Hi Linus,
Commit 79a61cc3fc04 ("mm: avoid leaving partial pfn mappings around in
error case") from Sep 11, 2024 (linux-next), leads to the following
Smatch static checker warning:
mm/memory.c:2709 remap_pfn_range_notrack()
warn: sleeping in atomic context
mm/memory.c
2696 int remap_pfn_range_notrack(struct vm_area_struct *vma, unsigned long addr,
2697 unsigned long pfn, unsigned long size, pgprot_t prot)
2698 {
2699 int error = remap_pfn_range_internal(vma, addr, pfn, size, prot);
2700
2701 if (!error)
2702 return 0;
2703
2704 /*
2705 * A partial pfn range mapping is dangerous: it does not
2706 * maintain page reference counts, and callers may free
2707 * pages due to the error. So zap it early.
2708 */
--> 2709 zap_page_range_single(vma, addr, size, NULL);
The lru_add_drain() function at the start of zap_page_range_single() takes a
mutext.
2710 return error;
2711 }
It's the preempt_disable() in gru_fault() which is the issue. The call tree
is:
gru_fault() <- disables preempt
-> remap_pfn_range()
-> remap_pfn_range_notrack()
regards,
dan carpenter
