Comment 0 for bug 1987232

I have systems that are regularly hitting a WARN in trace_event_dyn_put_ref.

The exact message is:

WARNING: CPU: 1 PID: 30309 at kernel/trace/trace_dynevent.c:46
+trace_event_dyn_put_ref+0x15/0x20

With the following stacktrace:

 perf_trace_init+0x8f/0xd0
 perf_tp_event_init+0x1f/0x40
 perf_try_init_event+0x4a/0x130
 perf_event_alloc+0x497/0xf40
 __do_sys_perf_event_open+0x1d4/0xf70
 __x64_sys_perf_event_open+0x20/0x30
 do_syscall_64+0x5c/0xc0
 entry_SYSCALL_64_after_hwframe+0x44/0xae

I've debugged this and worked with upstream to get a fix into Linux. It was recently merged in 6.0-rc2. See here: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v6.0-rc2&id=7249921d94ff64f67b733eca0b68853a62032b3d

The problem started appearing as soon as our systems picked up the linux-aws-5.15 branch for Focal. (That was 5.15.0-1015-aws, if memory serves). Could you please cherry pick this fix and pull it back to the the linux and linux-aws kernels for Focal? There's test here: https://<email address hidden>/ that reproduces the problem very reliably for me. With the patch applied, I no longer get the WARNs.