CVE-2023-54045
Description
In the Linux kernel, the following vulnerability has been resolved:
audit: fix possible soft lockup in __audit_inode_child()
Tracefs or debugfs maybe cause hundreds to thousands of PATH records, too many PATH records maybe cause soft lockup.
For example: 1. CONFIG_KASAN=y && CONFIG_PREEMPTION=n 2. auditctl -a exit,always -S open -k key 3. sysctl -w kernel.watchdog_thresh=5 4. mkdir /sys/kernel/debug/tracing/instances/test
There may be a soft lockup as follows: watchdog: BUG: soft lockup - CPU#45 stuck for 7s! [mkdir:15498] Kernel panic - not syncing: softlockup: hung tasks Call trace: dump_backtrace+0x0/0x30c show_stack+0x20/0x30 dump_stack+0x11c/0x174 panic+0x27c/0x494 watchdog_timer_fn+0x2bc/0x390 __run_hrtimer+0x148/0x4fc __hrtimer_run_queues+0x154/0x210 hrtimer_interrupt+0x2c4/0x760 arch_timer_handler_phys+0x48/0x60 handle_percpu_devid_irq+0xe0/0x340 __handle_domain_irq+0xbc/0x130 gic_handle_irq+0x78/0x460 el1_irq+0xb8/0x140 __audit_inode_child+0x240/0x7bc tracefs_create_file+0x1b8/0x2a0 trace_create_file+0x18/0x50 event_create_dir+0x204/0x30c __trace_add_new_event+0xac/0x100 event_trace_add_tracer+0xa0/0x130 trace_array_create_dir+0x60/0x140 trace_array_create+0x1e0/0x370 instance_mkdir+0x90/0xd0 tracefs_syscall_mkdir+0x68/0xa0 vfs_mkdir+0x21c/0x34c do_mkdirat+0x1b4/0x1d4 __arm64_sys_mkdirat+0x4c/0x60 el0_svc_common.constprop.0+0xa8/0x240 do_el0_svc+0x8c/0xc0 el0_svc+0x20/0x30 el0_sync_handler+0xb0/0xb4 el0_sync+0x160/0x180
Therefore, we add cond_resched() to __audit_inode_child() to fix it.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
A missing cond_resched() in __audit_inode_child() can cause a soft lockup when tracefs/debugfs generates thousands of PATH audit records.
Vulnerability
In the Linux kernel, the __audit function __audit_inode_child() can be called repeatedly when tracefs or debugfs creates many entries (e.g., during mkdir /sys/kernel/debug/tracing/instances/test`). Under certain configurations (CONFIG_KASAN=y and CONFIG_PREEMPTION=n), this can generate hundreds to thousands of PATH audit records without yielding the CPU, leading to a soft lockup [1].
Exploitation
Anation
The soft lockup occurs because the kernel watchdog detects that a CPU has been stuck in __audit_inode_child() for over 7 seconds (with kernel.watchdog_thresh=5). The call chain shows that tracefs_create_file and related functions trigger many audit events, and without a reschedule point, the CPU cannot handle other tasks [1].
Impact
An attacker with local access and the ability to create directories in tracefs (e.g., via mkdir in debugfs instances) can trigger a soft lockup, causing a kernel panic and denial of service. No special privileges beyond local user privileges are required [1].
Mitigation
The fix adds a cond_resched() call inside __audit_inode_child() to voluntarily yield the CPU after processing a batch of records, preventing the lockup. The patch has been applied to the stable kernel branches [1][2][3][4].
AI Insight generated on May 19, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.
Affected products
1Patches
9d061e2bfc20f1640c7bd4eddf6364fa751d798ef243d59000152e7758cc49ca08adb75fb8a40b49137298e76b944a7b9b59bc6e37237Vulnerability mechanics
Root cause
"The `__audit_inode_child()` function lacks a mechanism to yield the CPU while processing a large number of PATH records, leading to a soft lockup."
Attack vector
An attacker can trigger this vulnerability by configuring audit rules to monitor system calls (e.g., `open`) and then performing operations that generate a high volume of PATH records, such as creating directories in `tracefs` or `debugfs`. The excessive processing time required to handle these records on a single CPU can exceed the kernel's watchdog threshold, resulting in a soft lockup and potential kernel panic [patch_id=4457].
Affected code
The vulnerability is located in the `__audit_inode_child()` function within the Linux kernel audit subsystem. This function fails to yield the CPU when processing a large number of PATH records, leading to a soft lockup [patch_id=4457].
What the fix does
The fix introduces a call to `cond_resched()` within the `__audit_inode_child()` function [patch_id=4457]. This allows the kernel to voluntarily yield the CPU during the processing of large numbers of PATH records, preventing the task from monopolizing the CPU and triggering a soft lockup.
Preconditions
- configAudit rules must be configured to monitor relevant system calls (e.g., 'auditctl -a exit,always -S open -k key').
- inputThe system must perform operations that generate a large number of PATH records, such as creating directories in tracefs or debugfs.
Generated on May 17, 2026. Inputs: CWE entries + fix-commit diffs from this CVE's patches. Citations validated against bundle.
References
9- git.kernel.org/stable/c/0152e7758cc4e9f8bfba8dbea4438d8e488d6c08nvd
- git.kernel.org/stable/c/1640c7bd4eddec6c72f3a99cbb74e333a2ce9f5dnvd
- git.kernel.org/stable/c/8a40b491372966ba5426e138a53460985565d5a6nvd
- git.kernel.org/stable/c/8e76b944a7b9bddef190ffe2e29c9ae342ab91ednvd
- git.kernel.org/stable/c/98ef243d5900d75a64539a2165745bffbb155d43nvd
- git.kernel.org/stable/c/9ca08adb75fb40a8f742c371927ee73f9dc753bfnvd
- git.kernel.org/stable/c/b59bc6e37237e37eadf50cd5de369e913f524463nvd
- git.kernel.org/stable/c/d061e2bfc20f2914656385816e0d20566213c54cnvd
- git.kernel.org/stable/c/f6364fa751d7486502c777f124a14d4d543fc5ebnvd
News mentions
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