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Possible deadlock of timer callbacks #274

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jphickey opened this issue Oct 23, 2019 · 0 comments · Fixed by #281
Closed

Possible deadlock of timer callbacks #274

jphickey opened this issue Oct 23, 2019 · 0 comments · Fixed by #281
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Describe the bug
If the actual timer interval is larger than the requested timer interval, due to the system tick timer resolution, then it is possible for timers to become deadlocked.

To Reproduce
Configure a timer with OS_TimerCreate() and OS_TimerSet(). Configure the interval such that it must be rounded up to a whole number of system ticks.

The timer works fine for a while, but then callbacks will cease once the first overrun occurs.

Expected behavior
Callbacks should continue until canceled by the application.

System observed on:
RTEMS 4.11 (pc686) running in QEMU
MPC750 VxWorks 6.9

Additional context
Discovered as part of the fix for #271, submitted as a separate bug for review as it affects the shared/common layer.

Reporter Info
Joseph Hickey, Vantage Systems, Inc.
jphickey added a commit that referenced this issue Oct 23, 2019
@jphickey
Fix #274: Avoid possible deadlock of timer callback
cf96c46 
If the tick_time from the wait routine was perpetually
greater than the interval time, eventually the wait_time
became such that it was always below zero.  Once this
occurs, application callbacks would cease entirely.

To avoid this, run the callback condition in a loop
for periodic timers only (not for one-shot config).
@jphickey jphickey mentioned this issue Oct 23, 2019
Merged
@skliper skliper added the bug label Oct 30, 2019
@skliper skliper added this to the 5.1.0 milestone Oct 30, 2019
skliper pushed a commit that referenced this issue Oct 31, 2019
@jphickey @skliper
Fix #274: Avoid possible deadlock of timer callback
6357c2d 
If the tick_time from the wait routine was perpetually
greater than the interval time, eventually the wait_time
became such that it was always below zero.  Once this
occurs, application callbacks would cease entirely.

To avoid this, run the callback condition in a loop
for periodic timers only (not for one-shot config).
skliper added a commit that referenced this issue Oct 31, 2019
@skliper
CCB 20191030: Merge #257 #276 #277 #278
58d4d74 
Fixes #271 #272 #273 #274
Code reviewed and approved at 20191030 CCB
@skliper skliper mentioned this issue Oct 31, 2019
Merged
skliper added a commit that referenced this issue Nov 7, 2019
@skliper
Merge pull request #278 from nasa/fix-274-timer-deadlock
1f450b2 
Fix #274: Avoid possible deadlock of timer callback
@jphickey jphickey mentioned this issue Dec 18, 2019
Closed
jphickey pushed a commit to jphickey/osal that referenced this issue Aug 10, 2022
@skliper
Fix nasa#274, Calculate child tasks when reported
8558411 
No longer keeps a running count of child tasks
jphickey pushed a commit to jphickey/osal that referenced this issue Aug 10, 2022
@astrogeco
Merge pull request nasa#485 from dmknutsen/issue_274
dccf3b2 
Fix nasa#274, NumOfChildTasks not decremented
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Integration Candidate 20191030 nasa/osal
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@jphickey @skliper