Commit-ID: b6959a362177053c1c90db6dc1af25b6bddd8548
Gitweb: http://git.kernel.org/tip/b6959a362177053c1c90db6dc1af25b6bddd8548
Author: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
AuthorDate: Wed, 26 Oct 2016 10:41:51 -0500
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 27 Oct 2016 08:32:38 +0200
x86/unwind: Detect bad stack return address
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 <jpoimboe@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/2d897898f324e275943b590d160b55e482bba65f.1477496147.git.jpoimboe@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
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 9be9a8f..5639db6 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);
--
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