This patch stops unwinding backtrace in case of below 2 cases.
(Issue observed while porting stackdepot on ARM, duplicate
entries created in stackdepot
reference patch for workaround in stackdepot:-
https://lkml.org/lkml/2017/10/11/353
).
1. If address belongs to irq/exception code, ignore it.
save_stack+0x40/0xec
__set_page_owner+0x2c/0x64
....
....
__handle_domain_irq+0x9c/0x130
gic_handle_irq+0x40/0x80
__irq_usr+0x4c/0x60
0xb6507818
^^^^^^^
2. If address belongs to junk entry, ignore it
kmem_cache_alloc_trace+0x1e8/0x21c
rb_allocate_cpu_buffer+0xf0/0x25c
__ring_buffer_alloc+0xf8/0x1e0
trace_init+0xe0/0x2cc
start_kernel+0x30c/0x448
0x400080a0
^^^^^^^
Signed-off-by: Maninder Singh <maninder...@samsung.com>
Signed-off-by: Vaneet Narang <v.nar...@samsung.com>
---
arch/arm/kernel/stacktrace.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
index 3a2fa20..80e953e 100644
--- a/arch/arm/kernel/stacktrace.c
+++ b/arch/arm/kernel/stacktrace.c
@@ -82,6 +82,9 @@ static int save_trace(struct stackframe *frame, void *d)
return 0;
}
+ if (!__kernel_text_address(addr))
+ return 1;
+
trace->entries[trace->nr_entries++] = addr;
if (trace->nr_entries >= trace->max_entries)
@@ -98,12 +101,8 @@ static int save_trace(struct stackframe *frame, void *d)
data->last_pc = frame->pc;
if (!in_exception_text(addr))
return 0;
-
- regs = (struct pt_regs *)frame->sp;
-
- trace->entries[trace->nr_entries++] = regs->ARM_pc;
-
- return trace->nr_entries >= trace->max_entries;
+ else
+ return 1;
}
/* This must be noinline to so that our skip calculation works correctly */
--
1.9.1
