| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
ext4: validate p_idx bounds in ext4_ext_correct_indexes
ext4_ext_correct_indexes() walks up the extent tree correcting
index entries when the first extent in a leaf is modified. Before
accessing path[k].p_idx->ei_block, there is no validation that
p_idx falls within the valid range of index entries for that
level.
If the on-disk extent header contains a corrupted or crafted
eh_entries value, p_idx can point past the end of the allocated
buffer, causing a slab-out-of-bounds read.
Fix this by validating path[k].p_idx against EXT_LAST_INDEX() at
both access sites: before the while loop and inside it. Return
-EFSCORRUPTED if the index pointer is out of range, consistent
with how other bounds violations are handled in the ext4 extent
tree code. |
| In the Linux kernel, the following vulnerability has been resolved:
ext4: replace BUG_ON with proper error handling in ext4_read_inline_folio
Replace BUG_ON() with proper error handling when inline data size
exceeds PAGE_SIZE. This prevents kernel panic and allows the system to
continue running while properly reporting the filesystem corruption.
The error is logged via ext4_error_inode(), the buffer head is released
to prevent memory leak, and -EFSCORRUPTED is returned to indicate
filesystem corruption. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Fix drm_edid leak in amdgpu_dm
[WHAT]
When a sink is connected, aconnector->drm_edid was overwritten without
freeing the previous allocation, causing a memory leak on resume.
[HOW]
Free the previous drm_edid before updating it.
(cherry picked from commit 52024a94e7111366141cfc5d888b2ef011f879e5) |
| In the Linux kernel, the following vulnerability has been resolved:
ksmbd: do not expire session on binding failure
When a multichannel session binding request fails (e.g. wrong password),
the error path unconditionally sets sess->state = SMB2_SESSION_EXPIRED.
However, during binding, sess points to the target session looked up via
ksmbd_session_lookup_slowpath() -- which belongs to another connection's
user. This allows a remote attacker to invalidate any active session by
simply sending a binding request with a wrong password (DoS).
Fix this by skipping session expiration when the failed request was
a binding attempt, since the session does not belong to the current
connection. The reference taken by ksmbd_session_lookup_slowpath() is
still correctly released via ksmbd_user_session_put(). |
| In the Linux kernel, the following vulnerability has been resolved:
nvme-pci: ensure we're polling a polled queue
A user can change the polled queue count at run time. There's a brief
window during a reset where a hipri task may try to poll that queue
before the block layer has updated the queue maps, which would race with
the now interrupt driven queue and may cause double completions. |
| In the Linux kernel, the following vulnerability has been resolved:
HID: asus: avoid memory leak in asus_report_fixup()
The asus_report_fixup() function was returning a newly allocated
kmemdup()-allocated buffer, but never freeing it. Switch to
devm_kzalloc() to ensure the memory is managed and freed automatically
when the device is removed.
The caller of report_fixup() does not take ownership of the returned
pointer, but it is permitted to return a pointer whose lifetime is at
least that of the input buffer.
Also fix a harmless out-of-bounds read by copying only the original
descriptor size. |
| In the Linux kernel, the following vulnerability has been resolved:
X.509: Fix out-of-bounds access when parsing extensions
Leo reports an out-of-bounds access when parsing a certificate with
empty Basic Constraints or Key Usage extension because the first byte of
the extension is read before checking its length. Fix it.
The bug can be triggered by an unprivileged user by submitting a
specially crafted certificate to the kernel through the keyrings(7) API.
Leo has demonstrated this with a proof-of-concept program responsibly
disclosed off-list. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: check if ext_caps is valid in BL setup
LVDS connectors don't have extended backlight caps so check
if the pointer is valid before accessing it.
(cherry picked from commit 3f797396d7f4eb9bb6eded184bbc6f033628a6f6) |
| In the Linux kernel, the following vulnerability has been resolved:
ASoC: sma1307: fix double free of devm_kzalloc() memory
A previous change added NULL checks and cleanup for allocation
failures in sma1307_setting_loaded().
However, the cleanup for mode_set entries is wrong. Those entries are
allocated with devm_kzalloc(), so they are device-managed resources and
must not be freed with kfree(). Manually freeing them in the error path
can lead to a double free when devres later releases the same memory.
Drop the manual kfree() loop and let devres handle the cleanup. |
| In the Linux kernel, the following vulnerability has been resolved:
cxl/region: Fix leakage in __construct_region()
Failing the first sysfs_update_group() needs to explicitly
kfree the resource as it is too early for cxl_region_iomem_release()
to do so. |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix leak of kobject name for sub-group space_info
When create_space_info_sub_group() allocates elements of
space_info->sub_group[], kobject_init_and_add() is called for each
element via btrfs_sysfs_add_space_info_type(). However, when
check_removing_space_info() frees these elements, it does not call
btrfs_sysfs_remove_space_info() on them. As a result, kobject_put() is
not called and the associated kobj->name objects are leaked.
This memory leak is reproduced by running the blktests test case
zbd/009 on kernels built with CONFIG_DEBUG_KMEMLEAK. The kmemleak
feature reports the following error:
unreferenced object 0xffff888112877d40 (size 16):
comm "mount", pid 1244, jiffies 4294996972
hex dump (first 16 bytes):
64 61 74 61 2d 72 65 6c 6f 63 00 c4 c6 a7 cb 7f data-reloc......
backtrace (crc 53ffde4d):
__kmalloc_node_track_caller_noprof+0x619/0x870
kstrdup+0x42/0xc0
kobject_set_name_vargs+0x44/0x110
kobject_init_and_add+0xcf/0x150
btrfs_sysfs_add_space_info_type+0xfc/0x210 [btrfs]
create_space_info_sub_group.constprop.0+0xfb/0x1b0 [btrfs]
create_space_info+0x211/0x320 [btrfs]
btrfs_init_space_info+0x15a/0x1b0 [btrfs]
open_ctree+0x33c7/0x4a50 [btrfs]
btrfs_get_tree.cold+0x9f/0x1ee [btrfs]
vfs_get_tree+0x87/0x2f0
vfs_cmd_create+0xbd/0x280
__do_sys_fsconfig+0x3df/0x990
do_syscall_64+0x136/0x1540
entry_SYSCALL_64_after_hwframe+0x76/0x7e
To avoid the leak, call btrfs_sysfs_remove_space_info() instead of
kfree() for the elements. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/damon/core: avoid use of half-online-committed context
One major usage of damon_call() is online DAMON parameters update. It is
done by calling damon_commit_ctx() inside the damon_call() callback
function. damon_commit_ctx() can fail for two reasons: 1) invalid
parameters and 2) internal memory allocation failures. In case of
failures, the damon_ctx that attempted to be updated (commit destination)
can be partially updated (or, corrupted from a perspective), and therefore
shouldn't be used anymore. The function only ensures the damon_ctx object
can safely deallocated using damon_destroy_ctx().
The API callers are, however, calling damon_commit_ctx() only after
asserting the parameters are valid, to avoid damon_commit_ctx() fails due
to invalid input parameters. But it can still theoretically fail if the
internal memory allocation fails. In the case, DAMON may run with the
partially updated damon_ctx. This can result in unexpected behaviors
including even NULL pointer dereference in case of damos_commit_dests()
failure [1]. Such allocation failure is arguably too small to fail, so
the real world impact would be rare. But, given the bad consequence, this
needs to be fixed.
Avoid such partially-committed (maybe-corrupted) damon_ctx use by saving
the damon_commit_ctx() failure on the damon_ctx object. For this,
introduce damon_ctx->maybe_corrupted field. damon_commit_ctx() sets it
when it is failed. kdamond_call() checks if the field is set after each
damon_call_control->fn() is executed. If it is set, ignore remaining
callback requests and return. All kdamond_call() callers including
kdamond_fn() also check the maybe_corrupted field right after
kdamond_call() invocations. If the field is set, break the kdamond_fn()
main loop so that DAMON sill doesn't use the context that might be
corrupted.
[sj@kernel.org: let kdamond_call() with cancel regardless of maybe_corrupted] |
| In the Linux kernel, the following vulnerability has been resolved:
spi: spi-fsl-lpspi: fix teardown order issue (UAF)
There is a teardown order issue in the driver. The SPI controller is
registered using devm_spi_register_controller(), which delays
unregistration of the SPI controller until after the fsl_lpspi_remove()
function returns.
As the fsl_lpspi_remove() function synchronously tears down the DMA
channels, a running SPI transfer triggers the following NULL pointer
dereference due to use after free:
| fsl_lpspi 42550000.spi: I/O Error in DMA RX
| Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
[...]
| Call trace:
| fsl_lpspi_dma_transfer+0x260/0x340 [spi_fsl_lpspi]
| fsl_lpspi_transfer_one+0x198/0x448 [spi_fsl_lpspi]
| spi_transfer_one_message+0x49c/0x7c8
| __spi_pump_transfer_message+0x120/0x420
| __spi_sync+0x2c4/0x520
| spi_sync+0x34/0x60
| spidev_message+0x20c/0x378 [spidev]
| spidev_ioctl+0x398/0x750 [spidev]
[...]
Switch from devm_spi_register_controller() to spi_register_controller() in
fsl_lpspi_probe() and add the corresponding spi_unregister_controller() in
fsl_lpspi_remove(). |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: btintel: serialize btintel_hw_error() with hci_req_sync_lock
btintel_hw_error() issues two __hci_cmd_sync() calls (HCI_OP_RESET
and Intel exception-info retrieval) without holding
hci_req_sync_lock(). This lets it race against
hci_dev_do_close() -> btintel_shutdown_combined(), which also runs
__hci_cmd_sync() under the same lock. When both paths manipulate
hdev->req_status/req_rsp concurrently, the close path may free the
response skb first, and the still-running hw_error path hits a
slab-use-after-free in kfree_skb().
Wrap the whole recovery sequence in hci_req_sync_lock/unlock so it
is serialized with every other synchronous HCI command issuer.
Below is the data race report and the kasan report:
BUG: data-race in __hci_cmd_sync_sk / btintel_shutdown_combined
read of hdev->req_rsp at net/bluetooth/hci_sync.c:199
by task kworker/u17:1/83:
__hci_cmd_sync_sk+0x12f2/0x1c30 net/bluetooth/hci_sync.c:200
__hci_cmd_sync+0x55/0x80 net/bluetooth/hci_sync.c:223
btintel_hw_error+0x114/0x670 drivers/bluetooth/btintel.c:254
hci_error_reset+0x348/0xa30 net/bluetooth/hci_core.c:1030
write/free by task ioctl/22580:
btintel_shutdown_combined+0xd0/0x360
drivers/bluetooth/btintel.c:3648
hci_dev_close_sync+0x9ae/0x2c10 net/bluetooth/hci_sync.c:5246
hci_dev_do_close+0x232/0x460 net/bluetooth/hci_core.c:526
BUG: KASAN: slab-use-after-free in
sk_skb_reason_drop+0x43/0x380 net/core/skbuff.c:1202
Read of size 4 at addr ffff888144a738dc
by task kworker/u17:1/83:
__hci_cmd_sync_sk+0x12f2/0x1c30 net/bluetooth/hci_sync.c:200
__hci_cmd_sync+0x55/0x80 net/bluetooth/hci_sync.c:223
btintel_hw_error+0x186/0x670 drivers/bluetooth/btintel.c:260 |
| In the Linux kernel, the following vulnerability has been resolved:
net/smc: fix double-free of smc_spd_priv when tee() duplicates splice pipe buffer
smc_rx_splice() allocates one smc_spd_priv per pipe_buffer and stores
the pointer in pipe_buffer.private. The pipe_buf_operations for these
buffers used .get = generic_pipe_buf_get, which only increments the page
reference count when tee(2) duplicates a pipe buffer. The smc_spd_priv
pointer itself was not handled, so after tee() both the original and the
cloned pipe_buffer share the same smc_spd_priv *.
When both pipes are subsequently released, smc_rx_pipe_buf_release() is
called twice against the same object:
1st call: kfree(priv) sock_put(sk) smc_rx_update_cons() [correct]
2nd call: kfree(priv) sock_put(sk) smc_rx_update_cons() [UAF]
KASAN reports a slab-use-after-free in smc_rx_pipe_buf_release(), which
then escalates to a NULL-pointer dereference and kernel panic via
smc_rx_update_consumer() when it chases the freed priv->smc pointer:
BUG: KASAN: slab-use-after-free in smc_rx_pipe_buf_release+0x78/0x2a0
Read of size 8 at addr ffff888004a45740 by task smc_splice_tee_/74
Call Trace:
<TASK>
dump_stack_lvl+0x53/0x70
print_report+0xce/0x650
kasan_report+0xc6/0x100
smc_rx_pipe_buf_release+0x78/0x2a0
free_pipe_info+0xd4/0x130
pipe_release+0x142/0x160
__fput+0x1c6/0x490
__x64_sys_close+0x4f/0x90
do_syscall_64+0xa6/0x1a0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>
BUG: kernel NULL pointer dereference, address: 0000000000000020
RIP: 0010:smc_rx_update_consumer+0x8d/0x350
Call Trace:
<TASK>
smc_rx_pipe_buf_release+0x121/0x2a0
free_pipe_info+0xd4/0x130
pipe_release+0x142/0x160
__fput+0x1c6/0x490
__x64_sys_close+0x4f/0x90
do_syscall_64+0xa6/0x1a0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>
Kernel panic - not syncing: Fatal exception
Beyond the memory-safety problem, duplicating an SMC splice buffer is
semantically questionable: smc_rx_update_cons() would advance the
consumer cursor twice for the same data, corrupting receive-window
accounting. A refcount on smc_spd_priv could fix the double-free, but
the cursor-accounting issue would still need to be addressed separately.
The .get callback is invoked by both tee(2) and splice_pipe_to_pipe()
for partial transfers; both will now return -EFAULT. Users who need
to duplicate SMC socket data must use a copy-based read path. |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: L2CAP: Fix null-ptr-deref on l2cap_sock_ready_cb
Before using sk pointer, check if it is null.
Fix the following:
KASAN: null-ptr-deref in range [0x0000000000000260-0x0000000000000267]
CPU: 0 UID: 0 PID: 5985 Comm: kworker/0:5 Not tainted 7.0.0-rc4-00029-ga989fde763f4 #1 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-9.fc43 06/10/2025
Workqueue: events l2cap_info_timeout
RIP: 0010:kasan_byte_accessible+0x12/0x30
Code: 79 ff ff ff 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 48 c1 ef 03 48 b8 00 00 00 00 00 fc ff df <0f> b6 04 07 3c 08 0f 92 c0 c3 cc cce
veth0_macvtap: entered promiscuous mode
RSP: 0018:ffffc90006e0f808 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffffffff89746018 RCX: 0000000080000001
RDX: 0000000000000000 RSI: ffffffff89746018 RDI: 000000000000004c
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff8aae3e70 R12: 0000000000000000
R13: 0000000000000260 R14: 0000000000000260 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8880983c2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005582615a5008 CR3: 000000007007e000 CR4: 0000000000752ef0
PKRU: 55555554
Call Trace:
<TASK>
__kasan_check_byte+0x12/0x40
lock_acquire+0x79/0x2e0
lock_sock_nested+0x48/0x100
? l2cap_sock_ready_cb+0x46/0x160
l2cap_sock_ready_cb+0x46/0x160
l2cap_conn_start+0x779/0xff0
? __pfx_l2cap_conn_start+0x10/0x10
? l2cap_info_timeout+0x60/0xa0
? __pfx___mutex_lock+0x10/0x10
l2cap_info_timeout+0x68/0xa0
? process_scheduled_works+0xa8d/0x18c0
process_scheduled_works+0xb6e/0x18c0
? __pfx_process_scheduled_works+0x10/0x10
? assign_work+0x3d5/0x5e0
worker_thread+0xa53/0xfc0
kthread+0x388/0x470
? __pfx_worker_thread+0x10/0x10
? __pfx_kthread+0x10/0x10
ret_from_fork+0x51e/0xb90
? __pfx_ret_from_fork+0x10/0x10
veth1_macvtap: entered promiscuous mode
? __switch_to+0xc7d/0x1450
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
batman_adv: batadv0: Interface activated: batadv_slave_0
batman_adv: batadv0: Interface activated: batadv_slave_1
netdevsim netdevsim7 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim7 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim7 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim7 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
RIP: 0010:kasan_byte_accessible+0x12/0x30
Code: 79 ff ff ff 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 48 c1 ef 03 48 b8 00 00 00 00 00 fc ff df <0f> b6 04 07 3c 08 0f 92 c0 c3 cc cce
ieee80211 phy39: Selected rate control algorithm 'minstrel_ht'
RSP: 0018:ffffc90006e0f808 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffffffff89746018 RCX: 0000000080000001
RDX: 0000000000000000 RSI: ffffffff89746018 RDI: 000000000000004c
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff8aae3e70 R12: 0000000000000000
R13: 0000000000000260 R14: 0000000000000260 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8880983c2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7e16139e9c CR3: 000000000e74e000 CR4: 0000000000752ef0
PKRU: 55555554
Kernel panic - not syncing: Fatal exception |
| In the Linux kernel, the following vulnerability has been resolved:
module: Fix kernel panic when a symbol st_shndx is out of bounds
The module loader doesn't check for bounds of the ELF section index in
simplify_symbols():
for (i = 1; i < symsec->sh_size / sizeof(Elf_Sym); i++) {
const char *name = info->strtab + sym[i].st_name;
switch (sym[i].st_shndx) {
case SHN_COMMON:
[...]
default:
/* Divert to percpu allocation if a percpu var. */
if (sym[i].st_shndx == info->index.pcpu)
secbase = (unsigned long)mod_percpu(mod);
else
/** HERE --> **/ secbase = info->sechdrs[sym[i].st_shndx].sh_addr;
sym[i].st_value += secbase;
break;
}
}
A symbol with an out-of-bounds st_shndx value, for example 0xffff
(known as SHN_XINDEX or SHN_HIRESERVE), may cause a kernel panic:
BUG: unable to handle page fault for address: ...
RIP: 0010:simplify_symbols+0x2b2/0x480
...
Kernel panic - not syncing: Fatal exception
This can happen when module ELF is legitimately using SHN_XINDEX or
when it is corrupted.
Add a bounds check in simplify_symbols() to validate that st_shndx is
within the valid range before using it.
This issue was discovered due to a bug in llvm-objcopy, see relevant
discussion for details [1].
[1] https://lore.kernel.org/linux-modules/20251224005752.201911-1-ihor.solodrai@linux.dev/ |
| In the Linux kernel, the following vulnerability has been resolved:
virtio_net: Fix UAF on dst_ops when IFF_XMIT_DST_RELEASE is cleared and napi_tx is false
A UAF issue occurs when the virtio_net driver is configured with napi_tx=N
and the device's IFF_XMIT_DST_RELEASE flag is cleared
(e.g., during the configuration of tc route filter rules).
When IFF_XMIT_DST_RELEASE is removed from the net_device, the network stack
expects the driver to hold the reference to skb->dst until the packet
is fully transmitted and freed. In virtio_net with napi_tx=N,
skbs may remain in the virtio transmit ring for an extended period.
If the network namespace is destroyed while these skbs are still pending,
the corresponding dst_ops structure has freed. When a subsequent packet
is transmitted, free_old_xmit() is triggered to clean up old skbs.
It then calls dst_release() on the skb associated with the stale dst_entry.
Since the dst_ops (referenced by the dst_entry) has already been freed,
a UAF kernel paging request occurs.
fix it by adds skb_dst_drop(skb) in start_xmit to explicitly release
the dst reference before the skb is queued in virtio_net.
Call Trace:
Unable to handle kernel paging request at virtual address ffff80007e150000
CPU: 2 UID: 0 PID: 6236 Comm: ping Kdump: loaded Not tainted 7.0.0-rc1+ #6 PREEMPT
...
percpu_counter_add_batch+0x3c/0x158 lib/percpu_counter.c:98 (P)
dst_release+0xe0/0x110 net/core/dst.c:177
skb_release_head_state+0xe8/0x108 net/core/skbuff.c:1177
sk_skb_reason_drop+0x54/0x2d8 net/core/skbuff.c:1255
dev_kfree_skb_any_reason+0x64/0x78 net/core/dev.c:3469
napi_consume_skb+0x1c4/0x3a0 net/core/skbuff.c:1527
__free_old_xmit+0x164/0x230 drivers/net/virtio_net.c:611 [virtio_net]
free_old_xmit drivers/net/virtio_net.c:1081 [virtio_net]
start_xmit+0x7c/0x530 drivers/net/virtio_net.c:3329 [virtio_net]
...
Reproduction Steps:
NETDEV="enp3s0"
config_qdisc_route_filter() {
tc qdisc del dev $NETDEV root
tc qdisc add dev $NETDEV root handle 1: prio
tc filter add dev $NETDEV parent 1:0 \
protocol ip prio 100 route to 100 flowid 1:1
ip route add 192.168.1.100/32 dev $NETDEV realm 100
}
test_ns() {
ip netns add testns
ip link set $NETDEV netns testns
ip netns exec testns ifconfig $NETDEV 10.0.32.46/24
ip netns exec testns ping -c 1 10.0.32.1
ip netns del testns
}
config_qdisc_route_filter
test_ns
sleep 2
test_ns |
| In the Linux kernel, the following vulnerability has been resolved:
team: fix header_ops type confusion with non-Ethernet ports
Similar to commit 950803f72547 ("bonding: fix type confusion in
bond_setup_by_slave()") team has the same class of header_ops type
confusion.
For non-Ethernet ports, team_setup_by_port() copies port_dev->header_ops
directly. When the team device later calls dev_hard_header() or
dev_parse_header(), these callbacks can run with the team net_device
instead of the real lower device, so netdev_priv(dev) is interpreted as
the wrong private type and can crash.
The syzbot report shows a crash in bond_header_create(), but the root
cause is in team: the topology is gre -> bond -> team, and team calls
the inherited header_ops with its own net_device instead of the lower
device, so bond_header_create() receives a team device and interprets
netdev_priv() as bonding private data, causing a type confusion crash.
Fix this by introducing team header_ops wrappers for create/parse,
selecting a team port under RCU, and calling the lower device callbacks
with port->dev, so each callback always sees the correct net_device
context.
Also pass the selected lower device to the lower parse callback, so
recursion is bounded in stacked non-Ethernet topologies and parse
callbacks always run with the correct device context. |
| In the Linux kernel, the following vulnerability has been resolved:
cxl/port: Fix use after free of parent_port in cxl_detach_ep()
cxl_detach_ep() is called during bottom-up removal when all CXL memory
devices beneath a switch port have been removed. For each port in the
hierarchy it locks both the port and its parent, removes the endpoint,
and if the port is now empty, marks it dead and unregisters the port
by calling delete_switch_port(). There are two places during this work
where the parent_port may be used after freeing:
First, a concurrent detach may have already processed a port by the
time a second worker finds it via bus_find_device(). Without pinning
parent_port, it may already be freed when we discover port->dead and
attempt to unlock the parent_port. In a production kernel that's a
silent memory corruption, with lock debug, it looks like this:
[]DEBUG_LOCKS_WARN_ON(__owner_task(owner) != get_current())
[]WARNING: kernel/locking/mutex.c:949 at __mutex_unlock_slowpath+0x1ee/0x310
[]Call Trace:
[]mutex_unlock+0xd/0x20
[]cxl_detach_ep+0x180/0x400 [cxl_core]
[]devm_action_release+0x10/0x20
[]devres_release_all+0xa8/0xe0
[]device_unbind_cleanup+0xd/0xa0
[]really_probe+0x1a6/0x3e0
Second, delete_switch_port() releases three devm actions registered
against parent_port. The last of those is unregister_port() and it
calls device_unregister() on the child port, which can cascade. If
parent_port is now also empty the device core may unregister and free
it too. So by the time delete_switch_port() returns, parent_port may
be free, and the subsequent device_unlock(&parent_port->dev) operates
on freed memory. The kernel log looks same as above, with a different
offset in cxl_detach_ep().
Both of these issues stem from the absence of a lifetime guarantee
between a child port and its parent port.
Establish a lifetime rule for ports: child ports hold a reference to
their parent device until release. Take the reference when the port
is allocated and drop it when released. This ensures the parent is
valid for the full lifetime of the child and eliminates the use after
free window in cxl_detach_ep().
This is easily reproduced with a reload of cxl_acpi in QEMU with CXL
devices present. |
