Re: [PATCH 2/5] fs/procfs: implement efficient VMA querying API for /proc/<pid>/maps

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

Hi Andrii,

kernel test robot noticed the following build warnings:

[auto build test WARNING on next-20240503]
[also build test WARNING on v6.9-rc6]
[cannot apply to bpf-next/master bpf/master perf-tools-next/perf-tools-next tip/perf/core perf-tools/perf-tools brauner-vfs/vfs.all linus/master acme/perf/core v6.9-rc6 v6.9-rc5 v6.9-rc4]
[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/Andrii-Nakryiko/fs-procfs-extract-logic-for-getting-VMA-name-constituents/20240504-083146
base:   next-20240503
patch link:    https://lore.kernel.org/r/20240504003006.3303334-3-andrii%40kernel.org
patch subject: [PATCH 2/5] fs/procfs: implement efficient VMA querying API for /proc/<pid>/maps
config: openrisc-allnoconfig (https://download.01.org/0day-ci/archive/20240505/202405050750.5oyajnPF-lkp@intel.com/config)
compiler: or1k-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240505/202405050750.5oyajnPF-lkp@intel.com/reproduce)

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>
| Closes: https://lore.kernel.org/oe-kbuild-all/202405050750.5oyajnPF-lkp@intel.com/

All warnings (new ones prefixed by >>):

   fs/proc/task_mmu.c: In function 'do_procmap_query':
>> fs/proc/task_mmu.c:505:48: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
     505 |         if (karg.vma_name_size && copy_to_user((void __user *)karg.vma_name_addr,
         |                                                ^
   fs/proc/task_mmu.c:512:48: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
     512 |         if (karg.build_id_size && copy_to_user((void __user *)karg.build_id_addr,
         |                                                ^


vim +505 fs/proc/task_mmu.c

   378	
   379	static int do_procmap_query(struct proc_maps_private *priv, void __user *uarg)
   380	{
   381		struct procfs_procmap_query karg;
   382		struct vma_iterator iter;
   383		struct vm_area_struct *vma;
   384		struct mm_struct *mm;
   385		const char *name = NULL;
   386		char build_id_buf[BUILD_ID_SIZE_MAX], *name_buf = NULL;
   387		__u64 usize;
   388		int err;
   389	
   390		if (copy_from_user(&usize, (void __user *)uarg, sizeof(usize)))
   391			return -EFAULT;
   392		if (usize > PAGE_SIZE)
   393			return -E2BIG;
   394		if (usize < offsetofend(struct procfs_procmap_query, query_addr))
   395			return -EINVAL;
   396		err = copy_struct_from_user(&karg, sizeof(karg), uarg, usize);
   397		if (err)
   398			return err;
   399	
   400		if (karg.query_flags & ~PROCFS_PROCMAP_EXACT_OR_NEXT_VMA)
   401			return -EINVAL;
   402		if (!!karg.vma_name_size != !!karg.vma_name_addr)
   403			return -EINVAL;
   404		if (!!karg.build_id_size != !!karg.build_id_addr)
   405			return -EINVAL;
   406	
   407		mm = priv->mm;
   408		if (!mm || !mmget_not_zero(mm))
   409			return -ESRCH;
   410		if (mmap_read_lock_killable(mm)) {
   411			mmput(mm);
   412			return -EINTR;
   413		}
   414	
   415		vma_iter_init(&iter, mm, karg.query_addr);
   416		vma = vma_next(&iter);
   417		if (!vma) {
   418			err = -ENOENT;
   419			goto out;
   420		}
   421		/* user wants covering VMA, not the closest next one */
   422		if (!(karg.query_flags & PROCFS_PROCMAP_EXACT_OR_NEXT_VMA) &&
   423		    vma->vm_start > karg.query_addr) {
   424			err = -ENOENT;
   425			goto out;
   426		}
   427	
   428		karg.vma_start = vma->vm_start;
   429		karg.vma_end = vma->vm_end;
   430	
   431		if (vma->vm_file) {
   432			const struct inode *inode = file_user_inode(vma->vm_file);
   433	
   434			karg.vma_offset = ((__u64)vma->vm_pgoff) << PAGE_SHIFT;
   435			karg.dev_major = MAJOR(inode->i_sb->s_dev);
   436			karg.dev_minor = MINOR(inode->i_sb->s_dev);
   437			karg.inode = inode->i_ino;
   438		} else {
   439			karg.vma_offset = 0;
   440			karg.dev_major = 0;
   441			karg.dev_minor = 0;
   442			karg.inode = 0;
   443		}
   444	
   445		karg.vma_flags = 0;
   446		if (vma->vm_flags & VM_READ)
   447			karg.vma_flags |= PROCFS_PROCMAP_VMA_READABLE;
   448		if (vma->vm_flags & VM_WRITE)
   449			karg.vma_flags |= PROCFS_PROCMAP_VMA_WRITABLE;
   450		if (vma->vm_flags & VM_EXEC)
   451			karg.vma_flags |= PROCFS_PROCMAP_VMA_EXECUTABLE;
   452		if (vma->vm_flags & VM_MAYSHARE)
   453			karg.vma_flags |= PROCFS_PROCMAP_VMA_SHARED;
   454	
   455		if (karg.build_id_size) {
   456			__u32 build_id_sz = BUILD_ID_SIZE_MAX;
   457	
   458			err = build_id_parse(vma, build_id_buf, &build_id_sz);
   459			if (!err) {
   460				if (karg.build_id_size < build_id_sz) {
   461					err = -ENAMETOOLONG;
   462					goto out;
   463				}
   464				karg.build_id_size = build_id_sz;
   465			}
   466		}
   467	
   468		if (karg.vma_name_size) {
   469			size_t name_buf_sz = min_t(size_t, PATH_MAX, karg.vma_name_size);
   470			const struct path *path;
   471			const char *name_fmt;
   472			size_t name_sz = 0;
   473	
   474			get_vma_name(vma, &path, &name, &name_fmt);
   475	
   476			if (path || name_fmt || name) {
   477				name_buf = kmalloc(name_buf_sz, GFP_KERNEL);
   478				if (!name_buf) {
   479					err = -ENOMEM;
   480					goto out;
   481				}
   482			}
   483			if (path) {
   484				name = d_path(path, name_buf, name_buf_sz);
   485				if (IS_ERR(name)) {
   486					err = PTR_ERR(name);
   487					goto out;
   488				}
   489				name_sz = name_buf + name_buf_sz - name;
   490			} else if (name || name_fmt) {
   491				name_sz = 1 + snprintf(name_buf, name_buf_sz, name_fmt ?: "%s", name);
   492				name = name_buf;
   493			}
   494			if (name_sz > name_buf_sz) {
   495				err = -ENAMETOOLONG;
   496				goto out;
   497			}
   498			karg.vma_name_size = name_sz;
   499		}
   500	
   501		/* unlock and put mm_struct before copying data to user */
   502		mmap_read_unlock(mm);
   503		mmput(mm);
   504	
 > 505		if (karg.vma_name_size && copy_to_user((void __user *)karg.vma_name_addr,
   506						       name, karg.vma_name_size)) {
   507			kfree(name_buf);
   508			return -EFAULT;
   509		}
   510		kfree(name_buf);
   511	
   512		if (karg.build_id_size && copy_to_user((void __user *)karg.build_id_addr,
   513						       build_id_buf, karg.build_id_size))
   514			return -EFAULT;
   515	
   516		if (copy_to_user(uarg, &karg, min_t(size_t, sizeof(karg), usize)))
   517			return -EFAULT;
   518	
   519		return 0;
   520	
   521	out:
   522		mmap_read_unlock(mm);
   523		mmput(mm);
   524		kfree(name_buf);
   525		return err;
   526	}
   527	

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