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Altera_Forum's avatar
Altera_Forum
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16 years ago

Nested interrupts again

Hello Linux masters, I need to make a small patch inside uClinux kernel for NIOS2. I need to enable one specific IRQ to have absolute priority over all atomic processes running in Linux - over ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

Hi for the last time at this topic :-)

I tried a small test, not to re-enable interrupts immediatelly, but after first hundred interrupts. Means first hundred interrupts has been serviced with nested interrupts disabled and and all next are serviced with nested interrupts enabled. And exactly on 101. interrupt I got error message:

BUG: failure at kernel/posix-cpu-timers.c:1295/run_posix_cpu_timers()!

Kernel panic - not syncing: BUG!

I checked this bug and run_posix_cpu_timers() is stated as function running with interrupts disabled, means if I want to have interrupts enabled (due to nesting), then I need to change this function to be reentrant in interrupt means. And I suggest there are lots such functions required to be changed in order to allow interrupt nesting. Ok Michael, you made me sure to select another solution than nested interrupts :-)

jan