If __kernel_text_address() doesn't recognize a return address on the
stack, it probably means that it's some generated code which
__kernel_text_address() doesn't know about yet.
Otherwise there's probably some stack corruption.
Either way, warn about it.
Use printk_deferred_once() because the unwinder can be called with the
console lock by lockdep via save_stack_trace().
Signed-off-by: Josh Poimboeuf <jpoim...@redhat.com>
---
arch/x86/kernel/unwind_frame.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c
index 0d8d2f2..b6fcf44 100644
--- a/arch/x86/kernel/unwind_frame.c
+++ b/arch/x86/kernel/unwind_frame.c
@@ -20,7 +20,15 @@ unsigned long unwind_get_return_address(struct unwind_state
*state)
addr = ftrace_graph_ret_addr(state->task, &state->graph_idx, *addr_p,
addr_p);
- return __kernel_text_address(addr) ? addr : 0;
+ if (!__kernel_text_address(addr)) {
+ printk_deferred_once(KERN_WARNING
+ "WARNING: unrecognized kernel stack return address %p
at %p in %s:%d\n",
+ (void *)addr, addr_p, state->task->comm,
+ state->task->pid);
+ return 0;
+ }
+
+ return addr;
}
EXPORT_SYMBOL_GPL(unwind_get_return_address);
--
2.7.4
