(2013/04/04 21:51), Oskar Andero wrote:
> Some blackpoints are only valid for specific architectures. To let each
> architecture specify its own blackpoints the list has been split in two
> lists: common and arch. The common list is kept in kernel/kprobes.c and
> the arch list is kept in the arch/ directory.
>
Here I missed one racing issue.
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 0a270e5..7654278 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
[...]
>
> /* it can take some time ( > 100ms ) to initialise the
> * blacklist so we delay this until we actually need it
> */
> static void init_kprobe_blacklist(void)
> {
> - int i;
> - unsigned long offset = 0, size = 0;
> - char *modname, namebuf[128];
> - const char *symbol_name;
> - void *addr;
> - struct kprobe_blackpoint *kb;
> + int i, j = 0;
>
> mutex_lock(&kprobe_mutex);
> - if (kprobe_blacklist_initialized)
> + if (kprobe_blacklist)
> goto out;
>
> + kprobe_blacklist_size = common_kprobes_blacksyms_size +
> + arch_kprobes_blacksyms_size;
> + kprobe_blacklist = kzalloc(sizeof(*kprobe_blacklist) *
> + kprobe_blacklist_size, GFP_KERNEL);
If you'd like to use kprobe_blacklist itself as an initialized flag,
you must prepare the "blacklist" local pointer to allocate and
initialize entries.
> @@ -151,7 +175,6 @@ static void init_kprobe_blacklist(void)
> kretprobe_blacklist[i].name);
> }
> }
> - kprobe_blacklist_initialized = 1;
And after initialized, assign blacklist to kprobe_blacklist.
Without that, other thread may refer the uninitialized (but allocated)
black list.
Thank you,
--
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@xxxxxxxxxxx
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