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author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2012-05-15 09:20:06 +0200 |
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committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2012-05-16 14:42:46 +0200 |
commit | eda0c6d6b04d3cf72f5e8d656e39bffe3568e6db (patch) | |
tree | 5f57e3581729dfad7a7999ee24fd044b47018b8e /drivers/s390 | |
parent | e5b8d7553f87d939295e9eb0ca699c0030dc5ff1 (diff) | |
download | linux-stable-eda0c6d6b04d3cf72f5e8d656e39bffe3568e6db.tar.gz linux-stable-eda0c6d6b04d3cf72f5e8d656e39bffe3568e6db.tar.bz2 linux-stable-eda0c6d6b04d3cf72f5e8d656e39bffe3568e6db.zip |
s390: fix race on TIF_MCCK_PENDING
There is a small race window in the __switch_to code in regard to
the transfer of the TIF_MCCK_PENDING bit from the previous to the
next task. The bit is transferred before the task struct pointer
and the thread-info pointer for the next task has been stored to
lowcore. If a machine check sets the TIF_MCCK_PENDING bit between
the transfer code and the store of current/thread_info the bit
is still set for the previous task. And if the previous task has
terminated it can get lost. The effect is that a pending CRW is
not retrieved until the next machine checks sets TIF_MCCK_PENDING.
To fix this reorder __switch_to to first store the task struct
and thread-info pointer and then do the transfer of the bit.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'drivers/s390')
0 files changed, 0 insertions, 0 deletions