Function graph tracing recurses into itself when stackleak is enabled, causing the ftrace graph selftest to run for up to 90 seconds and trigger the softlockup watchdog.
Breakpoint 2, ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:200 200 mcount_get_lr_addr x0 // pointer to function's saved lr (gdb) bt \#0 ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:200 \#1 0xffffff80081d5280 in ftrace_caller () at ../arch/arm64/kernel/entry-ftrace.S:153 \#2 0xffffff8008555484 in stackleak_track_stack () at ../kernel/stackleak.c:106 \#3 0xffffff8008421ff8 in ftrace_ops_test (ops=0xffffff8009eaa840 <graph_ops>, ip=18446743524091297036, regs=<optimized out>) at ../kernel/trace/ftrace.c:1507 \#4 0xffffff8008428770 in __ftrace_ops_list_func (regs=<optimized out>, ignored=<optimized out>, parent_ip=<optimized out>, ip=<optimized out>) at ../kernel/trace/ftrace.c:6286 \#5 ftrace_ops_no_ops (ip=18446743524091297036, parent_ip=18446743524091242824) at ../kernel/trace/ftrace.c:6321 \#6 0xffffff80081d5280 in ftrace_caller () at ../arch/arm64/kernel/entry-ftrace.S:153 \#7 0xffffff800832fd10 in irq_find_mapping (domain=0xffffffc03fc4bc80, hwirq=27) at ../kernel/irq/irqdomain.c:876 \#8 0xffffff800832294c in __handle_domain_irq (domain=0xffffffc03fc4bc80, hwirq=27, lookup=true, regs=0xffffff800814b840) at ../kernel/irq/irqdesc.c:650 \#9 0xffffff80081d52b4 in ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:205 Rework so we mark stackleak_track_stack as notrace Co-developed-by: Arnd Bergmann <[email protected]> Signed-off-by: Arnd Bergmann <[email protected]> Signed-off-by: Anders Roxell <[email protected]> --- kernel/stackleak.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/stackleak.c b/kernel/stackleak.c index e42892926244..5de3bf596dd7 100644 --- a/kernel/stackleak.c +++ b/kernel/stackleak.c @@ -102,7 +102,7 @@ asmlinkage void stackleak_erase(void) current->lowest_stack = current_top_of_stack() - THREAD_SIZE/64; } -void __used stackleak_track_stack(void) +void __used notrace stackleak_track_stack(void) { /* * N.B. stackleak_erase() fills the kernel stack with the poison value, -- 2.19.2
