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linux/fs/ocfs2
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Wengang Wang be99ca2716 fs/ocfs2: fix race in ocfs2_dentry_attach_lock() 
ocfs2_dentry_attach_lock() can be executed in parallel threads against the
same dentry.  Make that race safe.  The race is like this:

            thread A                               thread B

(A1) enter ocfs2_dentry_attach_lock,
seeing dentry->d_fsdata is NULL,
and no alias found by
ocfs2_find_local_alias, so kmalloc
a new ocfs2_dentry_lock structure
to local variable "dl", dl1

               .....

                                    (B1) enter ocfs2_dentry_attach_lock,
                                    seeing dentry->d_fsdata is NULL,
                                    and no alias found by
                                    ocfs2_find_local_alias so kmalloc
                                    a new ocfs2_dentry_lock structure
                                    to local variable "dl", dl2.

                                                   ......

(A2) set dentry->d_fsdata with dl1,
call ocfs2_dentry_lock() and increase
dl1->dl_lockres.l_ro_holders to 1 on
success.
              ......

                                    (B2) set dentry->d_fsdata with dl2
                                    call ocfs2_dentry_lock() and increase
				    dl2->dl_lockres.l_ro_holders to 1 on
				    success.

                                                  ......

(A3) call ocfs2_dentry_unlock()
and decrease
dl2->dl_lockres.l_ro_holders to 0
on success.
             ....

                                    (B3) call ocfs2_dentry_unlock(),
                                    decreasing
				    dl2->dl_lockres.l_ro_holders, but
				    see it's zero now, panic

Link: http://lkml.kernel.org/r/20190529174636.22364-1-wen.gang.wang@oracle.com
Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Reported-by: Daniel Sobe <daniel.sobe@nxp.com>
Tested-by: Daniel Sobe <daniel.sobe@nxp.com>
Reviewed-by: Changwei Ge <gechangwei@live.cn>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 		2019-06-13 17:34:56 -10:00
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cluster treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 275 2019-06-05 17:30:30 +02:00
dlm treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
dlmfs treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile ocfs2: improve ocfs2 Makefile 2018-12-28 12:11:45 -08:00
acl.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
acl.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
alloc.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
alloc.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
aops.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
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blockcheck.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
blockcheck.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
buffer_head_io.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
buffer_head_io.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
dcache.c fs/ocfs2: fix race in ocfs2_dentry_attach_lock() 2019-06-13 17:34:56 -10:00
dcache.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
dir.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
dir.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
dlmglue.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
dlmglue.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
export.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
export.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
extent_map.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 405 2019-06-05 17:37:13 +02:00
extent_map.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 405 2019-06-05 17:37:13 +02:00
file.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
file.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
filecheck.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 286 2019-06-05 17:36:37 +02:00
filecheck.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 286 2019-06-05 17:36:37 +02:00
heartbeat.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
heartbeat.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
inode.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
inode.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
ioctl.c ocfs2: eliminate a misreported warning 2018-06-07 17:34:33 -07:00
ioctl.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
journal.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
journal.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
localalloc.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
localalloc.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
locks.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
locks.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
mmap.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
mmap.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
move_extents.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
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namei.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
ocfs1_fs_compat.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 405 2019-06-05 17:37:13 +02:00
ocfs2.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
ocfs2_fs.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 405 2019-06-05 17:37:13 +02:00
ocfs2_ioctl.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
ocfs2_lockid.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
ocfs2_lockingver.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
ocfs2_trace.h ocfs2: fix the application IO timeout when fstrim is running 2019-03-05 21:07:13 -08:00
quota.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
quota_global.c ocfs2: convert to new i_version API 2018-01-29 06:42:21 -05:00
quota_local.c ocfs2: return -EROFS when filesystem becomes read-only 2018-08-17 16:20:27 -07:00
refcounttree.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
refcounttree.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
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slot_map.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
slot_map.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
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stack_user.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 286 2019-06-05 17:36:37 +02:00
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suballoc.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
suballoc.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
super.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
super.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
symlink.c vfs: remove ".readlink = generic_readlink" assignments 2016-12-09 16:45:04 +01:00
symlink.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
sysfile.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
sysfile.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
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