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Re: [Qemu-devel] [PATCH v3 00/15] A number of fixes for ThreadSanitizer
From: |
Alex Bennée |
Subject: |
Re: [Qemu-devel] [PATCH v3 00/15] A number of fixes for ThreadSanitizer |
Date: |
Mon, 03 Oct 2016 10:43:58 +0100 |
User-agent: |
mu4e 0.9.17; emacs 25.1.50.3 |
Paolo Bonzini <address@hidden> writes:
> On 30/09/2016 23:30, Alex Bennée wrote:
>> Hi,
>>
>> This is v3 of the ThreadSanitizer fixes. Changes from the last
>> version:
>>
>> - added some more review tags
>> - made clear C11 undefined behaviour is the main issue
>> - added two minor fixes to atomic.h
>> - change type of tb_page_addr_t back to target_ulong
>> - dropped ui/vnc-enc-tight patch (already picked up an merged)
>> - dropped the blacklist patch (not needed with gcc)
>> - fixed a number of remaining issues with:
>> - TranslationBuffer access
>> - PageDesc access
>>
>> A number of the patches fix fairly rare race conditions. In fact I had
>> to repeat my test case a number of times to trigger some of them:
>>
>> retry.py -n 100 -c -- ./arm-linux-user/qemu-arm ./pigz.armhf \
>> -c -9 linux-4.6.3.tar > /dev/null 2> tsan-user-async.log
>>
>> On a build with a light patch to reduce the size of the translation
>> buffer so we trigger lots of flushes.
>>
>> With this series applied you can enable ThreadSanitizer with the
>> following command line:
>>
>> ./configure --extra-cflags="-g3 -O0 -fsanitize=thread
>> -D__SANITIZE_THREAD__" \
>> --with-coroutine=gthread --disable-pie --enable-debug --enable-debug-info
>>
>> breakdown:
>> -fsanitize=thread - enables sanitizer
>> --with-coroutine=gthread - tsan chokes on other forms of coroutine
>> --disable-pie - tsan no longer works with PIE
>> --enable-debug --enable-debug-info - better backtraces
>>
>> Remaining work:
>>
>> Running make check with the sanitzer enabled flags up a number of
>> warnings. I'm going to leave those for others to investigate as I need
>> to press on with the next MTTCG re-base ;-)
>>
>> Alex Bennée (14):
>> atomic.h: fix __SANITIZE_THREAD__ build
>> atomic.h: comment on use of atomic_read/set
>> exec-all.h: revert tb_page_addr_t to target_ulong
>> tcg/optimize: move default return out of if statement
>> qom/object: update class cache atomically
>> qom/cpu: atomically clear the tb_jmp_cache
>> cpu: atomically modify cpu->exit_request
>> util/qht: atomically set b->hashes
>> linux-user/syscall: extend lock around cpu-list
>> qga/command: use QEMU atomic primitives
>> .travis.yml: add gcc sanitizer build
>> tcg: ensure cpu_tb_exec/tb_gen_code use atomic_read/write
>> tcg: update remaining TranslationBuffer fields atomically
>> translate-all: mark updates to PageDesc as atomic
>>
>> Paolo Bonzini (1):
>> seqlock: use atomic writes for the sequence
>>
>> .travis.yml | 45 ++++++++++++++++++++++++++
>> cpu-exec.c | 30 ++++++++---------
>> include/exec/exec-all.h | 13 +++++++-
>> include/qemu/atomic.h | 8 ++++-
>> include/qemu/seqlock.h | 4 +--
>> linux-user/syscall.c | 7 +++-
>> qga/commands.c | 17 +++++-----
>> qom/cpu.c | 10 ++++--
>> qom/object.c | 15 +++++----
>> tcg/optimize.c | 3 +-
>> translate-all.c | 86
>> +++++++++++++++++++++++++------------------------
>> util/qht.c | 10 +++---
>> 12 files changed, 161 insertions(+), 87 deletions(-)
>>
>
> Queueing patches 1, 2 and 4-12.
OK. We can revisit the rest when we decide what the best plan of action
is for 64-on-32 atomic accesses should be.
--
Alex Bennée