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authorDelyan Kratunov <delyank@fb.com>2022-05-11 18:28:36 +0000
committerPeter Zijlstra <peterz@infradead.org>2022-05-12 00:37:11 +0200
commit9c2136be0878c88c53dea26943ce40bb03ad8d8d (patch)
tree63ea6e07f82cc650db9a4d14d87f4b82df34a9c6 /kernel/trace/fgraph.c
parentc5eb0a61238dd6faf37f58c9ce61c9980aaffd7a (diff)
sched/tracing: Append prev_state to tp args instead
Commit fa2c3254d7cf (sched/tracing: Don't re-read p->state when emitting sched_switch event, 2022-01-20) added a new prev_state argument to the sched_switch tracepoint, before the prev task_struct pointer. This reordering of arguments broke BPF programs that use the raw tracepoint (e.g. tp_btf programs). The type of the second argument has changed and existing programs that assume a task_struct* argument (e.g. for bpf_task_storage access) will now fail to verify. If we instead append the new argument to the end, all existing programs would continue to work and can conditionally extract the prev_state argument on supported kernel versions. Fixes: fa2c3254d7cf (sched/tracing: Don't re-read p->state when emitting sched_switch event, 2022-01-20) Signed-off-by: Delyan Kratunov <delyank@fb.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org> Link: https://lkml.kernel.org/r/c8a6930dfdd58a4a5755fc01732675472979732b.camel@fb.com
Diffstat (limited to 'kernel/trace/fgraph.c')
-rw-r--r--kernel/trace/fgraph.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index 8f4fb328133a..a7e84c8543cb 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -404,9 +404,9 @@ free:
static void
ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
- unsigned int prev_state,
struct task_struct *prev,
- struct task_struct *next)
+ struct task_struct *next,
+ unsigned int prev_state)
{
unsigned long long timestamp;
int index;