semaphore: fix corner case sem_waitirq assert crash

[   11.041077] [25] [ EMERG] [ap] up_assert: Assertion failed at file:semaphore/sem_waitirq.c line: 84 task: thermal service
[   11.041407] [25] [ EMERG] [ap] backtrace:
[   11.041517] [25] [ EMERG] [ap] [25] [<0x2c687c9e>] up_backtrace+0xa/0x164
[   11.041627] [25] [ EMERG] [ap] [25] [<0x2c676e6c>] sched_dumpstack+0x1c/0x5c
[   11.041682] [25] [ EMERG] [ap] [25] [<0x2c68763a>] up_assert+0x42/0x24c
[   11.041792] [25] [ EMERG] [ap] [25] [<0x2c67355e>] _assert+0x2/0xc
[   11.041847] [25] [ EMERG] [ap] [25] [<0x2c65d536>] nxsem_wait_irq+0x3e/0x134
[   11.042288] [25] [ EMERG] [ap] [25] [<0x2c65d378>] nxsem_timeout+0x24/0x34
[   11.043169] [25] [ EMERG] [ap] [25] [<0x2c65f74c>] wd_timer+0xc0/0x104
[   11.043995] [25] [ EMERG] [ap] [25] [<0x2c65c930>] nxsched_alarm_expiration+0x4c/0xdc
[   11.044986] [25] [ EMERG] [ap] [25] [<0x2c670872>] oneshot_callback+0x16/0x24
[   11.045867] [25] [ EMERG] [ap] [25] [<0x2c6822b8>] bes_oneshot_irq_handler+0x18/0x28
[   11.046858] [25] [ EMERG] [ap] [25] [<0x57e5c>] up_irq_handler+0x4/0xc
[   11.047684] [25] [ EMERG] [ap] [25] [<0x2c65a20e>] irq_dispatch+0x5a/0xb8
[   11.048510] [25] [ EMERG] [ap] [25] [<0x2c6864d8>] arm_doirq+0x28/0x3c
[   11.049336] [25] [ EMERG] [ap] [25] [<0x2c681732>] exception_common+0x4a/0xac
[   11.050272] [25] [ EMERG] [ap] [25] [<0x2c65a324>] leave_critical_section+0x2c/0x54
[   11.051208] [25] [ EMERG] [ap] [25] [<0x2c65f472>] timer_settime+0x9e/0x10c

There are 2 ways can caused this:
1. sem_timedwait
   HW IRQ sem_post
   TIMER IRQ do wd_timer -> nxsem_timeout -> crash

   Note: The 2 IRQS happens amost at same time

2. sem_timedwait
   TIMER IRQ do wd_timer -> wd_func1 sem_post
                         -> wd_func2 nxsem_timeout -> crash

Resolve:
Stop the watchdog when sem_post

Signed-off-by: ligd <liguiding1@xiaomi.com>
This commit is contained in:
ligd 2022-02-16 13:37:38 +08:00 committed by Xiang Xiao
parent b2048f985c
commit 756c9fb60d

View File

@ -147,6 +147,10 @@ int nxsem_post(FAR sem_t *sem)
nxsem_add_holder_tcb(stcb, sem);
/* Stop the watchdog timer */
wd_cancel(&stcb->waitdog);
/* It is, let the task take the semaphore */
stcb->waitsem = NULL;