faca92f2f1
First commit: Revert "Revert "ambe741d47: am2f460fbe: am73b5cad9: Merge "bionic: Fix wrong kernel_id in pthread descriptor after fork()""" This reverts commit06823da2f0. Second commit: bionic: fix atfork hanlder_mutex deadlock This cherry-picks commit34e89c232dAfter applying the kernel_id fix, the system refused to boot up and we got following crash log: I/DEBUG ( 113): pid: 618, tid: 618 >>> org.simalliance.openmobileapi.service:remote <<< I/DEBUG ( 113): signal 16 (SIGSTKFLT), code -6 (?), fault addr -------- I/DEBUG ( 113): eax fffffe00 ebx b77de994 ecx 00000080 edx 00724002 I/DEBUG ( 113): esi 00000000 edi 00004000 I/DEBUG ( 113): xcs 00000073 xds 0000007b xes 0000007b xfs 00000000 xss 0000007b I/DEBUG ( 113): eip b7761351 ebp bfdf3de8 esp bfdf3dc4 flags 00000202 I/DEBUG ( 113): #00 eip: 00015351 /system/lib/libc.so I/DEBUG ( 113): #01 eip: 0000d13c /system/lib/libc.so (pthread_mutex_lock) I/DEBUG ( 113): #02 eip: 00077b48 /system/lib/libc.so (__bionic_atfork_run_prepare) I/DEBUG ( 113): #03 eip: 00052cdb /system/lib/libc.so (fork) I/DEBUG ( 113): #04 eip: 0009ae91 /system/lib/libdvm.so (_Z18dvmOptimizeDexFileillPKcjjb) I/DEBUG ( 113): #05 eip: 000819d6 /system/lib/libdvm.so (_Z14dvmJarFileOpenPKcS0_PP7JarFileb) I/DEBUG ( 113): #06 eip: 000b175e /system/lib/libdvm.so (_ZL40Dalvik_dalvik_system_DexFile_openDexFilePKjP6JValue) I/DEBUG ( 113): #07 eip: 0011fb94 /system/lib/libdvm.so Root cause: The atfork uses the mutex handler_mutex to protect the atfork_head. The parent will call __bionic_atfork_run_prepare() to lock the handler_mutex, and need both the parent and child to unlock their own copy of handler_mutex after fork. At that time, the owner of hanlder_mutex is set as the parent. If we apply the kernel_id fix, then the child's kernel_id will be set as child's tid. The handler_mutex is a recursive lock, and pthread_mutex_unlock(&hander_mutex) will fail because the mutex owner is the parent, while the current tid (__get_thread()->kernel_id) is child, not matched with the mutex owner. At that time, the handler_mutex is left in lock state.If the child wants to fork other process after than, then it will try to lock handler_mutex, and then be deadlocked. Fix: Since the child has its own copy of vm space from the the parent, the child space's handler_mutex should be reset to the initialized state. Change-Id: I3907dd9a153418fb78862f2aa6d0302c375d9e27 Signed-off-by: Jack Ren <jack.ren@intel.com> Signed-off-by: Chenyang Du <chenyang.du@intel.com> Signed-off-by: Bruce Beare <bruce.j.beare@intel.com> Change-Id: Ic8072f366a877443a60fe215f3c00b3df5a259c8
65 lines
2.4 KiB
C
65 lines
2.4 KiB
C
/*
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* Copyright (C) 2008 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <unistd.h>
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#include "pthread_internal.h"
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#include "bionic_pthread.h"
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#include "cpuacct.h"
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extern int __fork(void);
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int fork(void)
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{
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int ret;
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/* Posix mandates that the timers of a fork child process be
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* disarmed, but not destroyed. To avoid a race condition, we're
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* going to stop all timers now, and only re-start them in case
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* of error, or in the parent process
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*/
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__timer_table_start_stop(1);
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__bionic_atfork_run_prepare();
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ret = __fork();
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if (ret != 0) { /* not a child process */
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__timer_table_start_stop(0);
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__bionic_atfork_run_parent();
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} else {
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/* Adjusting the kernel id after a fork */
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(void)__pthread_settid(pthread_self(), gettid());
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/*
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* Newly created process must update cpu accounting.
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* Call cpuacct_add passing in our uid, which will take
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* the current task id and add it to the uid group passed
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* as a parameter.
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*/
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cpuacct_add(getuid());
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__bionic_atfork_run_child();
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}
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return ret;
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}
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