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kernel: smp: CPU start may result in null pointer access

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It is observed that starting up CPU may result in other CPUs
crashing due to de-referencing NULL pointers. Note that this
happened on the up_squared board, but there was no way to
attach debugger to verify. It started working again after
moving z_dummy_thread_init() before smp_timer_init(), which
was the old behavior before commit
eefaeee061 where the issue
first appeared. So mimic the old behavior to workaround
the issue.

Fixes #68115

Signed-off-by: Daniel Leung <daniel.leung@intel.com>
This commit is contained in:
Daniel Leung 2024-01-31 10:54:53 -08:00 committed by David Leach
parent 065253c173
commit caacc27d37
1 changed files with 7 additions and 5 deletions
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12
kernel/smp.c
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@ -119,6 +119,13 @@ static inline void smp_init_top(void *arg)
*/ */
wait_for_start_signal(&cpu_start_flag); wait_for_start_signal(&cpu_start_flag);
if ((csc == NULL) || csc->invoke_sched) {
/* Initialize the dummy thread struct so that
* the scheduler can schedule actual threads to run.
*/
z_dummy_thread_init(&dummy_thread);
}
#ifdef CONFIG_SYS_CLOCK_EXISTS #ifdef CONFIG_SYS_CLOCK_EXISTS
if ((csc == NULL) || csc->reinit_timer) { if ((csc == NULL) || csc->reinit_timer) {
smp_timer_init(); smp_timer_init();
@ -135,11 +142,6 @@ static inline void smp_init_top(void *arg)
return; return;
} }
/* Initialize the dummy thread struct so that
* the scheduler can schedule actual threads to run.
*/
z_dummy_thread_init(&dummy_thread);
/* Let scheduler decide what thread to run next. */ /* Let scheduler decide what thread to run next. */
z_swap_unlocked(); z_swap_unlocked();