Messages in this thread |  | | | Date | Tue, 13 Jun 2006 13:04:26 +0300 | | From | "Pekka Enberg" <> | | Subject | Re: [PATCH 2.6.17-rc6 7/9] Remove some of the kmemleak false positives |
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On 13/06/06, Pekka J Enberg <penberg@cs.helsinki.fi> wrote: > > As far as I understood, Ingo is worried about: > > > > struct s { /* some fields */; char *buf; }; > > > > struct s *p = kmalloc(sizeof(struct s) + BUF_SIZE); > > p->buf = p + sizeof(struct s); > > > > Which could lead to false negative due to p->buf pointing to p. However, > > for us to even _find_ p->buf, we would need an incoming pointer _to_ p > > which makes me think this is not a problem in practice. Hmm?
On 6/13/06, Catalin Marinas <catalin.marinas@gmail.com> wrote: > Not exactly. In the above case, Ingo (and me) is worried about having > a incoming pointer (from other block) equal to p->buf and therefore > inside the block allocated with kmalloc.
Ah, right, I overlooked that case. But, is it really a leak? That is, even though we currently don't have a pointer to the beginning fo the block, we don't know for sure it was a leak. You're now allowed to do:
p = kmalloc(...); p = p + HDR_SIZE;
/* ... */ kfree(p - HDR_SIZE);
Do you think we should ban the above?
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