The function mem_dump_obj() can sometimes provide valuable debugging information, but it cannot be called in an interrupt context because spinlock vmap_area_lock has not been protected against IRQs. If the current task has held the lock before hard/soft interrupt handler calls mem_dump_obj(), simply abandoning the dump operation can avoid deadlock. That is, no deadlock occurs in extreme cases, and dump succeeds in most cases. Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx> --- mm/vmalloc.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index ccaa461998f3c37..cdd36c5a1aa16f8 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -4034,6 +4034,9 @@ bool vmalloc_dump_obj(void *object) struct vm_struct *vm; void *objp = (void *)PAGE_ALIGN((unsigned long)object); + if (unlikely(spin_is_locked(&vmap_area_lock))) + return false; + vm = find_vm_area(objp); if (!vm) return false; -- 2.25.1
