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Kprobes: print details of kretprobe on assertion failure

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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: Ananth 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ananth N Mavinakayanahalli 2007-05-08 00:28:27 -07:00 committed by Linus Torvalds
parent 8f0c45cdf8
commit 0f95b7fc83
5 changed files with 15 additions and 5 deletions
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3
arch/i386/kernel/kprobes.c
View file

@ -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) {

3
arch/ia64/kernel/kprobes.c
View file

@ -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();

2
arch/powerpc/kernel/kprobes.c
View file

@ -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();

2
arch/x86_64/kernel/kprobes.c
View file

@ -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();

10
include/linux/kprobes.h
View file

@ -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);