Messages in this thread | | | Date | Sun, 26 Feb 2012 08:44:03 +0000 | From | Eric Wong <> | Subject | Re: [PATCH] fadvise: avoid EINVAL if user input is valid |
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Hillf Danton <dhillf@gmail.com> wrote: > On Sat, Feb 25, 2012 at 10:27 AM, Eric Wong <normalperson@yhbt.net> wrote: > > index 469491e0..f9e48dd 100644 > > --- a/mm/fadvise.c > > +++ b/mm/fadvise.c > > @@ -43,13 +43,13 @@ SYSCALL_DEFINE(fadvise64_64)(int fd, loff_t offset, loff_t len, int advice) > > goto out; > > } > > > > - mapping = file->f_mapping; > > - if (!mapping || len < 0) { > > + if (len < 0) { > > Current code makes sure mapping is valid after the above check,
Right. I moved the !mapping check down a few lines.
> > ret = -EINVAL; > > goto out; > > }
Now the check hits the "goto out" the get_xip_mem check hits:
> > - if (mapping->a_ops->get_xip_mem) { > > + mapping = file->f_mapping; > > + if (!mapping || mapping->a_ops->get_xip_mem) { > > switch (advice) { > > case POSIX_FADV_NORMAL: > > case POSIX_FADV_RANDOM:
case POSIX_FADV_SEQUENTIAL: case POSIX_FADV_WILLNEED: case POSIX_FADV_NOREUSE: case POSIX_FADV_DONTNEED: /* no bad return value, but ignore advice */ break; default: ret = -EINVAL; } goto out; <------ we hit this if (mapping == NULL) }
> but backing devices info is no longer evaluated with that > guarantee in your change. > > -hd > > 75: bdi = mapping->backing_dev_info;
The above line still doesn't evaluated because of the goto.
out: fput(file); return ret; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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