[Bug] soft lockup in xfrm_timer_handler in Linux kernel v6.15

[Bug] soft lockup in xfrm_timer_handler in Linux kernel v6.15

[Luka]

Dear Linux Kernel Maintainers,

I hope this message finds you well.

I am writing to report a potential vulnerability I encountered during
testing of the Linux Kernel version v6.15.

Git Commit: 0ff41df1cb268fc69e703a08a57ee14ae967d0ca (tag: v6.15)

Bug Location: xfrm_timer_handler+0x824/0xbb0 net/xfrm/xfrm_state.c:718

Bug report: https://pastebin.com/mSiia4CU

Entire kernel config: https://pastebin.com/jQ30sdLk

Root Cause Analysis:

A soft lockup occurs in the IPsec state expiration handler
xfrm_timer_handler(), caused by excessive execution time during state
notification, likely due to long-running operations in
xfrm_send_state_notify() under high-resolution timer context,
resulting in CPU starvation and scheduling failure on the softirq
path.

At present, I have not yet obtained a minimal reproducer for this
issue. However, I am actively working on reproducing it, and I will
promptly share any additional findings or a working reproducer as soon
as it becomes available.

Thank you very much for your time and attention to this matter. I
truly appreciate the efforts of the Linux kernel community.

Best regards,
Luka