On 11/08/23 08:15, Athira Rajeev wrote: > Test "object cocde reading" fails sometimes for kernel address > as below: > > Reading object code for memory address: 0xc000000000004c3c > File is: [kernel.kallsyms] > On file address is: 0x14c3c > dso__data_read_offset failed > test child finished with -1 > ---- end ---- > Object code reading: FAILED! > > Here the dso__data_read_offset fails for symbol address > 0xc000000000004c3c. This is because, the dso long_name here > is [kernel.kallsyms] and hence open_dso fails to open this > file. There is an incorrect dso to map handling here. The > key points here is: > - dso long_name is set to [kernel.kallsyms]. This file is > not present and hence returns error > - DSO binary type is set to DSO_BINARY_TYPE__NOT_FOUND > - dso adjust_symbols is set to zero > > In the end dso__data_read_offset() returns -1 and the address > 0x14c3c can not be resolved. Hence the test fails. But the > address actually maps to kernel dso > > # objdump -z -d --start-address=0xc000000000004c3c > --stop-address=0xc000000000004cbc /home/athira/linux/vmlinux > > /home/athira/linux/vmlinux: file format elf64-powerpcle > > Disassembly of section .head.text: > > c000000000004c3c <exc_virt_0x4c00_system_call+0x3c>: > c000000000004c3c: a6 02 9b 7d mfsrr1 r12 > c000000000004c40: 78 13 42 7c mr r2,r2 > c000000000004c44: 18 00 4d e9 ld r10,24(r13) > c000000000004c48: 60 c6 4a 61 ori r10,r10,50784 > c000000000004c4c: a6 03 49 7d mtctr r10 > > Fix the dso__process_kernel_symbol function to set the > binary_type and adjust_symbols. adjust_symbols is used by > function "map__rip_2objdump" which converts symbol start > address to objdump address. Also set the dso long_name during > dso__load_vmlinux function. > > Suggested-by: Adrian Hunter <adrian.hun...@intel.com> > Signed-off-by: Athira Rajeev <atraj...@linux.vnet.ibm.com>
Acked-by: Adrian Hunter <adrian.hun...@intel.com> > --- > Note: Found similar discussion here in thread: > https://www.spinics.net/lists/linux-perf-users/msg06337.html > where Adrian proposed the fix, but looks like this was > not added to the perf. Hence addeed Suggested-by from Adrian. > > Additional to the fix proposed by Adrian, the patch also > adds setting of adjust_symbols which is needed for > map__rip_2objdump to convert symbol start to objdump address. > > tools/perf/util/symbol-elf.c | 2 ++ > tools/perf/util/symbol.c | 15 ++++++++++----- > 2 files changed, 12 insertions(+), 5 deletions(-) > > diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c > index 252d26a59e64..9e7eeaf616b8 100644 > --- a/tools/perf/util/symbol-elf.c > +++ b/tools/perf/util/symbol-elf.c > @@ -1440,6 +1440,8 @@ static int dso__process_kernel_symbol(struct dso *dso, > struct map *map, > curr_dso->kernel = dso->kernel; > curr_dso->long_name = dso->long_name; > curr_dso->long_name_len = dso->long_name_len; > + curr_dso->binary_type = dso->binary_type; > + curr_dso->adjust_symbols = dso->adjust_symbols; > curr_map = map__new2(start, curr_dso); > dso__put(curr_dso); > if (curr_map == NULL) > diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c > index f849f9ef68e6..3f36675b7c8f 100644 > --- a/tools/perf/util/symbol.c > +++ b/tools/perf/util/symbol.c > @@ -2204,15 +2204,20 @@ int dso__load_vmlinux(struct dso *dso, struct map > *map, > if (symsrc__init(&ss, dso, symfs_vmlinux, symtab_type)) > return -1; > > + /* > + * dso__load_sym() may copy 'dso' which will result in the copies having > + * an incorrect long name unless we set it here first. > + */ > + dso__set_long_name(dso, vmlinux, vmlinux_allocated); > + if (dso->kernel == DSO_SPACE__KERNEL_GUEST) > + dso->binary_type = DSO_BINARY_TYPE__GUEST_VMLINUX; > + else > + dso->binary_type = DSO_BINARY_TYPE__VMLINUX; > + > err = dso__load_sym(dso, map, &ss, &ss, 0); > symsrc__destroy(&ss); > > if (err > 0) { > - if (dso->kernel == DSO_SPACE__KERNEL_GUEST) > - dso->binary_type = DSO_BINARY_TYPE__GUEST_VMLINUX; > - else > - dso->binary_type = DSO_BINARY_TYPE__VMLINUX; > - dso__set_long_name(dso, vmlinux, vmlinux_allocated); > dso__set_loaded(dso); > pr_debug("Using %s for symbols\n", symfs_vmlinux); > }
