After successfully stepping the cursor on ARM, the proc info is
invalidated only in dwarf_step(). Invalidate the proc info also when
stepping with the non-dwarf based methods. This fixes
unw_get_proc_info() returning stale data.
The core dump unwinder can be used for demonstrating the bug. When
unwinding based only on DWARF data, the proc info is correct:
$ UNW_ARM_UNWIND_METHOD=1 ./test-coredump-unwind core `cat backing_files`
2>/dev/null
ip=0x000086d8 proc=000086d4-000086dc handler=0x00000000 lsda=0x00000000
ip=0x000086ef proc=000086dc-000086f2 handler=0x00000000 lsda=0x00000000
ip=0x000086e7 proc=000086dc-000086f2 handler=0x00000000 lsda=0x00000000
ip=0x00008597 proc=00008584-0000859a handler=0x00000000 lsda=0x00000000
ip=0x76e3ac3b proc=76e3aba0-76e3acec handler=0x00000000 lsda=0x00000000
When unwinding based only on the exidx method, we see the proc info
lagging behind:
$ UNW_ARM_UNWIND_METHOD=4 ./test-coredump-unwind core `cat backing_files`
2>/dev/null
ip=0x000086d8 proc=000086d4-000086db handler=0x00000000 lsda=0x00000000
ip=0x000086ef proc=000086d4-000086db handler=0x00000000 lsda=0x00000000
ip=0x000086e7 proc=000086dc-000086f3 handler=0x00000000 lsda=0x00000000
ip=0x00008597 proc=000086dc-000086f3 handler=0x00000000 lsda=0x00000000
ip=0x76e3ac3b proc=00008584-0000859b handler=0x00000000 lsda=0x00000000
ip=0x000085c3 proc=76e3aba0-76e3ae4b handler=0x00000000 lsda=0x00000000
Finally, with this patch applied, we get the desired proc info also with
the exidx unwinder:
$ UNW_ARM_UNWIND_METHOD=4 ./test-coredump-unwind core `cat backing_files`
2>/dev/null
ip=0x000086d8 proc=000086d4-000086db handler=0x00000000 lsda=0x00000000
ip=0x000086ef proc=000086dc-000086f3 handler=0x00000000 lsda=0x00000000
ip=0x000086e7 proc=000086dc-000086f3 handler=0x00000000 lsda=0x00000000
ip=0x00008597 proc=00008584-0000859b handler=0x00000000 lsda=0x00000000
ip=0x76e3ac3b proc=76e3aba0-76e3ae4b handler=0x00000000 lsda=0x00000000
ip=0x000085c3 proc=0000859c-00008613 handler=0x00000000 lsda=0x00000000
---
src/arm/Gstep.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/src/arm/Gstep.c b/src/arm/Gstep.c
index b96d5e2..3c65ac0 100644
--- a/src/arm/Gstep.c
+++ b/src/arm/Gstep.c
@@ -68,6 +68,8 @@ arm_exidx_step (struct cursor *c)
return -UNW_EBADFRAME;
}
+ c->dwarf.pi_valid = 0;
+
return (c->dwarf.ip == 0) ? 0 : 1;
}
@@ -157,6 +159,8 @@ unw_handle_signal_frame (unw_cursor_t *cursor)
dwarf_get (&c->dwarf, c->dwarf.loc[UNW_ARM_R13], &c->dwarf.cfa);
dwarf_get (&c->dwarf, c->dwarf.loc[UNW_ARM_R15], &c->dwarf.ip);
+ c->dwarf.pi_valid = 0;
+
return 1;
}
@@ -253,6 +257,7 @@ unw_step (unw_cursor_t *cursor)
}
c->dwarf.loc[UNW_ARM_R12] = ip_loc;
c->dwarf.loc[UNW_ARM_R11] = fp_loc;
+ c->dwarf.pi_valid = 0;
Debug(15, "ip=%lx\n", c->dwarf.ip);
}
else
--
1.7.9.5
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