[erlang-bugs] Segmentation fault in the runtime.

[Sverker Eriksson]

Could be a symptom of OTP-7898, fixed in R13B01.

OTP-7898  Fixed a bug that caused error logging from driver_select
	      sometimes with additional symptoms such as failing IP
	      communications or even an emulator crash.

You could try to print the value of variable "drv_ev_state_len". If it 
is smaller than 256 then it can not be OTP-7898. There are however two 
variables called "drv_ev_state_len". One should be 0 and the other have 
a value larger than 128. For me, gdb picks the right one (>128) when I 
run without kernel-poll (erl +K false).

/Sverker, Erlang/OTP


Erik Rigtorp wrote:
> Hi!
>
> I encountered a segfault in the runtime when communicating with it
> using erl_interface. I suspect what I am sending is malformed, but the
> runtime shouldn't segfault becasue of that.
>
> Erlang (SMP,ASYNC_THREADS) (BEAM) emulator version 5.7.1
>
> Stacktrace:
> #0  0x080e0a91 in dec_term (dep=0x92294a8, hpp=0xb6355dd4,
> ep=0xb5548dd6 " N h\005a\004a.d", off_heap=0xb54118cc,
>     objp=0xb6355bec) at beam/external.c:1061
> #1  0x080e1fca in erts_from_external_format (dep=0x92294a8,
> hpp=0xb6355dd4, ext=0xb6355dd8, off_heap=0xb54118cc)
>     at beam/external.c:1036
> #2  0x080e4b6c in erts_net_message (prt=0xb7cc3398, dep=0x92294a8,
> hbuf=0x0, hlen=0,
>     buf=0xb5548cdc "p\203h\003a\002d", len=212) at beam/dist.c:1086
> #3  0x080bd444 in driver_output2 (ix=713, hbuf=0xb5548cdc
> "p\203h\003a\002d", hlen=250, buf=0x0, len=0)
>     at beam/io.c:3262
> #4  0x0816f835 in tcp_deliver (desc=0x928bf28, len=254) at
> drivers/common/inet_drv.c:1915
> #5  0x08171f2a in tcp_recv (desc=0x928bf28, request_len=0) at
> drivers/common/inet_drv.c:8037
> #6  0x08172281 in tcp_inet_drv_input (data=0x928bf28, event=0xf) at
> drivers/common/inet_drv.c:8375
> #7  0x080d817b in erts_port_task_execute (runq=0xb7c530e0,
> curr_port_pp=0xb7c5c628) at beam/erl_port_task.c:852
> #8  0x080d10ed in schedule (p=0xb541167c, calls=7) at beam/erl_process.c:5429
> #9  0x08132fce in process_main () at beam/beam_emu.c:1155
> #10 0x080c68d8 in sched_thread_func (vesdp=0xb7c595f8) at
> beam/erl_process.c:2933
> #11 0x0819a702 in thr_wrapper (vtwd=0xbfb58aac) at common/ethread.c:475
> #12 0xb7fb44ff in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
> #13 0xb7f2649e in clone () from /lib/tls/i686/cmov/libc.so.6
>
> The data at the pointer buf=0xb5548cdc, len=212 for stackframe #2:
> 00000000  70 83 68 03 61 02 64 00  00 67 64 00 10 78 78 78  |p.h.a.d..gd..xxx|
> 00000010  78 78 78 40 6c 6f 63 61  6c 68 6f 73 74 00 00 00  |xxx@REDACTED|
> 00000020  d5 00 00 00 00 03 83 68  03 64 00 16 78 78 78 78  |.......h.d..xxxx|
> 00000030  78 78 78 78 78 78 78 78  78 78 78 78 78 78 78 78  |xxxxxxxxxxxxxxxx|
> 00000040  78 78 6c ff ff ff ff 68  02 64 00 0f 78 78 78 78  |xxl....h.d..xxxx|
> 00000050  78 78 78 78 78 78 78 78  78 78 78 68 03 62 00 00  |xxxxxxxxxxxh.b..|
> 00000060  04 e0 62 00 04 30 4c 62  00 04 5d 49 68 03 62 00  |..b..0Lb..]Ih.b.|
> 00000070  00 04 e0 62 00 04 30 4c  62 00 04 5d 20 6c 00 00  |...b..0Lb..] l..|
> 00000080  00 02 68 03 6c 00 00 00  01 68 05 61 05 61 2d 64  |..h.l....h.a.a-d|
> 00000090  00 04 73 65 6c 6c 63 39  2e 35 35 30 30 30 30 30  |..sellc9.5500000|
> 000000a0  30 30 30 30 30 30 30 30  30 30 30 30 30 65 2b 30  |0000000000000e+0|
> 000000b0  31 00 00 00 00 00 62 00  00 10 68 6a 6a 6a 68 03  |1.....b...hjjjh.|
> 000000c0  6c 00 00 00 01 68 05 61  06 61 2e 64 00 03 62 75  |l....h.a.a.d..bu|
> 000000d0  79 63 38 2e                                       |yc8.|
> 000000d4
>
>
> Sorry I can't provide code or core dumps. I can provide more memory
> dumps if needed.
>
> Erik Rigtorp
>
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