Message ID | 1523442262-4823-1-git-send-email-baijiaju1990@gmail.com |
---|---|
State | Deferred, archived |
Delegated to: | David Miller |
Headers | show |
Series | [v3] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in tipc_mon_create | expand |
On 04/11/2018 06:24 PM, Jia-Ju Bai wrote: > tipc_mon_create() is never called in atomic context. > > The call chain ending up at tipc_mon_create() is: > [1] tipc_mon_create() <- tipc_enable_bearer() <- tipc_nl_bearer_enable() > tipc_nl_bearer_enable() calls rtnl_lock(), which indicates this function > is not called in atomic context. > > Despite never getting called from atomic context, > tipc_mon_create() calls kzalloc() with GFP_ATOMIC, > which does not sleep for allocation. > GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL, > which can sleep and improve the possibility of successful allocation. > > This is found by a static analysis tool named DCNS written by myself. > And I also manually check it. > > Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> Acked-by: Ying Xue <ying.xue@windriver.com> > --- > v2: > * Modify the description of GFP_ATOMIC in v1. > Thank Eric for good advice. > v3: > * Modify wrong text in description in v2. > Thank Ying for good advice. > --- > net/tipc/monitor.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/net/tipc/monitor.c b/net/tipc/monitor.c > index 9e109bb..9714d80 100644 > --- a/net/tipc/monitor.c > +++ b/net/tipc/monitor.c > @@ -604,9 +604,9 @@ int tipc_mon_create(struct net *net, int bearer_id) > if (tn->monitors[bearer_id]) > return 0; > > - mon = kzalloc(sizeof(*mon), GFP_ATOMIC); > - self = kzalloc(sizeof(*self), GFP_ATOMIC); > - dom = kzalloc(sizeof(*dom), GFP_ATOMIC); > + mon = kzalloc(sizeof(*mon), GFP_KERNEL); > + self = kzalloc(sizeof(*self), GFP_KERNEL); > + dom = kzalloc(sizeof(*dom), GFP_KERNEL); > if (!mon || !self || !dom) { > kfree(mon); > kfree(self); >
> -----Original Message----- > From: Ying Xue [mailto:ying.xue@windriver.com] > Sent: Wednesday, April 11, 2018 06:27 > To: Jia-Ju Bai <baijiaju1990@gmail.com>; Jon Maloy > <jon.maloy@ericsson.com>; davem@davemloft.net > Cc: netdev@vger.kernel.org; tipc-discussion@lists.sourceforge.net; linux- > kernel@vger.kernel.org > Subject: Re: [PATCH v3] net: tipc: Replace GFP_ATOMIC with GFP_KERNEL in > tipc_mon_create > > On 04/11/2018 06:24 PM, Jia-Ju Bai wrote: > > tipc_mon_create() is never called in atomic context. > > > > The call chain ending up at tipc_mon_create() is: > > [1] tipc_mon_create() <- tipc_enable_bearer() <- > > tipc_nl_bearer_enable() > > tipc_nl_bearer_enable() calls rtnl_lock(), which indicates this > > function is not called in atomic context. > > > > Despite never getting called from atomic context, > > tipc_mon_create() calls kzalloc() with GFP_ATOMIC, which does not > > sleep for allocation. > > GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL, > which > > can sleep and improve the possibility of successful allocation. > > > > This is found by a static analysis tool named DCNS written by myself. > > And I also manually check it. > > > > Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> > > Acked-by: Ying Xue <ying.xue@windriver.com> Acked-by: Jon Maloy <jon.maloy@ericsson.com> > > > --- > > v2: > > * Modify the description of GFP_ATOMIC in v1. > > Thank Eric for good advice. > > v3: > > * Modify wrong text in description in v2. > > Thank Ying for good advice. > > --- > > net/tipc/monitor.c | 6 +++--- > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/net/tipc/monitor.c b/net/tipc/monitor.c index > > 9e109bb..9714d80 100644 > > --- a/net/tipc/monitor.c > > +++ b/net/tipc/monitor.c > > @@ -604,9 +604,9 @@ int tipc_mon_create(struct net *net, int bearer_id) > > if (tn->monitors[bearer_id]) > > return 0; > > > > - mon = kzalloc(sizeof(*mon), GFP_ATOMIC); > > - self = kzalloc(sizeof(*self), GFP_ATOMIC); > > - dom = kzalloc(sizeof(*dom), GFP_ATOMIC); > > + mon = kzalloc(sizeof(*mon), GFP_KERNEL); > > + self = kzalloc(sizeof(*self), GFP_KERNEL); > > + dom = kzalloc(sizeof(*dom), GFP_KERNEL); > > if (!mon || !self || !dom) { > > kfree(mon); > > kfree(self); > >
diff --git a/net/tipc/monitor.c b/net/tipc/monitor.c index 9e109bb..9714d80 100644 --- a/net/tipc/monitor.c +++ b/net/tipc/monitor.c @@ -604,9 +604,9 @@ int tipc_mon_create(struct net *net, int bearer_id) if (tn->monitors[bearer_id]) return 0; - mon = kzalloc(sizeof(*mon), GFP_ATOMIC); - self = kzalloc(sizeof(*self), GFP_ATOMIC); - dom = kzalloc(sizeof(*dom), GFP_ATOMIC); + mon = kzalloc(sizeof(*mon), GFP_KERNEL); + self = kzalloc(sizeof(*self), GFP_KERNEL); + dom = kzalloc(sizeof(*dom), GFP_KERNEL); if (!mon || !self || !dom) { kfree(mon); kfree(self);
tipc_mon_create() is never called in atomic context. The call chain ending up at tipc_mon_create() is: [1] tipc_mon_create() <- tipc_enable_bearer() <- tipc_nl_bearer_enable() tipc_nl_bearer_enable() calls rtnl_lock(), which indicates this function is not called in atomic context. Despite never getting called from atomic context, tipc_mon_create() calls kzalloc() with GFP_ATOMIC, which does not sleep for allocation. GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL, which can sleep and improve the possibility of successful allocation. This is found by a static analysis tool named DCNS written by myself. And I also manually check it. Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> --- v2: * Modify the description of GFP_ATOMIC in v1. Thank Eric for good advice. v3: * Modify wrong text in description in v2. Thank Ying for good advice. --- net/tipc/monitor.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)