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Subject[PATCH v7 5/6] perf annotate: Fix jump target outside of function address range
Date
If jump target is outside of function range, perf is not handling it
correctly. Especially when target address is lesser than function start
address, target offset will be negative. But, target address declared
to be unsigned, converts negative number into 2's complement. See below
example. Here target of 'jumpq' instruction at 34cf8 is 34ac0 which is
lesser than function start address(34cf0).

34ac0 - 34cf0 = -0x230 = 0xfffffffffffffdd0

Objdump output:

0000000000034cf0 <__sigaction>:
__GI___sigaction():
34cf0: lea -0x20(%rdi),%eax
34cf3: cmp -bashx1,%eax
34cf6: jbe 34d00 <__sigaction+0x10>
34cf8: jmpq 34ac0 <__GI___libc_sigaction>
34cfd: nopl (%rax)
34d00: mov 0x386161(%rip),%rax # 3bae68 <_DYNAMIC+0x2e8>
34d07: movl -bashx16,%fs:(%rax)
34d0e: mov -bashxffffffff,%eax
34d13: retq

perf annotate before applying patch:

__GI___sigaction /usr/lib64/libc-2.22.so
lea -0x20(%rdi),%eax
cmp -bashx1,%eax
v jbe 10
v jmpq fffffffffffffdd0
nop
10: mov _DYNAMIC+0x2e8,%rax
movl -bashx16,%fs:(%rax)
mov -bashxffffffff,%eax
retq

perf annotate after applying patch:

__GI___sigaction /usr/lib64/libc-2.22.so
lea -0x20(%rdi),%eax
cmp -bashx1,%eax
v jbe 10
^ jmpq 34ac0 <__GI___libc_sigaction>
nop
10: mov _DYNAMIC+0x2e8,%rax
movl -bashx16,%fs:(%rax)
mov -bashxffffffff,%eax
retq

Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
---
Changes in v7:
- No changes

tools/perf/ui/browsers/annotate.c | 5 +++--
tools/perf/util/annotate.c | 14 +++++++++-----
tools/perf/util/annotate.h | 5 +++--
3 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/tools/perf/ui/browsers/annotate.c b/tools/perf/ui/browsers/annotate.c
index 214a14a..2d04bdf 100644
--- a/tools/perf/ui/browsers/annotate.c
+++ b/tools/perf/ui/browsers/annotate.c
@@ -215,7 +215,7 @@ static void annotate_browser__write(struct ui_browser *browser, void *entry, int
ui_browser__set_color(browser, color);
if (dl->ins && dl->ins->ops->scnprintf) {
if (ins__is_jump(dl->ins)) {
- bool fwd = dl->ops.target.offset > (u64)dl->offset;
+ bool fwd = dl->ops.target.offset > dl->offset;

ui_browser__write_graph(browser, fwd ? SLSMG_DARROW_CHAR :
SLSMG_UARROW_CHAR);
@@ -245,7 +245,8 @@ static bool disasm_line__is_valid_jump(struct disasm_line *dl, struct symbol *sy
{
if (!dl || !dl->ins || !ins__is_jump(dl->ins)
|| !disasm_line__has_offset(dl)
- || dl->ops.target.offset >= symbol__size(sym))
+ || dl->ops.target.offset < 0
+ || dl->ops.target.offset >= (s64)symbol__size(sym))
return false;

return true;
diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index a9dbac1..fc44dd1 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -129,10 +129,12 @@ static int jump__parse(struct ins_operands *ops, struct map *map __maybe_unused)
else
ops->target.addr = strtoull(ops->raw, NULL, 16);

- if (s++ != NULL)
+ if (s++ != NULL) {
ops->target.offset = strtoull(s, NULL, 16);
- else
- ops->target.offset = UINT64_MAX;
+ ops->target.offset_avail = true;
+ } else {
+ ops->target.offset_avail = false;
+ }

return 0;
}
@@ -140,7 +142,7 @@ static int jump__parse(struct ins_operands *ops, struct map *map __maybe_unused)
static int jump__scnprintf(struct ins *ins, char *bf, size_t size,
struct ins_operands *ops)
{
- if (!ops->target.addr)
+ if (!ops->target.addr || ops->target.offset < 0)
return ins__raw_scnprintf(ins, bf, size, ops);

return scnprintf(bf, size, "%-6.6s %" PRIx64, ins->name, ops->target.offset);
@@ -1373,9 +1375,11 @@ static int symbol__parse_objdump_line(struct symbol *sym, struct map *map,
if (dl == NULL)
return -1;

- if (dl->ops.target.offset == UINT64_MAX)
+ if (!disasm_line__has_offset(dl)) {
dl->ops.target.offset = dl->ops.target.addr -
map__rip_2objdump(map, sym->start);
+ dl->ops.target.offset_avail = true;
+ }

/* kcore has no symbols, so add the call target name */
if (dl->ins && ins__is_call(dl->ins) && !dl->ops.target.name) {
diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h
index 4400269..7ba3579 100644
--- a/tools/perf/util/annotate.h
+++ b/tools/perf/util/annotate.h
@@ -19,7 +19,8 @@ struct ins_operands {
char *raw;
char *name;
u64 addr;
- u64 offset;
+ s64 offset;
+ bool offset_avail;
} target;
union {
struct {
@@ -67,7 +68,7 @@ struct disasm_line {

static inline bool disasm_line__has_offset(const struct disasm_line *dl)
{
- return dl->ops.target.offset != UINT64_MAX;
+ return dl->ops.target.offset_avail;
}

void disasm_line__free(struct disasm_line *dl);
--
2.5.5
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