[Backport v2.7-branch] STM32 UART fixes #43156
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ycsin
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all, Sorry for the mess, I chose the wrong branch |
|
I think I messed up the CI pipelines |
We need a rerun. Would you mind editing your branch with a minor change and force push to trigger CI again? |
A lock was added to manage situation where the API poll_out and irq API are used in same time. Signed-off-by: Julien D'ascenzio <[email protected]>
A dead lock could happen if 2 threads with differents priorities use
poll_out. In fact, the lock data->tx_lock could be lock by a thread with
lower priority and then a thread with higher priority can't take the
lock. There was a race condition here:
/* Wait for TXE flag to be raised */
while (1) {
if (atomic_cas(&data->tx_lock, 0, 1)) {
/* !!!!!!!! RACE CONDITION !!!!!!!!!!!!!!
if (LL_USART_IsActiveFlag_TXE(UartInstance)) {
break;
}
atomic_set(&data->tx_lock, 0);
}
}
To fix race condition, the interrupts are locked in poll_out.
Signed-off-by: Julien D'ascenzio <[email protected]>
Some tests like:
tests/kernel/sched/metairq/kernel.scheduler.metairq
tests/kernel/profiling/profiling_api/kernel.common.profiling
tests/kernel/sched/schedule_api/kernel.scheduler
tests/kernel/sched/schedule_api/kernel.scheduler.multiq
tests/kernel/profiling/profiling_api/kernel.common.profiling
tests/kernel/workq/work_queue/kernel.workqueue
don't support that the current thread change when writing a message with
printk (which uses poll_out). So, we remove the call to k_yield which is
useful only for optimizing cpu usage by forcing a thread change if the
usart send stack is full.
Signed-off-by: Julien D'ascenzio <[email protected]>
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I clicked the rebase button |
ycsin
added
area: UART
erwango
approved these changes
Feb 25, 2022
dcpleung
approved these changes
Feb 25, 2022
FRASTM
approved these changes
Mar 2, 2022
|
Looks good - I just wanted to double check that the superceded backport PRs were closed, and it looks like thats the case. |
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This backport consists of #40173, #40782 & #41116
Fixes #40775