| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
sctp: avoid NULL dereference when chunk data buffer is missing
chunk->skb pointer is dereferenced in the if-block where it's supposed
to be NULL only.
chunk->skb can only be NULL if chunk->head_skb is not. Check for frag_list
instead and do it just before replacing chunk->skb. We're sure that
otherwise chunk->skb is non-NULL because of outer if() condition. |
| In the Linux kernel, the following vulnerability has been resolved:
sctp: prevent possible shift-out-of-bounds in sctp_transport_update_rto
syzbot reported a possible shift-out-of-bounds [1]
Blamed commit added rto_alpha_max and rto_beta_max set to 1000.
It is unclear if some sctp users are setting very large rto_alpha
and/or rto_beta.
In order to prevent user regression, perform the test at run time.
Also add READ_ONCE() annotations as sysctl values can change under us.
[1]
UBSAN: shift-out-of-bounds in net/sctp/transport.c:509:41
shift exponent 64 is too large for 32-bit type 'unsigned int'
CPU: 0 UID: 0 PID: 16704 Comm: syz.2.2320 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x16c/0x1f0 lib/dump_stack.c:120
ubsan_epilogue lib/ubsan.c:233 [inline]
__ubsan_handle_shift_out_of_bounds+0x27f/0x420 lib/ubsan.c:494
sctp_transport_update_rto.cold+0x1c/0x34b net/sctp/transport.c:509
sctp_check_transmitted+0x11c4/0x1c30 net/sctp/outqueue.c:1502
sctp_outq_sack+0x4ef/0x1b20 net/sctp/outqueue.c:1338
sctp_cmd_process_sack net/sctp/sm_sideeffect.c:840 [inline]
sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1372 [inline] |
| In the Linux kernel, the following vulnerability has been resolved:
nbd: defer config put in recv_work
There is one uaf issue in recv_work when running NBD_CLEAR_SOCK and
NBD_CMD_RECONFIGURE:
nbd_genl_connect // conf_ref=2 (connect and recv_work A)
nbd_open // conf_ref=3
recv_work A done // conf_ref=2
NBD_CLEAR_SOCK // conf_ref=1
nbd_genl_reconfigure // conf_ref=2 (trigger recv_work B)
close nbd // conf_ref=1
recv_work B
config_put // conf_ref=0
atomic_dec(&config->recv_threads); -> UAF
Or only running NBD_CLEAR_SOCK:
nbd_genl_connect // conf_ref=2
nbd_open // conf_ref=3
NBD_CLEAR_SOCK // conf_ref=2
close nbd
nbd_release
config_put // conf_ref=1
recv_work
config_put // conf_ref=0
atomic_dec(&config->recv_threads); -> UAF
Commit 87aac3a80af5 ("nbd: call nbd_config_put() before notifying the
waiter") moved nbd_config_put() to run before waking up the waiter in
recv_work, in order to ensure that nbd_start_device_ioctl() would not
be woken up while nbd->task_recv was still uncleared.
However, in nbd_start_device_ioctl(), after being woken up it explicitly
calls flush_workqueue() to make sure all current works are finished.
Therefore, there is no need to move the config put ahead of the wakeup.
Move nbd_config_put() to the end of recv_work, so that the reference is
held for the whole lifetime of the worker thread. This makes sure the
config cannot be freed while recv_work is still running, even if clear
+ reconfigure interleave.
In addition, we don't need to worry about recv_work dropping the last
nbd_put (which causes deadlock):
path A (netlink with NBD_CFLAG_DESTROY_ON_DISCONNECT):
connect // nbd_refs=1 (trigger recv_work)
open nbd // nbd_refs=2
NBD_CLEAR_SOCK
close nbd
nbd_release
nbd_disconnect_and_put
flush_workqueue // recv_work done
nbd_config_put
nbd_put // nbd_refs=1
nbd_put // nbd_refs=0
queue_work
path B (netlink without NBD_CFLAG_DESTROY_ON_DISCONNECT):
connect // nbd_refs=2 (trigger recv_work)
open nbd // nbd_refs=3
NBD_CLEAR_SOCK // conf_refs=2
close nbd
nbd_release
nbd_config_put // conf_refs=1
nbd_put // nbd_refs=2
recv_work done // conf_refs=0, nbd_refs=1
rmmod // nbd_refs=0
Depends-on: e2daec488c57 ("nbd: Fix hungtask when nbd_config_put") |
| In the Linux kernel, the following vulnerability has been resolved:
nfs4_setup_readdir(): insufficient locking for ->d_parent->d_inode dereferencing
Theoretically it's an oopsable race, but I don't believe one can manage
to hit it on real hardware; might become doable on a KVM, but it still
won't be easy to attack.
Anyway, it's easy to deal with - since xdr_encode_hyper() is just a call of
put_unaligned_be64(), we can put that under ->d_lock and be done with that. |
| In the Linux kernel, the following vulnerability has been resolved:
ima: Handle error code returned by ima_filter_rule_match()
In ima_match_rules(), if ima_filter_rule_match() returns -ENOENT due to
the rule being NULL, the function incorrectly skips the 'if (!rc)' check
and sets 'result = true'. The LSM rule is considered a match, causing
extra files to be measured by IMA.
This issue can be reproduced in the following scenario:
After unloading the SELinux policy module via 'semodule -d', if an IMA
measurement is triggered before ima_lsm_rules is updated,
in ima_match_rules(), the first call to ima_filter_rule_match() returns
-ESTALE. This causes the code to enter the 'if (rc == -ESTALE &&
!rule_reinitialized)' block, perform ima_lsm_copy_rule() and retry. In
ima_lsm_copy_rule(), since the SELinux module has been removed, the rule
becomes NULL, and the second call to ima_filter_rule_match() returns
-ENOENT. This bypasses the 'if (!rc)' check and results in a false match.
Call trace:
selinux_audit_rule_match+0x310/0x3b8
security_audit_rule_match+0x60/0xa0
ima_match_rules+0x2e4/0x4a0
ima_match_policy+0x9c/0x1e8
ima_get_action+0x48/0x60
process_measurement+0xf8/0xa98
ima_bprm_check+0x98/0xd8
security_bprm_check+0x5c/0x78
search_binary_handler+0x6c/0x318
exec_binprm+0x58/0x1b8
bprm_execve+0xb8/0x130
do_execveat_common.isra.0+0x1a8/0x258
__arm64_sys_execve+0x48/0x68
invoke_syscall+0x50/0x128
el0_svc_common.constprop.0+0xc8/0xf0
do_el0_svc+0x24/0x38
el0_svc+0x44/0x200
el0t_64_sync_handler+0x100/0x130
el0t_64_sync+0x3c8/0x3d0
Fix this by changing 'if (!rc)' to 'if (rc <= 0)' to ensure that error
codes like -ENOENT do not bypass the check and accidentally result in a
successful match. |
| In the Linux kernel, the following vulnerability has been resolved:
ipvs: fix ipv4 null-ptr-deref in route error path
The IPv4 code path in __ip_vs_get_out_rt() calls dst_link_failure()
without ensuring skb->dev is set, leading to a NULL pointer dereference
in fib_compute_spec_dst() when ipv4_link_failure() attempts to send
ICMP destination unreachable messages.
The issue emerged after commit ed0de45a1008 ("ipv4: recompile ip options
in ipv4_link_failure") started calling __ip_options_compile() from
ipv4_link_failure(). This code path eventually calls fib_compute_spec_dst()
which dereferences skb->dev. An attempt was made to fix the NULL skb->dev
dereference in commit 0113d9c9d1cc ("ipv4: fix null-deref in
ipv4_link_failure"), but it only addressed the immediate dev_net(skb->dev)
dereference by using a fallback device. The fix was incomplete because
fib_compute_spec_dst() later in the call chain still accesses skb->dev
directly, which remains NULL when IPVS calls dst_link_failure().
The crash occurs when:
1. IPVS processes a packet in NAT mode with a misconfigured destination
2. Route lookup fails in __ip_vs_get_out_rt() before establishing a route
3. The error path calls dst_link_failure(skb) with skb->dev == NULL
4. ipv4_link_failure() → ipv4_send_dest_unreach() →
__ip_options_compile() → fib_compute_spec_dst()
5. fib_compute_spec_dst() dereferences NULL skb->dev
Apply the same fix used for IPv6 in commit 326bf17ea5d4 ("ipvs: fix
ipv6 route unreach panic"): set skb->dev from skb_dst(skb)->dev before
calling dst_link_failure().
KASAN: null-ptr-deref in range [0x0000000000000328-0x000000000000032f]
CPU: 1 PID: 12732 Comm: syz.1.3469 Not tainted 6.6.114 #2
RIP: 0010:__in_dev_get_rcu include/linux/inetdevice.h:233
RIP: 0010:fib_compute_spec_dst+0x17a/0x9f0 net/ipv4/fib_frontend.c:285
Call Trace:
<TASK>
spec_dst_fill net/ipv4/ip_options.c:232
spec_dst_fill net/ipv4/ip_options.c:229
__ip_options_compile+0x13a1/0x17d0 net/ipv4/ip_options.c:330
ipv4_send_dest_unreach net/ipv4/route.c:1252
ipv4_link_failure+0x702/0xb80 net/ipv4/route.c:1265
dst_link_failure include/net/dst.h:437
__ip_vs_get_out_rt+0x15fd/0x19e0 net/netfilter/ipvs/ip_vs_xmit.c:412
ip_vs_nat_xmit+0x1d8/0xc80 net/netfilter/ipvs/ip_vs_xmit.c:764 |
| In the Linux kernel, the following vulnerability has been resolved:
usb: dwc3: Fix race condition between concurrent dwc3_remove_requests() call paths
This patch addresses a race condition caused by unsynchronized
execution of multiple call paths invoking `dwc3_remove_requests()`,
leading to premature freeing of USB requests and subsequent crashes.
Three distinct execution paths interact with `dwc3_remove_requests()`:
Path 1:
Triggered via `dwc3_gadget_reset_interrupt()` during USB reset
handling. The call stack includes:
- `dwc3_ep0_reset_state()`
- `dwc3_ep0_stall_and_restart()`
- `dwc3_ep0_out_start()`
- `dwc3_remove_requests()`
- `dwc3_gadget_del_and_unmap_request()`
Path 2:
Also initiated from `dwc3_gadget_reset_interrupt()`, but through
`dwc3_stop_active_transfers()`. The call stack includes:
- `dwc3_stop_active_transfers()`
- `dwc3_remove_requests()`
- `dwc3_gadget_del_and_unmap_request()`
Path 3:
Occurs independently during `adb root` execution, which triggers
USB function unbind and bind operations. The sequence includes:
- `gserial_disconnect()`
- `usb_ep_disable()`
- `dwc3_gadget_ep_disable()`
- `dwc3_remove_requests()` with `-ESHUTDOWN` status
Path 3 operates asynchronously and lacks synchronization with Paths
1 and 2. When Path 3 completes, it disables endpoints and frees 'out'
requests. If Paths 1 or 2 are still processing these requests,
accessing freed memory leads to a crash due to use-after-free conditions.
To fix this added check for request completion and skip processing
if already completed and added the request status for ep0 while queue. |
| In the Linux kernel, the following vulnerability has been resolved:
nbd: defer config unlock in nbd_genl_connect
There is one use-after-free warning when running NBD_CMD_CONNECT and
NBD_CLEAR_SOCK:
nbd_genl_connect
nbd_alloc_and_init_config // config_refs=1
nbd_start_device // config_refs=2
set NBD_RT_HAS_CONFIG_REF open nbd // config_refs=3
recv_work done // config_refs=2
NBD_CLEAR_SOCK // config_refs=1
close nbd // config_refs=0
refcount_inc -> uaf
------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 24 PID: 1014 at lib/refcount.c:25 refcount_warn_saturate+0x12e/0x290
nbd_genl_connect+0x16d0/0x1ab0
genl_family_rcv_msg_doit+0x1f3/0x310
genl_rcv_msg+0x44a/0x790
The issue can be easily reproduced by adding a small delay before
refcount_inc(&nbd->config_refs) in nbd_genl_connect():
mutex_unlock(&nbd->config_lock);
if (!ret) {
set_bit(NBD_RT_HAS_CONFIG_REF, &config->runtime_flags);
+ printk("before sleep\n");
+ mdelay(5 * 1000);
+ printk("after sleep\n");
refcount_inc(&nbd->config_refs);
nbd_connect_reply(info, nbd->index);
} |
| In the Linux kernel, the following vulnerability has been resolved:
EDAC/versalnet: Fix device_node leak in mc_probe()
of_parse_phandle() returns a device_node reference that must be released with
of_node_put(). The original code never freed r5_core_node on any exit path,
causing a memory leak.
Fix this by using the automatic cleanup attribute __free(device_node) which
ensures of_node_put() is called when the variable goes out of scope. |
| In the Linux kernel, the following vulnerability has been resolved:
net: ks8851: Reinstate disabling of BHs around IRQ handler
If the driver executes ks8851_irq() AND a TX packet has been sent, then
the driver enables TX queue via netif_wake_queue() which schedules TX
softirq to queue packets for this device.
If CONFIG_PREEMPT_RT=y is set AND a packet has also been received by
the MAC, then ks8851_rx_pkts() calls netdev_alloc_skb_ip_align() to
allocate SKBs for the received packets. If netdev_alloc_skb_ip_align()
is called with BH enabled, then local_bh_enable() at the end of
netdev_alloc_skb_ip_align() will trigger the pending softirq processing,
which may ultimately call the .xmit callback ks8851_start_xmit_par().
The ks8851_start_xmit_par() will try to lock struct ks8851_net_par
.lock spinlock, which is already locked by ks8851_irq() from which
ks8851_start_xmit_par() was called. This leads to a deadlock, which
is reported by the kernel, including a trace listed below.
If CONFIG_PREEMPT_RT is not set, then since commit 0913ec336a6c0
("net: ks8851: Fix deadlock with the SPI chip variant") the deadlock
can also be triggered without received packet in the RX FIFO. The
pending softirqs will be processed on return from
spin_unlock_bh(&ks->statelock) in ks8851_irq(), which triggers the
deadlock as well.
Fix the problem by disabling BH around critical sections, including the
IRQ handler, thus preventing the net_tx_action() softirq from triggering
during these critical sections. The net_tx_action() softirq is triggered
once BH are re-enabled and at the end of the IRQ handler, once all the
other IRQ handler actions have been completed.
__schedule from schedule_rtlock+0x1c/0x34
schedule_rtlock from rtlock_slowlock_locked+0x548/0x904
rtlock_slowlock_locked from rt_spin_lock+0x60/0x9c
rt_spin_lock from ks8851_start_xmit_par+0x74/0x1a8
ks8851_start_xmit_par from netdev_start_xmit+0x20/0x44
netdev_start_xmit from dev_hard_start_xmit+0xd0/0x188
dev_hard_start_xmit from sch_direct_xmit+0xb8/0x25c
sch_direct_xmit from __qdisc_run+0x1f8/0x4ec
__qdisc_run from qdisc_run+0x1c/0x28
qdisc_run from net_tx_action+0x1f0/0x268
net_tx_action from handle_softirqs+0x1a4/0x270
handle_softirqs from __local_bh_enable_ip+0xcc/0xe0
__local_bh_enable_ip from __alloc_skb+0xd8/0x128
__alloc_skb from __netdev_alloc_skb+0x3c/0x19c
__netdev_alloc_skb from ks8851_irq+0x388/0x4d4
ks8851_irq from irq_thread_fn+0x24/0x64
irq_thread_fn from irq_thread+0x178/0x28c
irq_thread from kthread+0x12c/0x138
kthread from ret_from_fork+0x14/0x28 |
| In the Linux kernel, the following vulnerability has been resolved:
vfio/cdx: Fix NULL pointer dereference in interrupt trigger path
Add validation to ensure MSI is configured before accessing cdx_irqs
array in vfio_cdx_set_msi_trigger(). Without this check, userspace
can trigger a NULL pointer dereference by calling VFIO_DEVICE_SET_IRQS
with VFIO_IRQ_SET_DATA_BOOL or VFIO_IRQ_SET_DATA_NONE flags before
ever setting up interrupts via VFIO_IRQ_SET_DATA_EVENTFD.
The vfio_cdx_msi_enable() function allocates the cdx_irqs array and
sets config_msi to 1 only when called through the EVENTFD path. The
trigger loop (for DATA_BOOL/DATA_NONE) assumed this had already been
done, but there was no enforcement of this call ordering.
This matches the protection used in the PCI VFIO driver where
vfio_pci_set_msi_trigger() checks irq_is() before the trigger loop. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/page_alloc: return NULL early from alloc_frozen_pages_nolock() in NMI on UP
On UP kernels (!CONFIG_SMP), spin_trylock() is a no-op that
unconditionally succeeds even when the lock is already held. As a
result, alloc_frozen_pages_nolock() called from NMI context can
re-enter rmqueue() and acquire the zone lock that the interrupted
context is already holding, corrupting the freelists.
With CONFIG_DEBUG_SPINLOCK on UP, the following BUG is triggered with
the slub_kunit test module:
BUG: spinlock trylock failure on UP on CPU#0, kunit_try_catch/243
[...]
Call Trace:
<NMI>
dump_stack_lvl+0x3f/0x60
do_raw_spin_trylock+0x41/0x50
_raw_spin_trylock+0x24/0x50
rmqueue.isra.0+0x2a9/0xa70
get_page_from_freelist+0xeb/0x450
alloc_frozen_pages_nolock_noprof+0x111/0x1e0
allocate_slab+0x42a/0x500
___slab_alloc+0xa7/0x4c0
kmalloc_nolock_noprof+0x164/0x310
[...]
</NMI>
Fix this by returning NULL early when invoked from NMI on a UP kernel. |
| In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix memory leak in cifs_construct_tcon()
When having a multiuser mount with domain= specified and using
cifscreds, cifs_set_cifscreds() will end up setting @ctx->domainname,
so it needs to be freed before leaving cifs_construct_tcon().
This fixes the following memory leak reported by kmemleak:
mount.cifs //srv/share /mnt -o domain=ZELDA,multiuser,...
su - testuser
cifscreds add -d ZELDA -u testuser
...
ls /mnt/1
...
umount /mnt
echo scan > /sys/kernel/debug/kmemleak
cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff8881203c3f08 (size 8):
comm "ls", pid 5060, jiffies 4307222943
hex dump (first 8 bytes):
5a 45 4c 44 41 00 cc cc ZELDA...
backtrace (crc d109a8cf):
__kmalloc_node_track_caller_noprof+0x572/0x710
kstrdup+0x3a/0x70
cifs_sb_tlink+0x1209/0x1770 [cifs]
cifs_get_fattr+0xe1/0xf50 [cifs]
cifs_get_inode_info+0xb5/0x240 [cifs]
cifs_revalidate_dentry_attr+0x2d1/0x470 [cifs]
cifs_getattr+0x28e/0x450 [cifs]
vfs_getattr_nosec+0x126/0x180
vfs_statx+0xf6/0x220
do_statx+0xab/0x110
__x64_sys_statx+0xd5/0x130
do_syscall_64+0xbb/0x380
entry_SYSCALL_64_after_hwframe+0x77/0x7f |
| In the Linux kernel, the following vulnerability has been resolved:
usbnet: Prevents free active kevent
The root cause of this issue are:
1. When probing the usbnet device, executing usbnet_link_change(dev, 0, 0);
put the kevent work in global workqueue. However, the kevent has not yet
been scheduled when the usbnet device is unregistered. Therefore, executing
free_netdev() results in the "free active object (kevent)" error reported
here.
2. Another factor is that when calling usbnet_disconnect()->unregister_netdev(),
if the usbnet device is up, ndo_stop() is executed to cancel the kevent.
However, because the device is not up, ndo_stop() is not executed.
The solution to this problem is to cancel the kevent before executing
free_netdev(). |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: target: tcm_loop: Fix segfault in tcm_loop_tpg_address_show()
If the allocation of tl_hba->sh fails in tcm_loop_driver_probe() and we
attempt to dereference it in tcm_loop_tpg_address_show() we will get a
segfault, see below for an example. So, check tl_hba->sh before
dereferencing it.
Unable to allocate struct scsi_host
BUG: kernel NULL pointer dereference, address: 0000000000000194
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP NOPTI
CPU: 1 PID: 8356 Comm: tokio-runtime-w Not tainted 6.6.104.2-4.azl3 #1
Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.1 09/28/2024
RIP: 0010:tcm_loop_tpg_address_show+0x2e/0x50 [tcm_loop]
...
Call Trace:
<TASK>
configfs_read_iter+0x12d/0x1d0 [configfs]
vfs_read+0x1b5/0x300
ksys_read+0x6f/0xf0
... |
| In the Linux kernel, the following vulnerability has been resolved:
iommu: disable SVA when CONFIG_X86 is set
Patch series "Fix stale IOTLB entries for kernel address space", v7.
This proposes a fix for a security vulnerability related to IOMMU Shared
Virtual Addressing (SVA). In an SVA context, an IOMMU can cache kernel
page table entries. When a kernel page table page is freed and
reallocated for another purpose, the IOMMU might still hold stale,
incorrect entries. This can be exploited to cause a use-after-free or
write-after-free condition, potentially leading to privilege escalation or
data corruption.
This solution introduces a deferred freeing mechanism for kernel page
table pages, which provides a safe window to notify the IOMMU to
invalidate its caches before the page is reused.
This patch (of 8):
In the IOMMU Shared Virtual Addressing (SVA) context, the IOMMU hardware
shares and walks the CPU's page tables. The x86 architecture maps the
kernel's virtual address space into the upper portion of every process's
page table. Consequently, in an SVA context, the IOMMU hardware can walk
and cache kernel page table entries.
The Linux kernel currently lacks a notification mechanism for kernel page
table changes, specifically when page table pages are freed and reused.
The IOMMU driver is only notified of changes to user virtual address
mappings. This can cause the IOMMU's internal caches to retain stale
entries for kernel VA.
Use-After-Free (UAF) and Write-After-Free (WAF) conditions arise when
kernel page table pages are freed and later reallocated. The IOMMU could
misinterpret the new data as valid page table entries. The IOMMU might
then walk into attacker-controlled memory, leading to arbitrary physical
memory DMA access or privilege escalation. This is also a
Write-After-Free issue, as the IOMMU will potentially continue to write
Accessed and Dirty bits to the freed memory while attempting to walk the
stale page tables.
Currently, SVA contexts are unprivileged and cannot access kernel
mappings. However, the IOMMU will still walk kernel-only page tables all
the way down to the leaf entries, where it realizes the mapping is for the
kernel and errors out. This means the IOMMU still caches these
intermediate page table entries, making the described vulnerability a real
concern.
Disable SVA on x86 architecture until the IOMMU can receive notification
to flush the paging cache before freeing the CPU kernel page table pages. |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix deadlock in wait_current_trans() due to ignored transaction type
When wait_current_trans() is called during start_transaction(), it
currently waits for a blocked transaction without considering whether
the given transaction type actually needs to wait for that particular
transaction state. The btrfs_blocked_trans_types[] array already defines
which transaction types should wait for which transaction states, but
this check was missing in wait_current_trans().
This can lead to a deadlock scenario involving two transactions and
pending ordered extents:
1. Transaction A is in TRANS_STATE_COMMIT_DOING state
2. A worker processing an ordered extent calls start_transaction()
with TRANS_JOIN
3. join_transaction() returns -EBUSY because Transaction A is in
TRANS_STATE_COMMIT_DOING
4. Transaction A moves to TRANS_STATE_UNBLOCKED and completes
5. A new Transaction B is created (TRANS_STATE_RUNNING)
6. The ordered extent from step 2 is added to Transaction B's
pending ordered extents
7. Transaction B immediately starts commit by another task and
enters TRANS_STATE_COMMIT_START
8. The worker finally reaches wait_current_trans(), sees Transaction B
in TRANS_STATE_COMMIT_START (a blocked state), and waits
unconditionally
9. However, TRANS_JOIN should NOT wait for TRANS_STATE_COMMIT_START
according to btrfs_blocked_trans_types[]
10. Transaction B is waiting for pending ordered extents to complete
11. Deadlock: Transaction B waits for ordered extent, ordered extent
waits for Transaction B
This can be illustrated by the following call stacks:
CPU0 CPU1
btrfs_finish_ordered_io()
start_transaction(TRANS_JOIN)
join_transaction()
# -EBUSY (Transaction A is
# TRANS_STATE_COMMIT_DOING)
# Transaction A completes
# Transaction B created
# ordered extent added to
# Transaction B's pending list
btrfs_commit_transaction()
# Transaction B enters
# TRANS_STATE_COMMIT_START
# waiting for pending ordered
# extents
wait_current_trans()
# waits for Transaction B
# (should not wait!)
Task bstore_kv_sync in btrfs_commit_transaction waiting for ordered
extents:
__schedule+0x2e7/0x8a0
schedule+0x64/0xe0
btrfs_commit_transaction+0xbf7/0xda0 [btrfs]
btrfs_sync_file+0x342/0x4d0 [btrfs]
__x64_sys_fdatasync+0x4b/0x80
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Task kworker in wait_current_trans waiting for transaction commit:
Workqueue: btrfs-syno_nocow btrfs_work_helper [btrfs]
__schedule+0x2e7/0x8a0
schedule+0x64/0xe0
wait_current_trans+0xb0/0x110 [btrfs]
start_transaction+0x346/0x5b0 [btrfs]
btrfs_finish_ordered_io.isra.0+0x49b/0x9c0 [btrfs]
btrfs_work_helper+0xe8/0x350 [btrfs]
process_one_work+0x1d3/0x3c0
worker_thread+0x4d/0x3e0
kthread+0x12d/0x150
ret_from_fork+0x1f/0x30
Fix this by passing the transaction type to wait_current_trans() and
checking btrfs_blocked_trans_types[cur_trans->state] against the given
type before deciding to wait. This ensures that transaction types which
are allowed to join during certain blocked states will not unnecessarily
wait and cause deadlocks. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/damon/core: validate damos_quota_goal->nid for node_mem_{used,free}_bp
Patch series "mm/damon/core: validate damos_quota_goal->nid".
node_mem[cg]_{used,free}_bp DAMOS quota goals receive the node id. The
node id is used for si_meminfo_node() and NODE_DATA() without proper
validation. As a result, privileged users can trigger an out of bounds
memory access using DAMON_SYSFS. Fix the issues.
The issue was originally reported [1] with a fix by another author. The
original author announced [2] that they will stop working including the
fix that was still in the review stage. Hence I'm restarting this.
This patch (of 2):
Users can set damos_quota_goal->nid with arbitrary value for
node_mem_{used,free}_bp. But DAMON core is using those for
si_meminfo_node() without the validation of the value. This can result in
out of bounds memory access. The issue can actually triggered using DAMON
user-space tool (damo), like below.
$ sudo ./damo start --damos_action stat \
--damos_quota_goal node_mem_used_bp 50% -1 \
--damos_quota_interval 1s
$ sudo dmesg
[...]
[ 65.565986] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000098
Fix this issue by adding the validation of the given node. If an invalid
node id is given, it returns 0% for used memory ratio, and 100% for free
memory ratio. |
| In the Linux kernel, the following vulnerability has been resolved:
libceph: Prevent potential null-ptr-deref in ceph_handle_auth_reply()
If a message of type CEPH_MSG_AUTH_REPLY contains a zero value for both
protocol and result, this is currently not treated as an error. In case
of ac->negotiating == true and ac->protocol > 0, this leads to setting
ac->protocol = 0 and ac->ops = NULL. Thereafter, the check for
ac->protocol != protocol returns false, and init_protocol() is not
called. Subsequently, ac->ops->handle_reply() is called, which leads to
a null pointer dereference, because ac->ops is still NULL.
This patch changes the check for ac->protocol != protocol to
!ac->protocol, as this also includes the case when the protocol was set
to zero in the message. This causes the message to be treated as
containing a bad auth protocol. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/damon/core: fix damon_call() vs kdamond_fn() exit race
Patch series "mm/damon/core: fix damon_call()/damos_walk() vs kdmond exit
race".
damon_call() and damos_walk() can leak memory and/or deadlock when they
race with kdamond terminations. Fix those.
This patch (of 2);
When kdamond_fn() main loop is finished, the function cancels all
remaining damon_call() requests and unset the damon_ctx->kdamond so that
API callers and API functions themselves can know the context is
terminated. damon_call() adds the caller's request to the queue first.
After that, it shows if the kdamond of the damon_ctx is still running
(damon_ctx->kdamond is set). Only if the kdamond is running, damon_call()
starts waiting for the kdamond's handling of the newly added request.
The damon_call() requests registration and damon_ctx->kdamond unset are
protected by different mutexes, though. Hence, damon_call() could race
with damon_ctx->kdamond unset, and result in deadlocks.
For example, let's suppose kdamond successfully finished the damon_call()
requests cancelling. Right after that, damon_call() is called for the
context. It registers the new request, and shows the context is still
running, because damon_ctx->kdamond unset is not yet done. Hence the
damon_call() caller starts waiting for the handling of the request.
However, the kdamond is already on the termination steps, so it never
handles the new request. As a result, the damon_call() caller threads
infinitely waits.
Fix this by introducing another damon_ctx field, namely
call_controls_obsolete. It is protected by the
damon_ctx->call_controls_lock, which protects damon_call() requests
registration. Initialize (unset) it in kdamond_fn() before letting
damon_start() returns and set it just before the cancelling of remaining
damon_call() requests is executed. damon_call() reads the obsolete field
under the lock and avoids adding a new request.
After this change, only requests that are guaranteed to be handled or
cancelled are registered. Hence the after-registration DAMON context
termination check is no longer needed. Remove it together.
Note that the deadlock will not happen when damon_call() is called for
repeat mode request. In tis case, damon_call() returns instead of waiting
for the handling when the request registration succeeds and it shows the
kdamond is running. However, if the request also has dealloc_on_cancel,
the request memory would be leaked.
The issue is found by sashiko [1]. |
