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>
---
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);
}
--
2.31.1
