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| author | Oleg Nesterov <oleg@redhat.com> | 2015-07-21 15:40:18 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-07-31 10:38:05 +0200 |
| commit | 7b868e4802a86d867aad1be0471b5767d9c20e10 (patch) | |
| tree | c56275f7bdc1bddbb34b393a1747b7514f77f994 | |
| parent | 97da89767d398c1dfa1f34e5f312eb8ebb382f7f (diff) | |
| download | linux-7b868e4802a86d867aad1be0471b5767d9c20e10.tar.gz | |
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>
| -rw-r--r-- | arch/x86/kernel/uprobes.c | 5 | ||||
| -rw-r--r-- | include/linux/uprobes.h | 1 | ||||
| -rw-r--r-- | kernel/events/uprobes.c | 1 |
3 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 66476244731e..58e9b842633f 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -985,3 +985,8 @@ arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs return -1; } + +bool arch_uretprobe_is_alive(struct return_instance *ret, struct pt_regs *regs) +{ + return regs->sp <= ret->stack; +} diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index 50d2764d66a8..7ab6d2c8be49 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -95,6 +95,7 @@ struct uprobe_task { struct return_instance { struct uprobe *uprobe; unsigned long func; + unsigned long stack; /* stack pointer */ unsigned long orig_ret_vaddr; /* original return address */ bool chained; /* true, if instance is nested */ diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 1c71b6242a7e..c5f316e06dc0 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1562,6 +1562,7 @@ static void prepare_uretprobe(struct uprobe *uprobe, struct pt_regs *regs) ri->uprobe = get_uprobe(uprobe); ri->func = instruction_pointer(regs); + ri->stack = user_stack_pointer(regs); ri->orig_ret_vaddr = orig_ret_vaddr; ri->chained = chained; |