On 2023/05/20 20:33, Tetsuo Handa wrote: > @@ -405,7 +405,10 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, > * contexts and I/O. > */ > alloc_flags &= ~GFP_ZONEMASK; > - alloc_flags &= (GFP_ATOMIC | GFP_KERNEL); > + if (!(alloc_flags & __GFP_DIRECT_RECLAIM)) > + alloc_flags &= __GFP_HIGH; > + else > + alloc_flags &= GFP_KERNEL; > alloc_flags |= __GFP_NOWARN; Well, comparing with a report which reached __stack_depot_save() via fill_pool() ( https://syzkaller.appspot.com/bug?extid=358bb3e221c762a1adbb ), I feel that above lines might be bogus. Maybe we want to enable __GFP_HIGH even if alloc_flags == GFP_NOWAIT because fill_pool() uses __GFPHIGH | __GFP_NOWARN regardless of the caller's context. Then, these lines could be simplified like below. if (!(alloc_flags & __GFP_DIRECT_RECLAIM)) alloc_flags = __GFP_HIGH | __GFP_NOWARN; else alloc_flags = (alloc_flags & GFP_KERNEL) | __GFP_NOWARN; How is the importance of memory allocation in __stack_depot_save() ? If allocation failure is welcome, maybe we should not trigger OOM killer by clearing __GFP_NORETRY when alloc_flags contained __GFP_FS ... > page = alloc_pages(alloc_flags, DEPOT_POOL_ORDER); > if (page)
