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charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2 (3.56.2-2.fc42) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Wed, 2026-05-27 at 11:37 -0400, Steven Rostedt wrote: > On Wed, 27 May 2026 11:13:01 -0400 > Rik van Riel wrote: >=20 > > perf_ftrace_function_unregister() unconditionally calls > > unregister_ftrace_function() without checking whether the > > ftrace_ops > > was ever successfully registered. This triggers a WARN_ON in > > __unregister_ftrace_function() when the ops doesn't have > > FTRACE_OPS_FL_ENABLED set. > >=20 > > This can happen during perf_event_alloc() error cleanup when > > perf_trace_destroy() is called via __free_event() on an event whose > > ftrace_ops registration failed or was already torn down by > > perf_try_init_event()'s err_destroy path. > >=20 > > The call path is: > > =C2=A0 perf_event_alloc() error cleanup > > =C2=A0=C2=A0=C2=A0 -> __free_event() > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 -> event->destroy() [tp_perf_event_destr= oy] > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 -> perf_trace_destroy() > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 -> perf_trace_ev= ent_close() > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 -> T= RACE_REG_PERF_CLOSE > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0 -> perf_ftrace_function_unregister() > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0 -> unregister_ftrace_function() > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 -> __unregister_ftrace_function() > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 -> WARN_ON(!(ops->flags & > > FTRACE_OPS_FL_ENABLED))=C2=A0=20 > >=20 > > Fix this by checking FTRACE_OPS_FL_ENABLED before attempting to > > unregister. If the ops is not enabled, just free the filter and > > return success. > >=20 > > Signed-off-by: Rik van Riel >=20 > Thanks Rik. Is this urgent where it should have a Fixes tag and Cc > stable as well as be sent to Linus during the -rc release, or can it > wait for the next merge window? >=20 I don't think this patch has any particular urgency. It can go in using whatever flow is most convenient. --=20 All Rights Reversed.