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linux/fs
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Jeff Moyer e2ea6a3e16 block: fix infinite loop in __getblk_slow 
commit 91f68c89d8 upstream.

Commit 080399aaaf ("block: don't mark buffers beyond end of disk as
mapped") exposed a bug in __getblk_slow that causes mount to hang as it
loops infinitely waiting for a buffer that lies beyond the end of the
disk to become uptodate.

The problem was initially reported by Torsten Hilbrich here:

    https://lkml.org/lkml/2012/6/18/54

and also reported independently here:

    http://www.sysresccd.org/forums/viewtopic.php?f=13&t=4511

and then Richard W.M.  Jones and Marcos Mello noted a few separate
bugzillas also associated with the same issue.  This patch has been
confirmed to fix:

    https://bugzilla.redhat.com/show_bug.cgi?id=835019

The main problem is here, in __getblk_slow:

        for (;;) {
                struct buffer_head * bh;
                int ret;

                bh = __find_get_block(bdev, block, size);
                if (bh)
                        return bh;

                ret = grow_buffers(bdev, block, size);
                if (ret < 0)
                        return NULL;
                if (ret == 0)
                        free_more_memory();
        }

__find_get_block does not find the block, since it will not be marked as
mapped, and so grow_buffers is called to fill in the buffers for the
associated page.  I believe the for (;;) loop is there primarily to
retry in the case of memory pressure keeping grow_buffers from
succeeding.  However, we also continue to loop for other cases, like the
block lying beond the end of the disk.  So, the fix I came up with is to
only loop when grow_buffers fails due to memory allocation issues
(return value of 0).

The attached patch was tested by myself, Torsten, and Rich, and was
found to resolve the problem in call cases.

Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Reported-and-Tested-by: Torsten Hilbrich <torsten.hilbrich@secunet.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Reviewed-by: Josh Boyer <jwboyer@redhat.com>
[ Jens is on vacation, taking this directly  - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-07-19 08:58:55 -07:00
..
9p 9p changes for the 3.4 merge window 2012-03-28 09:58:38 -07:00
adfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
affs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
afs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
autofs4 autofs: make the autofsv5 packet file descriptor use a packetized pipe 2012-04-29 13:30:08 -07:00
befs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
bfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
btrfs Btrfs: run delayed directory updates during log replay 2012-07-16 09:04:05 -07:00
cachefiles switch touch_atime to struct path 2012-03-20 21:29:41 -04:00
ceph Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client 2012-03-28 10:01:29 -07:00
cifs cifs: when server doesn't set CAP_LARGE_READ_X, cap default rsize at MaxBufferSize 2012-07-16 09:03:54 -07:00
coda Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
configfs make configfs_pin_fs() return root dentry on success 2012-03-20 21:29:48 -04:00
cramfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
debugfs simple_open: automatically convert to simple_open() 2012-04-05 15:25:50 -07:00
devpts Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
dlm dlm fixes for 3.4 2012-04-23 18:22:42 -07:00
ecryptfs eCryptfs: Properly check for O_RDONLY flag before doing privileged open 2012-07-16 09:04:26 -07:00
efs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
exofs exofs: Fix CRASH on very early IO errors. 2012-06-10 00:36:05 +09:00
exportfs
ext2 migrate ext2_fs.h guts to fs/ext2/ext2.h 2012-03-31 16:03:16 -04:00
ext3 ext3: move headers to fs/ext3/ 2012-03-31 16:03:16 -04:00
ext4 ext4: fix the free blocks calculation for ext3 file systems w/ uninit_bg 2012-06-17 11:21:23 -07:00
fat fat: fix bug in enforcing Long File Name length 2012-03-23 16:58:40 -07:00
freevxfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
fscache FS-Cache: Fix __fscache_uncache_all_inode_pages()'s outer loop 2011-07-21 10:59:16 -07:00
fuse fuse: fix stat call on 32 bit platforms 2012-06-17 11:21:29 -07:00
gfs2 GFS2: Instruct DLM to avoid queue convert slowdown 2012-04-24 13:26:50 +01:00
hfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
hfsplus hfsplus: fix bless ioctl when used with hardlinks 2012-06-22 11:36:57 -07:00
hostfs Merge branch 'for-linus-3.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml 2012-03-27 18:29:53 -07:00
hpfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
hppfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
hugetlbfs hugetlbfs: lockdep annotate root inode properly 2012-04-25 21:26:34 -07:00
isofs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
jbd Power management updates for 3.4 2012-03-21 10:15:51 -07:00
jbd2 jbd2: use GFP_NOFS for blkdev_issue_flush 2012-04-23 21:43:41 -04:00
jffs2 jffs2: Fix lock acquisition order bug in gc path 2012-05-07 20:30:14 +01:00
jfs jfs: mising cleanup on register_filesystem() failure 2012-03-20 21:29:48 -04:00
lockd SUNRPC: move per-net operations from svc_destroy() 2012-07-16 09:04:39 -07:00
logfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
minix Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
ncpfs Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
nfs NFS: hard-code init_net for NFS callback transports 2012-07-16 09:04:40 -07:00
nfs_common
nfsd SUNRPC: move per-net operations from svc_destroy() 2012-07-16 09:04:39 -07:00
nilfs2 nilfs2: ensure proper cache clearing for gc-inodes 2012-07-16 09:03:51 -07:00
nls NLS: raname "maxlen" to "maxout" in UTF conversion routines 2011-11-26 19:58:47 -08:00
notify fs/notify/notification.c: make subsys_initcall function static 2012-03-23 16:58:31 -07:00
ntfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
ocfs2 ocfs2: fix NULL pointer dereference in __ocfs2_change_file_space() 2012-07-16 09:04:45 -07:00
omfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
openpromfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
proc vfs: Fix /proc/<tid>/fdinfo/<fd> file handling 2012-06-10 00:36:18 +09:00
pstore Merge branch 'akpm' (Andrew's patch-bomb) 2012-04-05 15:30:34 -07:00
qnx4 qnx4: new helper - try_extent() 2012-03-20 21:29:52 -04:00
qnx6 fs: initial qnx6fs addition 2012-03-20 21:29:38 -04:00
quota Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2012-03-28 10:00:14 -07:00
ramfs fs: ramfs: file-nommu: add SetPageUptodate() 2012-07-16 09:04:45 -07:00
reiserfs Disintegrate and delete asm/system.h 2012-03-28 15:58:21 -07:00
romfs MTD merge for 3.4 2012-03-30 17:31:56 -07:00
squashfs Add an extra mount time sanity check, plus some code cleanups and bug fixes. 2012-03-28 18:05:54 -07:00
sysfs sysfs: handle 'parent deleted before child added' 2012-04-10 14:48:51 -07:00
sysv switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
ubifs - Improve error messages 2012-03-23 09:27:40 -07:00
udf udf: Fortify loading of sparing table 2012-07-16 09:03:51 -07:00
ufs Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
xfs Disintegrate and delete asm/system.h 2012-03-28 15:58:21 -07:00
aio.c vfs: make AIO use the proper rw_verify_area() area helpers 2012-06-01 15:18:14 +08:00
anon_inodes.c anon_inodes: move allocation of anon_inode into ->mount() 2012-03-20 21:29:45 -04:00
attr.c vfs: increment iversion when a file is truncated 2012-06-10 00:36:12 +09:00
bad_inode.c fs: reduce the use of module.h wherever possible 2012-02-28 19:31:58 -05:00
binfmt_aout.c VM: add "vm_mmap()" helper function 2012-04-20 17:29:13 -07:00
binfmt_elf_fdpic.c VM: add "vm_mmap()" helper function 2012-04-20 17:29:13 -07:00
binfmt_elf.c VM: add "vm_mmap()" helper function 2012-04-20 17:29:13 -07:00
binfmt_em86.c __register_binfmt() made void 2012-03-20 21:29:46 -04:00
binfmt_flat.c VM: add "vm_mmap()" helper function 2012-04-20 17:29:13 -07:00
binfmt_misc.c magic.h: move some FS magic numbers into magic.h 2012-03-23 16:58:31 -07:00
binfmt_script.c __register_binfmt() made void 2012-03-20 21:29:46 -04:00
binfmt_som.c VM: add "vm_mmap()" helper function 2012-04-20 17:29:13 -07:00
bio-integrity.c fs: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:21 +08:00
bio.c bio allocation failure due to bio_get_nr_vecs() 2012-05-11 16:45:12 +02:00
block_dev.c block: don't mark buffers beyond end of disk as mapped 2012-05-11 16:42:14 +02:00
buffer.c block: fix infinite loop in __getblk_slow 2012-07-19 08:58:55 -07:00
char_dev.c char_dev.c: fix up some whitespace errors 2011-12-13 11:18:17 -08:00
compat_binfmt_elf.c
compat_ioctl.c The following text was taken from the original review request: 2012-03-24 10:24:31 -07:00
compat.c Merge branch 'x86-x32-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-03-29 18:12:23 -07:00
dcache.c vfs: make word-at-a-time accesses handle a non-existing page 2012-05-03 14:01:40 -07:00
dcookies.c fs: reduce the use of module.h wherever possible 2012-02-28 19:31:58 -05:00
direct-io.c Restore direct_io / truncate locking API 2012-02-23 15:56:21 -08:00
drop_caches.c
eventfd.c fs: reduce the use of module.h wherever possible 2012-02-28 19:31:58 -05:00
eventpoll.c epoll: clear the tfile_check_list on -ELOOP 2012-04-25 21:26:33 -07:00
exec.c mm: correctly synchronize rss-counters at exit/exec 2012-07-16 09:04:08 -07:00
fcntl.c Wrap accesses to the fd_sets in struct fdtable 2012-02-19 10:30:52 -08:00
fhandle.c vfs: prefer ->dentry->d_sb to ->mnt->mnt_sb 2012-01-06 23:16:53 -05:00
fifo.c
file_table.c vfs: drop_file_write_access() made static 2012-03-20 21:29:32 -04:00
file.c Merge branch 'x86-x32-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-03-29 18:12:23 -07:00
filesystems.c vfs: convert fs_supers to hlist 2012-01-03 22:52:39 -05:00
fs_struct.c The following text was taken from the original review request: 2012-03-24 10:24:31 -07:00
fs-writeback.c trivial writeback fixes 2012-03-28 10:07:27 -07:00
generic_acl.c switch posix_acl_equiv_mode() to umode_t * 2011-08-01 02:10:06 -04:00
inode.c trim includes in inode.c 2012-03-20 21:29:51 -04:00
internal.h vfs: protect remounting superblock read-only 2012-01-06 23:20:12 -05:00
ioctl.c fs: reduce the use of module.h wherever possible 2012-02-28 19:31:58 -05:00
ioprio.c block: strip out locking optimization in put_io_context() 2012-02-07 07:51:30 +01:00
Kconfig Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
Kconfig.binfmt fs: binfmt_elf: create Kconfig variable for PIE randomization 2012-01-10 16:30:51 -08:00
libfs.c dentry leak in simple_fill_super() failure exit 2012-04-09 01:39:22 -04:00
locks.c Remove easily user-triggerable BUG from generic_setlease 2012-07-19 08:58:54 -07:00
Makefile fs: initial qnx6fs addition 2012-03-20 21:29:38 -04:00
mbcache.c
mount.h vfs: keep list of mounts for each superblock 2012-01-06 23:20:12 -05:00
mpage.c fs: reduce the use of module.h wherever possible 2012-02-28 19:31:58 -05:00
namei.c vfs: make word-at-a-time accesses handle a non-existing page 2012-05-03 14:01:40 -07:00
namespace.c vfs: umount_tree() might be called on subtree that had never made it 2012-06-10 00:36:12 +09:00
no-block.c
open.c vfs: make O_PATH file descriptors usable for 'fchdir()' 2012-07-16 09:04:23 -07:00
pipe.c pipes: add a "packetized pipe" mode for writing 2012-04-29 13:12:42 -07:00
pnode.c vfs: switch pnode.h macros to struct mount * 2012-01-03 22:57:11 -05:00
pnode.h vfs: switch pnode.h macros to struct mount * 2012-01-03 22:57:11 -05:00
posix_acl.c fs: reduce the use of module.h wherever possible 2012-02-28 19:31:58 -05:00
proc_namespace.c vfs: switch ->show_options() to struct dentry * 2012-01-06 23:19:54 -05:00
read_write.c fs: reduce the use of module.h wherever possible 2012-02-28 19:31:58 -05:00
read_write.h
readdir.c fs: reduce the use of module.h wherever possible 2012-02-28 19:31:58 -05:00
select.c Merge branch 'x86-x32-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-03-29 18:12:23 -07:00
seq_file.c The following text was taken from the original review request: 2012-03-24 10:24:31 -07:00
signalfd.c epoll: ep_unregister_pollwait() can use the freed pwq->whead 2012-02-24 11:42:50 -08:00
splice.c splice: fix racy pipe->buffers uses 2012-07-16 09:04:42 -07:00
stack.c fs: reduce the use of module.h wherever possible 2012-02-28 19:31:58 -05:00
stat.c The following text was taken from the original review request: 2012-03-24 10:24:31 -07:00
statfs.c fs: reduce the use of module.h wherever possible 2012-02-28 19:31:58 -05:00
super.c The following text was taken from the original review request: 2012-03-24 10:24:31 -07:00
sync.c fs: reduce the use of module.h wherever possible 2012-02-28 19:31:58 -05:00
timerfd.c
utimes.c
xattr_acl.c fs: reduce the use of module.h wherever possible 2012-02-28 19:31:58 -05:00
xattr.c fs/xattr.c:setxattr(): improve handling of allocation failures 2012-04-05 15:25:50 -07:00