From: Nikita Yushchenko nikita.yushchenko@virtuozzo.com
mainline inclusion from mainline-v5.17-rc1 commit 0878355b51f5f26632e652c848a8e174bb02d22d category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I699A9 CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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If start_per_cpu_kthreads() called from osnoise_workload_start() returns error, event hooks are left in broken state: unhook_irq_events() called but unhook_thread_events() and unhook_softirq_events() not called, and trace_osnoise_callback_enabled flag not cleared.
On the next tracer enable, hooks get not installed due to trace_osnoise_callback_enabled flag.
And on the further tracer disable an attempt to remove non-installed hooks happened, hitting a WARN_ON_ONCE() in tracepoint_remove_func().
Fix the error path by adding the missing part of cleanup. While at this, introduce osnoise_unhook_events() to avoid code duplication between this error path and normal tracer disable.
Link: https://lkml.kernel.org/r/20220109153459.3701773-1-nikita.yushchenko@virtuoz...
Cc: stable@vger.kernel.org Fixes: bce29ac9ce0b ("trace: Add osnoise tracer") Acked-by: Daniel Bristot de Oliveira bristot@kernel.org Signed-off-by: Nikita Yushchenko nikita.yushchenko@virtuozzo.com Signed-off-by: Steven Rostedt rostedt@goodmis.org Signed-off-by: Zheng Yejian zhengyejian1@huawei.com Reviewed-by: Yang Jihong yangjihong1@huawei.com Signed-off-by: Jialin Zhang zhangjialin11@huawei.com --- kernel/trace/trace_osnoise.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c index cfb80feb291e..3f806a3be8b2 100644 --- a/kernel/trace/trace_osnoise.c +++ b/kernel/trace/trace_osnoise.c @@ -2103,6 +2103,13 @@ static int osnoise_hook_events(void) return -EINVAL; }
+static void osnoise_unhook_events(void) +{ + unhook_thread_events(); + unhook_softirq_events(); + unhook_irq_events(); +} + /* * osnoise_workload_start - start the workload and hook to events */ @@ -2135,7 +2142,14 @@ static int osnoise_workload_start(void)
retval = start_per_cpu_kthreads(); if (retval) { - unhook_irq_events(); + trace_osnoise_callback_enabled = false; + /* + * Make sure that ftrace_nmi_enter/exit() see + * trace_osnoise_callback_enabled as false before continuing. + */ + barrier(); + + osnoise_unhook_events(); return retval; }
@@ -2166,9 +2180,7 @@ static void osnoise_workload_stop(void)
stop_per_cpu_kthreads();
- unhook_irq_events(); - unhook_softirq_events(); - unhook_thread_events(); + osnoise_unhook_events(); }
static void osnoise_tracer_start(struct trace_array *tr)