mirror of
https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
synced 2025-10-14 00:38:39 +10:00
33b3b04154
Implement a function, direct_file_splice(), that deals with this by using an ITER_BVEC iterator instead of an ITER_PIPE iterator as the former won't free its buffers when reverted. The function bulk allocates all the buffers it thinks it is going to use in advance, does the read synchronously and only then trims the buffer down. The pages we did use get pushed into the pipe. This fixes a problem with the upcoming iov_iter_extract_pages() function, whereby pages extracted from a non-user-backed iterator such as ITER_PIPE aren't pinned. __iomap_dio_rw(), however, calls iov_iter_revert() to shorten the iterator to just the bufferage it is going to use - which has the side-effect of freeing the excess pipe buffers, even though they're attached to a bio and may get written to by DMA (thanks to Hillf Danton for spotting this[1]). This then causes memory corruption that is particularly noticeable when the syzbot test[2] is run. The test boils down to: out = creat(argv[1], 0666); ftruncate(out, 0x800); lseek(out, 0x200, SEEK_SET); in = open(argv[1], O_RDONLY | O_DIRECT | O_NOFOLLOW); sendfile(out, in, NULL, 0x1dd00); run repeatedly in parallel. What I think is happening is that ftruncate() occasionally shortens the DIO read that's about to be made by sendfile's splice core by reducing i_size. This should be more efficient for DIO read by virtue of doing a bulk page allocation, but slightly less efficient by ignoring any partial page in the pipe. Reported-by: syzbot+a440341a59e3b7142895@syzkaller.appspotmail.com Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jens Axboe <axboe@kernel.dk> cc: Christoph Hellwig <hch@lst.de> cc: Al Viro <viro@zeniv.linux.org.uk> cc: David Hildenbrand <david@redhat.com> cc: John Hubbard <jhubbard@nvidia.com> cc: linux-mm@kvack.org cc: linux-block@vger.kernel.org cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/20230207094731.1390-1-hdanton@sina.com/ [1] Link: https://lore.kernel.org/r/000000000000b0b3c005f3a09383@google.com/ [2] Signed-off-by: Steve French <stfrench@microsoft.com> |
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| .. | ||
| 9p | ||
| adfs | ||
| affs | ||
| afs | ||
| autofs | ||
| befs | ||
| bfs | ||
| btrfs | ||
| cachefiles | ||
| ceph | ||
| cifs | ||
| coda | ||
| configfs | ||
| cramfs | ||
| crypto | ||
| debugfs | ||
| devpts | ||
| dlm | ||
| ecryptfs | ||
| efivarfs | ||
| efs | ||
| erofs | ||
| exfat | ||
| exportfs | ||
| ext2 | ||
| ext4 | ||
| f2fs | ||
| fat | ||
| freevxfs | ||
| fscache | ||
| fuse | ||
| gfs2 | ||
| hfs | ||
| hfsplus | ||
| hostfs | ||
| hpfs | ||
| hugetlbfs | ||
| iomap | ||
| isofs | ||
| jbd2 | ||
| jffs2 | ||
| jfs | ||
| kernfs | ||
| ksmbd | ||
| lockd | ||
| minix | ||
| netfs | ||
| nfs | ||
| nfs_common | ||
| nfsd | ||
| nilfs2 | ||
| nls | ||
| notify | ||
| ntfs | ||
| ntfs3 | ||
| ocfs2 | ||
| omfs | ||
| openpromfs | ||
| orangefs | ||
| overlayfs | ||
| proc | ||
| pstore | ||
| qnx4 | ||
| qnx6 | ||
| quota | ||
| ramfs | ||
| reiserfs | ||
| romfs | ||
| smbfs_common | ||
| squashfs | ||
| sysfs | ||
| sysv | ||
| tracefs | ||
| ubifs | ||
| udf | ||
| ufs | ||
| unicode | ||
| vboxsf | ||
| verity | ||
| xfs | ||
| zonefs | ||
| aio.c | ||
| anon_inodes.c | ||
| attr.c | ||
| bad_inode.c | ||
| binfmt_elf_fdpic.c | ||
| binfmt_elf_test.c | ||
| binfmt_elf.c | ||
| binfmt_flat.c | ||
| binfmt_misc.c | ||
| binfmt_script.c | ||
| buffer.c | ||
| char_dev.c | ||
| compat_binfmt_elf.c | ||
| coredump.c | ||
| d_path.c | ||
| dax.c | ||
| dcache.c | ||
| direct-io.c | ||
| drop_caches.c | ||
| eventfd.c | ||
| eventpoll.c | ||
| exec.c | ||
| fcntl.c | ||
| fhandle.c | ||
| file_table.c | ||
| file.c | ||
| filesystems.c | ||
| fs_context.c | ||
| fs_parser.c | ||
| fs_pin.c | ||
| fs_struct.c | ||
| fs_types.c | ||
| fs-writeback.c | ||
| fsopen.c | ||
| init.c | ||
| inode.c | ||
| internal.h | ||
| ioctl.c | ||
| Kconfig | ||
| Kconfig.binfmt | ||
| kernel_read_file.c | ||
| libfs.c | ||
| locks.c | ||
| Makefile | ||
| mbcache.c | ||
| mount.h | ||
| mpage.c | ||
| namei.c | ||
| namespace.c | ||
| no-block.c | ||
| nsfs.c | ||
| open.c | ||
| pipe.c | ||
| pnode.c | ||
| pnode.h | ||
| posix_acl.c | ||
| proc_namespace.c | ||
| read_write.c | ||
| readdir.c | ||
| remap_range.c | ||
| select.c | ||
| seq_file.c | ||
| signalfd.c | ||
| splice.c | ||
| stack.c | ||
| stat.c | ||
| statfs.c | ||
| super.c | ||
| sync.c | ||
| sysctls.c | ||
| timerfd.c | ||
| userfaultfd.c | ||
| utimes.c | ||
| xattr.c | ||