fprintf: Fixup handling classes with no members
Will Cohen reported this NULL pointer dereference while processing some
object linking with cuda:
#0 0x00007ffff7f91453 in __class__fprintf (class=0x522560, cu=0x40ff80, conf=0x7fffffffa930, fp=0x7ffff7ece780 <_IO_2_1_stdout_>)
at /home/acme/git/pahole/dwarves_fprintf.c:1624
#1 0x00007ffff7f92195 in tag__fprintf (tag=0x522560, cu=0x40ff80, conf=0x7fffffffa930, fp=0x7ffff7ece780 <_IO_2_1_stdout_>)
at /home/acme/git/pahole/dwarves_fprintf.c:1835
#2 0x00007ffff7f90b57 in __class__fprintf (class=0x5224c0, cu=0x40ff80, conf=0x7fffffffaaa0, fp=0x7ffff7ece780 <_IO_2_1_stdout_>)
at /home/acme/git/pahole/dwarves_fprintf.c:1406
#3 0x00007ffff7f92195 in tag__fprintf (tag=0x5224c0, cu=0x40ff80, conf=0x40a200 <conf>, fp=0x7ffff7ece780 <_IO_2_1_stdout_>)
at /home/acme/git/pahole/dwarves_fprintf.c:1835
#4 0x0000000000402d03 in class_formatter (class=0x5224c0, cu=0x40ff80, id=1257) at /home/acme/git/pahole/pahole.c:224
#5 0x0000000000403074 in print_classes (cu=0x40ff80) at /home/acme/git/pahole/pahole.c:319
#6 0x0000000000404bb2 in pahole_stealer (cu=0x40ff80, conf_load=0x40a240 <conf_load>) at /home/acme/git/pahole/pahole.c:1174
#7 0x00007ffff7f9ff73 in finalize_cu (cus=0x40b2b0, cu=0x40ff80, dcu=0x7fffffffacf0, conf=0x40a240 <conf_load>)
at /home/acme/git/pahole/dwarf_loader.c:2227
#8 0x00007ffff7f9ffac in finalize_cu_immediately (cus=0x40b2b0, cu=0x40ff80, dcu=0x7fffffffacf0, conf=0x40a240 <conf_load>)
at /home/acme/git/pahole/dwarf_loader.c:2236
#9 0x00007ffff7fa064c in cus__load_module (cus=0x40b2b0, conf=0x40a240 <conf_load>, mod=0x40d760, dw=0x40e980, elf=0x40b360,
filename=0x7fffffffd5e3 "examples/wcohen/02_Exercise.cuda") at /home/acme/git/pahole/dwarf_loader.c:2389
#10 0x00007ffff7fa0760 in cus__process_dwflmod (dwflmod=0x40d760, userdata=0x40d770, name=0x40d910 "examples/wcohen/02_Exercise.cuda",
base=4194304, arg=0x7fffffffcf10) at /home/acme/git/pahole/dwarf_loader.c:2434
#11 0x00007ffff7f32be1 in dwfl_getmodules () from /lib64/libdw.so.1
#12 0x00007ffff7fa0820 in cus__process_file (cus=0x40b2b0, conf=0x40a240 <conf_load>, fd=3,
filename=0x7fffffffd5e3 "examples/wcohen/02_Exercise.cuda") at /home/acme/git/pahole/dwarf_loader.c:2487
#13 0x00007ffff7fa089c in dwarf__load_file (cus=0x40b2b0, conf=0x40a240 <conf_load>, filename=0x7fffffffd5e3 "examples/wcohen/02_Exercise.cuda")
at /home/acme/git/pahole/dwarf_loader.c:2504
#14 0x00007ffff7f8b0dd in cus__load_file (cus=0x40b2b0, conf=0x40a240 <conf_load>, filename=0x7fffffffd5e3 "examples/wcohen/02_Exercise.cuda")
at /home/acme/git/pahole/dwarves.c:1745
#15 0x00007ffff7f8bc2a in cus__load_files (cus=0x40b2b0, conf=0x40a240 <conf_load>, filenames=0x7fffffffd150)
at /home/acme/git/pahole/dwarves.c:2109
#16 0x0000000000404ff0 in main (argc=2, argv=0x7fffffffd148) at /home/acme/git/pahole/pahole.c:1294
(gdb)
(gdb) p class__name(class, cu)
$6 = 0x5cbb85 "__nv_hdl_helper_trait<__nv_dl_tag<int (*)(int, char**), main, 1u>, void (main(int, char**)::__lambda0::*)(int, double&)const>"
(gdb) p class->type.nr_members
$7 = 0
(gdb) p last
$8 = (struct class_member *) 0x0
(gdb)
So, before checking for bitfield details, first check if there were
members.
Now, if we show all structs/classes in that object file and look for the
above data structure, we find it inside another:
$ pahole examples/wcohen/02_Exercise.cuda
<SNIP>
struct __nv_hdl_helper_trait_outer<false, false, int, Kokkos::View<double**>, Kokkos::View<double*>, Kokkos::View<double*> > {
struct __nv_hdl_helper_trait<__nv_dl_tag<int (*)(int, char**), main, 1u>, void (main(int, char**)::__lambda0::*)(int, double&)const> {
class __nv_hdl_wrapper_t<false, false, __nv_dl_tag<int (*)(int, char**), main, 1u>, void(int, double&), int, Kokkos::View<doubl get<main(int, char**)::__lambda0>(class __lambda0, int, class View<double**>, class View<double*>, class View<double*>);
/* size: 1, cachelines: 0, members: 0 */
/* padding: 1 */
/* last cacheline: 1 bytes */
};
/* size: 1, cachelines: 0, members: 0 */
/* padding: 1 */
/* last cacheline: 1 bytes */
};
<SNIP>
$
Reported-by: William Cohen <wcohen@redhat.com>
Fixes: 13e5b9fc00ee ("fprintf: Add unnamed bitfield padding at the end to rebuild original type")
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
1 file changed
