi_data_ready_work()
 process_scheduled_works()             pdr_locator_new_server()
                                         pdr->locator_init_complete=true;
   pdr_locator_work()
    mutex_lock(&pdr->list_lock);

     pdr_locate_service()                  mutex_lock(&pdr->list_lock);

      pdr_get_domain_list()
       pr_err("PDR: %s get domain list
               txn wait failed: %d\n",
               req->service_name,
               ret);

Timeout error log due to deadlock:

"
 PDR: tms/servreg get domain list txn wait failed: -110
 PDR: service lookup for msm/adsp/sensor_pd:tms/servreg failed: -110
"

Thanks to Bjorn and Johan for letting me know that this commit also fixes
an audio regression when using the in-kernel pd-mapper as that makes it
easier to hit this race. [1]
CVE-2025-3155 (Important severity, published 2025-04-02)
CVSS score: 7.4 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N)
CWE: CWE-829
Description: A flaw was found in Yelp. The Gnome user help application allows the help document to execute arbitrary scripts. This vulnerability allows malicious users to input help documents, which may exfiltrate user files to an external environment.
Statement: Red Hat has evaluated this with a Important severity as this requires user interaction and possibly access to add malicious JavaScript content, allowing the attacker to exfiltrate files from the victim's end with minimal user interaction.
Mitigation: Currently, no mitigation is available for this vulnerability.
CVE-2025-1492 (Moderate severity, published 2025-02-19)
CVSS score: 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
CWE: CWE-674
Description: A flaw was found in Wireshark. Bundle Protocol and CBOR dissector crashes in Wireshark allow denial of service via packet injection or crafted capture file.
Statement: No any Red Hat offerings are impacted by this vulnerability.
Mitigation: No mitigation is available for this issue other than updating the affected package to the version containing the fix. However, by disabling BP and avoiding opening capture files from non trusted sources reduces the risk of triggering this vulnerability and crashing Wireshark.
CVE-2025-21854 (Moderate severity, published 2025-03-11)
CVSS score: 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
CWE: CWE-476
Description: In the Linux kernel, the following vulnerability has been resolved:

sockmap, vsock: For connectible sockets allow only connected

sockmap expects all vsocks to have a transport assigned, which is expressed
in vsock_proto::psock_update_sk_prot(). However, there is an edge case
where an unconnected (connectible) socket may lose its previously assigned
transport. This is handled with a NULL check in the vsock/BPF recv path.

Another design detail is that listening vsocks are not supposed to have any
transport assigned at all. Which implies they are not supported by the
sockmap. But this is complicated by the fact that a socket, before
switching to TCP_LISTEN, may have had some transport assigned during a
failed connect() attempt. Hence, we may end up with a listening vsock in a
sockmap, which blows up quickly:

KASAN: null-ptr-deref in range [0x0000000000000120-0x0000000000000127]
CPU: 7 UID: 0 PID: 56 Comm: kworker/7:0 Not tainted 6.14.0-rc1+
Workqueue: vsock-loopback vsock_loopback_work
RIP: 0010:vsock_read_skb+0x4b/0x90
Call Trace:
 sk_psock_verdict_data_ready+0xa4/0x2e0
 virtio_transport_recv_pkt+0x1ca8/0x2acc
 vsock_loopback_work+0x27d/0x3f0
 process_one_work+0x846/0x1420
 worker_thread+0x5b3/0xf80
 kthread+0x35a/0x700
 ret_from_fork+0x2d/0x70
 ret_from_fork_asm+0x1a/0x30

For connectible sockets, instead of relying solely on the state of
vsk->transport, tell sockmap to only allow those representing established
connections. This aligns with the behaviour for AF_INET and AF_UNIX.
CVE-2025-37980 (Low severity, published 2025-05-19)
CVSS score: 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Description: In the Linux kernel, the following vulnerability has been resolved:

block: fix resource leak in blk_register_queue() error path

When registering a queue fails after blk_mq_sysfs_register() is
successful but the function later encounters an error, we need
to clean up the blk_mq_sysfs resources.

Add the missing blk_mq_sysfs_unregister() call in the error path
to properly clean up these resources and prevent a memory leak.
CVE-2025-40014 (Moderate severity, published 2025-04-17)
CVSS score: 7.1 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H)
CWE: CWE-125
Description: In the Linux kernel, the following vulnerability has been resolved:

objtool, spi: amd: Fix out-of-bounds stack access in amd_set_spi_freq()

If speed_hz < AMD_SPI_MIN_HZ, amd_set_spi_freq() iterates over the
entire amd_spi_freq array without breaking out early, causing 'i' to go
beyond the array bounds.

Fix that by stopping the loop when it gets to the last entry, so the low
speed_hz value gets clamped up to AMD_SPI_MIN_HZ.

Fixes the following warning with an UBSAN kernel:

  drivers/spi/spi-amd.o: error: objtool: amd_set_spi_freq() falls through to next function amd_spi_set_opcode()
CVE-2025-38399 (Moderate severity, published 2025-07-24)
CVSS score: 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
CWE: CWE-754
Description: No description is available for this CVE.
Statement: This patch fixes a kernel NULL pointer dereference in the target_core_pr module when handling malformed SPC-3 Persistent Reservation (SPEC_I_PT) commands.
Without the fix, an uninitialized dest_se_deve pointer may be dereferenced, leading to a kernel panic or crash.
A simple NULL check prevents this error in the error path logic of core_scsi3_decode_spec_i_port().
Mitigation: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
CVE-2025-5351 (Moderate severity, published 2025-06-23)
CVSS score: 4.2 (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N)
CWE: CWE-415
Description: A flaw was found in the key export functionality of libssh. The issue occurs in the internal function responsible for converting cryptographic keys into serialized formats. During error handling, a memory structure is freed but not cleared, leading to a potential double free issue if an additional failure occurs later in the function. This condition may result in heap corruption or application instability in low-memory scenarios, posing a risk to system reliability where key export operations are performed.
Statement: The Red Hat Product Security team has rated the severity of this issue as Moderate. The vulnerability arises from a double free condition that is only exploitable under rare and constrained scenarios such as low memory environments. Furthermore, exploitation requires an authenticated user with access to key export functionality, limiting the scope and impact. Despite the restricted preconditions, the flaw still presents a stability concern for services utilizing libssh in sensitive environments.
Mitigation: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. Administrators should apply vendor-supplied patches as soon as they become available.
CVE-2025-38233 (Moderate severity, published 2025-07-03)
CVSS score: 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Description: In the Linux kernel, the following vulnerability has been resolved:

powerpc64/ftrace: fix clobbered r15 during livepatching

While r15 is clobbered always with PPC_FTRACE_OUT_OF_LINE, it is
not restored in livepatch sequence leading to not so obvious fails
like below:

  BUG: Unable to handle kernel data access on write at 0xc0000000000f9078
  Faulting instruction address: 0xc0000000018ff958
  Oops: Kernel access of bad area, sig: 11 [#1]
  ...
  NIP:  c0000000018ff958 LR: c0000000018ff930 CTR: c0000000009c0790
  REGS: c00000005f2e7790 TRAP: 0300   Tainted: G              K      (6.14.0+)
  MSR:  8000000000009033 <SF,EE,ME,IR,DR,RI,LE>  CR: 2822880b  XER: 20040000
  CFAR: c0000000008addc0 DAR: c0000000000f9078 DSISR: 0a000000 IRQMASK: 1
  GPR00: c0000000018f2584 c00000005f2e7a30 c00000000280a900 c000000017ffa488
  GPR04: 0000000000000008 0000000000000000 c0000000018f24fc 000000000000000d
  GPR08: fffffffffffe0000 000000000000000d 0000000000000000 0000000000008000
  GPR12: c0000000009c0790 c000000017ffa480 c00000005f2e7c78 c0000000000f9070
  GPR16: c00000005f2e7c90 0000000000000000 0000000000000000 0000000000000000
  GPR20: 0000000000000000 c00000005f3efa80 c00000005f2e7c60 c00000005f2e7c88
  GPR24: c00000005f2e7c60 0000000000000001 c0000000000f9078 0000000000000000
  GPR28: 00007fff97960000 c000000017ffa480 0000000000000000 c0000000000f9078
  ...
  Call Trace:
    check_heap_object+0x34/0x390 (unreliable)
  __mutex_unlock_slowpath.isra.0+0xe4/0x230
  seq_read_iter+0x430/0xa90
  proc_reg_read_iter+0xa4/0x200
  vfs_read+0x41c/0x510
  ksys_read+0xa4/0x190
  system_call_exception+0x1d0/0x440
  system_call_vectored_common+0x15c/0x2ec

Fix it by restoring r15 always.
CVE-2025-50151 (Moderate severity, published 2025-07-21)
CVSS score: 6.5 (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N)
CWE: CWE-20
Description: A file path validation flaw has been discovered in Apache Jena. This flaw allows users with administrative access to upload arbitrary configurations.
Mitigation: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
CVE-2025-21911 (Moderate severity, published 2025-03-31)
CVSS score: 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
CWE: CWE-667
Description: In the Linux kernel, the following vulnerability has been resolved:

drm/imagination: avoid deadlock on fence release

Do scheduler queue fence release processing on a workqueue, rather
than in the release function itself.

Fixes deadlock issues such as the following:

[  607.400437] ============================================
[  607.405755] WARNING: possible recursive locking detected
[  607.415500] --------------------------------------------
[  607.420817] weston:zfq0/24149 is trying to acquire lock:
[  607.426131] ffff000017d041a0 (reservation_ww_class_mutex){+.+.}-{3:3}, at: pvr_gem_object_vunmap+0x40/0xc0 [powervr]
[  607.436728]
               but task is already holding lock:
[  607.442554] ffff000017d105a0 (reservation_ww_class_mutex){+.+.}-{3:3}, at: dma_buf_ioctl+0x250/0x554
[  607.451727]
               other info that might help us debug this:
[  607.458245]  Possible unsafe locking scenario:

[  607.464155]        CPU0
[  607.466601]        ----
[  607.469044]   lock(reservation_ww_class_mutex);
[  607.473584]   lock(reservation_ww_class_mutex);
[  607.478114]
                *** DEADLOCK ***
CVE-2025-1938 (Important severity, published 2025-03-04)
CVSS score: 8.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H)
CWE: CWE-120
Description: Memory safety bugs present in Firefox 135, Thunderbird 135, Firefox ESR 128.7, and Thunderbird 128.7. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 136, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.
Statement: Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
CVE-2025-5994 (Important severity, published 2025-07-16)
CVSS score: 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N)
CWE: CWE-349
Description: A cache poisoning flaw was found in Unbound. Resolvers supporting EDNS Client Subnet (ECS) must segregate outgoing queries to accommodate different outgoing ECS information. This issue reopens resolvers to a birthday paradox attack, known as the Rebirthday Attack, which attempts to match the DNS transaction ID with cache non-ECS poisoned replies.
Statement: This vulnerability is considered Important rather than Moderate because it directly compromises the integrity of DNS caching mechanisms in resolvers supporting EDNS Client Subnet (ECS). The flaw allows an attacker to exploit the birthday paradox by generating a high volume of concurrent queries with different ECS values, thereby increasing the chance of a transaction ID collision with a spoofed response. If the resolver fails to properly segregate cache entries by ECS scope, it may accept and cache a malicious non-ECS response, effectively leading to DNS cache poisoning. Unlike typical poisoning attempts that require precise timing or privileged network positions, this attack can be carried out remotely with a high success rate, especially in resolvers that do not correctly isolate ECS queries.
Mitigation: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
CVE-2025-22002 (Moderate severity, published 2025-04-02)
CVSS score: 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
CWE: CWE-476
Description: In the Linux kernel, the following vulnerability has been resolved:

netfs: Call `invalidate_cache` only if implemented

Many filesystems such as NFS and Ceph do not implement the
`invalidate_cache` method.  On those filesystems, if writing to the
cache (`NETFS_WRITE_TO_CACHE`) fails for some reason, the kernel
crashes like this:

 BUG: kernel NULL pointer dereference, address: 0000000000000000
 #PF: supervisor instruction fetch in kernel mode
 #PF: error_code(0x0010) - not-present page
 PGD 0 P4D 0
 Oops: Oops: 0010 [#1] SMP PTI
 CPU: 9 UID: 0 PID: 3380 Comm: kworker/u193:11 Not tainted 6.13.3-cm4all1-hp #437
 Hardware name: HP ProLiant DL380 Gen9/ProLiant DL380 Gen9, BIOS P89 10/17/2018
 Workqueue: events_unbound netfs_write_collection_worker
 RIP: 0010:0x0
 Code: Unable to access opcode bytes at 0xffffffffffffffd6.
 RSP: 0018:ffff9b86e2ca7dc0 EFLAGS: 00010202
 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 7fffffffffffffff
 RDX: 0000000000000001 RSI: ffff89259d576a18 RDI: ffff89259d576900
 RBP: ffff89259d5769b0 R08: ffff9b86e2ca7d28 R09: 0000000000000002
 R10: ffff89258ceaca80 R11: 0000000000000001 R12: 0000000000000020
 R13: ffff893d158b9338 R14: ffff89259d576900 R15: ffff89259d5769b0
 FS:  0000000000000000(0000) GS:ffff893c9fa40000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: ffffffffffffffd6 CR3: 000000054442e003 CR4: 00000000001706f0
 Call Trace:
  <TASK>
  ? __die+0x1f/0x60
  ? page_fault_oops+0x15c/0x460
  ? try_to_wake_up+0x2d2/0x530
  ? exc_page_fault+0x5e/0x100
  ? asm_exc_page_fault+0x22/0x30
  netfs_write_collection_worker+0xe9f/0x12b0
  ? xs_poll_check_readable+0x3f/0x80
  ? xs_stream_data_receive_workfn+0x8d/0x110
  process_one_work+0x134/0x2d0
  worker_thread+0x299/0x3a0
  ? __pfx_worker_thread+0x10/0x10
  kthread+0xba/0xe0
  ? __pfx_kthread+0x10/0x10
  ret_from_fork+0x30/0x50
  ? __pfx_kthread+0x10/0x10
  ret_from_fork_asm+0x1a/0x30
  </TASK>
 Modules linked in:
 CR2: 0000000000000000

This patch adds the missing `NULL` check.
CVE-2025-21784 (Moderate severity, published 2025-02-26)
CVSS score: 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Description: In the Linux kernel, the following vulnerability has been resolved:

drm/amdgpu: bail out when failed to load fw in psp_init_cap_microcode()

In function psp_init_cap_microcode(), it should bail out when failed to
load firmware, otherwise it may cause invalid memory access.
CVE-2025-38321 (Moderate severity, published 2025-07-09)
CVSS score: 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Description: In the Linux kernel, the following vulnerability has been resolved:

smb: Log an error when close_all_cached_dirs fails

Under low-memory conditions, close_all_cached_dirs() can't move the
dentries to a separate list to dput() them once the locks are dropped.
This will result in a "Dentry still in use" error, so add an error
message that makes it clear this is what happened:

[  495.281119] CIFS: VFS: \\otters.example.com\share Out of memory while dropping dentries
[  495.281595] ------------[ cut here ]------------
[  495.281887] BUG: Dentry ffff888115531138{i=78,n=/}  still in use (2) [unmount of cifs cifs]
[  495.282391] WARNING: CPU: 1 PID: 2329 at fs/dcache.c:1536 umount_check+0xc8/0xf0

Also, bail out of looping through all tcons as soon as a single
allocation fails, since we're already in trouble, and kmalloc() attempts
for subseqeuent tcons are likely to fail just like the first one did.