uprobes/x86: Reimplement arch_uretprobe_is_alive()
authorOleg Nesterov <oleg@redhat.com>
Tue, 21 Jul 2015 13:40:18 +0000 (15:40 +0200)
committerIngo Molnar <mingo@kernel.org>
Fri, 31 Jul 2015 08:38:05 +0000 (10:38 +0200)
commit7b868e4802a86d867aad1be0471b5767d9c20e10
treec56275f7bdc1bddbb34b393a1747b7514f77f994
parent97da89767d398c1dfa1f34e5f312eb8ebb382f7f
uprobes/x86: Reimplement arch_uretprobe_is_alive()

Add the x86 specific version of arch_uretprobe_is_alive()
helper. It returns true if the stack frame mangled by
prepare_uretprobe() is still on stack. So if it returns false,
we know that the probed function has already returned.

We add the new return_instance->stack member and change the
generic code to initialize it in prepare_uretprobe, but it
should be equally useful for other architectures.

TODO: this assumes that the probed application can't use
      multiple stacks (say sigaltstack). We will try to improve
      this logic later.

Tested-by: Pratyush Anand <panand@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Anton Arapov <arapov@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150721134018.GA4766@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch/x86/kernel/uprobes.c
include/linux/uprobes.h
kernel/events/uprobes.c