linux-stable.git/include/linux, branch v4.19.256

watchdog: export lockup_detector_reconfigure

2022-08-25T09:15:46+00:00

[ Upstream commit 7c56a8733d0a2a4be2438a7512566e5ce552fccf ]

In some circumstances it may be interesting to reconfigure the watchdog
from inside the kernel.

On PowerPC, this may helpful before and after a LPAR migration (LPM) is
initiated, because it implies some latencies, watchdog, and especially NMI
watchdog is expected to be triggered during this operation. Reconfiguring
the watchdog with a factor, would prevent it to happen too frequently
during LPM.

Rename lockup_detector_reconfigure() as __lockup_detector_reconfigure() and
create a new function lockup_detector_reconfigure() calling
__lockup_detector_reconfigure() under the protection of watchdog_mutex.

Signed-off-by: Laurent Dufour 
[mpe: Squash in build fix from Laurent, reported by Sachin]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20220713154729.80789-3-ldufour@linux.ibm.com
Signed-off-by: Sasha Levin

KVM: Add infrastructure and macro to mark VM as bugged

2022-08-25T09:15:31+00:00

commit 0b8f11737cffc1a406d1134b58687abc29d76b52 upstream

Signed-off-by: Sean Christopherson 
Signed-off-by: Isaku Yamahata 
Reviewed-by: Paolo Bonzini 
Message-Id: <3a0998645c328bf0895f1290e61821b70f048549.1625186503.git.isaku.yamahata@intel.com>
Signed-off-by: Paolo Bonzini 
[SG: Adjusted context for kernel version 4.19]
Signed-off-by: Stefan Ghinea 
Signed-off-by: Greg Kroah-Hartman

mfd: t7l66xb: Drop platform disable callback

2022-08-25T09:15:23+00:00

[ Upstream commit 128ac294e1b437cb8a7f2ff8ede1cde9082bddbe ]

None of the in-tree instantiations of struct t7l66xb_platform_data
provides a disable callback. So better don't dereference this function
pointer unconditionally. As there is no user, drop it completely instead
of calling it conditional.

This is a preparation for making platform remove callbacks return void.

Fixes: 1f192015ca5b ("mfd: driver for the T7L66XB TMIO SoC")
Signed-off-by: Uwe Kleine-König 
Signed-off-by: Lee Jones 
Link: https://lore.kernel.org/r/20220530192430.2108217-3-u.kleine-koenig@pengutronix.de
Signed-off-by: Sasha Levin

kfifo: fix kfifo_to_user() return type

2022-08-25T09:15:23+00:00

[ Upstream commit 045ed31e23aea840648c290dbde04797064960db ]

The kfifo_to_user() macro is supposed to return zero for success or
negative error codes.  Unfortunately, there is a signedness bug so it
returns unsigned int.  This only affects callers which try to save the
result in ssize_t and as far as I can see the only place which does that
is line6_hwdep_read().

TL;DR: s/_uint/_int/.

Link: https://lkml.kernel.org/r/YrVL3OJVLlNhIMFs@kili
Fixes: 144ecf310eb5 ("kfifo: fix kfifo_alloc() to return a signed int value")
Signed-off-by: Dan Carpenter 
Cc: Stefani Seibold 
Cc: Randy Dunlap 
Signed-off-by: Andrew Morton 
Signed-off-by: Sasha Levin

USB: HCD: Fix URB giveback issue in tasklet function

2022-08-25T09:14:57+00:00

commit 26c6c2f8a907c9e3a2f24990552a4d77235791e6 upstream.

Usb core introduce the mechanism of giveback of URB in tasklet context to
reduce hardware interrupt handling time. On some test situation(such as
FIO with 4KB block size), when tasklet callback function called to
giveback URB, interrupt handler add URB node to the bh->head list also.
If check bh->head list again after finish all URB giveback of local_list,
then it may introduce a "dynamic balance" between giveback URB and add URB
to bh->head list. This tasklet callback function may not exit for a long
time, which will cause other tasklet function calls to be delayed. Some
real-time applications(such as KB and Mouse) will see noticeable lag.

In order to prevent the tasklet function from occupying the cpu for a long
time at a time, new URBS will not be added to the local_list even though
the bh->head list is not empty. But also need to ensure the left URB
giveback to be processed in time, so add a member high_prio for structure
giveback_urb_bh to prioritize tasklet and schelule this tasklet again if
bh->head list is not empty.

At the same time, we are able to prioritize tasklet through structure
member high_prio. So, replace the local high_prio_bh variable with this
structure member in usb_hcd_giveback_urb.

Fixes: 94dfd7edfd5c ("USB: HCD: support giveback of URB in tasklet context")
Cc: stable 
Reviewed-by: Alan Stern 
Signed-off-by: Weitao Wang 
Link: https://lore.kernel.org/r/20220726074918.5114-1-WeitaoWang-oc@zhaoxin.com
Signed-off-by: Greg Kroah-Hartman

PCI: Add defines for normal and subtractive PCI bridges

2022-08-25T09:14:56+00:00

commit 904b10fb189cc15376e9bfce1ef0282e68b0b004 upstream.

Add these PCI class codes to pci_ids.h:

  PCI_CLASS_BRIDGE_PCI_NORMAL
  PCI_CLASS_BRIDGE_PCI_SUBTRACTIVE

Use these defines in all kernel code for describing PCI class codes for
normal and subtractive PCI bridges.

[bhelgaas: similar change in pci-mvebu.c]
Link: https://lore.kernel.org/r/20220214114109.26809-1-pali@kernel.org
Signed-off-by: Pali Rohár 
Signed-off-by: Bjorn Helgaas 
Cc: Guenter Roeck a
Cc: Naresh Kamboju 
[ gregkh - take only the pci_ids.h portion for stable backports ]
Signed-off-by: Greg Kroah-Hartman

add barriers to buffer_uptodate and set_buffer_uptodate

2022-08-25T09:14:51+00:00

commit d4252071b97d2027d246f6a82cbee4d52f618b47 upstream.

Let's have a look at this piece of code in __bread_slow:

	get_bh(bh);
	bh->b_end_io = end_buffer_read_sync;
	submit_bh(REQ_OP_READ, 0, bh);
	wait_on_buffer(bh);
	if (buffer_uptodate(bh))
		return bh;

Neither wait_on_buffer nor buffer_uptodate contain any memory barrier.
Consequently, if someone calls sb_bread and then reads the buffer data,
the read of buffer data may be executed before wait_on_buffer(bh) on
architectures with weak memory ordering and it may return invalid data.

Fix this bug by adding a memory barrier to set_buffer_uptodate and an
acquire barrier to buffer_uptodate (in a similar way as
folio_test_uptodate and folio_mark_uptodate).

Signed-off-by: Mikulas Patocka 
Reviewed-by: Matthew Wilcox (Oracle) 
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

tty: use new tty_insert_flip_string_and_push_buffer() in pty_write()

2022-07-29T15:10:37+00:00

commit a501ab75e7624d133a5a3c7ec010687c8b961d23 upstream.

There is a race in pty_write(). pty_write() can be called in parallel
with e.g. ioctl(TIOCSTI) or ioctl(TCXONC) which also inserts chars to
the buffer. Provided, tty_flip_buffer_push() in pty_write() is called
outside the lock, it can commit inconsistent tail. This can lead to out
of bounds writes and other issues. See the Link below.

To fix this, we have to introduce a new helper called
tty_insert_flip_string_and_push_buffer(). It does both
tty_insert_flip_string() and tty_flip_buffer_commit() under the port
lock. It also calls queue_work(), but outside the lock. See
71a174b39f10 (pty: do tty_flip_buffer_push without port->lock in
pty_write) for the reasons.

Keep the helper internal-only (in drivers' tty.h). It is not intended to
be used widely.

Link: https://seclists.org/oss-sec/2022/q2/155
Fixes: 71a174b39f10 (pty: do tty_flip_buffer_push without port->lock in pty_write)
Cc: 一只狗 
Cc: Dan Carpenter 
Suggested-by: Hillf Danton 
Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20220707082558.9250-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

tty: drop tty_schedule_flip()

2022-07-29T15:10:37+00:00

commit 5db96ef23bda6c2a61a51693c85b78b52d03f654 upstream.

Since commit a9c3f68f3cd8d (tty: Fix low_latency BUG) in 2014,
tty_flip_buffer_push() is only a wrapper to tty_schedule_flip(). All
users were converted in the previous patches, so remove
tty_schedule_flip() completely while inlining its body into
tty_flip_buffer_push().

One less exported function.

Reviewed-by: Johan Hovold 
Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20211122111648.30379-4-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

cgroup: Use separate src/dst nodes when preloading css_sets for migration

2022-07-21T19:09:26+00:00

commit 07fd5b6cdf3cc30bfde8fe0f644771688be04447 upstream.

Each cset (css_set) is pinned by its tasks. When we're moving tasks around
across csets for a migration, we need to hold the source and destination
csets to ensure that they don't go away while we're moving tasks about. This
is done by linking cset->mg_preload_node on either the
mgctx->preloaded_src_csets or mgctx->preloaded_dst_csets list. Using the
same cset->mg_preload_node for both the src and dst lists was deemed okay as
a cset can't be both the source and destination at the same time.

Unfortunately, this overloading becomes problematic when multiple tasks are
involved in a migration and some of them are identity noop migrations while
others are actually moving across cgroups. For example, this can happen with
the following sequence on cgroup1:

 #1> mkdir -p /sys/fs/cgroup/misc/a/b
 #2> echo $$ > /sys/fs/cgroup/misc/a/cgroup.procs
 #3> RUN_A_COMMAND_WHICH_CREATES_MULTIPLE_THREADS &
 #4> PID=$!
 #5> echo $PID > /sys/fs/cgroup/misc/a/b/tasks
 #6> echo $PID > /sys/fs/cgroup/misc/a/cgroup.procs

the process including the group leader back into a. In this final migration,
non-leader threads would be doing identity migration while the group leader
is doing an actual one.

After #3, let's say the whole process was in cset A, and that after #4, the
leader moves to cset B. Then, during #6, the following happens:

 1. cgroup_migrate_add_src() is called on B for the leader.

 2. cgroup_migrate_add_src() is called on A for the other threads.

 3. cgroup_migrate_prepare_dst() is called. It scans the src list.

 4. It notices that B wants to migrate to A, so it tries to A to the dst
    list but realizes that its ->mg_preload_node is already busy.

 5. and then it notices A wants to migrate to A as it's an identity
    migration, it culls it by list_del_init()'ing its ->mg_preload_node and
    putting references accordingly.

 6. The rest of migration takes place with B on the src list but nothing on
    the dst list.

This means that A isn't held while migration is in progress. If all tasks
leave A before the migration finishes and the incoming task pins it, the
cset will be destroyed leading to use-after-free.

This is caused by overloading cset->mg_preload_node for both src and dst
preload lists. We wanted to exclude the cset from the src list but ended up
inadvertently excluding it from the dst list too.

This patch fixes the issue by separating out cset->mg_preload_node into
->mg_src_preload_node and ->mg_dst_preload_node, so that the src and dst
preloadings don't interfere with each other.

Signed-off-by: Tejun Heo 
Reported-by: Mukesh Ojha 
Reported-by: shisiyuan 
Link: http://lkml.kernel.org/r/1654187688-27411-1-git-send-email-shisiyuan@xiaomi.com
Link: https://www.spinics.net/lists/cgroups/msg33313.html
Fixes: f817de98513d ("cgroup: prepare migration path for unified hierarchy")
Cc: stable@vger.kernel.org # v3.16+
Signed-off-by: Greg Kroah-Hartman