On ARM64, cat /sys/kernel/debug/page_owner, all pages return the same
stack:
stack_trace_save+0x4c/0x78
register_early_stack+0x34/0x70
init_page_owner+0x34/0x230
page_ext_init+0x1bc/0x1dc
The reason is that:
check_recursive_alloc always return 1 because that
entries[0] is always equal to ip (__set_page_owner+0x3c/0x60).
The root cause is that:
commit 5fc57df2f6fd ("arm64: stacktrace: Convert to ARCH_STACKWALK")
make the save_trace save 2 more entries.
Add skip in arch_stack_walk when task == current.
Fixes: 5fc57df2f6fd ("arm64: stacktrace: Convert to ARCH_STACKWALK")
Signed-off-by: Chen Jun <chenjun...@huawei.com>
---
arch/arm64/kernel/stacktrace.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index ad20981..c26b0ac 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -201,11 +201,12 @@ void arch_stack_walk(stack_trace_consume_fn
consume_entry, void *cookie,
if (regs)
start_backtrace(&frame, regs->regs[29], regs->pc);
- else if (task == current)
+ else if (task == current) {
+ ((struct stacktrace_cookie *)cookie)->skip += 2;
start_backtrace(&frame,
(unsigned long)__builtin_frame_address(0),
(unsigned long)arch_stack_walk);
- else
+ } else
start_backtrace(&frame, thread_saved_fp(task),
thread_saved_pc(task));
--
2.9.4
