From 9c47753167a6a585d0305663c6912f042e131c2d Mon Sep 17 00:00:00 2001 From: "Uladzislau Rezki (Sony)" Date: Tue, 7 Oct 2025 14:20:29 +0200 Subject: mm/vmalloc: defer freeing partly initialized vm_struct __vmalloc_area_node() may call free_vmap_area() or vfree() on error paths, both of which can sleep. This becomes problematic if the function is invoked from an atomic context, such as when GFP_ATOMIC or GFP_NOWAIT is passed via gfp_mask. To fix this, unify error paths and defer the cleanup of partly initialized vm_struct objects to a workqueue. This ensures that freeing happens in a process context and avoids invalid sleeps in atomic regions. Link: https://lkml.kernel.org/r/20251007122035.56347-5-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) Acked-by: Michal Hocko Reviewed-by: Baoquan He Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Marco Elver Cc: Michal Hocko Signed-off-by: Andrew Morton --- include/linux/vmalloc.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'include/linux/vmalloc.h') diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index eb54b7b3202f..1e43181369f1 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -50,7 +50,11 @@ struct iov_iter; /* in uio.h */ #endif struct vm_struct { - struct vm_struct *next; + union { + struct vm_struct *next; /* Early registration of vm_areas. */ + struct llist_node llnode; /* Asynchronous freeing on error paths. */ + }; + void *addr; unsigned long size; unsigned long flags; -- cgit v1.2.3 From 8da89ba18ed4e9000d9b9b5b1f699e5004f4abf6 Mon Sep 17 00:00:00 2001 From: "Uladzislau Rezki (Sony)" Date: Tue, 7 Oct 2025 14:20:30 +0200 Subject: mm/vmalloc: handle non-blocking GFP in __vmalloc_area_node() Make __vmalloc_area_node() respect non-blocking GFP masks such as GFP_ATOMIC and GFP_NOWAIT. - Add memalloc_apply_gfp_scope()/memalloc_restore_scope() helpers to apply a proper scope. - Apply memalloc_apply_gfp_scope()/memalloc_restore_scope() around vmap_pages_range() for page table setup. - Set "nofail" to false if a non-blocking mask is used, as they are mutually exclusive. This is particularly important for page table allocations that internally use GFP_PGTABLE_KERNEL, which may sleep unless such scope restrictions are applied. For example: __pte_alloc_kernel() pte_alloc_one_kernel(&init_mm); pagetable_alloc_noprof(GFP_PGTABLE_KERNEL & ~__GFP_HIGHMEM, 0); Note: in most cases, PTE entries are established only up to the level required by current vmap space usage, meaning the page tables are typically fully populated during the mapping process. Link: https://lkml.kernel.org/r/20251007122035.56347-6-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) Acked-by: Michal Hocko Reviewed-by: Baoquan He Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Marco Elver Cc: Michal Hocko Signed-off-by: Andrew Morton --- include/linux/vmalloc.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/vmalloc.h') diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index 1e43181369f1..e8e94f90d686 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -332,4 +332,6 @@ bool vmalloc_dump_obj(void *object); static inline bool vmalloc_dump_obj(void *object) { return false; } #endif +unsigned int memalloc_apply_gfp_scope(gfp_t gfp_mask); +void memalloc_restore_scope(unsigned int flags); #endif /* _LINUX_VMALLOC_H */ -- cgit v1.2.3