linux/fs
Roman Gushchin 3ca8138f01 fuse: break infinite loop in fuse_fill_write_pages()
I got a report about unkillable task eating CPU. Further
investigation shows, that the problem is in the fuse_fill_write_pages()
function. If iov's first segment has zero length, we get an infinite
loop, because we never reach iov_iter_advance() call.

Fix this by calling iov_iter_advance() before repeating an attempt to
copy data from userspace.

A similar problem is described in 124d3b7041 ("fix writev regression:
pan hanging unkillable and un-straceable"). If zero-length segmend
is followed by segment with invalid address,
iov_iter_fault_in_readable() checks only first segment (zero-length),
iov_iter_copy_from_user_atomic() skips it, fails at second and
returns zero -> goto again without skipping zero-length segment.

Patch calls iov_iter_advance() before goto again: we'll skip zero-length
segment at second iteraction and iov_iter_fault_in_readable() will detect
invalid address.

Special thanks to Konstantin Khlebnikov, who helped a lot with the commit
description.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Maxim Patlasov <mpatlasov@parallels.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Roman Gushchin <klamm@yandex-team.ru>
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Fixes: ea9b9907b8 ("fuse: implement perform_write")
Cc: <stable@vger.kernel.org>
2015-11-10 10:32:37 +01:00
..
9p 9p: fix return code of read() when count is 0 2015-08-23 14:21:36 -05:00
adfs
affs fs/affs: make root lookup from blkdev logical size 2015-09-10 13:29:01 -07:00
afs
autofs4
befs
bfs
btrfs Merge branch 'for-linus-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs 2015-10-24 07:17:58 +09:00
cachefiles
ceph Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client 2015-09-11 12:33:03 -07:00
cifs mm, fs: obey gfp_mapping for add_to_page_cache() 2015-10-16 11:42:28 -07:00
coda fs/coda: fix readlink buffer overflow 2015-09-10 13:29:01 -07:00
configfs
cramfs
debugfs
devpts
dlm dlm for 4.3 2015-09-03 12:57:48 -07:00
ecryptfs Invalidate stale eCryptfs dcache entries caused by unlinked lower inodes 2015-09-08 11:26:17 -07:00
efivarfs
efs
exofs
exportfs
ext2 ext2: huge page fault support 2015-09-08 15:35:28 -07:00
ext4 Merge branch 'akpm' (patches from Andrew) 2015-10-16 11:42:37 -07:00
f2fs Merge tag 'for-f2fs-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs 2015-09-03 13:10:22 -07:00
fat
freevxfs freevxfs: Grammar s/an negative/a negative/ 2015-08-07 13:59:24 +02:00
fscache
fuse fuse: break infinite loop in fuse_fill_write_pages() 2015-11-10 10:32:37 +01:00
gfs2 GFS2: merge window 2015-09-11 12:23:51 -07:00
hfs hfs: fix B-tree corruption after insertion at position 0 2015-09-10 13:29:01 -07:00
hfsplus hfs,hfsplus: cache pages correctly between bnode_create and bnode_free 2015-09-10 13:29:01 -07:00
hostfs fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
hpfs hpfs: update ctime and mtime on directory modification 2015-09-03 11:55:30 -07:00
hugetlbfs hugetlbfs: add hugetlbfs_fallocate() 2015-09-08 15:35:28 -07:00
isofs
jbd2
jffs2
jfs Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2015-09-03 12:28:30 -07:00
kernfs kernfs: implement kernfs_path_len() 2015-08-18 15:49:15 -07:00
lockd lockd: NLM grace period shouldn't block NFSv4 opens 2015-08-13 10:22:06 -04:00
logfs block: remove bio_get_nr_vecs() 2015-08-13 12:32:04 -06:00
minix
ncpfs
nfs NFS: Fix a tracepoint NULL-pointer dereference 2015-10-06 18:56:25 -04:00
nfs_common lockd: NLM grace period shouldn't block NFSv4 opens 2015-08-13 10:22:06 -04:00
nfsd nfsd/blocklayout: accept any minlength 2015-10-09 16:11:40 -04:00
nilfs2 block: remove bio_get_nr_vecs() 2015-08-13 12:32:04 -06:00
nls
notify Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-09-05 20:34:28 -07:00
ntfs ntfs: delete unnecessary checks before calling iput() 2015-09-04 16:54:41 -07:00
ocfs2 ocfs2/dlm: unlock lockres spinlock before dlm_lockres_put 2015-10-23 17:55:10 +09:00
omfs
openpromfs
overlayfs Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 2015-10-31 14:49:19 -07:00
proc proc: convert to kstrto*()/kstrto*_from_user() 2015-09-10 13:29:01 -07:00
pstore
qnx4
qnx6
quota Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-09-05 20:34:28 -07:00
ramfs mm, fs: obey gfp_mapping for add_to_page_cache() 2015-10-16 11:42:28 -07:00
reiserfs fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
romfs
squashfs
sysfs
sysv
tracefs
ubifs UBIFS: Kill unneeded locking in ubifs_init_security 2015-09-29 12:45:42 +02:00
udf udf: Don't modify filesystem for read-only mounts 2015-08-20 14:58:35 +02:00
ufs fix ufs write vs readpage race when writing into a hole 2015-09-09 10:43:12 -07:00
xfs xfs: huge page fault support 2015-09-08 15:35:28 -07:00
aio.c mm: move ->mremap() from file_operations to vm_operations_struct 2015-09-04 16:54:41 -07:00
anon_inodes.c
attr.c
bad_inode.c
binfmt_aout.c
binfmt_elf_fdpic.c
binfmt_elf.c
binfmt_em86.c
binfmt_flat.c
binfmt_misc.c
binfmt_script.c
block_dev.c blockdev: don't set S_DAX for misaligned partitions 2015-09-15 20:08:05 -04:00
buffer.c fs: use helper bio_add_page() instead of open coding on bi_io_vec 2015-08-13 12:32:00 -06:00
char_dev.c fs/char_dev.c: fix incorrect documentation for unregister_chrdev_region 2015-08-05 13:49:35 -07:00
compat_binfmt_elf.c
compat_ioctl.c
compat.c
coredump.c fs: Don't dump core if the corefile would become world-readable. 2015-09-10 13:29:01 -07:00
dax.c mm, dax: fix DAX deadlocks 2015-10-16 11:42:28 -07:00
dcache.c dcache: Reduce the scope of i_lock in d_splice_alias 2015-08-21 02:34:37 -04:00
dcookies.c
direct-io.c block: remove bio_get_nr_vecs() 2015-08-13 12:32:04 -06:00
drop_caches.c inode: convert inode_sb_list_lock to per-sb 2015-08-17 18:39:46 -04:00
eventfd.c
eventpoll.c
exec.c
fcntl.c
fhandle.c
file_table.c fs, file table: reinit files_stat.max_files after deferred memory initialisation 2015-08-07 04:39:40 +03:00
file.c
filesystems.c
fs_pin.c
fs_struct.c
fs-writeback.c writeback: bdi_writeback iteration must not skip dying ones 2015-10-12 10:31:12 -06:00
inode.c inode: don't softlockup when evicting inodes 2015-08-18 10:20:09 -07:00
internal.h inode: rename i_wb_list to i_io_list 2015-08-17 23:38:10 -04:00
ioctl.c
Kconfig
Kconfig.binfmt
libfs.c fs: Set the size of empty dirs to 0. 2015-08-12 15:28:45 -05:00
locks.c fs: fix fs/locks.c kernel-doc warning 2015-08-31 16:27:25 -04:00
Makefile userfaultfd: buildsystem activation 2015-09-04 16:54:41 -07:00
mbcache.c
mount.h
mpage.c mm, fs: obey gfp_mapping for add_to_page_cache() 2015-10-16 11:42:28 -07:00
namei.c namei: results of d_is_negative() should be checked after dentry revalidation 2015-10-10 10:17:27 -07:00
namespace.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2015-09-01 16:13:25 -07:00
no-block.c
nsfs.c fs/seq_file: convert int seq_vprint/seq_printf/etc... returns to void 2015-09-11 15:21:34 -07:00
open.c
pipe.c
pnode.c
pnode.h
posix_acl.c
proc_namespace.c
read_write.c
readdir.c
select.c
seq_file.c fs/seq_file: convert int seq_vprint/seq_printf/etc... returns to void 2015-09-11 15:21:34 -07:00
signalfd.c signalfd: fix information leak in signalfd_copyinfo 2015-08-07 04:39:40 +03:00
splice.c
stack.c
stat.c
statfs.c
super.c Merge branch 'superblock-scaling' of git://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-next into for-next 2015-08-21 02:31:20 -04:00
sync.c
timerfd.c
userfaultfd.c userfaultfd: revert "userfaultfd: waitqueue: add nr wake parameter to __wake_up_locked_key" 2015-09-22 15:09:53 -07:00
utimes.c
xattr.c