Em Thu, Dec 20, 2018 at 11:14:48PM +0000, Yonghong Song escreveu: > > > On 12/20/18 10:31 AM, Arnaldo Carvalho de Melo wrote: > > Adding dwarves@xxxxxxxxxxxxxxx to the CC list. > > > > Em Tue, Dec 18, 2018 at 02:09:38PM -0800, Yonghong Song escreveu: > >> This patch set included three btf related changes. > > > >> Patch #1 added support to do dwarf->btf conversion > >> for multiple cu's and multiple binaries. > >> Patch #2 added support to generate types for struct, > >> union and fwd using kind_flag. The kernel support > >> for kind_flag is here: > >> https://urldefense.proofpoint.com/v2/url?u=https-3A__www.spinics.net_lists_netdev_msg539088.html&d=DwIBAg&c=5VD0RTtNlTh3ycd41b3MUw&r=DA8e1B5r073vIqRrFz7MRA&m=yUci7csgF5JQxbKJ-Qbe7_WSnzpZGNHBeR9v6sbfOX8&s=x1n4q5bAFOwgK8gMbeRHbtQ-PEXqurdDjCkhEjY-d6s&e= > >> Patch #3 added func_proto support. The kernel support > >> is here: > >> https://urldefense.proofpoint.com/v2/url?u=https-3A__www.spinics.net_lists_netdev_msg534643.html&d=DwIBAg&c=5VD0RTtNlTh3ycd41b3MUw&r=DA8e1B5r073vIqRrFz7MRA&m=yUci7csgF5JQxbKJ-Qbe7_WSnzpZGNHBeR9v6sbfOX8&s=BLITwXmBAnM1RkuzWM9DFwGNw1YPlZArh7qR9OY-Azc&e= > > > >> Please see individual patch for details. > > > >> Yonghong Song (3): > >> btf: permit multiple cu's for dwarf->btf conversion > >> btf: fix struct/union/fwd types with kind_flag > >> btf: add func_proto support > > > > Ok, I tested and processed those and added a few more, adding a btf > > loader, pushed out to my git.kernel.org pahole repo. > > > > The btf loader is at: > > > > https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=472256d3c57bef53250686d55bd011f5dab4b657 > > > > Please take a look to see if I made some mistake. > > I looked at this issue. The reason is you did not take into the > consideration of recent kind_flag. Basically, bitfield_size can be oops, thanks for the quick review+fix > determined without looking at member types. > if (kind_flag) > bitfield_size = BTF_MEMBER_BITFIELD_SIZE(offset) > else > bitfield_size = 0 > > I will send a separate patch to address this issue. Feel free to reuse > any part of it if you need more changes. > > > > > For a net/ipv4/tcp.o from a kernel build, for struct sk_buff, shows > > differences wrt the bit size of bitfield members, that is not encoded in > > BTF at the moment: > > > > $ pahole -F btf -C sk_buff ~/git/build/v4.20-rc5+/net/ipv4/tcp.o > /tmp/sk_buff.btf > > $ pahole -F dwarf -C sk_buff ~/git/build/v4.20-rc5+/net/ipv4/tcp.o > /tmp/sk_buff.dwarf > > $ diff -u /tmp/sk_buff.dwarf /tmp/sk_buff.btf > > --- /tmp/sk_buff.dwarf 2018-12-20 14:50:51.428653046 -0300 > > +++ /tmp/sk_buff.btf 2018-12-20 14:50:46.302601516 -0300 > > @@ -38,45 +38,45 @@ > > __u16 hdr_len; /* 138 2 */ > > __u16 queue_mapping; /* 140 2 */ > > __u8 __cloned_offset[0]; /* 142 0 */ > > - __u8 cloned:1; /* 142: 7 1 */ > > - __u8 nohdr:1; /* 142: 6 1 */ > > - __u8 fclone:2; /* 142: 4 1 */ > > - __u8 peeked:1; /* 142: 3 1 */ > > - __u8 head_frag:1; /* 142: 2 1 */ > > - __u8 xmit_more:1; /* 142: 1 1 */ > > - __u8 pfmemalloc:1; /* 142: 0 1 */ > > + __u8 cloned; /* 142 1 */ > > + __u8 nohdr; /* 142 1 */ > > + __u8 fclone; /* 142 1 */ > > + __u8 peeked; /* 142 1 */ > > + __u8 head_frag; /* 142 1 */ > > + __u8 xmit_more; /* 142 1 */ > > + __u8 pfmemalloc; /* 142 1 */ > > With fixed btf loader, I got > > /* --- cacheline 2 boundary (128 bytes) --- */ > __u16 mac_len; /* 128 2 */ > __u16 hdr_len; /* 130 2 */ > __u16 queue_mapping; /* 132 2 */ > __u8 __cloned_offset[0]; /* 134 0 */ > __u8 cloned:1; /* 134: 0 1 */ > __u8 nohdr:1; /* 134: 1 1 */ > __u8 fclone:2; /* 134: 2 1 */ > __u8 peeked:1; /* 134: 4 1 */ > __u8 head_frag:1; /* 134: 5 1 */ > __u8 xmit_more:1; /* 134: 6 1 */ > __u8 pfmemalloc:1; /* 134: 7 1 */ > > /* XXX 1 byte hole, try to pack */ > > __u32 headers_start[0]; /* 136 0 */ > __u8 __pkt_type_offset[0]; /* 136 0 */ > __u8 pkt_type:3; /* 136: 0 1 */ > __u8 ignore_df:1; /* 136: 3 1 */ > __u8 nf_trace:1; /* 136: 4 1 */ > __u8 ip_summed:2; /* 136: 5 1 */ > __u8 ooo_okay:1; /* 136: 7 1 */ > __u8 l4_hash:1; /* 137: 0 1 */ > __u8 sw_hash:1; /* 137: 1 1 */ > > Ignore the byte offset which may due to different kernel configurations. > The bitfield offset in BTF starts from lower number to bigger one. That > is, it is always following the big endian convention, bitfield_offset > will be smaller if close to the top of structure. > > This is different from what dwarf is doing, which will show different > things on little endian vs. big endian. > > You can make simple adjustment based on all available info. In > btf_encoder.s, we did similar adjustment for little endian from > dwarf to btf. Ok, will fix > > > > /* XXX 1 byte hole, try to pack */ > > > > __u32 headers_start[0]; /* 144 0 */ > > __u8 __pkt_type_offset[0]; /* 144 0 */ > > - __u8 pkt_type:3; /* 144: 5 1 */ > > - __u8 ignore_df:1; /* 144: 4 1 */ > > - __u8 nf_trace:1; /* 144: 3 1 */ > > - __u8 ip_summed:2; /* 144: 1 1 */ > > - __u8 ooo_okay:1; /* 144: 0 1 */ > > - __u8 l4_hash:1; /* 145: 7 1 */ > > - __u8 sw_hash:1; /* 145: 6 1 */ > > - __u8 wifi_acked_valid:1; /* 145: 5 1 */ > > - __u8 wifi_acked:1; /* 145: 4 1 */ > > - __u8 no_fcs:1; /* 145: 3 1 */ > > - __u8 encapsulation:1; /* 145: 2 1 */ > > - __u8 encap_hdr_csum:1; /* 145: 1 1 */ > > - __u8 csum_valid:1; /* 145: 0 1 */ > > - __u8 csum_complete_sw:1; /* 146: 7 1 */ > > - __u8 csum_level:2; /* 146: 5 1 */ > > - __u8 csum_not_inet:1; /* 146: 4 1 */ > > - __u8 dst_pending_confirm:1; /* 146: 3 1 */ > > - __u8 ndisc_nodetype:2; /* 146: 1 1 */ > > - __u8 ipvs_property:1; /* 146: 0 1 */ > > - __u8 inner_protocol_type:1; /* 147: 7 1 */ > > - __u8 remcsum_offload:1; /* 147: 6 1 */ > > - __u8 offload_fwd_mark:1; /* 147: 5 1 */ > > - __u8 offload_mr_fwd_mark:1; /* 147: 4 1 */ > > - __u8 tc_skip_classify:1; /* 147: 3 1 */ > > - __u8 tc_at_ingress:1; /* 147: 2 1 */ > > - __u8 tc_redirected:1; /* 147: 1 1 */ > > - __u8 tc_from_ingress:1; /* 147: 0 1 */ > > + __u8 pkt_type; /* 144 1 */ > > + __u8 ignore_df; /* 144 1 */ > > + __u8 nf_trace; /* 144 1 */ > > + __u8 ip_summed; /* 144 1 */ > > + __u8 ooo_okay; /* 144 1 */ > > + __u8 l4_hash; /* 145 1 */ > > + __u8 sw_hash; /* 145 1 */ > > + __u8 wifi_acked_valid; /* 145 1 */ > > + __u8 wifi_acked; /* 145 1 */ > > + __u8 no_fcs; /* 145 1 */ > > + __u8 encapsulation; /* 145 1 */ > > + __u8 encap_hdr_csum; /* 145 1 */ > > + __u8 csum_valid; /* 145 1 */ > > + __u8 csum_complete_sw; /* 146 1 */ > > + __u8 csum_level; /* 146 1 */ > > + __u8 csum_not_inet; /* 146 1 */ > > + __u8 dst_pending_confirm; /* 146 1 */ > > + __u8 ndisc_nodetype; /* 146 1 */ > > + __u8 ipvs_property; /* 146 1 */ > > + __u8 inner_protocol_type; /* 147 1 */ > > + __u8 remcsum_offload; /* 147 1 */ > > + __u8 offload_fwd_mark; /* 147 1 */ > > + __u8 offload_mr_fwd_mark; /* 147 1 */ > > + __u8 tc_skip_classify; /* 147 1 */ > > + __u8 tc_at_ingress; /* 147 1 */ > > + __u8 tc_redirected; /* 147 1 */ > > + __u8 tc_from_ingress; /* 147 1 */ > > __u16 tc_index; /* 148 2 */ > > > > /* XXX 2 bytes hole, try to pack */ > > $ > > > > For the whole net/ipv6/tcp.o: > > > > I'm getting a segfault when processing this entry: > > > > [acme@quaco pahole]$ pahole -F dwarf -C fpregs_state ~/git/build/v4.20-rc5+/net/ipv4/tcp.o > > union fpregs_state { > > struct fxregs_state fxsave; /* 0 512 */ > > struct swregs_state soft; /* 0 136 */ > > struct xregs_state xsave; /* 0 576 */ > > u8 __padding[4096]; /* 0 4096 */ > > }; > > [acme@quaco pahole]$ > > > > [acme@quaco pahole]$ pahole -F btf -C fpregs_state ~/git/build/v4.20-rc5+/net/ipv4/tcp.o > > Segmentation fault (core dumped) > > [acme@quaco pahole]$ > > I can easily reproduce with the following simple file. > -bash-4.4$ cat t.c > union t { > int a; > int b; > } g; > > Looks like the call chain likes > print_classes > cu__for_each_struct_or_union(cu, id, pos) { > .... > class__filter(...) > > But in btf_loader.c, struct is allocated with class__new(), but union is > allocated with type__new(). Maybe some issue here? Will investigate. > > > > Have to stop now, will try to fix this later, please let me know if you > > found the problem meanwhile :-) > > > > The difference up to the point where it tries to process that union is > > just related to bitfields: > > > > --- /tmp/tcp.o.dwarf.c 2018-12-20 15:00:09.249222711 -0300 > > +++ /tmp/tcp.o.btf.c 2018-12-20 15:22:00.935246130 -0300 > > @@ -81,11 +81,13 @@ > > const char * function; /* 8 8 */ > > const char * filename; /* 16 8 */ > > const char * format; /* 24 8 */ > > - unsigned int lineno:18; /* 32:14 4 */ > > - unsigned int flags:8; /* 32: 6 4 */ > > + unsigned int lineno; /* 32 4 */ > > > > - /* XXX 6 bits hole, try to pack */ > > - /* XXX 4 bytes hole, try to pack */ > > + /* Bitfield combined with next fields */ > > + > > + unsigned int flags; /* 34 4 */ > > + > > + /* XXX 2 bytes hole, try to pack */ > > > > union { > > struct static_key_true dd_key_true; /* 40 16 */ > > @@ -93,8 +95,7 @@ > > } key; /* 40 16 */ > > > > /* size: 56, cachelines: 1, members: 7 */ > > - /* sum members: 52, holes: 1, sum holes: 4 */ > > - /* bit holes: 1, sum bit holes: 6 bits */ > > + /* sum members: 54, holes: 1, sum holes: 2 */ > > /* last cacheline: 56 bytes */ > > }; > > struct file_operations { > > @@ -223,7 +224,11 @@ > > } futex; /* 8 40 */ > > struct { > > clockid_t clockid; /* 8 4 */ > > - enum timespec_type type; /* 12 4 */ > > + enum timespec_type type:4; /* 12: 0 1 */ > > + > > + /* XXX 4 bits hole, try to pack */ > > + /* XXX 3 bytes hole, try to pack */ > > + > > union { > > struct timespec * rmtp; /* 16 8 */ > > struct old_timespec32 * compat_rmtp; /* 16 8 */ > > @@ -320,22 +325,16 @@ > > > > long unsigned int jobctl; /* 1120 8 */ > > unsigned int personality; /* 1128 4 */ > > - unsigned int sched_reset_on_fork:1; /* 1132:31 4 */ > > - unsigned int sched_contributes_to_load:1; /* 1132:30 4 */ > > - unsigned int sched_migrated:1; /* 1132:29 4 */ > > - unsigned int sched_remote_wakeup:1; /* 1132:28 4 */ > > - > > - /* XXX 28 bits hole, try to pack */ > > - > > - unsigned int in_execve:1; /* 1136:31 4 */ > > - unsigned int in_iowait:1; /* 1136:30 4 */ > > - unsigned int restore_sigmask:1; /* 1136:29 4 */ > > - unsigned int in_user_fault:1; /* 1136:28 4 */ > > - unsigned int no_cgroup_migration:1; /* 1136:27 4 */ > > - unsigned int use_memdelay:1; /* 1136:26 4 */ > > - > > - /* XXX 26 bits hole, try to pack */ > > - > > + unsigned int sched_reset_on_fork; /* 1132 4 */ > > + unsigned int sched_contributes_to_load; /* 1132 4 */ > > + unsigned int sched_migrated; /* 1132 4 */ > > + unsigned int sched_remote_wakeup; /* 1132 4 */ > > + unsigned int in_execve; /* 1136 4 */ > > + unsigned int in_iowait; /* 1136 4 */ > > + unsigned int restore_sigmask; /* 1136 4 */ > > + unsigned int in_user_fault; /* 1136 4 */ > > + unsigned int no_cgroup_migration; /* 1136 4 */ > > + unsigned int use_memdelay; /* 1136 4 */ > > unsigned int kernel_uaccess_faults_ok; /* 1140 4 */ > > long unsigned int atomic_flags; /* 1144 8 */ > > /* --- cacheline 18 boundary (1152 bytes) --- */ > > @@ -548,7 +547,6 @@ > > > > /* size: 11008, cachelines: 172, members: 207 */ > > /* sum members: 10906, holes: 15, sum holes: 102 */ > > - /* bit holes: 2, sum bit holes: 54 bits */ > > /* paddings: 3, sum paddings: 14 */ > > }; > > struct screen_info { > > @@ -811,40 +809,64 @@ > > struct desc_struct { > > u16 limit0; /* 0 2 */ > > u16 base0; /* 2 2 */ > > - u16 base1:8; /* 4: 8 2 */ > > - u16 type:4; /* 4: 4 2 */ > > - u16 s:1; /* 4: 3 2 */ > > - u16 dpl:2; /* 4: 1 2 */ > > - u16 p:1; /* 4: 0 2 */ > > - u16 limit1:4; /* 6:12 2 */ > > - u16 avl:1; /* 6:11 2 */ > > - u16 l:1; /* 6:10 2 */ > > - u16 d:1; /* 6: 9 2 */ > > - u16 g:1; /* 6: 8 2 */ > > - u16 base2:8; /* 6: 0 2 */ > > + u16 base1; /* 4 2 */ > > + > > + /* Bitfield combined with next fields */ > > + > > + u16 type; /* 5 2 */ > > + u16 s; /* 5 2 */ > > + u16 dpl; /* 5 2 */ > > + u16 p; /* 5 2 */ > > + > > + /* Bitfield combined with next fields */ > > + > > + u16 limit1; /* 6 2 */ > > + u16 avl; /* 6 2 */ > > + u16 l; /* 6 2 */ > > + u16 d; /* 6 2 */ > > + u16 g; /* 6 2 */ > > + > > + /* Bitfield combined with next fields */ > > + > > + u16 base2; /* 7 2 */ > > > > /* size: 8, cachelines: 1, members: 13 */ > > + /* padding: 65535 */ > > /* last cacheline: 8 bytes */ > > + > > + /* BRAIN FART ALERT! 8 != 9 + 0(holes), diff = -1 */ > > + > > }; > > struct idt_bits { > > - u16 ist:3; /* 0:13 2 */ > > - u16 zero:5; /* 0: 8 2 */ > > - u16 type:5; /* 0: 3 2 */ > > - u16 dpl:2; /* 0: 1 2 */ > > - u16 p:1; /* 0: 0 2 */ > > + u16 ist; /* 0 2 */ > > + u16 zero; /* 0 2 */ > > + > > + /* Bitfield combined with next fields */ > > + > > + u16 type; /* 1 2 */ > > + u16 dpl; /* 1 2 */ > > + u16 p; /* 1 2 */ > > > > /* size: 2, cachelines: 1, members: 5 */ > > + /* padding: 65535 */ > > /* last cacheline: 2 bytes */ > > + > > + /* BRAIN FART ALERT! 2 != 3 + 0(holes), diff = -1 */ > > + > > }; > > struct gate_struct { > > u16 offset_low; /* 0 2 */ > > u16 segment; /* 2 2 */ > > struct idt_bits bits; /* 4 2 */ > > + > > + /* XXX last struct has 65535 bytes of padding */ > > + > > u16 offset_middle; /* 6 2 */ > > u32 offset_high; /* 8 4 */ > > u32 reserved; /* 12 4 */ > > > > /* size: 16, cachelines: 1, members: 6 */ > > + /* paddings: 1, sum paddings: 65535 */ > > /* last cacheline: 16 bytes */ > > }; > > struct desc_ptr { > > @@ -884,9 +906,15 @@ > > void * s_mem; /* 40 8 */ > > long unsigned int counters; /* 40 8 */ > > struct { > > - unsigned int inuse:16; /* 40:16 4 */ > > - unsigned int objects:15; /* 40: 1 4 */ > > - unsigned int frozen:1; /* 40: 0 4 */ > > + unsigned int inuse; /* 40 4 */ > > + > > + /* Bitfield combined with next fields */ > > + > > + unsigned int objects; /* 42 4 */ > > + > > + /* Bitfield combined with next fields */ > > + > > + unsigned int frozen; /* 43 4 */ > > }; /* 40 4 */ > > }; /* 40 8 */ > > }; /* 8 40 */ > > @@ -1039,10 +1067,9 @@ > > /* XXX 4 bytes hole, try to pack */ > > > > mm_segment_t addr_limit; /* 152 8 */ > > - unsigned int sig_on_uaccess_err:1; /* 160:31 4 */ > > - unsigned int uaccess_err:1; /* 160:30 4 */ > > + unsigned int sig_on_uaccess_err; /* 160 4 */ > > + unsigned int uaccess_err; /* 160 4 */ > > > > - /* XXX 30 bits hole, try to pack */ > > /* XXX 28 bytes hole, try to pack */ > > > > /* --- cacheline 3 boundary (192 bytes) --- */ > > @@ -1050,7 +1077,6 @@ > > > > /* size: 4352, cachelines: 68, members: 21 */ > > /* sum members: 4320, holes: 2, sum holes: 32 */ > > - /* bit holes: 1, sum bit holes: 30 bits */ > > }; > > struct pv_irq_ops { > > struct paravirt_callee_save save_fl; /* 0 8 */ > > -- - Arnaldo
