In the Linux kernel, the following vulnerability has been resolved:
power: supply: bq25890: Fix external_power_changed race
bq25890_charger_external_power_changed() dereferences bq->charger,
which gets sets in bq25890_power_supply_init() like this:
bq->charger = devm_power_supply_register(bq->dev, &bq->desc, &psy_cfg);
As soon as devm_power_supply_register() has called device_add()
the external_power_changed callback can get called. So there is a window
where bq25890_charger_external_power_changed() may get called while
bq->charger has not been set yet leading to a NULL pointer dereference.
This race hits during boot sometimes on a Lenovo Yoga Book 1 yb1-x90f
when the cht_wcove_pwrsrc (extcon) power_supply is done with detecting
the connected charger-type which happens to exactly hit the small window:
BUG: kernel NULL pointer dereference, address: 0000000000000018
<snip>
RIP: 0010:__power_supply_is_supplied_by+0xb/0xb0
<snip>
Call Trace:
<TASK>
__power_supply_get_supplier_property+0x19/0x50
class_for_each_device+0xb1/0xe0
power_supply_get_property_from_supplier+0x2e/0x50
bq25890_charger_external_power_changed+0x38/0x1b0 [bq25890_charger]
__power_supply_changed_work+0x30/0x40
class_for_each_device+0xb1/0xe0
power_supply_changed_work+0x5f/0xe0
<snip>
Fixing this is easy. The external_power_changed callback gets passed
the power_supply which will eventually get stored in bq->charger,
so bq25890_charger_external_power_changed() can simply directly use
the passed in psy argument which is always valid.
In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix null pointer dereference in tracing_err_log_open()
Fix an issue in function 'tracing_err_log_open'.
The function doesn't call 'seq_open' if the file is opened only with
write permissions, which results in 'file->private_data' being left as null.
If we then use 'lseek' on that opened file, 'seq_lseek' dereferences
'file->private_data' in 'mutex_lock(&m->lock)', resulting in a kernel panic.
Writing to this node requires root privileges, therefore this bug
has very little security impact.
Tracefs node: /sys/kernel/tracing/error_log
Example Kernel panic:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000038
Call trace:
mutex_lock+0x30/0x110
seq_lseek+0x34/0xb8
__arm64_sys_lseek+0x6c/0xb8
invoke_syscall+0x58/0x13c
el0_svc_common+0xc4/0x10c
do_el0_svc+0x24/0x98
el0_svc+0x24/0x88
el0t_64_sync_handler+0x84/0xe4
el0t_64_sync+0x1b4/0x1b8
Code: d503201f aa0803e0 aa1f03e1 aa0103e9 (c8e97d02)
---[ end trace 561d1b49c12cf8a5 ]---
Kernel panic - not syncing: Oops: Fatal exception
In the Linux kernel, the following vulnerability has been resolved:
usb: ucsi_acpi: Increase the command completion timeout
Commit 130a96d698d7 ("usb: typec: ucsi: acpi: Increase command
completion timeout value") increased the timeout from 5 seconds
to 60 seconds due to issues related to alternate mode discovery.
After the alternate mode discovery switch to polled mode
the timeout was reduced, but instead of being set back to
5 seconds it was reduced to 1 second.
This is causing problems when using a Lenovo ThinkPad X1 yoga gen7
connected over Type-C to a LG 27UL850-W (charging DP over Type-C).
When the monitor is already connected at boot the following error
is logged: "PPM init failed (-110)", /sys/class/typec is empty and
on unplugging the NULL pointer deref fixed earlier in this series
happens.
When the monitor is connected after boot the following error
is logged instead: "GET_CONNECTOR_STATUS failed (-110)".
Setting the timeout back to 5 seconds fixes both cases.
In the Linux kernel, the following vulnerability has been resolved:
x86/resctrl: Clear staged_config[] before and after it is used
As a temporary storage, staged_config[] in rdt_domain should be cleared
before and after it is used. The stale value in staged_config[] could
cause an MSR access error.
Here is a reproducer on a system with 16 usable CLOSIDs for a 15-way L3
Cache (MBA should be disabled if the number of CLOSIDs for MB is less than
16.) :
mount -t resctrl resctrl -o cdp /sys/fs/resctrl
mkdir /sys/fs/resctrl/p{1..7}
umount /sys/fs/resctrl/
mount -t resctrl resctrl /sys/fs/resctrl
mkdir /sys/fs/resctrl/p{1..8}
An error occurs when creating resource group named p8:
unchecked MSR access error: WRMSR to 0xca0 (tried to write 0x00000000000007ff) at rIP: 0xffffffff82249142 (cat_wrmsr+0x32/0x60)
Call Trace:
<IRQ>
__flush_smp_call_function_queue+0x11d/0x170
__sysvec_call_function+0x24/0xd0
sysvec_call_function+0x89/0xc0
</IRQ>
<TASK>
asm_sysvec_call_function+0x16/0x20
When creating a new resource control group, hardware will be configured
by the following process:
rdtgroup_mkdir()
rdtgroup_mkdir_ctrl_mon()
rdtgroup_init_alloc()
resctrl_arch_update_domains()
resctrl_arch_update_domains() iterates and updates all resctrl_conf_type
whose have_new_ctrl is true. Since staged_config[] holds the same values as
when CDP was enabled, it will continue to update the CDP_CODE and CDP_DATA
configurations. When group p8 is created, get_config_index() called in
resctrl_arch_update_domains() will return 16 and 17 as the CLOSIDs for
CDP_CODE and CDP_DATA, which will be translated to an invalid register -
0xca0 in this scenario.
Fix it by clearing staged_config[] before and after it is used.
[reinette: re-order commit tags]
In the Linux kernel, the following vulnerability has been resolved:
vfio/type1: prevent underflow of locked_vm via exec()
When a vfio container is preserved across exec, the task does not change,
but it gets a new mm with locked_vm=0, and loses the count from existing
dma mappings. If the user later unmaps a dma mapping, locked_vm underflows
to a large unsigned value, and a subsequent dma map request fails with
ENOMEM in __account_locked_vm.
To avoid underflow, grab and save the mm at the time a dma is mapped.
Use that mm when adjusting locked_vm, rather than re-acquiring the saved
task's mm, which may have changed. If the saved mm is dead, do nothing.
locked_vm is incremented for existing mappings in a subsequent patch.
In the Linux kernel, the following vulnerability has been resolved:
igb: Fix igb_down hung on surprise removal
In a setup where a Thunderbolt hub connects to Ethernet and a display
through USB Type-C, users may experience a hung task timeout when they
remove the cable between the PC and the Thunderbolt hub.
This is because the igb_down function is called multiple times when
the Thunderbolt hub is unplugged. For example, the igb_io_error_detected
triggers the first call, and the igb_remove triggers the second call.
The second call to igb_down will block at napi_synchronize.
Here's the call trace:
__schedule+0x3b0/0xddb
? __mod_timer+0x164/0x5d3
schedule+0x44/0xa8
schedule_timeout+0xb2/0x2a4
? run_local_timers+0x4e/0x4e
msleep+0x31/0x38
igb_down+0x12c/0x22a [igb 6615058754948bfde0bf01429257eb59f13030d4]
__igb_close+0x6f/0x9c [igb 6615058754948bfde0bf01429257eb59f13030d4]
igb_close+0x23/0x2b [igb 6615058754948bfde0bf01429257eb59f13030d4]
__dev_close_many+0x95/0xec
dev_close_many+0x6e/0x103
unregister_netdevice_many+0x105/0x5b1
unregister_netdevice_queue+0xc2/0x10d
unregister_netdev+0x1c/0x23
igb_remove+0xa7/0x11c [igb 6615058754948bfde0bf01429257eb59f13030d4]
pci_device_remove+0x3f/0x9c
device_release_driver_internal+0xfe/0x1b4
pci_stop_bus_device+0x5b/0x7f
pci_stop_bus_device+0x30/0x7f
pci_stop_bus_device+0x30/0x7f
pci_stop_and_remove_bus_device+0x12/0x19
pciehp_unconfigure_device+0x76/0xe9
pciehp_disable_slot+0x6e/0x131
pciehp_handle_presence_or_link_change+0x7a/0x3f7
pciehp_ist+0xbe/0x194
irq_thread_fn+0x22/0x4d
? irq_thread+0x1fd/0x1fd
irq_thread+0x17b/0x1fd
? irq_forced_thread_fn+0x5f/0x5f
kthread+0x142/0x153
? __irq_get_irqchip_state+0x46/0x46
? kthread_associate_blkcg+0x71/0x71
ret_from_fork+0x1f/0x30
In this case, igb_io_error_detected detaches the network interface
and requests a PCIE slot reset, however, the PCIE reset callback is
not being invoked and thus the Ethernet connection breaks down.
As the PCIE error in this case is a non-fatal one, requesting a
slot reset can be avoided.
This patch fixes the task hung issue and preserves Ethernet
connection by ignoring non-fatal PCIE errors.
In the Linux kernel, the following vulnerability has been resolved:
ext4: avoid deadlock in fs reclaim with page writeback
Ext4 has a filesystem wide lock protecting ext4_writepages() calls to
avoid races with switching of journalled data flag or inode format. This
lock can however cause a deadlock like:
CPU0 CPU1
ext4_writepages()
percpu_down_read(sbi->s_writepages_rwsem);
ext4_change_inode_journal_flag()
percpu_down_write(sbi->s_writepages_rwsem);
- blocks, all readers block from now on
ext4_do_writepages()
ext4_init_io_end()
kmem_cache_zalloc(io_end_cachep, GFP_KERNEL)
fs_reclaim frees dentry...
dentry_unlink_inode()
iput() - last ref =>
iput_final() - inode dirty =>
write_inode_now()...
ext4_writepages() tries to acquire sbi->s_writepages_rwsem
and blocks forever
Make sure we cannot recurse into filesystem reclaim from writeback code
to avoid the deadlock.
In the Linux kernel, the following vulnerability has been resolved:
scsi: qla2xxx: Pointer may be dereferenced
Klocwork tool reported pointer 'rport' returned from call to function
fc_bsg_to_rport() may be NULL and will be dereferenced.
Add a fix to validate rport before dereferencing.
In the Linux kernel, the following vulnerability has been resolved:
md/raid10: prevent soft lockup while flush writes
Currently, there is no limit for raid1/raid10 plugged bio. While flushing
writes, raid1 has cond_resched() while raid10 doesn't, and too many
writes can cause soft lockup.
Follow up soft lockup can be triggered easily with writeback test for
raid10 with ramdisks:
watchdog: BUG: soft lockup - CPU#10 stuck for 27s! [md0_raid10:1293]
Call Trace:
<TASK>
call_rcu+0x16/0x20
put_object+0x41/0x80
__delete_object+0x50/0x90
delete_object_full+0x2b/0x40
kmemleak_free+0x46/0xa0
slab_free_freelist_hook.constprop.0+0xed/0x1a0
kmem_cache_free+0xfd/0x300
mempool_free_slab+0x1f/0x30
mempool_free+0x3a/0x100
bio_free+0x59/0x80
bio_put+0xcf/0x2c0
free_r10bio+0xbf/0xf0
raid_end_bio_io+0x78/0xb0
one_write_done+0x8a/0xa0
raid10_end_write_request+0x1b4/0x430
bio_endio+0x175/0x320
brd_submit_bio+0x3b9/0x9b7 [brd]
__submit_bio+0x69/0xe0
submit_bio_noacct_nocheck+0x1e6/0x5a0
submit_bio_noacct+0x38c/0x7e0
flush_pending_writes+0xf0/0x240
raid10d+0xac/0x1ed0
Fix the problem by adding cond_resched() to raid10 like what raid1 did.
Note that unlimited plugged bio still need to be optimized, for example,
in the case of lots of dirty pages writeback, this will take lots of
memory and io will spend a long time in plug, hence io latency is bad.