diff options
| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2016-02-28 22:22:40 -0600 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-02-29 08:35:12 +0100 |
| commit | 87aaff2ae09036cf699fde20dfd52ce7d3c8eabe (patch) | |
| tree | b9ee46469a5ec6c3a31f806f8b4ca552a77e2e75 | |
| parent | 049369487e2068294b61cee19233be0ffac7d243 (diff) | |
x86/kprobes: Mark kretprobe_trampoline() stack frame as non-standard
objtool reports the following warning for kretprobe_trampoline():
arch/x86/kernel/kprobes/core.o: warning: objtool: kretprobe_trampoline()+0x20: call without frame pointer save/setup
kretprobes are a special case where the stack is intentionally wrong.
The return address isn't known at the beginning of the trampoline, so
the stack frame can't be set up properly before it calls
trampoline_handler().
Because kretprobe handlers don't sleep, the frame pointer doesn't *have*
to be accurate in the trampoline. So it's ok to tell objtool to ignore
it. This results in no actual changes to the generated code.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/7eaf37de52456ff822ffc86b928edb5d48a40ef1.1456719558.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/x86/kernel/kprobes/core.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 48acaac35bd2..ae703acb85c1 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -49,6 +49,7 @@ #include <linux/kdebug.h> #include <linux/kallsyms.h> #include <linux/ftrace.h> +#include <linux/frame.h> #include <asm/cacheflush.h> #include <asm/desc.h> @@ -703,6 +704,7 @@ asm( ".size kretprobe_trampoline, .-kretprobe_trampoline\n" ); NOKPROBE_SYMBOL(kretprobe_trampoline); +STACK_FRAME_NON_STANDARD(kretprobe_trampoline); /* * Called from kretprobe_trampoline |