CVE-2022-49383: watchdog: rzg2l_wdt: Fix 'BUG: Invalid wait context'

CVE-2022-49383: watchdog: rzg2l_wdt: Fix 'BUG: Invalid wait context'

[Greg Kroah-Hartman]

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

watchdog: rzg2l_wdt: Fix 'BUG: Invalid wait context'

This patch fixes the issue 'BUG: Invalid wait context' during restart()
callback by using clk_prepare_enable() instead of pm_runtime_get_sync()
for turning on the clocks during restart.

This issue is noticed when testing with renesas_defconfig.

[   42.213802] reboot: Restarting system
[   42.217860]
[   42.219364] =============================
[   42.223368] [ BUG: Invalid wait context ]
[   42.227372] 5.17.0-rc5-arm64-renesas-00002-g10393723e35e #522 Not tainted
[   42.234153] -----------------------------
[   42.238155] systemd-shutdow/1 is trying to lock:
[   42.242766] ffff00000a650828 (&genpd->mlock){+.+.}-{3:3}, at: genpd_lock_mtx+0x14/0x20
[   42.250709] other info that might help us debug this:
[   42.255753] context-{4:4}
[   42.258368] 2 locks held by systemd-shutdow/1:
[   42.262806]  #0: ffff80000944e1c8 (system_transition_mutex#2){+.+.}-{3:3}, at: __do_sys_reboot+0xd0/0x250
[   42.272388]  #1: ffff8000094c4e40 (rcu_read_lock){....}-{1:2}, at: atomic_notifier_call_chain+0x0/0x150
[   42.281795] stack backtrace:
[   42.284672] CPU: 0 PID: 1 Comm: systemd-shutdow Not tainted 5.17.0-rc5-arm64-renesas-00002-g10393723e35e #522
[   42.294577] Hardware name: Renesas SMARC EVK based on r9a07g044c2 (DT)
[   42.301096] Call trace:
[   42.303538]  dump_backtrace+0xcc/0xd8
[   42.307203]  show_stack+0x14/0x30
[   42.310517]  dump_stack_lvl+0x88/0xb0
[   42.314180]  dump_stack+0x14/0x2c
[   42.317492]  __lock_acquire+0x1b24/0x1b50
[   42.321502]  lock_acquire+0x120/0x3a8
[   42.325162]  __mutex_lock+0x84/0x8f8
[   42.328737]  mutex_lock_nested+0x30/0x58
[   42.332658]  genpd_lock_mtx+0x14/0x20
[   42.336319]  genpd_runtime_resume+0xc4/0x228
[   42.340587]  __rpm_callback+0x44/0x170
[   42.344337]  rpm_callback+0x64/0x70
[   42.347824]  rpm_resume+0x4e0/0x6b8
[   42.351310]  __pm_runtime_resume+0x50/0x78
[   42.355404]  rzg2l_wdt_restart+0x28/0x68
[   42.359329]  watchdog_restart_notifier+0x1c/0x30
[   42.363943]  atomic_notifier_call_chain+0x94/0x150
[   42.368732]  do_kernel_restart+0x24/0x30
[   42.372652]  machine_restart+0x44/0x70
[   42.376399]  kernel_restart+0x3c/0x60
[   42.380058]  __do_sys_reboot+0x228/0x250
[   42.383977]  __arm64_sys_reboot+0x20/0x28
[   42.387983]  invoke_syscall+0x40/0xf8

The Linux kernel CVE team has assigned CVE-2022-49383 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 5.17 with commit 2cbc5cd0b55fa2310cc557c77b0665f5e00272de and fixed in 5.17.15 with commit 6505541e5298cea2b79da68ee626f583f8e18784
	Issue introduced in 5.17 with commit 2cbc5cd0b55fa2310cc557c77b0665f5e00272de and fixed in 5.18.4 with commit 0a635239cd5484d8f2e702713ccc49ec82aa7594
	Issue introduced in 5.17 with commit 2cbc5cd0b55fa2310cc557c77b0665f5e00272de and fixed in 5.19 with commit e4cf89596c1f1e33309556699f910ced4abbaf44

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2022-49383
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/watchdog/rzg2l_wdt.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/6505541e5298cea2b79da68ee626f583f8e18784
	https://git.kernel.org/stable/c/0a635239cd5484d8f2e702713ccc49ec82aa7594
	https://git.kernel.org/stable/c/e4cf89596c1f1e33309556699f910ced4abbaf44