Clean-up bounds checking for trace->nr in
__bpf_get_stack by limiting it only to
max_depth.
Acked-by: Song Liu <song@xxxxxxxxxx>
Cc: Song Liu <song@xxxxxxxxxx>
Signed-off-by: Arnaud Lecomte <contact@xxxxxxxxxxxxxx>
---
kernel/bpf/stackmap.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
index a794e04f5ae9..9a86b5acac10 100644
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -462,13 +462,15 @@ static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task,
if (may_fault)
rcu_read_lock(); /* need RCU for perf's callchain below */
- if (trace_in)
+ if (trace_in) {
trace = trace_in;
- else if (kernel && task)
+ trace->nr = min_t(u32, trace->nr, max_depth);
+ } else if (kernel && task) {
trace = get_callchain_entry_for_task(task, max_depth);
- else
+ } else {
trace = get_perf_callchain(regs, 0, kernel, user, max_depth,
crosstask, false);
+ }
if (unlikely(!trace) || trace->nr < skip) {
if (may_fault)
--
2.43.0
