lkml.org 
[lkml]   [2018]   [Nov]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/3] stackleak: mark stackleak_track_stack() as notrace
On Fri, 30 Nov 2018 16:08:59 +0100
Anders Roxell <anders.roxell@linaro.org> wrote:

> 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 <arnd@arndb.de>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Anders Roxell <anders.roxell@linaro.org>

Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

-- Steve

> ---
> 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,

\
 
 \ /
  Last update: 2018-11-30 16:22    [W:0.077 / U:1.356 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site