(2015/01/19 1:55), James Bottomley wrote:
> From: James Bottomley <JBottomley@xxxxxxxxxxxxx>
>
> After e513cc1 module: Remove stop_machine from module unloading,
> module_refcount() is returning (unsigned long)-1 when called from within
> a routine that runs in module_exit. This is confusing the scsi device
> put code which is coded to detect a module_refcount() of zero for
> running within a module exit routine and not try to do another
> module_put. The fix is to restore the original behaviour of
> module_refcount() and return zero if we're running inside an exit
> routine.
>
> Fixes: e513cc1c07e2ab93a4514eec9833e031df3e30bb
> Reported-by: Bart Van Assche <bvanassche@xxxxxxx>
> Signed-off-by: James Bottomley <JBottomley@xxxxxxxxxxxxx>
>
Yes, this should be fixed as you said, since it must return "unsigned long" value.
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Just one comment below;
> diff --git a/kernel/module.c b/kernel/module.c
> index 3965511..c33a113 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -774,7 +774,12 @@ static int try_stop_module(struct module *mod, int flags, int *forced)
>
> unsigned long module_refcount(struct module *mod)
> {
> - return (unsigned long)atomic_read(&mod->refcnt) - MODULE_REF_BASE;
> + unsigned long ret = atomic_read(&mod->refcnt);
> +
> + if (ret == 0)
This would better be "if (unlikely(ret == 0))".
Thank you,
> + /* ref is already zero (probably in module exit) */
> + return 0;
> + return ret - MODULE_REF_BASE;
> }
> EXPORT_SYMBOL(module_refcount);
>
>
>
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--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@xxxxxxxxxxx
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