| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: usb-audio: Prevent excessive number of frames
In this case, the user constructed the parameters with maxpacksize 40
for rate 22050 / pps 1000, and packsize[0] 22 packsize[1] 23. The buffer
size for each data URB is maxpacksize * packets, which in this example
is 40 * 6 = 240; When the user performs a write operation to send audio
data into the ALSA PCM playback stream, the calculated number of frames
is packsize[0] * packets = 264, which exceeds the allocated URB buffer
size, triggering the out-of-bounds (OOB) issue reported by syzbot [1].
Added a check for the number of single data URB frames when calculating
the number of frames to prevent [1].
[1]
BUG: KASAN: slab-out-of-bounds in copy_to_urb+0x261/0x460 sound/usb/pcm.c:1487
Write of size 264 at addr ffff88804337e800 by task syz.0.17/5506
Call Trace:
copy_to_urb+0x261/0x460 sound/usb/pcm.c:1487
prepare_playback_urb+0x953/0x13d0 sound/usb/pcm.c:1611
prepare_outbound_urb+0x377/0xc50 sound/usb/endpoint.c:333 |
| In the Linux kernel, the following vulnerability has been resolved:
spi: tegra210-quad: Protect curr_xfer check in IRQ handler
Now that all other accesses to curr_xfer are done under the lock,
protect the curr_xfer NULL check in tegra_qspi_isr_thread() with the
spinlock. Without this protection, the following race can occur:
CPU0 (ISR thread) CPU1 (timeout path)
---------------- -------------------
if (!tqspi->curr_xfer)
// sees non-NULL
spin_lock()
tqspi->curr_xfer = NULL
spin_unlock()
handle_*_xfer()
spin_lock()
t = tqspi->curr_xfer // NULL!
... t->len ... // NULL dereference!
With this patch, all curr_xfer accesses are now properly synchronized.
Although all accesses to curr_xfer are done under the lock, in
tegra_qspi_isr_thread() it checks for NULL, releases the lock and
reacquires it later in handle_cpu_based_xfer()/handle_dma_based_xfer().
There is a potential for an update in between, which could cause a NULL
pointer dereference.
To handle this, add a NULL check inside the handlers after acquiring
the lock. This ensures that if the timeout path has already cleared
curr_xfer, the handler will safely return without dereferencing the
NULL pointer. |
| In the Linux kernel, the following vulnerability has been resolved:
bonding: fix use-after-free due to enslave fail after slave array update
Fix a use-after-free which happens due to enslave failure after the new
slave has been added to the array. Since the new slave can be used for Tx
immediately, we can use it after it has been freed by the enslave error
cleanup path which frees the allocated slave memory. Slave update array is
supposed to be called last when further enslave failures are not expected.
Move it after xdp setup to avoid any problems.
It is very easy to reproduce the problem with a simple xdp_pass prog:
ip l add bond1 type bond mode balance-xor
ip l set bond1 up
ip l set dev bond1 xdp object xdp_pass.o sec xdp_pass
ip l add dumdum type dummy
Then run in parallel:
while :; do ip l set dumdum master bond1 1>/dev/null 2>&1; done;
mausezahn bond1 -a own -b rand -A rand -B 1.1.1.1 -c 0 -t tcp "dp=1-1023, flags=syn"
The crash happens almost immediately:
[ 605.602850] Oops: general protection fault, probably for non-canonical address 0xe0e6fc2460000137: 0000 [#1] SMP KASAN NOPTI
[ 605.602916] KASAN: maybe wild-memory-access in range [0x07380123000009b8-0x07380123000009bf]
[ 605.602946] CPU: 0 UID: 0 PID: 2445 Comm: mausezahn Kdump: loaded Tainted: G B 6.19.0-rc6+ #21 PREEMPT(voluntary)
[ 605.602979] Tainted: [B]=BAD_PAGE
[ 605.602998] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 605.603032] RIP: 0010:netdev_core_pick_tx+0xcd/0x210
[ 605.603063] Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 3e 01 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 6b 08 49 8d 7d 30 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 25 01 00 00 49 8b 45 30 4c 89 e2 48 89 ee 48 89
[ 605.603111] RSP: 0018:ffff88817b9af348 EFLAGS: 00010213
[ 605.603145] RAX: dffffc0000000000 RBX: ffff88817d28b420 RCX: 0000000000000000
[ 605.603172] RDX: 00e7002460000137 RSI: 0000000000000008 RDI: 07380123000009be
[ 605.603199] RBP: ffff88817b541a00 R08: 0000000000000001 R09: fffffbfff3ed8c0c
[ 605.603226] R10: ffffffff9f6c6067 R11: 0000000000000001 R12: 0000000000000000
[ 605.603253] R13: 073801230000098e R14: ffff88817d28b448 R15: ffff88817b541a84
[ 605.603286] FS: 00007f6570ef67c0(0000) GS:ffff888221dfa000(0000) knlGS:0000000000000000
[ 605.603319] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 605.603343] CR2: 00007f65712fae40 CR3: 000000011371b000 CR4: 0000000000350ef0
[ 605.603373] Call Trace:
[ 605.603392] <TASK>
[ 605.603410] __dev_queue_xmit+0x448/0x32a0
[ 605.603434] ? __pfx_vprintk_emit+0x10/0x10
[ 605.603461] ? __pfx_vprintk_emit+0x10/0x10
[ 605.603484] ? __pfx___dev_queue_xmit+0x10/0x10
[ 605.603507] ? bond_start_xmit+0xbfb/0xc20 [bonding]
[ 605.603546] ? _printk+0xcb/0x100
[ 605.603566] ? __pfx__printk+0x10/0x10
[ 605.603589] ? bond_start_xmit+0xbfb/0xc20 [bonding]
[ 605.603627] ? add_taint+0x5e/0x70
[ 605.603648] ? add_taint+0x2a/0x70
[ 605.603670] ? end_report.cold+0x51/0x75
[ 605.603693] ? bond_start_xmit+0xbfb/0xc20 [bonding]
[ 605.603731] bond_start_xmit+0x623/0xc20 [bonding] |
| In the Linux kernel, the following vulnerability has been resolved:
tracing: Add recursion protection in kernel stack trace recording
A bug was reported about an infinite recursion caused by tracing the rcu
events with the kernel stack trace trigger enabled. The stack trace code
called back into RCU which then called the stack trace again.
Expand the ftrace recursion protection to add a set of bits to protect
events from recursion. Each bit represents the context that the event is
in (normal, softirq, interrupt and NMI).
Have the stack trace code use the interrupt context to protect against
recursion.
Note, the bug showed an issue in both the RCU code as well as the tracing
stacktrace code. This only handles the tracing stack trace side of the
bug. The RCU fix will be handled separately. |
| In the Linux kernel, the following vulnerability has been resolved:
of: unittest: Fix memory leak in unittest_data_add()
In unittest_data_add(), if of_resolve_phandles() fails, the allocated
unittest_data is not freed, leading to a memory leak.
Fix this by using scope-based cleanup helper __free(kfree) for automatic
resource cleanup. This ensures unittest_data is automatically freed when
it goes out of scope in error paths.
For the success path, use retain_and_null_ptr() to transfer ownership
of the memory to the device tree and prevent double freeing. |
| In the Linux kernel, the following vulnerability has been resolved:
rxrpc: Fix data-race warning and potential load/store tearing
Fix the following:
BUG: KCSAN: data-race in rxrpc_peer_keepalive_worker / rxrpc_send_data_packet
which is reporting an issue with the reads and writes to ->last_tx_at in:
conn->peer->last_tx_at = ktime_get_seconds();
and:
keepalive_at = peer->last_tx_at + RXRPC_KEEPALIVE_TIME;
The lockless accesses to these to values aren't actually a problem as the
read only needs an approximate time of last transmission for the purposes
of deciding whether or not the transmission of a keepalive packet is
warranted yet.
Also, as ->last_tx_at is a 64-bit value, tearing can occur on a 32-bit
arch.
Fix both of these by switching to an unsigned int for ->last_tx_at and only
storing the LSW of the time64_t. It can then be reconstructed at need
provided no more than 68 years has elapsed since the last transmission. |
| In the Linux kernel, the following vulnerability has been resolved:
pNFS: Fix a deadlock when returning a delegation during open()
Ben Coddington reports seeing a hang in the following stack trace:
0 [ffffd0b50e1774e0] __schedule at ffffffff9ca05415
1 [ffffd0b50e177548] schedule at ffffffff9ca05717
2 [ffffd0b50e177558] bit_wait at ffffffff9ca061e1
3 [ffffd0b50e177568] __wait_on_bit at ffffffff9ca05cfb
4 [ffffd0b50e1775c8] out_of_line_wait_on_bit at ffffffff9ca05ea5
5 [ffffd0b50e177618] pnfs_roc at ffffffffc154207b [nfsv4]
6 [ffffd0b50e1776b8] _nfs4_proc_delegreturn at ffffffffc1506586 [nfsv4]
7 [ffffd0b50e177788] nfs4_proc_delegreturn at ffffffffc1507480 [nfsv4]
8 [ffffd0b50e1777f8] nfs_do_return_delegation at ffffffffc1523e41 [nfsv4]
9 [ffffd0b50e177838] nfs_inode_set_delegation at ffffffffc1524a75 [nfsv4]
10 [ffffd0b50e177888] nfs4_process_delegation at ffffffffc14f41dd [nfsv4]
11 [ffffd0b50e1778a0] _nfs4_opendata_to_nfs4_state at ffffffffc1503edf [nfsv4]
12 [ffffd0b50e1778c0] _nfs4_open_and_get_state at ffffffffc1504e56 [nfsv4]
13 [ffffd0b50e177978] _nfs4_do_open at ffffffffc15051b8 [nfsv4]
14 [ffffd0b50e1779f8] nfs4_do_open at ffffffffc150559c [nfsv4]
15 [ffffd0b50e177a80] nfs4_atomic_open at ffffffffc15057fb [nfsv4]
16 [ffffd0b50e177ad0] nfs4_file_open at ffffffffc15219be [nfsv4]
17 [ffffd0b50e177b78] do_dentry_open at ffffffff9c09e6ea
18 [ffffd0b50e177ba8] vfs_open at ffffffff9c0a082e
19 [ffffd0b50e177bd0] dentry_open at ffffffff9c0a0935
The issue is that the delegreturn is being asked to wait for a layout
return that cannot complete because a state recovery was initiated. The
state recovery cannot complete until the open() finishes processing the
delegations it was given.
The solution is to propagate the existing flags that indicate a
non-blocking call to the function pnfs_roc(), so that it knows not to
wait in this situation. |
| In the Linux kernel, the following vulnerability has been resolved:
dst: fix races in rt6_uncached_list_del() and rt_del_uncached_list()
syzbot was able to crash the kernel in rt6_uncached_list_flush_dev()
in an interesting way [1]
Crash happens in list_del_init()/INIT_LIST_HEAD() while writing
list->prev, while the prior write on list->next went well.
static inline void INIT_LIST_HEAD(struct list_head *list)
{
WRITE_ONCE(list->next, list); // This went well
WRITE_ONCE(list->prev, list); // Crash, @list has been freed.
}
Issue here is that rt6_uncached_list_del() did not attempt to lock
ul->lock, as list_empty(&rt->dst.rt_uncached) returned
true because the WRITE_ONCE(list->next, list) happened on the other CPU.
We might use list_del_init_careful() and list_empty_careful(),
or make sure rt6_uncached_list_del() always grabs the spinlock
whenever rt->dst.rt_uncached_list has been set.
A similar fix is neeed for IPv4.
[1]
BUG: KASAN: slab-use-after-free in INIT_LIST_HEAD include/linux/list.h:46 [inline]
BUG: KASAN: slab-use-after-free in list_del_init include/linux/list.h:296 [inline]
BUG: KASAN: slab-use-after-free in rt6_uncached_list_flush_dev net/ipv6/route.c:191 [inline]
BUG: KASAN: slab-use-after-free in rt6_disable_ip+0x633/0x730 net/ipv6/route.c:5020
Write of size 8 at addr ffff8880294cfa78 by task kworker/u8:14/3450
CPU: 0 UID: 0 PID: 3450 Comm: kworker/u8:14 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: netns cleanup_net
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xca/0x240 mm/kasan/report.c:482
kasan_report+0x118/0x150 mm/kasan/report.c:595
INIT_LIST_HEAD include/linux/list.h:46 [inline]
list_del_init include/linux/list.h:296 [inline]
rt6_uncached_list_flush_dev net/ipv6/route.c:191 [inline]
rt6_disable_ip+0x633/0x730 net/ipv6/route.c:5020
addrconf_ifdown+0x143/0x18a0 net/ipv6/addrconf.c:3853
addrconf_notify+0x1bc/0x1050 net/ipv6/addrconf.c:-1
notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
call_netdevice_notifiers net/core/dev.c:2282 [inline]
netif_close_many+0x29c/0x410 net/core/dev.c:1785
unregister_netdevice_many_notify+0xb50/0x2330 net/core/dev.c:12353
ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
ops_undo_list+0x3dc/0x990 net/core/net_namespace.c:248
cleanup_net+0x4de/0x7b0 net/core/net_namespace.c:696
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
</TASK>
Allocated by task 803:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
unpoison_slab_object mm/kasan/common.c:340 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4953 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
kmem_cache_alloc_noprof+0x18d/0x6c0 mm/slub.c:5270
dst_alloc+0x105/0x170 net/core/dst.c:89
ip6_dst_alloc net/ipv6/route.c:342 [inline]
icmp6_dst_alloc+0x75/0x460 net/ipv6/route.c:3333
mld_sendpack+0x683/0xe60 net/ipv6/mcast.c:1844
mld_send_cr net/ipv6/mcast.c:2154 [inline]
mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entr
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
drm/msm: Recover HW before retire hung submit
During recovery, it is not safe to retire the hung submit before we
recover the GPU. Retiring the submit triggers BO free and that can
result in GPU pagefaults since the GPU may be actively accessing those
BOs.
To fix this, retire the submits after gpu recovery is complete in
recover_worker().
Patchwork: https://patchwork.freedesktop.org/patch/730655/ |
| In the Linux kernel, the following vulnerability has been resolved:
staging: rtl8723bs: fix xmit_frame/xmit_buf leaks on mgnt-frame error paths
issue_beacon(), issue_probersp() and issue_asocrsp() obtain a management
xmit_frame together with its xmit_buf from the driver's fixed-size
management-TX pools via alloc_mgtxmitframe(). On the normal path the frame
is handed to dump_mgntframe(), which transfers ownership and eventually
returns both objects to their pools (the frame and, for beacons, the buf
in rtl8723bs_mgnt_xmit(); other bufs via the pending-xmitbuf/TX-completion
path).
Several error/edge paths return early after a successful
alloc_mgtxmitframe() but before dump_mgntframe(), so ownership is never
transferred and neither object is freed:
- issue_beacon(): beacon larger than 512 bytes
- issue_probersp(): cur_network->ie_length > MAX_IE_SZ
- issue_probersp(): kzalloc() of the SSID scratch buffer fails
- issue_asocrsp(): pkt_type is neither ASSOCRSP nor REASSOCRSP
Because alloc_mgtxmitframe() removes the frame and buf from their free
lists (list_del_init) without placing them on any pending list, an
orphaned pair is on no list and referenced by nobody, so it is only
reclaimed at driver teardown. Repeated hits progressively exhaust the
management-TX pools until alloc_mgtxmitframe() returns NULL and the
interface can no longer send beacons or probe/assoc responses.
Free the frame and buffer on these paths, matching the existing correct
error handling in issue_assocreq(). |
| In the Linux kernel, the following vulnerability has been resolved:
PCI: endpoint: Add missing NULL check for alloc_workqueue()
alloc_workqueue() can return NULL on memory allocation failure. Without
proper error checking, this may lead to a NULL pointer dereference when
queue_work() is later called with the NULL workqueue pointer in
epf_ntb_epc_init().
Add a NULL check immediately after alloc_workqueue() and return -ENOMEM on
failure to prevent the driver from loading with an invalid workqueue
pointer. |
| In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: handle attr_set_size() errors when truncating files
If attr_set_size() fails while truncating down, the error is silently
ignored and the inode may be left in an inconsistent state. |
| In the Linux kernel, the following vulnerability has been resolved:
net: qrtr: Drop the MHI auto_queue feature for IPCR DL channels
MHI stack offers the 'auto_queue' feature, which allows the MHI stack to
auto queue the buffers for the RX path (DL channel). Though this feature
simplifies the client driver design, it introduces race between the client
drivers and the MHI stack. For instance, with auto_queue, the 'dl_callback'
for the DL channel may get called before the client driver is fully probed.
This means, by the time the dl_callback gets called, the client driver's
structures might not be initialized, leading to NULL ptr dereference.
Currently, the drivers have to workaround this issue by initializing the
internal structures before calling mhi_prepare_for_transfer_autoqueue().
But even so, there is a chance that the client driver's internal code path
may call the MHI queue APIs before mhi_prepare_for_transfer_autoqueue() is
called, leading to similar NULL ptr dereference. This issue has been
reported on the Qcom X1E80100 CRD machines affecting boot.
So to properly fix all these races, drop the MHI 'auto_queue' feature
altogether and let the client driver (QRTR) manage the RX buffers manually.
In the QRTR driver, queue the RX buffers based on the ring length during
probe and recycle the buffers in 'dl_callback' once they are consumed. This
also warrants removing the setting of 'auto_queue' flag from controller
drivers.
Currently, this 'auto_queue' feature is only enabled for IPCR DL channel.
So only the QRTR client driver requires the modification. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: rtw88: Use devm_kmemdup() in rtw_set_supported_band()
Simplify the code by using device managed memory allocations.
This also fixes a memory leak in rtw_register_hw(). The supported bands
were not freed in the error path.
Copied from commit 145df52a8671 ("wifi: rtw89: Convert
rtw89_core_set_supported_band to use devm_*"). |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: don't WARN for connections on invalid channels
It's not clear (to me) how exactly syzbot managed to hit this,
but it seems conceivable that e.g. regulatory changed and has
disabled a channel between scanning (channel is checked to be
usable by cfg80211_get_ies_channel_number) and connecting on
the channel later.
With one scenario that isn't covered elsewhere described above,
the warning isn't good, replace it with a (more informative)
error message. |
| In the Linux kernel, the following vulnerability has been resolved:
iio: imu: st_lsm6dsx: fix iio_chan_spec for sensors without event detection
The st_lsm6dsx_acc_channels array of struct iio_chan_spec has a non-NULL
event_spec field, indicating support for IIO events. However, event
detection is not supported for all sensors, and if userspace tries to
configure accelerometer wakeup events on a sensor device that does not
support them (e.g. LSM6DS0), st_lsm6dsx_write_event() dereferences a NULL
pointer when trying to write to the wakeup register.
Define an additional struct iio_chan_spec array whose members have a NULL
event_spec field, and use this array instead of st_lsm6dsx_acc_channels for
sensors without event detection capability. |
| In the Linux kernel, the following vulnerability has been resolved:
phy: qcom-qusb2: Fix NULL pointer dereference on early suspend
Enabling runtime PM before attaching the QPHY instance as driver data
can lead to a NULL pointer dereference in runtime PM callbacks that
expect valid driver data. There is a small window where the suspend
callback may run after PM runtime enabling and before runtime forbid.
This causes a sporadic crash during boot:
```
Unable to handle kernel NULL pointer dereference at virtual address 00000000000000a1
[...]
CPU: 0 UID: 0 PID: 11 Comm: kworker/0:1 Not tainted 6.16.7+ #116 PREEMPT
Workqueue: pm pm_runtime_work
pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : qusb2_phy_runtime_suspend+0x14/0x1e0 [phy_qcom_qusb2]
lr : pm_generic_runtime_suspend+0x2c/0x44
[...]
```
Attach the QPHY instance as driver data before enabling runtime PM to
prevent NULL pointer dereference in runtime PM callbacks.
Reorder pm_runtime_enable() and pm_runtime_forbid() to prevent a
short window where an unnecessary runtime suspend can occur.
Use the devres-managed version to ensure PM runtime is symmetrically
disabled during driver removal for proper cleanup. |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix NULL dereference on root when tracing inode eviction
When evicting an inode the first thing we do is to setup tracing for it,
which implies fetching the root's id. But in btrfs_evict_inode() the
root might be NULL, as implied in the next check that we do in
btrfs_evict_inode().
Hence, we either should set the ->root_objectid to 0 in case the root is
NULL, or we move tracing setup after checking that the root is not
NULL. Setting the rootid to 0 at least gives us the possibility to trace
this call even in the case when the root is NULL, so that's the solution
taken here. |
| In the Linux kernel, the following vulnerability has been resolved:
net: dsa: properly keep track of conduit reference
Problem description
-------------------
DSA has a mumbo-jumbo of reference handling of the conduit net device
and its kobject which, sadly, is just wrong and doesn't make sense.
There are two distinct problems.
1. The OF path, which uses of_find_net_device_by_node(), never releases
the elevated refcount on the conduit's kobject. Nominally, the OF and
non-OF paths should result in objects having identical reference
counts taken, and it is already suspicious that
dsa_dev_to_net_device() has a put_device() call which is missing in
dsa_port_parse_of(), but we can actually even verify that an issue
exists. With CONFIG_DEBUG_KOBJECT_RELEASE=y, if we run this command
"before" and "after" applying this patch:
(unbind the conduit driver for net device eno2)
echo 0000:00:00.2 > /sys/bus/pci/drivers/fsl_enetc/unbind
we see these lines in the output diff which appear only with the patch
applied:
kobject: 'eno2' (ffff002009a3a6b8): kobject_release, parent 0000000000000000 (delayed 1000)
kobject: '109' (ffff0020099d59a0): kobject_release, parent 0000000000000000 (delayed 1000)
2. After we find the conduit interface one way (OF) or another (non-OF),
it can get unregistered at any time, and DSA remains with a long-lived,
but in this case stale, cpu_dp->conduit pointer. Holding the net
device's underlying kobject isn't actually of much help, it just
prevents it from being freed (but we never need that kobject
directly). What helps us to prevent the net device from being
unregistered is the parallel netdev reference mechanism (dev_hold()
and dev_put()).
Actually we actually use that netdev tracker mechanism implicitly on
user ports since commit 2f1e8ea726e9 ("net: dsa: link interfaces with
the DSA master to get rid of lockdep warnings"), via netdev_upper_dev_link().
But time still passes at DSA switch probe time between the initial
of_find_net_device_by_node() code and the user port creation time, time
during which the conduit could unregister itself and DSA wouldn't know
about it.
So we have to run of_find_net_device_by_node() under rtnl_lock() to
prevent that from happening, and release the lock only with the netdev
tracker having acquired the reference.
Do we need to keep the reference until dsa_unregister_switch() /
dsa_switch_shutdown()?
1: Maybe yes. A switch device will still be registered even if all user
ports failed to probe, see commit 86f8b1c01a0a ("net: dsa: Do not
make user port errors fatal"), and the cpu_dp->conduit pointers
remain valid. I haven't audited all call paths to see whether they
will actually use the conduit in lack of any user port, but if they
do, it seems safer to not rely on user ports for that reference.
2. Definitely yes. We support changing the conduit which a user port is
associated to, and we can get into a situation where we've moved all
user ports away from a conduit, thus no longer hold any reference to
it via the net device tracker. But we shouldn't let it go nonetheless
- see the next change in relation to dsa_tree_find_first_conduit()
and LAG conduits which disappear.
We have to be prepared to return to the physical conduit, so the CPU
port must explicitly keep another reference to it. This is also to
say: the user ports and their CPU ports may not always keep a
reference to the same conduit net device, and both are needed.
As for the conduit's kobject for the /sys/class/net/ entry, we don't
care about it, we can release it as soon as we hold the net device
object itself.
History and blame attribution
-----------------------------
The code has been refactored so many times, it is very difficult to
follow and properly attribute a blame, but I'll try to make a short
history which I hope to be correct.
We have two distinct probing paths:
- one for OF, introduced in 2016 i
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
drm/msm/dpu: Add missing NULL pointer check for pingpong interface
It is checked almost always in dpu_encoder_phys_wb_setup_ctl(), but in a
single place the check is missing.
Also use convenient locals instead of phys_enc->* where available.
Patchwork: https://patchwork.freedesktop.org/patch/693860/ |
