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| author | Pratyush Anand <panand@redhat.com> | 2016-09-05 08:03:16 +0530 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2016-09-05 13:41:52 +0100 |
| commit | 98ab10e9770e3ce9fbd263689644be9d81a06885 (patch) | |
| tree | 0b046ba330c0f58967bceab34e71be174b5b551d /arch/arm64/kernel/stacktrace.c | |
| parent | dc00247576fdb97211e1959b4dfd2a7893cf9d0b (diff) | |
| download | linux-98ab10e9770e3ce9fbd263689644be9d81a06885.tar.gz linux-98ab10e9770e3ce9fbd263689644be9d81a06885.tar.bz2 linux-98ab10e9770e3ce9fbd263689644be9d81a06885.zip | |
arm64: ftrace: add save_stack_trace_regs()
Currently, enabling stacktrace of a kprobe events generates warning:
echo stacktrace > /sys/kernel/debug/tracing/trace_options
echo "p xhci_irq" > /sys/kernel/debug/tracing/kprobe_events
echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable
save_stack_trace_regs() not implemented yet.
------------[ cut here ]------------
WARNING: CPU: 1 PID: 0 at ../kernel/stacktrace.c:74 save_stack_trace_regs+0x3c/0x48
Modules linked in:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.8.0-rc4-dirty #5128
Hardware name: ARM Juno development board (r1) (DT)
task: ffff800975dd1900 task.stack: ffff800975ddc000
PC is at save_stack_trace_regs+0x3c/0x48
LR is at save_stack_trace_regs+0x3c/0x48
pc : [<ffff000008126c64>] lr : [<ffff000008126c64>] pstate: 600003c5
sp : ffff80097ef52c00
Call trace:
save_stack_trace_regs+0x3c/0x48
__ftrace_trace_stack+0x168/0x208
trace_buffer_unlock_commit_regs+0x5c/0x7c
kprobe_trace_func+0x308/0x3d8
kprobe_dispatcher+0x58/0x60
kprobe_breakpoint_handler+0xbc/0x18c
brk_handler+0x50/0x90
do_debug_exception+0x50/0xbc
This patch implements save_stack_trace_regs(), so that stacktrace of a
kprobe events can be obtained.
After this patch, there is no warning and we can see the stacktrace for
kprobe events in trace buffer.
more /sys/kernel/debug/tracing/trace
<idle>-0 [004] d.h. 1356.000496: p_xhci_irq_0:(xhci_irq+0x0/0x9ac)
<idle>-0 [004] d.h. 1356.000497: <stack trace>
=> xhci_irq
=> __handle_irq_event_percpu
=> handle_irq_event_percpu
=> handle_irq_event
=> handle_fasteoi_irq
=> generic_handle_irq
=> __handle_domain_irq
=> gic_handle_irq
=> el1_irq
=> arch_cpu_idle
=> default_idle_call
=> cpu_startup_entry
=> secondary_start_kernel
=>
Tested-by: David A. Long <dave.long@linaro.org>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Pratyush Anand <panand@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/kernel/stacktrace.c')
| -rw-r--r-- | arch/arm64/kernel/stacktrace.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index d9751a4769e7..ca01addf8c4c 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -152,6 +152,27 @@ static int save_trace(struct stackframe *frame, void *d) return trace->nr_entries >= trace->max_entries; } +void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace) +{ + struct stack_trace_data data; + struct stackframe frame; + + data.trace = trace; + data.skip = trace->skip; + data.no_sched_functions = 0; + + frame.fp = regs->regs[29]; + frame.sp = regs->sp; + frame.pc = regs->pc; +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + frame.graph = current->curr_ret_stack; +#endif + + walk_stackframe(current, &frame, save_trace, &data); + if (trace->nr_entries < trace->max_entries) + trace->entries[trace->nr_entries++] = ULONG_MAX; +} + void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) { struct stack_trace_data data; |