android_kernel_xiaomi_sm8350/fs
Roland Dreier aa06117f19 eCryptfs: Fix lockdep-reported AB-BA mutex issue
Lockdep reports the following valid-looking possible AB-BA deadlock with
global_auth_tok_list_mutex and keysig_list_mutex:

  ecryptfs_new_file_context() ->
      ecryptfs_copy_mount_wide_sigs_to_inode_sigs() ->
          mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
          -> ecryptfs_add_keysig() ->
              mutex_lock(&crypt_stat->keysig_list_mutex);

vs

  ecryptfs_generate_key_packet_set() ->
      mutex_lock(&crypt_stat->keysig_list_mutex);
      -> ecryptfs_find_global_auth_tok_for_sig() ->
          mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);

ie the two mutexes are taken in opposite orders in the two different
code paths.  I'm not sure if this is a real bug where two threads could
actually hit the two paths in parallel and deadlock, but it at least
makes lockdep impossible to use with ecryptfs since this report triggers
every time and disables future lockdep reporting.

Since ecryptfs_add_keysig() is called only from the single callsite in
ecryptfs_copy_mount_wide_sigs_to_inode_sigs(), the simplest fix seems to
be to move the lock of keysig_list_mutex back up outside of the where
global_auth_tok_list_mutex is taken.  This patch does that, and fixes
the lockdep report on my system (and ecryptfs still works OK).

The full output of lockdep fixed by this patch is:

=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.31-2-generic #14~rbd2
-------------------------------------------------------
gdm/2640 is trying to acquire lock:
 (&mount_crypt_stat->global_auth_tok_list_mutex){+.+.+.}, at: [<ffffffff8121591e>] ecryptfs_find_global_auth_tok_for_sig+0x2e/0x90

but task is already holding lock:
 (&crypt_stat->keysig_list_mutex){+.+.+.}, at: [<ffffffff81217728>] ecryptfs_generate_key_packet_set+0x58/0x2b0

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&crypt_stat->keysig_list_mutex){+.+.+.}:
       [<ffffffff8108c897>] check_prev_add+0x2a7/0x370
       [<ffffffff8108cfc1>] validate_chain+0x661/0x750
       [<ffffffff8108d2e7>] __lock_acquire+0x237/0x430
       [<ffffffff8108d585>] lock_acquire+0xa5/0x150
       [<ffffffff815526cd>] __mutex_lock_common+0x4d/0x3d0
       [<ffffffff81552b56>] mutex_lock_nested+0x46/0x60
       [<ffffffff8121526a>] ecryptfs_add_keysig+0x5a/0xb0
       [<ffffffff81213299>] ecryptfs_copy_mount_wide_sigs_to_inode_sigs+0x59/0xb0
       [<ffffffff81214b06>] ecryptfs_new_file_context+0xa6/0x1a0
       [<ffffffff8120e42a>] ecryptfs_initialize_file+0x4a/0x140
       [<ffffffff8120e54d>] ecryptfs_create+0x2d/0x60
       [<ffffffff8113a7d4>] vfs_create+0xb4/0xe0
       [<ffffffff8113a8c4>] __open_namei_create+0xc4/0x110
       [<ffffffff8113d1c1>] do_filp_open+0xa01/0xae0
       [<ffffffff8112d8d9>] do_sys_open+0x69/0x140
       [<ffffffff8112d9f0>] sys_open+0x20/0x30
       [<ffffffff81013132>] system_call_fastpath+0x16/0x1b
       [<ffffffffffffffff>] 0xffffffffffffffff

-> #0 (&mount_crypt_stat->global_auth_tok_list_mutex){+.+.+.}:
       [<ffffffff8108c675>] check_prev_add+0x85/0x370
       [<ffffffff8108cfc1>] validate_chain+0x661/0x750
       [<ffffffff8108d2e7>] __lock_acquire+0x237/0x430
       [<ffffffff8108d585>] lock_acquire+0xa5/0x150
       [<ffffffff815526cd>] __mutex_lock_common+0x4d/0x3d0
       [<ffffffff81552b56>] mutex_lock_nested+0x46/0x60
       [<ffffffff8121591e>] ecryptfs_find_global_auth_tok_for_sig+0x2e/0x90
       [<ffffffff812177d5>] ecryptfs_generate_key_packet_set+0x105/0x2b0
       [<ffffffff81212f49>] ecryptfs_write_headers_virt+0xc9/0x120
       [<ffffffff8121306d>] ecryptfs_write_metadata+0xcd/0x200
       [<ffffffff8120e44b>] ecryptfs_initialize_file+0x6b/0x140
       [<ffffffff8120e54d>] ecryptfs_create+0x2d/0x60
       [<ffffffff8113a7d4>] vfs_create+0xb4/0xe0
       [<ffffffff8113a8c4>] __open_namei_create+0xc4/0x110
       [<ffffffff8113d1c1>] do_filp_open+0xa01/0xae0
       [<ffffffff8112d8d9>] do_sys_open+0x69/0x140
       [<ffffffff8112d9f0>] sys_open+0x20/0x30
       [<ffffffff81013132>] system_call_fastpath+0x16/0x1b
       [<ffffffffffffffff>] 0xffffffffffffffff

other info that might help us debug this:

2 locks held by gdm/2640:
 #0:  (&sb->s_type->i_mutex_key#11){+.+.+.}, at: [<ffffffff8113cb8b>] do_filp_open+0x3cb/0xae0
 #1:  (&crypt_stat->keysig_list_mutex){+.+.+.}, at: [<ffffffff81217728>] ecryptfs_generate_key_packet_set+0x58/0x2b0

stack backtrace:
Pid: 2640, comm: gdm Tainted: G         C 2.6.31-2-generic #14~rbd2
Call Trace:
 [<ffffffff8108b988>] print_circular_bug_tail+0xa8/0xf0
 [<ffffffff8108c675>] check_prev_add+0x85/0x370
 [<ffffffff81094912>] ? __module_text_address+0x12/0x60
 [<ffffffff8108cfc1>] validate_chain+0x661/0x750
 [<ffffffff81017275>] ? print_context_stack+0x85/0x140
 [<ffffffff81089c68>] ? find_usage_backwards+0x38/0x160
 [<ffffffff8108d2e7>] __lock_acquire+0x237/0x430
 [<ffffffff8108d585>] lock_acquire+0xa5/0x150
 [<ffffffff8121591e>] ? ecryptfs_find_global_auth_tok_for_sig+0x2e/0x90
 [<ffffffff8108b0b0>] ? check_usage_backwards+0x0/0xb0
 [<ffffffff815526cd>] __mutex_lock_common+0x4d/0x3d0
 [<ffffffff8121591e>] ? ecryptfs_find_global_auth_tok_for_sig+0x2e/0x90
 [<ffffffff8121591e>] ? ecryptfs_find_global_auth_tok_for_sig+0x2e/0x90
 [<ffffffff8108c02c>] ? mark_held_locks+0x6c/0xa0
 [<ffffffff81125b0d>] ? kmem_cache_alloc+0xfd/0x1a0
 [<ffffffff8108c34d>] ? trace_hardirqs_on_caller+0x14d/0x190
 [<ffffffff81552b56>] mutex_lock_nested+0x46/0x60
 [<ffffffff8121591e>] ecryptfs_find_global_auth_tok_for_sig+0x2e/0x90
 [<ffffffff812177d5>] ecryptfs_generate_key_packet_set+0x105/0x2b0
 [<ffffffff81212f49>] ecryptfs_write_headers_virt+0xc9/0x120
 [<ffffffff8121306d>] ecryptfs_write_metadata+0xcd/0x200
 [<ffffffff81210240>] ? ecryptfs_init_persistent_file+0x60/0xe0
 [<ffffffff8120e44b>] ecryptfs_initialize_file+0x6b/0x140
 [<ffffffff8120e54d>] ecryptfs_create+0x2d/0x60
 [<ffffffff8113a7d4>] vfs_create+0xb4/0xe0
 [<ffffffff8113a8c4>] __open_namei_create+0xc4/0x110
 [<ffffffff8113d1c1>] do_filp_open+0xa01/0xae0
 [<ffffffff8129a93e>] ? _raw_spin_unlock+0x5e/0xb0
 [<ffffffff8155410b>] ? _spin_unlock+0x2b/0x40
 [<ffffffff81139e9b>] ? getname+0x3b/0x240
 [<ffffffff81148a5a>] ? alloc_fd+0xfa/0x140
 [<ffffffff8112d8d9>] do_sys_open+0x69/0x140
 [<ffffffff81553b8f>] ? trace_hardirqs_on_thunk+0x3a/0x3f
 [<ffffffff8112d9f0>] sys_open+0x20/0x30
 [<ffffffff81013132>] system_call_fastpath+0x16/0x1b

Signed-off-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2009-09-23 09:10:30 -05:00
..
9p 9p: Add fscache support to 9p 2009-09-23 13:03:46 -05:00
adfs adfs: remove redundant test on unsigned 2009-09-24 07:21:05 -07:00
affs
afs seq_file: constify seq_operations 2009-09-23 07:39:29 -07:00
autofs trivial: remove unnecessary semicolons 2009-09-21 15:14:58 +02:00
autofs4 autofs4 - fix missed case when changing to use struct path 2009-08-31 17:44:05 -10:00
befs fs: Make unload_nls() NULL pointer safe 2009-09-24 07:47:42 -04:00
bfs
btrfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable 2009-09-24 08:57:29 -07:00
cachefiles
cifs truncate: use new helpers 2009-09-24 08:41:47 -04:00
coda sysctl: remove "struct file *" argument of ->proc_handler 2009-09-24 07:21:04 -07:00
configfs writeback: add name to backing_dev_info 2009-09-11 09:20:26 +02:00
cramfs
debugfs
devpts Move magic numbers into magic.h 2009-09-23 07:39:28 -07:00
dlm seq_file: constify seq_operations 2009-09-23 07:39:29 -07:00
ecryptfs eCryptfs: Fix lockdep-reported AB-BA mutex issue 2009-09-23 09:10:30 -05:00
efs
exofs exofs: remove BKL from super operations 2009-09-24 07:47:38 -04:00
exportfs
ext2 Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6 2009-09-24 07:53:22 -07:00
ext3 Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6 2009-09-24 07:53:22 -07:00
ext4 Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6 2009-09-24 07:53:22 -07:00
fat fs: Make unload_nls() NULL pointer safe 2009-09-24 07:47:42 -04:00
freevxfs
fscache
fuse truncate: use new helpers 2009-09-24 08:41:47 -04:00
gfs2 Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6 2009-09-24 07:53:22 -07:00
hfs fs: Make unload_nls() NULL pointer safe 2009-09-24 07:47:42 -04:00
hfsplus fs: Make unload_nls() NULL pointer safe 2009-09-24 07:47:42 -04:00
hostfs
hpfs
hppfs
hugetlbfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2009-09-24 08:32:11 -07:00
isofs fs: Make unload_nls() NULL pointer safe 2009-09-24 07:47:42 -04:00
jbd jbd: Annotate transaction start also for journal_restart() 2009-09-16 17:44:10 +02:00
jbd2 seq_file: constify seq_operations 2009-09-23 07:39:29 -07:00
jffs2 Merge git://git.infradead.org/mtd-2.6 2009-09-23 10:07:49 -07:00
jfs fs: Make unload_nls() NULL pointer safe 2009-09-24 07:47:42 -04:00
lockd headers: utsname.h redux 2009-09-23 18:13:10 -07:00
minix V3 minixfs: add missing directory type checking 2009-09-23 07:39:57 -07:00
ncpfs fs: Make unload_nls() NULL pointer safe 2009-09-24 07:47:42 -04:00
nfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2009-09-24 08:32:11 -07:00
nfs_common
nfsd headers: utsname.h redux 2009-09-23 18:13:10 -07:00
nilfs2 const: mark remaining inode_operations as const 2009-09-22 07:17:24 -07:00
nls fs: Make unload_nls() NULL pointer safe 2009-09-24 07:47:42 -04:00
notify inotify: update the group mask on mark addition 2009-08-28 12:51:14 -04:00
ntfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2009-09-24 08:32:11 -07:00
ocfs2 Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6 2009-09-24 07:53:22 -07:00
omfs const: mark remaining inode_operations as const 2009-09-22 07:17:24 -07:00
openpromfs
partitions const: make block_device_operations const 2009-09-22 07:17:25 -07:00
proc Merge branch 'cputime' of git://git390.marist.edu/pub/scm/linux-2.6 2009-09-24 09:04:24 -07:00
qnx4 qnx4: remove write support 2009-09-23 07:39:30 -07:00
quota const: make struct super_block::s_qcop const 2009-09-22 07:17:24 -07:00
ramfs truncate: use new helpers 2009-09-24 08:41:47 -04:00
reiserfs const: make struct super_block::s_qcop const 2009-09-22 07:17:24 -07:00
romfs fs/romfs: correct error-handling code 2009-09-24 07:21:05 -07:00
smbfs fs: Make unload_nls() NULL pointer safe 2009-09-24 07:47:42 -04:00
squashfs const: mark remaining super_operations const 2009-09-22 07:17:24 -07:00
sysfs Merge branch 'writeback' of git://git.kernel.dk/linux-2.6-block 2009-09-11 09:17:05 -07:00
sysv
ubifs const: mark remaining address_space_operations const 2009-09-22 07:17:24 -07:00
udf udf: Fix possible corruption when close races with write 2009-09-14 19:13:01 +02:00
ufs
xfs Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6 2009-09-24 07:53:22 -07:00
aio.c aio.c: move EXPORT* macros to line after function 2009-09-23 07:39:29 -07:00
anon_inodes.c anonfd: split interface into file creation and install 2009-09-23 07:39:29 -07:00
attr.c truncate: new helpers 2009-09-24 08:41:47 -04:00
bad_inode.c
binfmt_aout.c
binfmt_elf_fdpic.c fdpic: ignore the loader's PT_GNU_STACK when calculating the stack size 2009-09-24 07:21:02 -07:00
binfmt_elf.c elf: clean up fill_note_info() 2009-09-24 07:21:01 -07:00
binfmt_em86.c
binfmt_flat.c flat: use IS_ERR_VALUE() helper macro 2009-09-24 07:21:03 -07:00
binfmt_misc.c
binfmt_script.c
binfmt_som.c
bio-integrity.c
bio.c
block_dev.c freeze_bdev: grab active reference to frozen superblocks 2009-09-24 07:47:41 -04:00
buffer.c truncate: use new helpers 2009-09-24 08:41:47 -04:00
char_dev.c fs/char_dev.c: remove useless loop 2009-09-24 07:21:03 -07:00
compat_binfmt_elf.c
compat_ioctl.c
compat.c fs: fix overflow in sys_mount() for in-kernel calls 2009-09-24 08:40:15 -04:00
dcache.c
dcookies.c
direct-io.c
drop_caches.c sysctl: remove "struct file *" argument of ->proc_handler 2009-09-24 07:21:04 -07:00
eventfd.c anonfd: split interface into file creation and install 2009-09-23 07:39:29 -07:00
eventpoll.c
exec.c task_struct cleanup: move binfmt field to mm_struct 2009-09-24 07:21:05 -07:00
fcntl.c fcntl: add F_[SG]ETOWN_EX 2009-09-24 07:21:01 -07:00
fifo.c
file_table.c sysctl: remove "struct file *" argument of ->proc_handler 2009-09-24 07:21:04 -07:00
file.c
filesystems.c
fs_struct.c
fs-writeback.c writeback: fix possible bdi writeback refcounting problem 2009-09-16 15:18:53 +02:00
generic_acl.c
inode.c vfs: optimize touch_time() too 2009-09-24 07:47:27 -04:00
internal.h fs: fix overflow in sys_mount() for in-kernel calls 2009-09-24 08:40:15 -04:00
ioctl.c vfs: explicitly cast s_maxbytes in fiemap_check_ranges 2009-09-24 07:47:31 -04:00
ioprio.c
Kconfig tmpfs: depend on shmem 2009-09-22 07:17:41 -07:00
Kconfig.binfmt
libfs.c libfs: return error code on failed attr set 2009-09-24 07:47:30 -04:00
locks.c const: make lock_manager_operations const 2009-09-22 07:17:25 -07:00
Makefile
mbcache.c
mpage.c
namei.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6 2009-09-11 08:55:49 -07:00
namespace.c fs: fix overflow in sys_mount() for in-kernel calls 2009-09-24 08:40:15 -04:00
nfsctl.c
no-block.c
open.c fs: change sys_truncate length parameter type 2009-09-23 09:21:05 -07:00
pipe.c
pnode.c
pnode.h
posix_acl.c
read_write.c vfs: remove redundant position check in do_sendfile 2009-09-24 07:47:34 -04:00
read_write.h
readdir.c
select.c poll/select: avoid arithmetic overflow in __estimate_accuracy() 2009-09-23 07:39:27 -07:00
seq_file.c vfs: seq_file: add helpers for data filling 2009-09-24 07:47:35 -04:00
signalfd.c
splice.c Merge branch 'for-2.6.32' of git://git.kernel.dk/linux-2.6-block 2009-09-14 17:55:15 -07:00
stack.c
stat.c
super.c freeze_bdev: grab active reference to frozen superblocks 2009-09-24 07:47:41 -04:00
sync.c fs/buffer.c: clean up EXPORT* macros 2009-09-23 07:39:29 -07:00
timerfd.c
utimes.c
xattr_acl.c
xattr.c VFS: Factor out part of vfs_setxattr so it can be called from the SELinux hook for inode_setsecctx. 2009-09-10 10:11:22 +10:00