Messages in this thread Patch in this message | | | Date | Tue, 31 Jan 2012 13:35:10 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] kprobes: fix a memory leak in function pre_handler_kretprobe() |
| |
On Tue, 31 Jan 2012 00:10:12 +0800 Jiang Liu <liuj97@gmail.com> wrote:
> In function pre_handler_kretprobe(), the allocated kretprobe_instance object > will get leaked if the entry_handler callback returns non-zero. This may cause > all the preallocated kretprobe_instance objects exhausted. This issue could be > reproduced by changing samples/kprobes/kretprobe_example.c to probe > "mutex_unlock". And the fix is straight forward, just put the allocated > kretprobe_instance object back onto the free_instances list. > > Signed-off-by: Jiang Liu <jiang.liu@huawei.com> > Acked-by: Jim Keniston <jkenisto@us.ibm.com> > Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> > CC: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> > CC: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> > CC: "David S. Miller" <davem@davemloft.net> > CC: stable@vger.kernel.org > --- > kernel/kprobes.c | 6 +++++- > 1 files changed, 5 insertions(+), 1 deletions(-) > > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > index e5d8464..2423295 100644 > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -1673,8 +1673,12 @@ static int __kprobes pre_handler_kretprobe(struct kprobe *p, > ri->rp = rp; > ri->task = current; > > - if (rp->entry_handler && rp->entry_handler(ri, regs)) > + if (rp->entry_handler && rp->entry_handler(ri, regs)) { > + spin_lock_irqsave(&rp->lock, flags); > + hlist_add_head(&ri->hlist, &rp->free_instances); > + spin_unlock_irqrestore(&rp->lock, flags); > return 0; > + } >
kernel/kprobes.c: In function 'pre_handler_kretprobe': kernel/kprobes.c:1677: warning: passing argument 1 of 'spinlock_check' from incompatible pointer type include/linux/spinlock.h:272: note: expected 'struct spinlock_t *' but argument is of type 'struct raw_spinlock_t *' kernel/kprobes.c:1679: warning: passing argument 1 of 'spin_unlock_irqrestore' from incompatible pointer type include/linux/spinlock.h:338: note: expected 'struct spinlock_t *' but argument is of type 'struct raw_spinlock_t *'
--- a/kernel/kprobes.c~kprobes-fix-a-memory-leak-in-function-pre_handler_kretprobe-fix +++ a/kernel/kprobes.c @@ -1674,9 +1674,9 @@ static int __kprobes pre_handler_kretpro ri->task = current; if (rp->entry_handler && rp->entry_handler(ri, regs)) { - spin_lock_irqsave(&rp->lock, flags); + raw_spin_lock_irqsave(&rp->lock, flags); hlist_add_head(&ri->hlist, &rp->free_instances); - spin_unlock_irqrestore(&rp->lock, flags); + raw_spin_unlock_irqrestore(&rp->lock, flags); return 0; } I'm surprised you didn't notice the warning spew. How well tested is this code?
| |