CVE-2025-39829

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

trace/fgraph: Fix the warning caused by missing unregister notifier

This warning was triggered during testing on v6.16:

notifier callback ftrace_suspend_notifier_call already registered

WARNING: CPU: 2 PID: 86 at kernel/notifier.c:23 notifier_chain_register+0x44/0xb0

...

Call Trace:

<TASK>

blocking_notifier_chain_register+0x34/0x60

register_ftrace_graph+0x330/0x410

ftrace_profile_write+0x1e9/0x340

vfs_write+0xf8/0x420

? filp_flush+0x8a/0xa0

? filp_close+0x1f/0x30

? do_dup2+0xaf/0x160

ksys_write+0x65/0xe0

do_syscall_64+0xa4/0x260

entry_SYSCALL_64_after_hwframe+0x77/0x7f

When writing to the function_profile_enabled interface, the notifier was

not unregistered after start_graph_tracing failed, causing a warning the

next time function_profile_enabled was written.

Fixed by adding unregister_pm_notifier in the exception path.