From: Przemek Kitszel <przemyslaw.kitszel@intel.com> To: David Laight <David.Laight@ACULAB.COM>, 'Kees Cook' <keescook@chromium.org> Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>, Steven Zou <steven.zou@intel.com>, "intel-wired-lan@lists.osuosl.org" <intel-wired-lan@lists.osuosl.org>, "linux-hardening@vger.kernel.org" <linux-hardening@vger.kernel.org> Subject: Re: [Intel-wired-lan] [PATCH net-next v3 1/7] overflow: add DEFINE_FLEX() for on-stack allocs Date: Mon, 28 Aug 2023 16:41:15 +0200 [thread overview] Message-ID: <25ff3f7a-b1fe-15ab-ce41-1f1a62eeb624@intel.com> (raw) In-Reply-To: <33c1819b-7c26-ea3b-a8a4-9b14cde425d5@intel.com> On 8/23/23 22:52, Przemek Kitszel wrote: > On 8/18/23 12:49, David Laight wrote: >> From: Przemek Kitszel >>> Sent: Friday, August 18, 2023 11:28 AM >> ... >>>>>> I'm not sure you should be forcing the memset() either. >>>>> >>>>> This already got discussed: better to fail safe. >>>> >>>> Perhaps call it DEFINE_FLEX_Z() to make this clear and >>>> give the option for a non-zeroing version later. >>>> Not everyone wants the expense of zeroing everything. >>> >>> per Kees, zeroing should be removed by compiler when not needed: >>> https://lore.kernel.org/intel-wired-lan/202308101128.C4F0FA235@keescook/ >> >> Expect in the most trivial cases the compiler is pretty much never >> going to remove the zeroing of the data[] part. >> >> I'm also not at all sure what happens if there is a function >> call between the initialisation and any assignments. >> >> With a bit of effort you should be able to pass the '= {}' >> through into an inner #define. >> Possibly with the alternative of a caller-provider >> '= { .obj = call_supplied_initialiser }' >> The 'not _Z' form would pass an empty argument. >> >> David > > Thanks, makes sense, there could be also DEFINE_FLEX_COUNTED > (or DEFINE_FLEX_BOUNDED) to cover Kees's __counted_by() cases. > > Would you like me to cover/convert any existing code/use cases (as with > other patches in the series, to have some examples/actual usage of newly > introduced macros)? I did some manual searches and found no obvious candidate :/ will post next version/RFC without _NOINIT() variant. > >> >> - >> Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, >> MK1 1PT, UK >> Registration No: 1397386 (Wales) > > _______________________________________________ Intel-wired-lan mailing list Intel-wired-lan@osuosl.org https://lists.osuosl.org/mailman/listinfo/intel-wired-lan
WARNING: multiple messages have this Message-ID (diff)
From: Przemek Kitszel <przemyslaw.kitszel@intel.com> To: David Laight <David.Laight@ACULAB.COM>, 'Kees Cook' <keescook@chromium.org> Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>, Jacob Keller <jacob.e.keller@intel.com>, "intel-wired-lan@lists.osuosl.org" <intel-wired-lan@lists.osuosl.org>, Alexander Lobakin <aleksander.lobakin@intel.com>, "linux-hardening@vger.kernel.org" <linux-hardening@vger.kernel.org>, Steven Zou <steven.zou@intel.com> Subject: Re: [PATCH net-next v3 1/7] overflow: add DEFINE_FLEX() for on-stack allocs Date: Mon, 28 Aug 2023 16:41:15 +0200 [thread overview] Message-ID: <25ff3f7a-b1fe-15ab-ce41-1f1a62eeb624@intel.com> (raw) In-Reply-To: <33c1819b-7c26-ea3b-a8a4-9b14cde425d5@intel.com> On 8/23/23 22:52, Przemek Kitszel wrote: > On 8/18/23 12:49, David Laight wrote: >> From: Przemek Kitszel >>> Sent: Friday, August 18, 2023 11:28 AM >> ... >>>>>> I'm not sure you should be forcing the memset() either. >>>>> >>>>> This already got discussed: better to fail safe. >>>> >>>> Perhaps call it DEFINE_FLEX_Z() to make this clear and >>>> give the option for a non-zeroing version later. >>>> Not everyone wants the expense of zeroing everything. >>> >>> per Kees, zeroing should be removed by compiler when not needed: >>> https://lore.kernel.org/intel-wired-lan/202308101128.C4F0FA235@keescook/ >> >> Expect in the most trivial cases the compiler is pretty much never >> going to remove the zeroing of the data[] part. >> >> I'm also not at all sure what happens if there is a function >> call between the initialisation and any assignments. >> >> With a bit of effort you should be able to pass the '= {}' >> through into an inner #define. >> Possibly with the alternative of a caller-provider >> '= { .obj = call_supplied_initialiser }' >> The 'not _Z' form would pass an empty argument. >> >> David > > Thanks, makes sense, there could be also DEFINE_FLEX_COUNTED > (or DEFINE_FLEX_BOUNDED) to cover Kees's __counted_by() cases. > > Would you like me to cover/convert any existing code/use cases (as with > other patches in the series, to have some examples/actual usage of newly > introduced macros)? I did some manual searches and found no obvious candidate :/ will post next version/RFC without _NOINIT() variant. > >> >> - >> Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, >> MK1 1PT, UK >> Registration No: 1397386 (Wales) > >
next prev parent reply other threads:[~2023-08-28 14:41 UTC|newest] Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-08-16 14:06 [Intel-wired-lan] [PATCH net-next v3 0/7] introduce DEFINE_FLEX() macro Przemek Kitszel 2023-08-16 14:06 ` Przemek Kitszel 2023-08-16 14:06 ` [Intel-wired-lan] [PATCH net-next v3 1/7] overflow: add DEFINE_FLEX() for on-stack allocs Przemek Kitszel 2023-08-16 14:06 ` Przemek Kitszel 2023-08-16 16:35 ` kernel test robot 2023-08-16 16:35 ` [Intel-wired-lan] " kernel test robot 2023-08-18 10:37 ` Przemek Kitszel 2023-08-18 10:37 ` [Intel-wired-lan] " Przemek Kitszel 2023-08-18 11:10 ` Miguel Ojeda 2023-08-18 11:10 ` [Intel-wired-lan] " Miguel Ojeda 2023-08-18 12:07 ` Philip Li 2023-08-18 12:07 ` [Intel-wired-lan] " Philip Li 2023-08-19 10:06 ` Greg KH 2023-08-19 10:06 ` [Intel-wired-lan] " Greg KH 2023-08-16 20:38 ` Kees Cook 2023-08-16 20:38 ` [Intel-wired-lan] " Kees Cook 2023-08-17 14:35 ` David Laight 2023-08-17 14:35 ` [Intel-wired-lan] " David Laight 2023-08-17 17:00 ` Kees Cook 2023-08-17 17:00 ` [Intel-wired-lan] " Kees Cook 2023-08-18 7:14 ` David Laight 2023-08-18 7:14 ` [Intel-wired-lan] " David Laight 2023-08-18 10:28 ` Przemek Kitszel 2023-08-18 10:28 ` Przemek Kitszel 2023-08-18 10:49 ` [Intel-wired-lan] " David Laight 2023-08-18 10:49 ` David Laight 2023-08-23 20:52 ` [Intel-wired-lan] " Przemek Kitszel 2023-08-23 20:52 ` Przemek Kitszel 2023-08-28 14:41 ` Przemek Kitszel [this message] 2023-08-28 14:41 ` Przemek Kitszel 2023-08-16 14:06 ` [Intel-wired-lan] [PATCH net-next v3 2/7] ice: ice_sched_remove_elems: replace 1 elem array param by u32 Przemek Kitszel 2023-08-16 14:06 ` Przemek Kitszel 2023-08-16 14:06 ` [Intel-wired-lan] [PATCH net-next v3 3/7] ice: drop two params of ice_aq_move_sched_elems() Przemek Kitszel 2023-08-16 14:06 ` Przemek Kitszel 2023-08-16 14:06 ` [Intel-wired-lan] [PATCH net-next v3 4/7] ice: make use of DEFINE_FLEX() in ice_ddp.c Przemek Kitszel 2023-08-16 14:06 ` Przemek Kitszel 2023-08-16 14:06 ` [Intel-wired-lan] [PATCH net-next v3 5/7] ice: make use of DEFINE_FLEX() for struct ice_aqc_add_tx_qgrp Przemek Kitszel 2023-08-16 14:06 ` Przemek Kitszel 2023-08-16 14:06 ` [Intel-wired-lan] [PATCH net-next v3 6/7] ice: make use of DEFINE_FLEX() for struct ice_aqc_dis_txq_item Przemek Kitszel 2023-08-16 14:06 ` Przemek Kitszel 2023-08-16 14:06 ` [Intel-wired-lan] [PATCH net-next v3 7/7] ice: make use of DEFINE_FLEX() in ice_switch.c Przemek Kitszel 2023-08-16 14:06 ` Przemek Kitszel
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