Messages in this thread Patch in this message | | | From | Josh Poimboeuf <> | Subject | [PATCH v2 43/44] x86/unwind: warn on bad stack return address | Date | Thu, 4 Aug 2016 17:22:39 -0500 |
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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@redhat.com> --- arch/x86/kernel/unwind_frame.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c index d90c2c9..f943413 100644 --- a/arch/x86/kernel/unwind_frame.c +++ b/arch/x86/kernel/unwind_frame.c @@ -17,7 +17,13 @@ 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 in %s:%d\n", + (void *)addr, state->task->comm, state->task->pid); + return 0; + } + + return addr; } EXPORT_SYMBOL_GPL(unwind_get_return_address); -- 2.7.4
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