In the Linux kernel, the following vulnerability has been resolved:
scsi: megaraid_sas: Fix for a potential deadlock
This fixes a 'possible circular locking dependency detected' warning
CPU0 CPU1
---- ----
lock(&instance->reset_mutex);
lock(&shost->scan_mutex);
lock(&instance->reset_mutex);
lock(&shost->scan_mutex);
Fix this by temporarily releasing the reset_mutex.
In the Linux kernel, the following vulnerability has been resolved:
drm/dp_mst: Ensure mst_primary pointer is valid in drm_dp_mst_handle_up_req()
While receiving an MST up request message from one thread in
drm_dp_mst_handle_up_req(), the MST topology could be removed from
another thread via drm_dp_mst_topology_mgr_set_mst(false), freeing
mst_primary and setting drm_dp_mst_topology_mgr::mst_primary to NULL.
This could lead to a NULL deref/use-after-free of mst_primary in
drm_dp_mst_handle_up_req().
Avoid the above by holding a reference for mst_primary in
drm_dp_mst_handle_up_req() while it's used.
v2: Fix kfreeing the request if getting an mst_primary reference fails.
In the Linux kernel, the following vulnerability has been resolved:
drm/modes: Avoid divide by zero harder in drm_mode_vrefresh()
drm_mode_vrefresh() is trying to avoid divide by zero
by checking whether htotal or vtotal are zero. But we may
still end up with a div-by-zero of vtotal*htotal*...
In the Linux kernel, the following vulnerability has been resolved:
dma-debug: fix a possible deadlock on radix_lock
radix_lock() shouldn't be held while holding dma_hash_entry[idx].lock
otherwise, there's a possible deadlock scenario when
dma debug API is called holding rq_lock():
CPU0 CPU1 CPU2
dma_free_attrs()
check_unmap() add_dma_entry() __schedule() //out
(A) rq_lock()
get_hash_bucket()
(A) dma_entry_hash
check_sync()
(A) radix_lock() (W) dma_entry_hash
dma_entry_free()
(W) radix_lock()
// CPU2's one
(W) rq_lock()
CPU1 situation can happen when it extending radix tree and
it tries to wake up kswapd via wake_all_kswapd().
CPU2 situation can happen while perf_event_task_sched_out()
(i.e. dma sync operation is called while deleting perf_event using
etm and etr tmc which are Arm Coresight hwtracing driver backends).
To remove this possible situation, call dma_entry_free() after
put_hash_bucket() in check_unmap().
In the Linux kernel, the following vulnerability has been resolved:
dlm: fix possible lkb_resource null dereference
This patch fixes a possible null pointer dereference when this function is
called from request_lock() as lkb->lkb_resource is not assigned yet,
only after validate_lock_args() by calling attach_lkb(). Another issue
is that a resource name could be a non printable bytearray and we cannot
assume to be ASCII coded.
The log functionality is probably never being hit when DLM is used in
normal way and no debug logging is enabled. The null pointer dereference
can only occur on a new created lkb that does not have the resource
assigned yet, it probably never hits the null pointer dereference but we
should be sure that other changes might not change this behaviour and we
actually can hit the mentioned null pointer dereference.
In this patch we just drop the printout of the resource name, the lkb id
is enough to make a possible connection to a resource name if this
exists.
In the Linux kernel, the following vulnerability has been resolved:
pinmux: Use sequential access to access desc->pinmux data
When two client of the same gpio call pinctrl_select_state() for the
same functionality, we are seeing NULL pointer issue while accessing
desc->mux_owner.
Let's say two processes A, B executing in pin_request() for the same pin
and process A updates the desc->mux_usecount but not yet updated the
desc->mux_owner while process B see the desc->mux_usecount which got
updated by A path and further executes strcmp and while accessing
desc->mux_owner it crashes with NULL pointer.
Serialize the access to mux related setting with a mutex lock.
cpu0 (process A) cpu1(process B)
pinctrl_select_state() { pinctrl_select_state() {
pin_request() { pin_request() {
...
....
} else {
desc->mux_usecount++;
desc->mux_usecount && strcmp(desc->mux_owner, owner)) {
if (desc->mux_usecount > 1)
return 0;
desc->mux_owner = owner;
} }
In the Linux kernel, the following vulnerability has been resolved:
powerpc/prom_init: Fixup missing powermac #size-cells
On some powermacs `escc` nodes are missing `#size-cells` properties,
which is deprecated and now triggers a warning at boot since commit
045b14ca5c36 ("of: WARN on deprecated #address-cells/#size-cells
handling").
For example:
Missing '#size-cells' in /pci@f2000000/mac-io@c/escc@13000
WARNING: CPU: 0 PID: 0 at drivers/of/base.c:133 of_bus_n_size_cells+0x98/0x108
Hardware name: PowerMac3,1 7400 0xc0209 PowerMac
...
Call Trace:
of_bus_n_size_cells+0x98/0x108 (unreliable)
of_bus_default_count_cells+0x40/0x60
__of_get_address+0xc8/0x21c
__of_address_to_resource+0x5c/0x228
pmz_init_port+0x5c/0x2ec
pmz_probe.isra.0+0x144/0x1e4
pmz_console_init+0x10/0x48
console_init+0xcc/0x138
start_kernel+0x5c4/0x694
As powermacs boot via prom_init it's possible to add the missing
properties to the device tree during boot, avoiding the warning. Note
that `escc-legacy` nodes are also missing `#size-cells` properties, but
they are skipped by the macio driver, so leave them alone.
Depends-on: 045b14ca5c36 ("of: WARN on deprecated #address-cells/#size-cells handling")
In the Linux kernel, the following vulnerability has been resolved:
ACPI: x86: Add adev NULL check to acpi_quirk_skip_serdev_enumeration()
acpi_dev_hid_match() does not check for adev == NULL, dereferencing
it unconditional.
Add a check for adev being NULL before calling acpi_dev_hid_match().
At the moment acpi_quirk_skip_serdev_enumeration() is never called with
a controller_parent without an ACPI companion, but better safe than sorry.
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Adding array index check to prevent memory corruption
[Why & How]
Array indices out of bound caused memory corruption. Adding checks to
ensure that array index stays in bound.