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Commit 0f95b7fc authored by Ananth N Mavinakayanahalli's avatar Ananth N Mavinakayanahalli Committed by Linus Torvalds
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Kprobes: print details of kretprobe on assertion failure 



In certain cases like when the real return address can't be found or when
the number of tracked calls to a kretprobed function is less than the
number of returns, we may not be able to find the correct return address
after processing a kretprobe.  Currently we just do a BUG_ON, but no
information is provided about the actual failing kretprobe.

Print out details of the kretprobe before calling BUG().

Signed-off-by: default avatarAnanth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Maneesh Soni <maneesh@in.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8f0c45cd

arch/i386/kernel/kprobes.c

+1 −2
Original line number Diff line number Diff line
@@ -449,8 +449,7 @@ fastcall void *__kprobes trampoline_handler(struct pt_regs *regs) 
			break;

	}



	BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));



	kretprobe_assert(ri, orig_ret_address, trampoline_address);

	spin_unlock_irqrestore(&kretprobe_lock, flags);



	hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {

arch/ia64/kernel/kprobes.c

+2 −1
Original line number Diff line number Diff line
@@ -444,7 +444,8 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) 
			break;

	}



	BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));

	kretprobe_assert(ri, orig_ret_address, trampoline_address);



	regs->cr_iip = orig_ret_address;



	reset_current_kprobe();

arch/powerpc/kernel/kprobes.c

+1 −1
Original line number Diff line number Diff line
@@ -336,7 +336,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) 
			break;

	}



	BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));

	kretprobe_assert(ri, orig_ret_address, trampoline_address);

	regs->nip = orig_ret_address;



	reset_current_kprobe();

arch/x86_64/kernel/kprobes.c

+1 −1
Original line number Diff line number Diff line
@@ -447,7 +447,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) 
			break;

	}



	BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));

	kretprobe_assert(ri, orig_ret_address, trampoline_address);

	regs->rip = orig_ret_address;



	reset_current_kprobe();

include/linux/kprobes.h

+10 −0
Original line number Diff line number Diff line
@@ -157,6 +157,16 @@ struct kretprobe_instance { 
	struct task_struct *task;

};



static inline void kretprobe_assert(struct kretprobe_instance *ri,

	unsigned long orig_ret_address, unsigned long trampoline_address)

{

	if (!orig_ret_address || (orig_ret_address == trampoline_address)) {

		printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",

				ri->rp, ri->rp->kp.addr);

		BUG();

	}

}



extern spinlock_t kretprobe_lock;

extern struct mutex kprobe_mutex;

extern int arch_prepare_kprobe(struct kprobe *p);