Re: [PATCH V3] futex: set FLAGS_HAS_TIMEOUT during demux for FUTEX_WAIT

From: Darren Hart
Date: Thu Apr 14 2011 - 16:48:14 EST




On 04/14/2011 01:43 PM, Eric Dumazet wrote:
> Le jeudi 14 avril 2011 Ã 13:39 -0700, Darren Hart a Ãcrit :
>> The FLAGS_HAS_TIMEOUT flag was not getting set, causing the restart_block to
>> restart futex_wait() without a timeout after a signal.
>>
>> Commit b41277dc7a18ee332d in 2.6.38 introduced the regression by accidentally
>> removing the the FLAGS_HAS_TIMEOUT assignment from futex_wait() during the setup
>> of the restart block. Restore the originaly behavior.
>>
>> Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=32922
>>
>> V2: Added references to commit message.
>> V3: Set flag during restart block instead of do_futex()
>>
>> Signed-off-by: Darren Hart <dvhart@xxxxxxxxxxxxxxx>
>> Reported-by: Tim Smith <tsmith201104@xxxxxxxxx>
>> Reported-by: Torsten Hilbrich <torsten.hilbrich@xxxxxxxxxxx>
>> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
>> Cc: Ingo Molnar <mingo@xxxxxxx>
>> CC: Eric Dumazet <eric.dumazet@xxxxxxxxx>
>> CC: John Kacur <jkacur@xxxxxxxxxx>
>> ---
>> kernel/futex.c | 1 +
>> 1 files changed, 1 insertions(+), 0 deletions(-)
>>
>> diff --git a/kernel/futex.c b/kernel/futex.c
>> index bda4157..9d9c476 100644
>> --- a/kernel/futex.c
>> +++ b/kernel/futex.c
>> @@ -1887,6 +1887,7 @@ retry:
>> restart->futex.time = abs_time->tv64;
>> restart->futex.bitset = bitset;
>> restart->futex.flags = flags;
>> + flags |= FLAGS_HAS_TIMEOUT;
>>
>> ret = -ERESTART_RESTARTBLOCK;
>>
>
>
> Hmmm, I am sorry but this wont work... please try :
>
> - restart->futex.flags = flags;
> + restart->futex.flags = flags | FLAGS_HAS_TIMEOUT;

Ah crud... now that's just embarrassing... resending.


--
Darren Hart
Intel Open Source Technology Center
Yocto Project - Linux Kernel
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