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Commit 97da8976 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Ingo Molnar
Browse files

uprobes: Export 'struct return_instance', introduce arch_uretprobe_is_alive() 



Add the new "weak" helper, arch_uretprobe_is_alive(), used by
the next patches. It should return true if this return_instance
is still valid. The arch agnostic version just always returns
true.

The patch exports "struct return_instance" for the architectures
which want to override this hook. We can also cleanup
prepare_uretprobe() if we pass the new return_instance to
arch_uretprobe_hijack_return_addr().

Tested-by: default avatarPratyush Anand <panand@redhat.com>
Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Acked-by: default avatarSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: default avatarAnton 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/20150721134016.GA4762@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent a83cfeb9

include/linux/uprobes.h

+10 −0
Original line number Diff line number Diff line
@@ -92,6 +92,15 @@ struct uprobe_task { 
	unsigned int			depth;

};



struct return_instance {

	struct uprobe		*uprobe;

	unsigned long		func;

	unsigned long		orig_ret_vaddr; /* original return address */

	bool			chained;	/* true, if instance is nested */



	struct return_instance	*next;		/* keep as stack */

};



struct xol_area;



struct uprobes_state {
@@ -128,6 +137,7 @@ extern bool arch_uprobe_xol_was_trapped(struct task_struct *tsk); 
extern int  arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, void *data);

extern void arch_uprobe_abort_xol(struct arch_uprobe *aup, struct pt_regs *regs);

extern unsigned long arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs *regs);

extern bool arch_uretprobe_is_alive(struct return_instance *ret, struct pt_regs *regs);

extern bool arch_uprobe_ignore(struct arch_uprobe *aup, struct pt_regs *regs);

extern void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,

					 void *src, unsigned long len);

kernel/events/uprobes.c

+5 −9
Original line number Diff line number Diff line
@@ -86,15 +86,6 @@ struct uprobe { 
	struct arch_uprobe	arch;

};



struct return_instance {

	struct uprobe		*uprobe;

	unsigned long		func;

	unsigned long		orig_ret_vaddr; /* original return address */

	bool			chained;	/* true, if instance is nested */



	struct return_instance	*next;		/* keep as stack */

};



/*

 * Execute out of line area: anonymous executable mapping installed

 * by the probed task to execute the copy of the original instruction
@@ -1818,6 +1809,11 @@ bool __weak arch_uprobe_ignore(struct arch_uprobe *aup, struct pt_regs *regs) 
	return false;

}



bool __weak arch_uretprobe_is_alive(struct return_instance *ret, struct pt_regs *regs)

{

	return true;

}



/*

 * Run handler and ask thread to singlestep.

 * Ensure all non-fatal signals cannot interrupt thread while it singlesteps.