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Keyboard event may cause nemu deadlock #4

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swordfeng opened this issue Feb 21, 2016 · 1 comment
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Keyboard event may cause nemu deadlock #4

swordfeng opened this issue Feb 21, 2016 · 1 comment

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@swordfeng
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My backtrace:

The executable is obj/game/game.
For help, type "help"
(nemu) c
.�[kernel/src/main.c,74,init_cond] {kernel} Hello, NEMU world!
.....................................^C
Program received signal SIGINT, Interrupt.
0x00007ffff651f66b in __lll_lock_wait_private () from /usr/lib/libc.so.6
(gdb) bt
#0  0x00007ffff651f66b in __lll_lock_wait_private () from /usr/lib/libc.so.6
#1  0x00007ffff64a547a in malloc () from /usr/lib/libc.so.6
#2  0x00007ffff51a7fcc in ?? () from /usr/lib/libxcb.so.1
#3  0x00007ffff51a8548 in ?? () from /usr/lib/libxcb.so.1
#4  0x00007ffff53ffdc8 in ?? () from /usr/lib/libX11.so.6
#5  0x00007ffff53fff2b in ?? () from /usr/lib/libX11.so.6
#6  0x00007ffff540023d in _XEventsQueued () from /usr/lib/libX11.so.6
#7  0x00007ffff53e248a in XFlush () from /usr/lib/libX11.so.6
#8  0x00007ffff7390938 in ?? () from /usr/lib/libSDL-1.2.so.0
#9  0x00007ffff739214b in ?? () from /usr/lib/libSDL-1.2.so.0
#10 0x00007ffff736706c in SDL_PumpEvents () from /usr/lib/libSDL-1.2.so.0
#11 0x00007ffff73670a9 in SDL_PollEvent () from /usr/lib/libSDL-1.2.so.0
#12 0x0000000000430856 in device_update.lto_priv ()
#13 <signal handler called>
#14 0x00007ffff64a378e in _int_malloc () from /usr/lib/libc.so.6
#15 0x00007ffff64a53d4 in malloc () from /usr/lib/libc.so.6
#16 0x00007ffff76800e8 in operator new (sz=31) at /build/gcc-multilib/src/gcc-5-20160209/libstdc++-v3/libsupc++/new_op.cc:50
#17 0x00007ffff7711bed in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::reserve (this=0x7fffffffd870, __res=<optimized out>)
    at /build/gcc-multilib/src/gcc-build/x86_64-unknown-linux-gnu/libstdc++-v3/include/bits/basic_string.tcc:297
#18 0x000000000043a180 in print_instr(InstructionContext&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >) ()
#19 0x0000000000422827 in int push<(OperandName)15>(InstructionContext&, unsigned int) [clone .lto_priv.73] ()
#20 0x000000000042efd5 in cpu_exec ()
#21 0x000000000043b2ae in cmd_c.lto_priv ()
#22 0x000000000040b3ae in main ()
(gdb)

The signal came when in malloc(), and the handler called malloc() again so it sucks...
ghost pushed a commit that referenced this issue Feb 22, 2016
@sashimi-yzh
nemu,device: poll the SDL event out of the signal handler
f73383a 
* SDL_PollEvent() may eventually call malloc(), therefore it is
  not async singal safe, which may cause deadlock in malloc().
* Timer_intr() should be called in the signal handler, else hlt()
  will get stuck.
* Now device_update() should be called in the for loop of cpu_exec()
  to finish the bottom half of the signal handler.
* This patch fixed issue #4.
@ghost ghost mentioned this issue Feb 22, 2016
Closed
ghost pushed a commit that referenced this issue Feb 22, 2016
@sashimi-yzh
nemu,device: poll the SDL event out of the signal handler
2012d79 
* SDL_PollEvent() may eventually call malloc(), therefore it is
  not async singal safe, which may cause deadlock in malloc().
* timer_intr() should be called in the signal handler, else hlt()
  will get stuck.
* Now device_update() should be called in the for loop of cpu_exec()
  to finish the bottom half of the signal handler.
* This patch will fix issue #4.
@ghost ghost mentioned this issue Feb 22, 2016
Merged
@ghost
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ghost commented Feb 22, 2016

This issue has been fixed in #7.

@ghost ghost closed this as completed Feb 22, 2016
@ghost ghost mentioned this issue Jun 29, 2016
Closed
This issue was closed.
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@swordfeng