Messages in this thread Patch in this message | | | From | Jeff Kirsher <> | Subject | [PATCH] sched/deadline: fix one-bit signed bitfields to be unsigned | Date | Tue, 28 Nov 2017 12:36:19 -0800 |
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From: Jacob Keller <jacob.e.keller@intel.com>
Commit 799ba82de01e ("sched/deadline: Use C bitfields for the state flags", 2017-10-10) introduced the use of C bitfields for these variables. However, sparse complains about them:
./include/linux/sched.h:476:62: error: dubious one-bit signed bitfield ./include/linux/sched.h:477:62: error: dubious one-bit signed bitfield ./include/linux/sched.h:478:62: error: dubious one-bit signed bitfield ./include/linux/sched.h:479:62: error: dubious one-bit signed bitfield
This is because a one-bit signed bitfield can only hold the values 0 and -1, which can cause problems if the program expects to be able to represent the value positive 1.
In practice, this may not cause a bug since -1 would be considered "true" in logical tests, however we should avoid the practice anyways.
Fixes: 799ba82de01e ("sched/deadline: Use C bitfields for the state flags", 2017-10-10) Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Cc: luca abeni <luca.abeni@santannapisa.it> Tested-by: Andrew Bowers <andrewx.bowers@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> --- include/linux/sched.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h index a5dc7c98b0a2..21991d668d35 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -473,10 +473,10 @@ struct sched_dl_entity { * conditions between the inactive timer handler and the wakeup * code. */ - int dl_throttled : 1; - int dl_boosted : 1; - int dl_yielded : 1; - int dl_non_contending : 1; + unsigned int dl_throttled : 1; + unsigned int dl_boosted : 1; + unsigned int dl_yielded : 1; + unsigned int dl_non_contending : 1; /* * Bandwidth enforcement timer. Each -deadline task has its -- 2.15.0
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