Commit-ID: c280f7736ab26a601932b1ce017a3840dbedcfdc
Gitweb: http://git.kernel.org/tip/c280f7736ab26a601932b1ce017a3840dbedcfdc
Author: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
AuthorDate: Thu, 22 Dec 2016 09:02:49 -0600
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 23 Dec 2016 20:32:30 +0100
Revert "x86/unwind: Detect bad stack return address"
Revert the following commit:
b6959a362177 ("x86/unwind: Detect bad stack return address")
... because Andrey Konovalov reported an unwinder warning:
WARNING: unrecognized kernel stack return address ffffffffa0000001 at ffff88006377fa18 in a.out:4467
The unwind was initiated from an interrupt which occurred while running in the
generated code for a kprobe. The unwinder printed the warning because it
expected regs->ip to point to a valid text address, but instead it pointed to
the generated code.
Eventually we may want come up with a way to identify generated kprobe
code so the unwinder can know that it's a valid return address. Until
then, just remove the warning.
Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
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: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/02f296848fbf49fb72dfeea706413ecbd9d4caf6.1482418739.git.jpoimboe@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/unwind_frame.c | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)
diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c
index 20d4b4e..4443e49 100644
--- a/arch/x86/kernel/unwind_frame.c
+++ b/arch/x86/kernel/unwind_frame.c
@@ -51,16 +51,7 @@ unsigned long unwind_get_return_address(struct unwind_state *state)
addr = ftrace_graph_ret_addr(state->task, &state->graph_idx, *addr_p,
addr_p);
- 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);
- unwind_dump(state, addr_p);
- return 0;
- }
-
- return addr;
+ return __kernel_text_address(addr) ? addr : 0;
}
EXPORT_SYMBOL_GPL(unwind_get_return_address);
--
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