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

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

[Darren Hart]

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@linux.intel.com>
Reported-by: Tim Smith <tsmith201104@yahoo.com>
Reported-by: Torsten Hilbrich <torsten.hilbrich@secunet.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: John Kacur <jkacur@redhat.com>
---
 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;
 
-- 
1.7.1

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

[Eric Dumazet]

Le jeudi 14 avril 2011 à 13:39 -0700, Darren Hart a écrit :
> 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@linux.intel.com>
> Reported-by: Tim Smith <tsmith201104@yahoo.com>
> Reported-by: Torsten Hilbrich <torsten.hilbrich@secunet.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@elte.hu>
> CC: Eric Dumazet <eric.dumazet@gmail.com>
> CC: John Kacur <jkacur@redhat.com>
> ---
>  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;

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

[Darren Hart]

On 04/14/2011 01:43 PM, Eric Dumazet wrote:
> Le jeudi 14 avril 2011 à 13:39 -0700, Darren Hart a écrit :
>> 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@linux.intel.com>
>> Reported-by: Tim Smith <tsmith201104@yahoo.com>
>> Reported-by: Torsten Hilbrich <torsten.hilbrich@secunet.com>
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Peter Zijlstra <peterz@infradead.org>
>> Cc: Ingo Molnar <mingo@elte.hu>
>> CC: Eric Dumazet <eric.dumazet@gmail.com>
>> CC: John Kacur <jkacur@redhat.com>
>> ---
>>  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