sched/wqueue/notifier: protect the work notifier with critical section #2767
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replace the semaphore to avoid the notifier holding the lock in the interrupt context ASSERT: libs/libc/assert/lib_assert.c:36 :_assert sched/semphore/sem_wait.c:113 :nxsem_wait sched/semphore/sem_wait.c:222 :nxsem_wait_uniterruptible sched/wqueue/kwork_notifier.c:371 :work_notifier_signal mm/iob/iob_free.c:188 :iob_free drivers/syslog/syslog_stream.c:272 :syslogstream_destroy ... sched/irq/irq_dispatch.c:183 :irq_dispatch Signed-off-by: chao.an <anchao@xiaomi.com>
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replace the unique key to freerun counter to avoid traverse of the notifier list. Signed-off-by: chao.an <anchao@xiaomi.com>
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Ok that looks better.
Do we know what is the lifetime a notification can live in the list?
The older look up work_notifier_find(key) seams to imply that collision can happen and most be avoided. Even at 32 bits, the number will still wrap. Will this be an issue?
The lifetime of notifier is short and the generation rate(from tcp, iob and usb) is also slow, so the possibility is very low. And to reduce the possibity even furture, the patch extend key from 16bit to 32bit too. |
Summary
sched/wqueue/notifier: protect the work notifier with critical section
replace the semaphore to avoid the notifier holding the lock in the interrupt context
ASSERT:
Signed-off-by: chao.an anchao@xiaomi.com
Impact
call syslog() on interrupt context
Testing