The patch titled
Kprobes: print details of kretprobe on assertion failure
has been added to the -mm tree. Its filename is
kprobes-print-details-of-kretprobe-on-assertion-failure.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: Kprobes: print details of kretprobe on assertion failure
From: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxx>
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@xxxxxxxxxx>
Cc: Prasanna S Panchamukhi <prasanna@xxxxxxxxxx>
Cc: Jim Keniston <jkenisto@xxxxxxxxxx>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@xxxxxxxxx>
Cc: Maneesh Soni <maneesh@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/i386/kernel/kprobes.c | 3 +--
arch/ia64/kernel/kprobes.c | 3 ++-
arch/powerpc/kernel/kprobes.c | 2 +-
arch/x86_64/kernel/kprobes.c | 2 +-
include/linux/kprobes.h | 10 ++++++++++
5 files changed, 15 insertions(+), 5 deletions(-)
diff -puN arch/i386/kernel/kprobes.c~kprobes-print-details-of-kretprobe-on-assertion-failure arch/i386/kernel/kprobes.c
--- a/arch/i386/kernel/kprobes.c~kprobes-print-details-of-kretprobe-on-assertion-failure
+++ a/arch/i386/kernel/kprobes.c
@@ -449,8 +449,7 @@ fastcall void *__kprobes trampoline_hand
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) {
diff -puN arch/ia64/kernel/kprobes.c~kprobes-print-details-of-kretprobe-on-assertion-failure arch/ia64/kernel/kprobes.c
--- a/arch/ia64/kernel/kprobes.c~kprobes-print-details-of-kretprobe-on-assertion-failure
+++ a/arch/ia64/kernel/kprobes.c
@@ -444,7 +444,8 @@ int __kprobes trampoline_probe_handler(s
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();
diff -puN arch/powerpc/kernel/kprobes.c~kprobes-print-details-of-kretprobe-on-assertion-failure arch/powerpc/kernel/kprobes.c
--- a/arch/powerpc/kernel/kprobes.c~kprobes-print-details-of-kretprobe-on-assertion-failure
+++ a/arch/powerpc/kernel/kprobes.c
@@ -302,7 +302,7 @@ int __kprobes trampoline_probe_handler(s
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();
diff -puN arch/x86_64/kernel/kprobes.c~kprobes-print-details-of-kretprobe-on-assertion-failure arch/x86_64/kernel/kprobes.c
--- a/arch/x86_64/kernel/kprobes.c~kprobes-print-details-of-kretprobe-on-assertion-failure
+++ a/arch/x86_64/kernel/kprobes.c
@@ -447,7 +447,7 @@ int __kprobes trampoline_probe_handler(s
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();
diff -puN include/linux/kprobes.h~kprobes-print-details-of-kretprobe-on-assertion-failure include/linux/kprobes.h
--- a/include/linux/kprobes.h~kprobes-print-details-of-kretprobe-on-assertion-failure
+++ a/include/linux/kprobes.h
@@ -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);
_
Patches currently in -mm which might be from ananth@xxxxxxxxxx are
kprobes-make-kprobesymbol_name-const.patch
kprobes-fix-sparse-null-warning.patch
kprobes-print-details-of-kretprobe-on-assertion-failure.patch
kprobes-use-hlist_for_each_entry.patch
kprobes-codingstyle-cleanups.patch
kprobes-kretprobes-simplifcations.patch
-
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