In the Linux kernel, the following vulnerability has been resolved:
drm/amdkfd: Fix UBSAN shift-out-of-bounds warning
If get_num_sdma_queues or get_num_xgmi_sdma_queues is 0, we end up
doing a shift operation where the number of bits shifted equals
number of bits in the operand. This behaviour is undefined.
Set num_sdma_queues or num_xgmi_sdma_queues to ULLONG_MAX, if the
count is >= number of bits in the operand.
Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1472
In the Linux kernel, the following vulnerability has been resolved:
net: phylink: add lock for serializing concurrent pl->phydev writes with resolver
Currently phylink_resolve() protects itself against concurrent
phylink_bringup_phy() or phylink_disconnect_phy() calls which modify
pl->phydev by relying on pl->state_mutex.
The problem is that in phylink_resolve(), pl->state_mutex is in a lock
inversion state with pl->phydev->lock. So pl->phydev->lock needs to be
acquired prior to pl->state_mutex. But that requires dereferencing
pl->phydev in the first place, and without pl->state_mutex, that is
racy.
Hence the reason for the extra lock. Currently it is redundant, but it
will serve a functional purpose once mutex_lock(&phy->lock) will be
moved outside of the mutex_lock(&pl->state_mutex) section.
Another alternative considered would have been to let phylink_resolve()
acquire the rtnl_mutex, which is also held when phylink_bringup_phy()
and phylink_disconnect_phy() are called. But since phylink_disconnect_phy()
runs under rtnl_lock(), it would deadlock with phylink_resolve() when
calling flush_work(&pl->resolve). Additionally, it would have been
undesirable because it would have unnecessarily blocked many other call
paths as well in the entire kernel, so the smaller-scoped lock was
preferred.
In the Linux kernel, the following vulnerability has been resolved:
mfd: arizona: Use pm_runtime_resume_and_get() to prevent refcnt leak
In arizona_clk32k_enable(), we should use pm_runtime_resume_and_get()
as pm_runtime_get_sync() will increase the refcnt even when it
returns an error.
In the Linux kernel, the following vulnerability has been resolved:
firewire: net: fix use after free in fwnet_finish_incoming_packet()
The netif_rx() function frees the skb so we can't dereference it to
save the skb->len.
In the Linux kernel, the following vulnerability has been resolved:
media: uvcvideo: Handle cameras with invalid descriptors
If the source entity does not contain any pads, do not create a link.
In the Linux kernel, the following vulnerability has been resolved:
x86/MCE: Always save CS register on AMD Zen IF Poison errors
The Instruction Fetch (IF) units on current AMD Zen-based systems do not
guarantee a synchronous #MC is delivered for poison consumption errors.
Therefore, MCG_STATUS[EIPV|RIPV] will not be set. However, the
microarchitecture does guarantee that the exception is delivered within
the same context. In other words, the exact rIP is not known, but the
context is known to not have changed.
There is no architecturally-defined method to determine this behavior.
The Code Segment (CS) register is always valid on such IF unit poison
errors regardless of the value of MCG_STATUS[EIPV|RIPV].
Add a quirk to save the CS register for poison consumption from the IF
unit banks.
This is needed to properly determine the context of the error.
Otherwise, the severity grading function will assume the context is
IN_KERNEL due to the m->cs value being 0 (the initialized value). This
leads to unnecessary kernel panics on data poison errors due to the
kernel believing the poison consumption occurred in kernel context.
In the Linux kernel, the following vulnerability has been resolved:
media: platform: mediatek: vpu: fix NULL ptr dereference
If pdev is NULL, then it is still dereferenced.
This fixes this smatch warning:
drivers/media/platform/mediatek/vpu/mtk_vpu.c:570 vpu_load_firmware() warn: address of NULL pointer 'pdev'
In the Linux kernel, the following vulnerability has been resolved:
btrfs: don't check PageError in __extent_writepage
__extent_writepage currenly sets PageError whenever any error happens,
and the also checks for PageError to decide if to call error handling.
This leads to very unclear responsibility for cleaning up on errors.
In the VM and generic writeback helpers the basic idea is that once
I/O is fired off all error handling responsibility is delegated to the
end I/O handler. But if that end I/O handler sets the PageError bit,
and the submitter checks it, the bit could in some cases leak into the
submission context for fast enough I/O.
Fix this by simply not checking PageError and just using the local
ret variable to check for submission errors. This also fundamentally
solves the long problem documented in a comment in __extent_writepage
by never leaking the error bit into the submission context.
In the Linux kernel, the following vulnerability has been resolved:
rcu: Protect rcu_print_task_exp_stall() ->exp_tasks access
For kernels built with CONFIG_PREEMPT_RCU=y, the following scenario can
result in a NULL-pointer dereference:
CPU1 CPU2
rcu_preempt_deferred_qs_irqrestore rcu_print_task_exp_stall
if (special.b.blocked) READ_ONCE(rnp->exp_tasks) != NULL
raw_spin_lock_rcu_node
np = rcu_next_node_entry(t, rnp)
if (&t->rcu_node_entry == rnp->exp_tasks)
WRITE_ONCE(rnp->exp_tasks, np)
....
raw_spin_unlock_irqrestore_rcu_node
raw_spin_lock_irqsave_rcu_node
t = list_entry(rnp->exp_tasks->prev,
struct task_struct, rcu_node_entry)
(if rnp->exp_tasks is NULL, this
will dereference a NULL pointer)
The problem is that CPU2 accesses the rcu_node structure's->exp_tasks
field without holding the rcu_node structure's ->lock and CPU2 did
not observe CPU1's change to rcu_node structure's ->exp_tasks in time.
Therefore, if CPU1 sets rcu_node structure's->exp_tasks pointer to NULL,
then CPU2 might dereference that NULL pointer.
This commit therefore holds the rcu_node structure's ->lock while
accessing that structure's->exp_tasks field.
[ paulmck: Apply Frederic Weisbecker feedback. ]