Messages in this thread | | | Date | Fri, 05 Apr 2013 11:34:27 +0900 | From | Masami Hiramatsu <> | Subject | Re: [PATCH v2 2/4] kprobes: split blacklist into common and arch |
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(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@hitachi.com
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