On Mon, Jun 15, 2020 at 3:06 PM Nick Desaulniers <ndesaulni...@google.com> wrote: > > On Mon, Jun 15, 2020 at 1:37 PM Nick Desaulniers > <ndesaulni...@google.com> wrote: > > > > On Mon, Jun 15, 2020 at 1:36 PM Nick Desaulniers > > <ndesaulni...@google.com> wrote: > > > > > > On Mon, Jun 15, 2020 at 11:45 AM Eric Dumazet <eduma...@google.com> wrote: > > > > > > > > On Mon, Jun 15, 2020 at 11:07 AM Nick Desaulniers > > > > <ndesaulni...@google.com> wrote: > > > > > > > > > > On Mon, Jun 15, 2020 at 10:59 AM 'Eric Dumazet' via Clang Built Linux > > > > > <clang-built-li...@googlegroups.com> wrote: > > > > > > > > > > > > On Mon, Jun 15, 2020 at 10:54 AM Eric Dumazet <eduma...@google.com> > > > > > > wrote: > > > > > > > > > > > > > > On Mon, Jun 15, 2020 at 10:44 AM Nick Desaulniers > > > > > > > <ndesaulni...@google.com> wrote: > > > > > > > > > > > > > > > > On Mon, Jun 15, 2020 at 9:17 AM 'Eric Dumazet' via Clang Built > > > > > > > > Linux > > > > > > > > <clang-built-li...@googlegroups.com> wrote: > > > > > > > > > > > > > > > > > > On Sun, Jun 14, 2020 at 11:26 PM kernel test robot > > > > > > > > > <l...@intel.com> wrote: > > > > > > > > > > > > > > > > > > > > tree: > > > > > > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > > > > > > > > > > master > > > > > > > > > > head: 96144c58abe7ff767e754b5b80995f7b8846d49b > > > > > > > > > > commit: 39d010504e6b4485d7ceee167743620dd33f4417 net_sched: > > > > > > > > > > sch_fq: add horizon attribute > > > > > > > > > > date: 6 weeks ago > > > > > > > > > > :::::: branch date: 3 hours ago > > > > > > > > > > :::::: commit date: 6 weeks ago > > > > > > > > > > config: arm-randconfig-r006-20200614 (attached as .config) > > > > > > > > > > compiler: clang version 11.0.0 > > > > > > > > > > (https://github.com/llvm/llvm-project > > > > > > > > > > c669a1ed6386d57a75a602b53266466dae1e1d84) > > > > > > > > > > reproduce (this is a W=1 build): > > > > > > > > > > wget > > > > > > > > > > https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross > > > > > > > > > > -O ~/bin/make.cross > > > > > > > > > > chmod +x ~/bin/make.cross > > > > > > > > > > # install arm cross compiling tool for clang build > > > > > > > > > > # apt-get install binutils-arm-linux-gnueabi > > > > > > > > > > git checkout > > > > > > > > > > 39d010504e6b4485d7ceee167743620dd33f4417 > > > > > > > > > > # save the attached .config to linux build tree > > > > > > > > > > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang > > > > > > > > > > make.cross ARCH=arm > > > > > > > > > > > > > > > > > > > > If you fix the issue, kindly add following tag as > > > > > > > > > > appropriate > > > > > > > > > > Reported-by: kernel test robot <l...@intel.com> > > > > > > > > > > > > > > > > > > > > All warnings (new ones prefixed by >>, old ones prefixed by > > > > > > > > > > <<): > > > > > > > > > > > > > > > > > > > > >> net/sched/sch_fq.c:966:12: warning: stack frame size of > > > > > > > > > > >> 1400 bytes in function 'fq_dump' [-Wframe-larger-than=] > > > > > > > > > > static int fq_dump(struct Qdisc *sch, struct sk_buff *skb) > > > > > > > > > > ^ > > > > > > > > > > > > > > > > > > > > > > > > > > > This looks like a bug in CLANG on ARM, there is no way > > > > > > > > > fq_dump() could > > > > > > > > > consume so much stack space. > > > > > > > > > > > > > > > > You can use > > > > > > > > https://github.com/ClangBuiltLinux/frame-larger-than > > > > > > > > to help debug these. You might be surprised who's doing larger > > > > > > > > stack > > > > > > > > allocations than expected. > > > > > > > > > > > > > > What is wrong with scripts/checkstack.pl ? > > > > > > > > > > > > After using CLANG on x86 I get : > > > > > > > > > > > > $ objdump -d net/sched/sch_fq.o | scripts/checkstack.pl > > > > > > 0x00001136 fq_change [sch_fq.o]: 192 > > > > > > 0x00000016 __direct_call_Qdisc_enqueue1 [sch_fq.o]: 112 > > > > > > 0x000019e0 fq_dump_stats [sch_fq.o]: 112 > > > > > > 0x00001b43 fq_dump_stats [sch_fq.o]: 112 > > > > > > > > > > > > So CLANG on x86 seems fine. > > > > > > > > > > > > I said : " this looks like a bug in CLANG on ARM" > > > > > > > > > > This is a randconfig, so some option is turning on something that's > > > > > causing excessive stack usage with your patch on ARM. Building who > > > > > knows what config with x86 and claiming it works doesn't really cut > > > > > it. You looked at fq_dump and claimed it should be fine. Did you > > > > > verify each called function that was inlined? > > > > > > > > Nick, my patch added exactly _one_ u64 variable in the stack. > > > > That's a whooping 8 bytes, right ? > > > > > > What if I add a single byte of stack usage, and that's enough to trip > > > this warning? Not my problem? > > > > > > > > > > > We should be able to use as many nla_put_u32() calls in a function, > > > > without changing stack sizes. > > > > > > That's good to know, see below. (That not be the case here). > > > > > > > > > > > If CLANG can not do that, then this is a CLANG problem, I have no > > > > intention of fixing it, > > > > I hope this is very clear ;) > > > > > > At least you tested it with Clang, so I appreciate you taking the time > > > to do that. Here's how we might go about debugging this further: > > > > > > $ git checkout 39d010504e6b4485d7ceee167743620dd33f4417 > > > $ wget > > > https://lore.kernel.org/lkml/20200615062520.GK12456@shao2-debian/2-a.bin > > > -O .config.gz > > > $ gunzip .config.gz > > Also, it looks like CONFIG_UBSAN=y was set in this randconfig, so that > may play a part in the excessive stack usage. We've definitely seen > that with CONFIG_KASAN=y.
Running make with V=1 isn't printing any of the -fsanitize= flags, looks like UBSAN_SANITIZE_ALL needs to be set. If I do an ARCH=arm defconfig + CONFIG_NET_SCHED=y + CONFIG_NET_SCH_FQ=y + CONFIG_DEBUG=y, we don't get the warning, but I still see the 2 64b divides and multiple tmps. > > > > $ ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- make CC=clang -j71 > > > net/sched/sch_fq.o > > > ... > > > net/sched/sch_fq.c:966:12: warning: stack frame size of 1400 bytes in > > > function 'fq_dump' [-Wframe-larger-than=] > > > $ python3 /path/to/frame_larger_than.py net/sched/sch_fq.o fq_dump > > > fq_dump: > > > 8 u64 horizon > > > 8 u64 ce_threshold > > > 4 struct fq_sched_data* q > > > 4 struct nlattr* opts > > > qdisc_priv: > > > nla_nest_start_noflag: > > > 4 struct nlattr* start > > > 4 struct nlattr* start > > > skb_tail_pointer: > > > 4 uint32_t __base > > > 4 uint32_t __rem > > > is_power_of_2: > > > 4 uint32_t __n_lo > > > 4 uint32_t __res_lo > > > 8 uint64_t ___n > > > 8 uint64_t ___m > > > 4 uint32_t ___bias > > > 8 uint64_t ___res > > > 8 uint64_t ___t > > > 8 uint64_t ___x > > > 4 uint32_t ___p > > > __arch_xprod_64: > > > 4 unsigned int tmp > > > 8 long long unsigned int res > > > 4 unsigned int tmp > > > 8 long long unsigned int res > > > 4 uint32_t __base > > > 4 uint32_t __rem > > > is_power_of_2: > > > 4 uint32_t __n_lo > > > 4 uint32_t __res_lo > > > 8 uint64_t ___n > > > 8 uint64_t ___res > > > 8 uint64_t ___t > > > 8 uint64_t ___x > > > 8 uint64_t ___m > > > 4 uint32_t ___p > > > 4 uint32_t ___bias > > > __arch_xprod_64: > > > 4 unsigned int tmp > > > 8 long long unsigned int res > > > 4 unsigned int tmp > > > 8 long long unsigned int res > > > nla_put_u32: > > > 4 u32 tmp > > > 4 u32 tmp > > > nla_put_u32: > > > 4 u32 tmp > > > 4 u32 tmp > > > nla_put_u32: > > > 4 u32 tmp > > > 4 u32 tmp > > > nla_put_u32: > > > 4 u32 tmp > > > 4 u32 tmp > > > nla_put_u32: > > > 4 u32 tmp > > > 4 u32 tmp > > > 4 long unsigned int __UNIQUE_ID___y256 > > > 4 long unsigned int __UNIQUE_ID___x255 > > > nla_put_u32: > > > 4 u32 tmp > > > 4 u32 tmp > > > nla_put_u32: > > > 4 u32 tmp > > > 4 u32 tmp > > > nla_put_u32: > > > 4 u32 tmp > > > 4 u32 tmp > > > nla_put_u32: > > > 4 u32 tmp > > > 4 u32 tmp > > > nla_put_u32: > > > 4 u32 tmp > > > 4 u32 tmp > > > nla_put_u32: > > > 4 u32 tmp > > > 4 u32 tmp > > > nla_put_u32: > > > 4 u32 tmp > > > 4 u32 tmp > > > nla_put_u32: > > > 4 u32 tmp > > > 4 u32 tmp > > > nla_put_u8: > > > 1 u8 tmp > > > 1 u8 tmp > > > nla_nest_end: > > > skb_tail_pointer: > > > > > > So is_power_of_2/__arch_xprod_64 looks excessively large, and the > > > nla_put_u* routines seem to have 2 temporary variables? > > > > > > (I should update the tool to better denote the end of an inlined > > > frame; I don't think is_power_of_2 is the source, it looks like > > > do_div() calls with 64b non-integer constant expressions. Having those > > > be macros vs noinline_for_stack might be of interest for the non-ICE > > > case, cc Arnd). > > > > > > Let me see if I can extend the tool to print file+line numbers so we > > > can see if those `tmp`s are one in the same or not. > > > > > > > > > > > > > > > > > > > > > > And the issue with checkstack is it tells you the depth, but not *what > > > > > variables* and from which inlined function may be the cause. > > > > > > > > > > > > OK. Thank you. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > 1 warning generated. > > > > > > > > > > > > > > > > > > > > # > > > > > > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=39d010504e6b4485d7ceee167743620dd33f4417 > > > > > > > > > > git remote add linus > > > > > > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > > > > > > > > > > git remote update linus > > > > > > > > > > git checkout 39d010504e6b4485d7ceee167743620dd33f4417 > > > > > > > > > > vim +/fq_dump +966 net/sched/sch_fq.c > > > > > > > > > > > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 965 > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 @966 static int > > > > > > > > > > fq_dump(struct Qdisc *sch, struct sk_buff *skb) > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 967 { > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 968 > > > > > > > > > > struct fq_sched_data *q = qdisc_priv(sch); > > > > > > > > > > 48872c11b77271 Eric Dumazet 2018-11-11 969 u64 > > > > > > > > > > ce_threshold = q->ce_threshold; > > > > > > > > > > 39d010504e6b44 Eric Dumazet 2020-05-01 970 u64 > > > > > > > > > > horizon = q->horizon; > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 971 > > > > > > > > > > struct nlattr *opts; > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 972 > > > > > > > > > > ae0be8de9a53cd Michal Kubecek 2019-04-26 973 > > > > > > > > > > opts = nla_nest_start_noflag(skb, TCA_OPTIONS); > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 974 if > > > > > > > > > > (opts == NULL) > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 975 > > > > > > > > > > goto nla_put_failure; > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 976 > > > > > > > > > > 65c5189a2b57b9 Eric Dumazet 2013-11-15 977 /* > > > > > > > > > > TCA_FQ_FLOW_DEFAULT_RATE is not used anymore */ > > > > > > > > > > 65c5189a2b57b9 Eric Dumazet 2013-11-15 978 > > > > > > > > > > 48872c11b77271 Eric Dumazet 2018-11-11 979 > > > > > > > > > > do_div(ce_threshold, NSEC_PER_USEC); > > > > > > > > > > 39d010504e6b44 Eric Dumazet 2020-05-01 980 > > > > > > > > > > do_div(horizon, NSEC_PER_USEC); > > > > > > > > > > 48872c11b77271 Eric Dumazet 2018-11-11 981 > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 982 if > > > > > > > > > > (nla_put_u32(skb, TCA_FQ_PLIMIT, sch->limit) || > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 983 > > > > > > > > > > nla_put_u32(skb, TCA_FQ_FLOW_PLIMIT, q->flow_plimit) || > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 984 > > > > > > > > > > nla_put_u32(skb, TCA_FQ_QUANTUM, q->quantum) || > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 985 > > > > > > > > > > nla_put_u32(skb, TCA_FQ_INITIAL_QUANTUM, > > > > > > > > > > q->initial_quantum) || > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 986 > > > > > > > > > > nla_put_u32(skb, TCA_FQ_RATE_ENABLE, q->rate_enable) || > > > > > > > > > > 76a9ebe811fb3d Eric Dumazet 2018-10-15 987 > > > > > > > > > > nla_put_u32(skb, TCA_FQ_FLOW_MAX_RATE, > > > > > > > > > > 76a9ebe811fb3d Eric Dumazet 2018-10-15 988 > > > > > > > > > > min_t(unsigned long, q->flow_max_rate, ~0U)) || > > > > > > > > > > f52ed89971adbe Eric Dumazet 2013-11-15 989 > > > > > > > > > > nla_put_u32(skb, TCA_FQ_FLOW_REFILL_DELAY, > > > > > > > > > > f52ed89971adbe Eric Dumazet 2013-11-15 990 > > > > > > > > > > jiffies_to_usecs(q->flow_refill_delay)) || > > > > > > > > > > 06eb395fa9856b Eric Dumazet 2015-02-04 991 > > > > > > > > > > nla_put_u32(skb, TCA_FQ_ORPHAN_MASK, q->orphan_mask) || > > > > > > > > > > 77879147a3481b Eric Dumazet 2016-09-19 992 > > > > > > > > > > nla_put_u32(skb, TCA_FQ_LOW_RATE_THRESHOLD, > > > > > > > > > > 77879147a3481b Eric Dumazet 2016-09-19 993 > > > > > > > > > > q->low_rate_threshold) || > > > > > > > > > > 48872c11b77271 Eric Dumazet 2018-11-11 994 > > > > > > > > > > nla_put_u32(skb, TCA_FQ_CE_THRESHOLD, (u32)ce_threshold) || > > > > > > > > > > 583396f4ca4d6e Eric Dumazet 2020-03-16 995 > > > > > > > > > > nla_put_u32(skb, TCA_FQ_BUCKETS_LOG, q->fq_trees_log) || > > > > > > > > > > 39d010504e6b44 Eric Dumazet 2020-05-01 996 > > > > > > > > > > nla_put_u32(skb, TCA_FQ_TIMER_SLACK, q->timer_slack) || > > > > > > > > > > 39d010504e6b44 Eric Dumazet 2020-05-01 997 > > > > > > > > > > nla_put_u32(skb, TCA_FQ_HORIZON, (u32)horizon) || > > > > > > > > > > 39d010504e6b44 Eric Dumazet 2020-05-01 998 > > > > > > > > > > nla_put_u8(skb, TCA_FQ_HORIZON_DROP, q->horizon_drop)) > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 999 > > > > > > > > > > goto nla_put_failure; > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 1000 > > > > > > > > > > d59b7d8059ddc4 Yang Yingliang 2014-03-12 1001 > > > > > > > > > > return nla_nest_end(skb, opts); > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 1002 > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 1003 > > > > > > > > > > nla_put_failure: > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 1004 > > > > > > > > > > return -1; > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 1005 } > > > > > > > > > > afe4fd062416b1 Eric Dumazet 2013-08-29 1006 > > > > > > > > > > > > > > > > > > > > :::::: The code at line 966 was first introduced by commit > > > > > > > > > > :::::: afe4fd062416b158a8a8538b23adc1930a9b88dc pkt_sched: > > > > > > > > > > fq: Fair Queue packet scheduler > > > > > > > > > > > > > > > > > > > > :::::: TO: Eric Dumazet <eduma...@google.com> > > > > > > > > > > :::::: CC: David S. Miller <da...@davemloft.net> > > > > > > > > > > > > > > > > > > > > --- > > > > > > > > > > 0-DAY CI Kernel Test Service, Intel Corporation > > > > > > > > > > https://lists.01.org/hyperkitty/list/kbuild-...@lists.01.org > > > > > > > > > > _______________________________________________ > > > > > > > > > > kbuild mailing list -- kbu...@lists.01.org > > > > > > > > > > To unsubscribe send an email to kbuild-le...@lists.01.org > > > > > > > > > > > > > > > > > > -- > > > > > > > > > You received this message because you are subscribed to the > > > > > > > > > Google Groups "Clang Built Linux" group. > > > > > > > > > To unsubscribe from this group and stop receiving emails from > > > > > > > > > it, send an email to > > > > > > > > > clang-built-linux+unsubscr...@googlegroups.com. > > > > > > > > > To view this discussion on the web visit > > > > > > > > > https://groups.google.com/d/msgid/clang-built-linux/CANn89i%2Bs%3DoFTq6KFhT0z1CReQPZCGoEPShEFHVvXAmC9sUDH7g%40mail.gmail.com. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > > > Thanks, > > > > > > > > ~Nick Desaulniers > > > > > > > > > > > > -- > > > > > > You received this message because you are subscribed to the Google > > > > > > Groups "Clang Built Linux" group. > > > > > > To unsubscribe from this group and stop receiving emails from it, > > > > > > send an email to clang-built-linux+unsubscr...@googlegroups.com. > > > > > > To view this discussion on the web visit > > > > > > https://groups.google.com/d/msgid/clang-built-linux/CANn89iLnmKaa30tPoyK_GrJr-_ALYBwjcJ0pBcvmckA9PAvrgA%40mail.gmail.com. > > > > > > > > > > > > > > > > > > > > -- > > > > > Thanks, > > > > > ~Nick Desaulniers > > > > > > > > > > > > -- > > > Thanks, > > > ~Nick Desaulniers > > > > > > > > -- > > Thanks, > > ~Nick Desaulniers > > > > -- > Thanks, > ~Nick Desaulniers -- Thanks, ~Nick Desaulniers
