Re: [Libunwind-devel] unwinding from signal handler (ARM)

[Sven Neumann]

Hi,

On Fri, 2011-08-19 at 14:39 +0200, Sven Neumann wrote:

> 0x4016cde0 logUnwind() from /usr/lib/libraumfeld-1.0.so.0
> 0x40205654 ?? from /usr/lib/libunwind.so.7

To shed some more light on this, here's the debug output
(UNW_DEBUG_LEVEL=99) from the attempt to unwind from a signal handler
(I've removed the debug output from _Uelf32_lookup_symbol):

 >_ULarm_init_local: (cursor=0xbe9e9400)
 >_ULarm_step: (cursor=0xbe9e9400)
                >access_mem: mem[402200a0] -> e2866018
                >get_rs_cache: get_rs_cache: acquiring lock
              >_ULarm_find_proc_info: looking for IP=0x4022009f
                >access_mem: mem[4022c678] -> 7fff4f8c
                >access_mem: mem[4022c690] -> 7fff5a50
                >access_mem: mem[4022c688] -> 7fff5554
                >access_mem: mem[4022c680] -> 7fff5004
                >access_mem: mem[4022c678] -> 7fff4f8c
                >access_mem: mem[4022c680] -> 7fff5004
                >put_rs_cache: unmasking signals/interrupts and
releasing lock
               >_ULarm_dwarf_step: returning -10
 >_ULarm_step: dwarf_step()=-10
              >_ULarm_find_proc_info: looking for IP=0x402200a0
                >access_mem: mem[4022c678] -> 7fff4f8c
                >access_mem: mem[4022c690] -> 7fff5a50
                >access_mem: mem[4022c688] -> 7fff5554
                >access_mem: mem[4022c680] -> 7fff5004
                >access_mem: mem[4022c678] -> 7fff4f8c
                >access_mem: mem[4022c680] -> 7fff5004
                >access_mem: mem[4022c678] -> 7fff4f8c
                >access_mem: mem[4022c67c] -> 80aeb0b0
  >_ULarm_arm_exidx_extract: 0x40221604 compact model 0 [80aeb0b0]
  >_ULarm_arm_exidx_apply_cmd: pop {r4}
  >_ULarm_arm_exidx_apply_cmd: pop {r5}
  >_ULarm_arm_exidx_apply_cmd: pop {r6}
  >_ULarm_arm_exidx_apply_cmd: pop {r7}
  >_ULarm_arm_exidx_apply_cmd: pop {r8}
  >_ULarm_arm_exidx_apply_cmd: pop {r9}
  >_ULarm_arm_exidx_apply_cmd: pop {r10}
  >_ULarm_arm_exidx_apply_cmd: pop {r14}
 >_ULarm_step: (cursor=0xbe9e9400)
                >access_mem: mem[401ac670] -> 401953c8
                >get_rs_cache: get_rs_cache: acquiring lock
              >_ULarm_find_proc_info: looking for IP=0x401ac66f
                >access_mem: mem[4019fa28] -> 7fff2be0
                >access_mem: mem[4019fc98] -> 7fffdde0
                >access_mem: mem[4019fc98] -> 7fffdde0
                >put_rs_cache: unmasking signals/interrupts and
releasing lock
               >_ULarm_dwarf_step: returning -10
 >_ULarm_step: dwarf_step()=-10
              >_ULarm_find_proc_info: looking for IP=0x401ac670
                >access_mem: mem[4019fa28] -> 7fff2be0
                >access_mem: mem[4019fc98] -> 7fffdde0
                >access_mem: mem[4019fc98] -> 7fffdde0
                >access_mem: mem[4019fc98] -> 7fffdde0
                >access_mem: mem[4019fc9c] -> 1
  >_ULarm_arm_exidx_extract: 0x1 [can't unwind]