(2015/03/01 6:24), Peter Zijlstra wrote:
> While one must hold RCU-sched (aka. preempt_disable) for find_symbol()
> one must equally hold it over the use of the object returned.
>
> The moment you release the RCU-sched read lock, the object can be dead
> and gone.
>
> Cc: Seth Jennings <sjenn...@redhat.com>
> Cc: Josh Poimboeuf <jpoim...@redhat.com>
> Cc: Masami Hiramatsu <masami.hiramatsu...@hitachi.com>
> Cc: Miroslav Benes <mbe...@suse.cz>
> Cc: Petr Mladek <pmla...@suse.cz>
> Cc: Jiri Kosina <jkos...@suse.cz>
> Cc: "Paul E. McKenney" <paul...@linux.vnet.ibm.com>
> Cc: Rusty Russell <ru...@rustcorp.com.au>
> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Looks good to me.
Reviewed-by: Masami Hiramatsu <masami.hiramatsu...@hitachi.com>
Thank you,
> ---
> kernel/livepatch/core.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> --- a/kernel/livepatch/core.c
> +++ b/kernel/livepatch/core.c
> @@ -248,11 +248,12 @@ static int klp_find_external_symbol(stru
> /* first, check if it's an exported symbol */
> preempt_disable();
> sym = find_symbol(name, NULL, NULL, true, true);
> - preempt_enable();
> if (sym) {
> *addr = sym->value;
> + preempt_enable();
> return 0;
> }
> + preempt_enable();
>
> /* otherwise check if it's in another .o within the patch module */
> return klp_find_object_symbol(pmod->name, name, addr);
>
>
> --
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>
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com
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