Re: [RFC PATCH 1/3] mm: introduce new .mmap_proto() f_op callback

[kernel test robot <lkp@intel.com>]

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
In-Reply-To: <f1bf4b452cc10281ef831c5e38ce16f09923f8c5.1746040540.git.lorenzo.stoakes@oracle.com>
References: <f1bf4b452cc10281ef831c5e38ce16f09923f8c5.1746040540.git.lorenzo.stoakes@oracle.com>
TO: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>

Hi Lorenzo,

[This is a private test report for your RFC patch.]
kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]
[also build test WARNING on next-20250505]
[cannot apply to brauner-vfs/vfs.all linus/master v6.15-rc5]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Lorenzo-Stoakes/mm-introduce-new-mmap_proto-f_op-callback/20250501-035712
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/f1bf4b452cc10281ef831c5e38ce16f09923f8c5.1746040540.git.lorenzo.stoakes%40oracle.com
patch subject: [RFC PATCH 1/3] mm: introduce new .mmap_proto() f_op callback
:::::: branch date: 5 days ago
:::::: commit date: 5 days ago
config: x86_64-randconfig-161-20250505 (https://download.01.org/0day-ci/archive/20250505/202505052353.V1RLZ4v9-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Closes: https://lore.kernel.org/r/202505052353.V1RLZ4v9-lkp@intel.com/

smatch warnings:
mm/vma.c:2642 __mmap_region() error: we previously assumed 'vma' could be null (see line 2635)

vim +/vma +2642 mm/vma.c

d5b6d999086329 Lorenzo Stoakes 2025-04-30  2609  
f8d4a6cabb74f8 Lorenzo Stoakes 2025-01-02  2610  static unsigned long __mmap_region(struct file *file, unsigned long addr,
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2611  		unsigned long len, vm_flags_t vm_flags, unsigned long pgoff,
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2612  		struct list_head *uf)
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2613  {
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2614  	struct mm_struct *mm = current->mm;
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2615  	struct vm_area_struct *vma = NULL;
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2616  	int error;
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2617  	VMA_ITERATOR(vmi, mm, addr);
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2618  	MMAP_STATE(map, mm, &vmi, addr, len, pgoff, vm_flags, file);
d5b6d999086329 Lorenzo Stoakes 2025-04-30  2619  	bool have_proto = have_mmap_proto_hook(&map);
52956b0d7fb92e Lorenzo Stoakes 2024-10-25  2620  
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2621  	error = __mmap_prepare(&map, uf);
d5b6d999086329 Lorenzo Stoakes 2025-04-30  2622  	if (!error && have_proto)
d5b6d999086329 Lorenzo Stoakes 2025-04-30  2623  		error = call_proto(&map);
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2624  	if (error)
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2625  		goto abort_munmap;
52956b0d7fb92e Lorenzo Stoakes 2024-10-25  2626  
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2627  	/* Attempt to merge with adjacent VMAs... */
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2628  	if (map.prev || map.next) {
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2629  		VMG_MMAP_STATE(vmg, &map, /* vma = */ NULL);
52956b0d7fb92e Lorenzo Stoakes 2024-10-25  2630  
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2631  		vma = vma_merge_new_range(&vmg);
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2632  	}
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2633  
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2634  	/* ...but if we can't, allocate a new VMA. */
0d11630cc50a62 Lorenzo Stoakes 2024-10-25 @2635  	if (!vma) {
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2636  		error = __mmap_new_vma(&map, &vma);
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2637  		if (error)
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2638  			goto unacct_error;
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2639  	}
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2640  
d5b6d999086329 Lorenzo Stoakes 2025-04-30  2641  	if (have_proto)
d5b6d999086329 Lorenzo Stoakes 2025-04-30 @2642  		set_vma_user_defined_fields(vma, &map);
d5b6d999086329 Lorenzo Stoakes 2025-04-30  2643  
5ac87a885aecb3 Lorenzo Stoakes 2024-10-25  2644  	/* If flags changed, we might be able to merge, so try again. */
5ac87a885aecb3 Lorenzo Stoakes 2024-10-25  2645  	if (map.retry_merge) {
42c4e4b20d9c46 Lorenzo Stoakes 2024-12-06  2646  		struct vm_area_struct *merged;
5ac87a885aecb3 Lorenzo Stoakes 2024-10-25  2647  		VMG_MMAP_STATE(vmg, &map, vma);
5ac87a885aecb3 Lorenzo Stoakes 2024-10-25  2648  
5ac87a885aecb3 Lorenzo Stoakes 2024-10-25  2649  		vma_iter_config(map.vmi, map.addr, map.end);
42c4e4b20d9c46 Lorenzo Stoakes 2024-12-06  2650  		merged = vma_merge_existing_range(&vmg);
42c4e4b20d9c46 Lorenzo Stoakes 2024-12-06  2651  		if (merged)
42c4e4b20d9c46 Lorenzo Stoakes 2024-12-06  2652  			vma = merged;
5ac87a885aecb3 Lorenzo Stoakes 2024-10-25  2653  	}
5ac87a885aecb3 Lorenzo Stoakes 2024-10-25  2654  
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2655  	__mmap_complete(&map, vma);
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2656  
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2657  	return addr;
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2658  
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2659  	/* Accounting was done by __mmap_prepare(). */
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2660  unacct_error:
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2661  	if (map.charged)
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2662  		vm_unacct_memory(map.charged);
52956b0d7fb92e Lorenzo Stoakes 2024-10-25  2663  abort_munmap:
0d11630cc50a62 Lorenzo Stoakes 2024-10-25  2664  	vms_abort_munmap_vmas(&map.vms, &map.mas_detach);
52956b0d7fb92e Lorenzo Stoakes 2024-10-25  2665  	return error;
52956b0d7fb92e Lorenzo Stoakes 2024-10-25  2666  }
7d344babac9984 Lorenzo Stoakes 2024-12-03  2667  

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