On Tue, 31 Jan 2012 00:10:12 +0800 Jiang Liu <[email protected]> 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 <[email protected]> > Acked-by: Jim Keniston <[email protected]> > Acked-by: Ananth N Mavinakayanahalli <[email protected]> > CC: Masami Hiramatsu <[email protected]> > CC: Anil S Keshavamurthy <[email protected]> > CC: "David S. Miller" <[email protected]> > CC: [email protected] > --- > 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? -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
