Re: [PATCH] flow_dissector: avoid uninitialized variable access

2016-10-22 Thread Tom Herbert
On Sat, Oct 22, 2016 at 8:57 AM, Eric Garver wrote: > On Sat, Oct 22, 2016 at 12:16:29AM +0200, Arnd Bergmann wrote: >> On Friday, October 21, 2016 11:05:45 PM CEST Arnd Bergmann wrote: >> > >> > Can you explain why "dissector_uses_key(flow_dissector, >> > FLOW_DISSECTOR_KEY_VLAN) && skb_vlan_tag_

Re: [PATCH] flow_dissector: avoid uninitialized variable access

2016-10-22 Thread Eric Garver
On Sat, Oct 22, 2016 at 12:16:29AM +0200, Arnd Bergmann wrote: > On Friday, October 21, 2016 11:05:45 PM CEST Arnd Bergmann wrote: > > > > Can you explain why "dissector_uses_key(flow_dissector, > > FLOW_DISSECTOR_KEY_VLAN) && skb_vlan_tag_present(skb)" implies > > "eth_type_vlan(proto))"? > > >

Re: [PATCH] flow_dissector: avoid uninitialized variable access

2016-10-21 Thread Jiri Pirko
Sat, Oct 22, 2016 at 03:48:48AM CEST, torva...@linux-foundation.org wrote: >On Fri, Oct 21, 2016 at 9:31 AM, Jiri Pirko wrote: >> >> I don't see how vlan could be used uninitialized. But I understand that >> this is impossible for gcc to track it. Please just use uninitialized_var() > >Actually, I

Re: [PATCH] flow_dissector: avoid uninitialized variable access

2016-10-21 Thread Linus Torvalds
On Fri, Oct 21, 2016 at 9:31 AM, Jiri Pirko wrote: > > I don't see how vlan could be used uninitialized. But I understand that > this is impossible for gcc to track it. Please just use uninitialized_var() Actually, I think we should never use "uninitialized_var()" except possibly for arrays or st

Re: [PATCH] flow_dissector: avoid uninitialized variable access

2016-10-21 Thread Arnd Bergmann
On Friday, October 21, 2016 11:05:45 PM CEST Arnd Bergmann wrote: > > Can you explain why "dissector_uses_key(flow_dissector, > FLOW_DISSECTOR_KEY_VLAN) && skb_vlan_tag_present(skb)" implies > "eth_type_vlan(proto))"? > > If I add uninitialized_var() here, I would at least put that in > a comment

Re: [PATCH] flow_dissector: avoid uninitialized variable access

2016-10-21 Thread Arnd Bergmann
On Friday, October 21, 2016 6:31:18 PM CEST Jiri Pirko wrote: > Fri, Oct 21, 2016 at 05:55:53PM CEST, a...@arndb.de wrote: > >gcc warns about an uninitialized pointer dereference in the vlan > >priority handling: > > > >net/core/flow_dissector.c: In function '__skb_flow_dissect': > >net/core/flow_d

Re: [PATCH] flow_dissector: avoid uninitialized variable access

2016-10-21 Thread Jiri Pirko
Fri, Oct 21, 2016 at 05:55:53PM CEST, a...@arndb.de wrote: >gcc warns about an uninitialized pointer dereference in the vlan >priority handling: > >net/core/flow_dissector.c: In function '__skb_flow_dissect': >net/core/flow_dissector.c:281:61: error: 'vlan' may be used uninitialized in >this funct

[PATCH] flow_dissector: avoid uninitialized variable access

2016-10-21 Thread Arnd Bergmann
gcc warns about an uninitialized pointer dereference in the vlan priority handling: net/core/flow_dissector.c: In function '__skb_flow_dissect': net/core/flow_dissector.c:281:61: error: 'vlan' may be used uninitialized in this function [-Werror=maybe-uninitialized] >From all I can tell, this war