| Message ID | 1647597096-5480-1-git-send-email-shengjiu.wang@nxp.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | remoteproc: core: check rproc->power value before decreasing it | expand |
Hi Shengjiu, On Fri, Mar 18, 2022 at 05:51:36PM +0800, Shengjiu Wang wrote: > There are possibility that two 'stop' operation happen > in parallel, then the rproc->power may be decreased to > -1, that this reference count will be in wrong state. > So check rproc->power to make sure it is larger than > zero before decreasing it. > > Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com> > --- > drivers/remoteproc/remoteproc_core.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c > index c510125769b9..84e065ad8743 100644 > --- a/drivers/remoteproc/remoteproc_core.c > +++ b/drivers/remoteproc/remoteproc_core.c > @@ -2075,6 +2075,9 @@ int rproc_shutdown(struct rproc *rproc) > return ret; > } > > + if (atomic_read(&rproc->power) <= 0) > + goto out; > + Although the proposed solution will likely work, I think it is best to use rproc->state for this. Simply do the same test as in state_store()[1] and exit if the conditions are not satisfied. Please do the same thing for rproc_detach(). Thanks, Mathieu [1]. https://elixir.bootlin.com/linux/v5.17/source/drivers/remoteproc/remoteproc_sysfs.c#L205 > /* if the remote proc is still needed, bail out */ > if (!atomic_dec_and_test(&rproc->power)) > goto out; > -- > 2.17.1 >
diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c index c510125769b9..84e065ad8743 100644 --- a/drivers/remoteproc/remoteproc_core.c +++ b/drivers/remoteproc/remoteproc_core.c @@ -2075,6 +2075,9 @@ int rproc_shutdown(struct rproc *rproc) return ret; } + if (atomic_read(&rproc->power) <= 0) + goto out; + /* if the remote proc is still needed, bail out */ if (!atomic_dec_and_test(&rproc->power)) goto out;
There are possibility that two 'stop' operation happen in parallel, then the rproc->power may be decreased to -1, that this reference count will be in wrong state. So check rproc->power to make sure it is larger than zero before decreasing it. Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com> --- drivers/remoteproc/remoteproc_core.c | 3 +++ 1 file changed, 3 insertions(+)