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CVE Record

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

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

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Glexia's TakeAutomated analysislow

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel reboot reliability bug in the Renesas RZ/G2L watchdog path. Affected systems can hit a kernel bug while restarting. The sources do not show remote attack, privilege escalation, active exploitation, or CVSS scoring.

Executive priority

Treat as low urgency unless your environment includes Renesas RZ/G2L-based products where reboot reliability matters. Patch through normal kernel or firmware maintenance channels.

Technical view

In rzg2l_wdt_restart(), pm_runtime_get_sync could sleep or lock in the atomic notifier restart path, triggering an invalid wait context through genpd runtime resume. The fix uses clk_prepare_enable to turn on clocks during restart.

Likely exposure

Likely limited to Linux systems using the Renesas RZ/G2L watchdog driver, especially Renesas defconfig or SMARC EVK-class ARM64 builds. Generic Linux servers without this driver are unlikely exposed based on the provided evidence.

Exploitation context

No active exploitation is reported in KEV or the supplied sources. The evidence describes a restart-time kernel bug found during testing, not a public exploit path or network-reachable vulnerability.

Researcher notes

The record lacks CVSS, CWE, exploitability analysis, and detailed affected-version ranges. Analysis should stay scoped to the restart callback, runtime PM locking context, and the listed Linux stable commits.

Mitigation direction

  • Update to a Linux kernel or vendor BSP containing the referenced stable fixes.
  • Check Renesas, distribution, or device vendor advisories for backported kernel packages.
  • Prioritize embedded devices where reliable reboot or watchdog recovery is operationally important.
  • Avoid inventing local workarounds; follow kernel or vendor guidance for affected builds.

Validation and detection

  • Inventory systems for Linux kernels matching the listed affected versions or vendor backports.
  • Confirm whether the rzg2l_wdt watchdog driver is built and used.
  • Review kernel changelogs for the referenced stable commit identifiers.
  • Test controlled reboot behavior on representative Renesas hardware after patching.
Prepared
Confidence
medium
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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CVE-2022-49383 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
4Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

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Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux2cbc5cd0b55fa2310cc557c77b0665f5e00272de, 2cbc5cd0b55fa2310cc557c77b0665f5e00272de, 2cbc5cd0b55fa2310cc557c77b0665f5e00272deunaffected
LinuxLinux5.17, 0, 5.17.15, 5.18.4, 5.19affected
Weakness

CWE details

No CWE listed

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