| Age | Commit message (Collapse) | Author |
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reiserfs_unlink() may or may not be called under the reiserfs
lock.
But it also takes the reiserfs lock and can then acquire it
recursively which leads to do_journal_begin_r() that fails to
relax the reiserfs lock before grabbing the journal mutex,
creating an unexpected lock inversion.
We need to ensure reiserfs_unlink() won't get the reiserfs lock
recursively using reiserfs_write_lock_once().
This fixes the following warning that precedes a lock inversion
report (reiserfs lock <-> journal mutex).
------------[ cut here ]------------
WARNING: at fs/reiserfs/lock.c:95 reiserfs_lock_check_recursive+0x3a/0x50()
Hardware name: MS-7418
Unwanted recursive reiserfs lock!
Pid: 3208, comm: dbench Not tainted 2.6.32-atom #177
Call Trace:
[<c114327a>] ? reiserfs_lock_check_recursive+0x3a/0x50
[<c114327a>] ? reiserfs_lock_check_recursive+0x3a/0x50
[<c10373a7>] warn_slowpath_common+0x67/0xc0
[<c114327a>] ? reiserfs_lock_check_recursive+0x3a/0x50
[<c1037446>] warn_slowpath_fmt+0x26/0x30
[<c114327a>] reiserfs_lock_check_recursive+0x3a/0x50
[<c113c213>] do_journal_begin_r+0x83/0x360
[<c105eb16>] ? __lock_acquire+0x1296/0x19e0
[<c1142a57>] ? xattr_unlink+0x57/0xb0
[<c113c670>] journal_begin+0x80/0x130
[<c1116d5d>] reiserfs_unlink+0x7d/0x2d0
[<c1142a57>] ? xattr_unlink+0x57/0xb0
[<c1142a57>] ? xattr_unlink+0x57/0xb0
[<c1142a57>] ? xattr_unlink+0x57/0xb0
[<c1142a64>] xattr_unlink+0x64/0xb0
[<c1143169>] delete_one_xattr+0x29/0x100
[<c11427ab>] reiserfs_for_each_xattr+0x10b/0x290
[<c1143140>] ? delete_one_xattr+0x0/0x100
[<c1401ca9>] ? mutex_lock_nested+0x299/0x340
[<c11429aa>] reiserfs_delete_xattrs+0x1a/0x60
[<c11432f9>] ? reiserfs_write_lock_once+0x29/0x50
[<c111ea1f>] reiserfs_delete_inode+0x9f/0x150
[<c11b0d0f>] ? _atomic_dec_and_lock+0x4f/0x70
[<c111e980>] ? reiserfs_delete_inode+0x0/0x150
[<c10c9c32>] generic_delete_inode+0xa2/0x170
[<c10c9d4f>] generic_drop_inode+0x4f/0x70
[<c10c8b07>] iput+0x47/0x50
[<c10c0965>] do_unlinkat+0xd5/0x160
[<c10505c6>] ? up_read+0x16/0x30
[<c1022ab7>] ? do_page_fault+0x187/0x330
[<c1002fd8>] ? restore_all_notrace+0x0/0x18
[<c1022930>] ? do_page_fault+0x0/0x330
[<c105cbe4>] ? trace_hardirqs_on_caller+0x124/0x170
[<c10c0a00>] sys_unlink+0x10/0x20
[<c1002ec4>] sysenter_do_call+0x12/0x32
---[ end trace 2e35d71a6cc69d0c ]---
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Tested-by: Christian Kujau <lists@nerdbynature.de>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
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We call xattr_lookup() from reiserfs_xattr_get(). We then hold
the reiserfs lock when we grab the i_mutex. But later, we may
relax the reiserfs lock, creating dependency inversion between
both locks.
The lookups and creation jobs ar already protected by the
inode mutex, so we can safely relax the reiserfs lock, dropping
the unwanted reiserfs lock -> i_mutex dependency, as shown
in the following lockdep report:
=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.32-atom #173
-------------------------------------------------------
cp/3204 is trying to acquire lock:
(&REISERFS_SB(s)->lock){+.+.+.}, at: [<c11432b9>] reiserfs_write_lock_once+0x29/0x50
but task is already holding lock:
(&sb->s_type->i_mutex_key#4/3){+.+.+.}, at: [<c1141e18>] open_xa_dir+0xd8/0x1b0
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&sb->s_type->i_mutex_key#4/3){+.+.+.}:
[<c105ea7f>] __lock_acquire+0x11ff/0x19e0
[<c105f2c8>] lock_acquire+0x68/0x90
[<c1401a2b>] mutex_lock_nested+0x5b/0x340
[<c1141d83>] open_xa_dir+0x43/0x1b0
[<c1142722>] reiserfs_for_each_xattr+0x62/0x260
[<c114299a>] reiserfs_delete_xattrs+0x1a/0x60
[<c111ea1f>] reiserfs_delete_inode+0x9f/0x150
[<c10c9c32>] generic_delete_inode+0xa2/0x170
[<c10c9d4f>] generic_drop_inode+0x4f/0x70
[<c10c8b07>] iput+0x47/0x50
[<c10c0965>] do_unlinkat+0xd5/0x160
[<c10c0a00>] sys_unlink+0x10/0x20
[<c1002ec4>] sysenter_do_call+0x12/0x32
-> #0 (&REISERFS_SB(s)->lock){+.+.+.}:
[<c105f176>] __lock_acquire+0x18f6/0x19e0
[<c105f2c8>] lock_acquire+0x68/0x90
[<c1401a2b>] mutex_lock_nested+0x5b/0x340
[<c11432b9>] reiserfs_write_lock_once+0x29/0x50
[<c1117012>] reiserfs_lookup+0x62/0x140
[<c10bd85f>] __lookup_hash+0xef/0x110
[<c10bf21d>] lookup_one_len+0x8d/0xc0
[<c1141e2a>] open_xa_dir+0xea/0x1b0
[<c1141fe5>] xattr_lookup+0x15/0x160
[<c1142476>] reiserfs_xattr_get+0x56/0x2a0
[<c1144042>] reiserfs_get_acl+0xa2/0x360
[<c114461a>] reiserfs_cache_default_acl+0x3a/0x160
[<c111789c>] reiserfs_mkdir+0x6c/0x2c0
[<c10bea96>] vfs_mkdir+0xd6/0x180
[<c10c0c10>] sys_mkdirat+0xc0/0xd0
[<c10c0c40>] sys_mkdir+0x20/0x30
[<c1002ec4>] sysenter_do_call+0x12/0x32
other info that might help us debug this:
2 locks held by cp/3204:
#0: (&sb->s_type->i_mutex_key#4/1){+.+.+.}, at: [<c10bd8d6>] lookup_create+0x26/0xa0
#1: (&sb->s_type->i_mutex_key#4/3){+.+.+.}, at: [<c1141e18>] open_xa_dir+0xd8/0x1b0
stack backtrace:
Pid: 3204, comm: cp Not tainted 2.6.32-atom #173
Call Trace:
[<c13ff993>] ? printk+0x18/0x1a
[<c105d33a>] print_circular_bug+0xca/0xd0
[<c105f176>] __lock_acquire+0x18f6/0x19e0
[<c105d3aa>] ? check_usage+0x6a/0x460
[<c105f2c8>] lock_acquire+0x68/0x90
[<c11432b9>] ? reiserfs_write_lock_once+0x29/0x50
[<c11432b9>] ? reiserfs_write_lock_once+0x29/0x50
[<c1401a2b>] mutex_lock_nested+0x5b/0x340
[<c11432b9>] ? reiserfs_write_lock_once+0x29/0x50
[<c11432b9>] reiserfs_write_lock_once+0x29/0x50
[<c1117012>] reiserfs_lookup+0x62/0x140
[<c105ccca>] ? debug_check_no_locks_freed+0x8a/0x140
[<c105cbe4>] ? trace_hardirqs_on_caller+0x124/0x170
[<c10bd85f>] __lookup_hash+0xef/0x110
[<c10bf21d>] lookup_one_len+0x8d/0xc0
[<c1141e2a>] open_xa_dir+0xea/0x1b0
[<c1141fe5>] xattr_lookup+0x15/0x160
[<c1142476>] reiserfs_xattr_get+0x56/0x2a0
[<c1144042>] reiserfs_get_acl+0xa2/0x360
[<c10ca2e7>] ? new_inode+0x27/0xa0
[<c114461a>] reiserfs_cache_default_acl+0x3a/0x160
[<c1402eb7>] ? _spin_unlock+0x27/0x40
[<c111789c>] reiserfs_mkdir+0x6c/0x2c0
[<c10c7cb8>] ? __d_lookup+0x108/0x190
[<c105c932>] ? mark_held_locks+0x62/0x80
[<c1401c8d>] ? mutex_lock_nested+0x2bd/0x340
[<c10bd17a>] ? generic_permission+0x1a/0xa0
[<c11788fe>] ? security_inode_permission+0x1e/0x20
[<c10bea96>] vfs_mkdir+0xd6/0x180
[<c10c0c10>] sys_mkdirat+0xc0/0xd0
[<c10505c6>] ? up_read+0x16/0x30
[<c1002fd8>] ? restore_all_notrace+0x0/0x18
[<c10c0c40>] sys_mkdir+0x20/0x30
[<c1002ec4>] sysenter_do_call+0x12/0x32
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Tested-by: Christian Kujau <lists@nerdbynature.de>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
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Keeping the reiserfs lock while freeing the journal on
umount path triggers a lock inversion between bdev->bd_mutex
and the reiserfs lock.
We don't need the reiserfs lock at this stage. The filesystem
is not usable anymore, and there are no more pending commits,
everything got flushed (even this operation was done in parallel
and didn't required the reiserfs lock from the current process).
This fixes the following lockdep report:
=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.32-atom #172
-------------------------------------------------------
umount/3904 is trying to acquire lock:
(&bdev->bd_mutex){+.+.+.}, at: [<c10de2c2>] __blkdev_put+0x22/0x160
but task is already holding lock:
(&REISERFS_SB(s)->lock){+.+.+.}, at: [<c1143279>] reiserfs_write_lock+0x29/0x40
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&REISERFS_SB(s)->lock){+.+.+.}:
[<c105ea7f>] __lock_acquire+0x11ff/0x19e0
[<c105f2c8>] lock_acquire+0x68/0x90
[<c140199b>] mutex_lock_nested+0x5b/0x340
[<c1143229>] reiserfs_write_lock_once+0x29/0x50
[<c111c485>] reiserfs_get_block+0x85/0x1620
[<c10e1040>] do_mpage_readpage+0x1f0/0x6d0
[<c10e1640>] mpage_readpages+0xc0/0x100
[<c1119b89>] reiserfs_readpages+0x19/0x20
[<c108f1ec>] __do_page_cache_readahead+0x1bc/0x260
[<c108f2b8>] ra_submit+0x28/0x40
[<c1087e3e>] filemap_fault+0x40e/0x420
[<c109b5fd>] __do_fault+0x3d/0x430
[<c109d47e>] handle_mm_fault+0x12e/0x790
[<c1022a65>] do_page_fault+0x135/0x330
[<c1403663>] error_code+0x6b/0x70
[<c10ef9ca>] load_elf_binary+0x82a/0x1a10
[<c10ba130>] search_binary_handler+0x90/0x1d0
[<c10bb70f>] do_execve+0x1df/0x250
[<c1001746>] sys_execve+0x46/0x70
[<c1002fa5>] syscall_call+0x7/0xb
-> #2 (&mm->mmap_sem){++++++}:
[<c105ea7f>] __lock_acquire+0x11ff/0x19e0
[<c105f2c8>] lock_acquire+0x68/0x90
[<c109b1ab>] might_fault+0x8b/0xb0
[<c11b8f52>] copy_to_user+0x32/0x70
[<c10c3b94>] filldir64+0xa4/0xf0
[<c1109116>] sysfs_readdir+0x116/0x210
[<c10c3e1d>] vfs_readdir+0x8d/0xb0
[<c10c3ea9>] sys_getdents64+0x69/0xb0
[<c1002ec4>] sysenter_do_call+0x12/0x32
-> #1 (sysfs_mutex){+.+.+.}:
[<c105ea7f>] __lock_acquire+0x11ff/0x19e0
[<c105f2c8>] lock_acquire+0x68/0x90
[<c140199b>] mutex_lock_nested+0x5b/0x340
[<c110951c>] sysfs_addrm_start+0x2c/0xb0
[<c1109aa0>] create_dir+0x40/0x90
[<c1109b1b>] sysfs_create_dir+0x2b/0x50
[<c11b2352>] kobject_add_internal+0xc2/0x1b0
[<c11b2531>] kobject_add_varg+0x31/0x50
[<c11b25ac>] kobject_add+0x2c/0x60
[<c1258294>] device_add+0x94/0x560
[<c11036ea>] add_partition+0x18a/0x2a0
[<c110418a>] rescan_partitions+0x33a/0x450
[<c10de5bf>] __blkdev_get+0x12f/0x2d0
[<c10de76a>] blkdev_get+0xa/0x10
[<c11034b8>] register_disk+0x108/0x130
[<c11a87a9>] add_disk+0xd9/0x130
[<c12998e5>] sd_probe_async+0x105/0x1d0
[<c10528af>] async_thread+0xcf/0x230
[<c104bfd4>] kthread+0x74/0x80
[<c1003aab>] kernel_thread_helper+0x7/0x3c
-> #0 (&bdev->bd_mutex){+.+.+.}:
[<c105f176>] __lock_acquire+0x18f6/0x19e0
[<c105f2c8>] lock_acquire+0x68/0x90
[<c140199b>] mutex_lock_nested+0x5b/0x340
[<c10de2c2>] __blkdev_put+0x22/0x160
[<c10de40a>] blkdev_put+0xa/0x10
[<c113ce22>] free_journal_ram+0xd2/0x130
[<c113ea18>] do_journal_release+0x98/0x190
[<c113eb2a>] journal_release+0xa/0x10
[<c1128eb6>] reiserfs_put_super+0x36/0x130
[<c10b776f>] generic_shutdown_super+0x4f/0xe0
[<c10b7825>] kill_block_super+0x25/0x40
[<c11255df>] reiserfs_kill_sb+0x7f/0x90
[<c10b7f4a>] deactivate_super+0x7a/0x90
[<c10cccd8>] mntput_no_expire+0x98/0xd0
[<c10ccfcc>] sys_umount+0x4c/0x310
[<c10cd2a9>] sys_oldumount+0x19/0x20
[<c1002ec4>] sysenter_do_call+0x12/0x32
other info that might help us debug this:
2 locks held by umount/3904:
#0: (&type->s_umount_key#30){+++++.}, at: [<c10b7f45>] deactivate_super+0x75/0x90
#1: (&REISERFS_SB(s)->lock){+.+.+.}, at: [<c1143279>] reiserfs_write_lock+0x29/0x40
stack backtrace:
Pid: 3904, comm: umount Not tainted 2.6.32-atom #172
Call Trace:
[<c13ff903>] ? printk+0x18/0x1a
[<c105d33a>] print_circular_bug+0xca/0xd0
[<c105f176>] __lock_acquire+0x18f6/0x19e0
[<c108b66f>] ? free_pcppages_bulk+0x1f/0x250
[<c105f2c8>] lock_acquire+0x68/0x90
[<c10de2c2>] ? __blkdev_put+0x22/0x160
[<c10de2c2>] ? __blkdev_put+0x22/0x160
[<c140199b>] mutex_lock_nested+0x5b/0x340
[<c10de2c2>] ? __blkdev_put+0x22/0x160
[<c105c932>] ? mark_held_locks+0x62/0x80
[<c10afe12>] ? kfree+0x92/0xd0
[<c10de2c2>] __blkdev_put+0x22/0x160
[<c105cc3b>] ? trace_hardirqs_on+0xb/0x10
[<c10de40a>] blkdev_put+0xa/0x10
[<c113ce22>] free_journal_ram+0xd2/0x130
[<c113ea18>] do_journal_release+0x98/0x190
[<c113eb2a>] journal_release+0xa/0x10
[<c1128eb6>] reiserfs_put_super+0x36/0x130
[<c1050596>] ? up_write+0x16/0x30
[<c10b776f>] generic_shutdown_super+0x4f/0xe0
[<c10b7825>] kill_block_super+0x25/0x40
[<c10f41e0>] ? vfs_quota_off+0x0/0x20
[<c11255df>] reiserfs_kill_sb+0x7f/0x90
[<c10b7f4a>] deactivate_super+0x7a/0x90
[<c10cccd8>] mntput_no_expire+0x98/0xd0
[<c10ccfcc>] sys_umount+0x4c/0x310
[<c10cd2a9>] sys_oldumount+0x19/0x20
[<c1002ec4>] sysenter_do_call+0x12/0x32
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
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While deleting the xattrs of an inode, we hold the reiserfs lock
and grab the inode->i_mutex of the targeted inode and the root
private xattr directory.
Later on, we may relax the reiserfs lock for various reasons, this
creates inverted dependencies.
We can remove the reiserfs lock -> i_mutex dependency by relaxing
the former before calling open_xa_dir(). This is fine because the
lookup and creation of xattr private directories done in
open_xa_dir() are covered by the targeted inode mutexes. And deeper
operations in the tree are still done under the write lock.
This fixes the following lockdep report:
=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.32-atom #173
-------------------------------------------------------
cp/3204 is trying to acquire lock:
(&REISERFS_SB(s)->lock){+.+.+.}, at: [<c11432b9>] reiserfs_write_lock_once+0x29/0x50
but task is already holding lock:
(&sb->s_type->i_mutex_key#4/3){+.+.+.}, at: [<c1141e18>] open_xa_dir+0xd8/0x1b0
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&sb->s_type->i_mutex_key#4/3){+.+.+.}:
[<c105ea7f>] __lock_acquire+0x11ff/0x19e0
[<c105f2c8>] lock_acquire+0x68/0x90
[<c1401a2b>] mutex_lock_nested+0x5b/0x340
[<c1141d83>] open_xa_dir+0x43/0x1b0
[<c1142722>] reiserfs_for_each_xattr+0x62/0x260
[<c114299a>] reiserfs_delete_xattrs+0x1a/0x60
[<c111ea1f>] reiserfs_delete_inode+0x9f/0x150
[<c10c9c32>] generic_delete_inode+0xa2/0x170
[<c10c9d4f>] generic_drop_inode+0x4f/0x70
[<c10c8b07>] iput+0x47/0x50
[<c10c0965>] do_unlinkat+0xd5/0x160
[<c10c0a00>] sys_unlink+0x10/0x20
[<c1002ec4>] sysenter_do_call+0x12/0x32
-> #0 (&REISERFS_SB(s)->lock){+.+.+.}:
[<c105f176>] __lock_acquire+0x18f6/0x19e0
[<c105f2c8>] lock_acquire+0x68/0x90
[<c1401a2b>] mutex_lock_nested+0x5b/0x340
[<c11432b9>] reiserfs_write_lock_once+0x29/0x50
[<c1117012>] reiserfs_lookup+0x62/0x140
[<c10bd85f>] __lookup_hash+0xef/0x110
[<c10bf21d>] lookup_one_len+0x8d/0xc0
[<c1141e2a>] open_xa_dir+0xea/0x1b0
[<c1141fe5>] xattr_lookup+0x15/0x160
[<c1142476>] reiserfs_xattr_get+0x56/0x2a0
[<c1144042>] reiserfs_get_acl+0xa2/0x360
[<c114461a>] reiserfs_cache_default_acl+0x3a/0x160
[<c111789c>] reiserfs_mkdir+0x6c/0x2c0
[<c10bea96>] vfs_mkdir+0xd6/0x180
[<c10c0c10>] sys_mkdirat+0xc0/0xd0
[<c10c0c40>] sys_mkdir+0x20/0x30
[<c1002ec4>] sysenter_do_call+0x12/0x32
other info that might help us debug this:
2 locks held by cp/3204:
#0: (&sb->s_type->i_mutex_key#4/1){+.+.+.}, at: [<c10bd8d6>] lookup_create+0x26/0xa0
#1: (&sb->s_type->i_mutex_key#4/3){+.+.+.}, at: [<c1141e18>] open_xa_dir+0xd8/0x1b0
stack backtrace:
Pid: 3204, comm: cp Not tainted 2.6.32-atom #173
Call Trace:
[<c13ff993>] ? printk+0x18/0x1a
[<c105d33a>] print_circular_bug+0xca/0xd0
[<c105f176>] __lock_acquire+0x18f6/0x19e0
[<c105d3aa>] ? check_usage+0x6a/0x460
[<c105f2c8>] lock_acquire+0x68/0x90
[<c11432b9>] ? reiserfs_write_lock_once+0x29/0x50
[<c11432b9>] ? reiserfs_write_lock_once+0x29/0x50
[<c1401a2b>] mutex_lock_nested+0x5b/0x340
[<c11432b9>] ? reiserfs_write_lock_once+0x29/0x50
[<c11432b9>] reiserfs_write_lock_once+0x29/0x50
[<c1117012>] reiserfs_lookup+0x62/0x140
[<c105ccca>] ? debug_check_no_locks_freed+0x8a/0x140
[<c105cbe4>] ? trace_hardirqs_on_caller+0x124/0x170
[<c10bd85f>] __lookup_hash+0xef/0x110
[<c10bf21d>] lookup_one_len+0x8d/0xc0
[<c1141e2a>] open_xa_dir+0xea/0x1b0
[<c1141fe5>] xattr_lookup+0x15/0x160
[<c1142476>] reiserfs_xattr_get+0x56/0x2a0
[<c1144042>] reiserfs_get_acl+0xa2/0x360
[<c10ca2e7>] ? new_inode+0x27/0xa0
[<c114461a>] reiserfs_cache_default_acl+0x3a/0x160
[<c1402eb7>] ? _spin_unlock+0x27/0x40
[<c111789c>] reiserfs_mkdir+0x6c/0x2c0
[<c10c7cb8>] ? __d_lookup+0x108/0x190
[<c105c932>] ? mark_held_locks+0x62/0x80
[<c1401c8d>] ? mutex_lock_nested+0x2bd/0x340
[<c10bd17a>] ? generic_permission+0x1a/0xa0
[<c11788fe>] ? security_inode_permission+0x1e/0x20
[<c10bea96>] vfs_mkdir+0xd6/0x180
[<c10c0c10>] sys_mkdirat+0xc0/0xd0
[<c10505c6>] ? up_read+0x16/0x30
[<c1002fd8>] ? restore_all_notrace+0x0/0x18
[<c10c0c40>] sys_mkdir+0x20/0x30
[<c1002ec4>] sysenter_do_call+0x12/0x32
v2: Don't drop reiserfs_mutex_lock_nested_safe() as we'll still
need it later
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Tested-by: Christian Kujau <lists@nerdbynature.de>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
|
|
When we relax the reiserfs lock to avoid creating unwanted
dependencies against others locks while grabbing these,
we want to ensure it has not been taken recursively, otherwise
the lock won't be really relaxed. Only its depth will be decreased.
The unwanted dependency would then actually happen.
To prevent from that, add a reiserfs_lock_check_recursive() call
in the places that need it.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
|
|
i_xattr_sem depends on the reiserfs lock. But after we grab
i_xattr_sem, we may relax/relock the reiserfs lock while waiting
on a freezed filesystem, creating a dependency inversion between
the two locks.
In order to avoid the i_xattr_sem -> reiserfs lock dependency, let's
create a reiserfs_down_read_safe() that acts like
reiserfs_mutex_lock_safe(): relax the reiserfs lock while grabbing
another lock to avoid undesired dependencies induced by the
heivyweight reiserfs lock.
This fixes the following warning:
[ 990.005931] =======================================================
[ 990.012373] [ INFO: possible circular locking dependency detected ]
[ 990.013233] 2.6.33-rc1 #1
[ 990.013233] -------------------------------------------------------
[ 990.013233] dbench/1891 is trying to acquire lock:
[ 990.013233] (&REISERFS_SB(s)->lock){+.+.+.}, at: [<ffffffff81159505>] reiserfs_write_lock+0x35/0x50
[ 990.013233]
[ 990.013233] but task is already holding lock:
[ 990.013233] (&REISERFS_I(inode)->i_xattr_sem){+.+.+.}, at: [<ffffffff8115899a>] reiserfs_xattr_set_handle+0x8a/0x470
[ 990.013233]
[ 990.013233] which lock already depends on the new lock.
[ 990.013233]
[ 990.013233]
[ 990.013233] the existing dependency chain (in reverse order) is:
[ 990.013233]
[ 990.013233] -> #1 (&REISERFS_I(inode)->i_xattr_sem){+.+.+.}:
[ 990.013233] [<ffffffff81063afc>] __lock_acquire+0xf9c/0x1560
[ 990.013233] [<ffffffff8106414f>] lock_acquire+0x8f/0xb0
[ 990.013233] [<ffffffff814ac194>] down_write+0x44/0x80
[ 990.013233] [<ffffffff8115899a>] reiserfs_xattr_set_handle+0x8a/0x470
[ 990.013233] [<ffffffff81158e30>] reiserfs_xattr_set+0xb0/0x150
[ 990.013233] [<ffffffff8115a6aa>] user_set+0x8a/0x90
[ 990.013233] [<ffffffff8115901a>] reiserfs_setxattr+0xaa/0xb0
[ 990.013233] [<ffffffff810e2596>] __vfs_setxattr_noperm+0x36/0xa0
[ 990.013233] [<ffffffff810e26bc>] vfs_setxattr+0xbc/0xc0
[ 990.013233] [<ffffffff810e2780>] setxattr+0xc0/0x150
[ 990.013233] [<ffffffff810e289d>] sys_fsetxattr+0x8d/0xa0
[ 990.013233] [<ffffffff81002dab>] system_call_fastpath+0x16/0x1b
[ 990.013233]
[ 990.013233] -> #0 (&REISERFS_SB(s)->lock){+.+.+.}:
[ 990.013233] [<ffffffff81063e30>] __lock_acquire+0x12d0/0x1560
[ 990.013233] [<ffffffff8106414f>] lock_acquire+0x8f/0xb0
[ 990.013233] [<ffffffff814aba77>] __mutex_lock_common+0x47/0x3b0
[ 990.013233] [<ffffffff814abebe>] mutex_lock_nested+0x3e/0x50
[ 990.013233] [<ffffffff81159505>] reiserfs_write_lock+0x35/0x50
[ 990.013233] [<ffffffff811340e5>] reiserfs_prepare_write+0x45/0x180
[ 990.013233] [<ffffffff81158bb6>] reiserfs_xattr_set_handle+0x2a6/0x470
[ 990.013233] [<ffffffff81158e30>] reiserfs_xattr_set+0xb0/0x150
[ 990.013233] [<ffffffff8115a6aa>] user_set+0x8a/0x90
[ 990.013233] [<ffffffff8115901a>] reiserfs_setxattr+0xaa/0xb0
[ 990.013233] [<ffffffff810e2596>] __vfs_setxattr_noperm+0x36/0xa0
[ 990.013233] [<ffffffff810e26bc>] vfs_setxattr+0xbc/0xc0
[ 990.013233] [<ffffffff810e2780>] setxattr+0xc0/0x150
[ 990.013233] [<ffffffff810e289d>] sys_fsetxattr+0x8d/0xa0
[ 990.013233] [<ffffffff81002dab>] system_call_fastpath+0x16/0x1b
[ 990.013233]
[ 990.013233] other info that might help us debug this:
[ 990.013233]
[ 990.013233] 2 locks held by dbench/1891:
[ 990.013233] #0: (&sb->s_type->i_mutex_key#12){+.+.+.}, at: [<ffffffff810e2678>] vfs_setxattr+0x78/0xc0
[ 990.013233] #1: (&REISERFS_I(inode)->i_xattr_sem){+.+.+.}, at: [<ffffffff8115899a>] reiserfs_xattr_set_handle+0x8a/0x470
[ 990.013233]
[ 990.013233] stack backtrace:
[ 990.013233] Pid: 1891, comm: dbench Not tainted 2.6.33-rc1 #1
[ 990.013233] Call Trace:
[ 990.013233] [<ffffffff81061639>] print_circular_bug+0xe9/0xf0
[ 990.013233] [<ffffffff81063e30>] __lock_acquire+0x12d0/0x1560
[ 990.013233] [<ffffffff8115899a>] ? reiserfs_xattr_set_handle+0x8a/0x470
[ 990.013233] [<ffffffff8106414f>] lock_acquire+0x8f/0xb0
[ 990.013233] [<ffffffff81159505>] ? reiserfs_write_lock+0x35/0x50
[ 990.013233] [<ffffffff8115899a>] ? reiserfs_xattr_set_handle+0x8a/0x470
[ 990.013233] [<ffffffff814aba77>] __mutex_lock_common+0x47/0x3b0
[ 990.013233] [<ffffffff81159505>] ? reiserfs_write_lock+0x35/0x50
[ 990.013233] [<ffffffff81159505>] ? reiserfs_write_lock+0x35/0x50
[ 990.013233] [<ffffffff81062592>] ? mark_held_locks+0x72/0xa0
[ 990.013233] [<ffffffff814ab81d>] ? __mutex_unlock_slowpath+0xbd/0x140
[ 990.013233] [<ffffffff810628ad>] ? trace_hardirqs_on_caller+0x14d/0x1a0
[ 990.013233] [<ffffffff814abebe>] mutex_lock_nested+0x3e/0x50
[ 990.013233] [<ffffffff81159505>] reiserfs_write_lock+0x35/0x50
[ 990.013233] [<ffffffff811340e5>] reiserfs_prepare_write+0x45/0x180
[ 990.013233] [<ffffffff81158bb6>] reiserfs_xattr_set_handle+0x2a6/0x470
[ 990.013233] [<ffffffff81158e30>] reiserfs_xattr_set+0xb0/0x150
[ 990.013233] [<ffffffff814abcb4>] ? __mutex_lock_common+0x284/0x3b0
[ 990.013233] [<ffffffff8115a6aa>] user_set+0x8a/0x90
[ 990.013233] [<ffffffff8115901a>] reiserfs_setxattr+0xaa/0xb0
[ 990.013233] [<ffffffff810e2596>] __vfs_setxattr_noperm+0x36/0xa0
[ 990.013233] [<ffffffff810e26bc>] vfs_setxattr+0xbc/0xc0
[ 990.013233] [<ffffffff810e2780>] setxattr+0xc0/0x150
[ 990.013233] [<ffffffff81056018>] ? sched_clock_cpu+0xb8/0x100
[ 990.013233] [<ffffffff8105eded>] ? trace_hardirqs_off+0xd/0x10
[ 990.013233] [<ffffffff810560a3>] ? cpu_clock+0x43/0x50
[ 990.013233] [<ffffffff810c6820>] ? fget+0xb0/0x110
[ 990.013233] [<ffffffff810c6770>] ? fget+0x0/0x110
[ 990.013233] [<ffffffff81002ddc>] ? sysret_check+0x27/0x62
[ 990.013233] [<ffffffff810e289d>] sys_fsetxattr+0x8d/0xa0
[ 990.013233] [<ffffffff81002dab>] system_call_fastpath+0x16/0x1b
Reported-and-tested-by: Christian Kujau <lists@nerdbynature.de>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
|
|
Commit 500f5a0bf5f0624dae34307010e240ec090e4cde
(reiserfs: Fix possible recursive lock) fixed a vmalloc under reiserfs
lock that triggered a lockdep warning because of a
IN-FS-RECLAIM <-> RECLAIM-FS-ON locking dependency inversion.
But this patch has ommitted another vmalloc call in the same path
that allocates the journal. Relax the lock for this one too.
Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
|
|
The reiserfs lock -> inode mutex dependency gets inverted when we
relax the lock while walking to the tree.
To fix this, use a specialized version of reiserfs_mutex_lock_safe
that takes care of mutex subclasses. Then we can grab the inode
mutex with I_MUTEX_XATTR subclass without any reiserfs lock
dependency.
This fixes the following report:
[ INFO: possible circular locking dependency detected ]
2.6.32-06793-gf405425-dirty #2
-------------------------------------------------------
mv/18566 is trying to acquire lock:
(&REISERFS_SB(s)->lock){+.+.+.}, at: [<c1110708>] reiserfs_write_lock+0x28=
/0x40
but task is already holding lock:
(&sb->s_type->i_mutex_key#5/3){+.+.+.}, at: [<c111033c>]
reiserfs_for_each_xattr+0x10c/0x380
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&sb->s_type->i_mutex_key#5/3){+.+.+.}:
[<c104f723>] validate_chain+0xa23/0xf70
[<c1050155>] __lock_acquire+0x4e5/0xa70
[<c105075a>] lock_acquire+0x7a/0xa0
[<c134c76f>] mutex_lock_nested+0x5f/0x2b0
[<c11102b4>] reiserfs_for_each_xattr+0x84/0x380
[<c1110615>] reiserfs_delete_xattrs+0x15/0x50
[<c10ef57f>] reiserfs_delete_inode+0x8f/0x140
[<c10a565c>] generic_delete_inode+0x9c/0x150
[<c10a574d>] generic_drop_inode+0x3d/0x60
[<c10a4667>] iput+0x47/0x50
[<c109cc0b>] do_unlinkat+0xdb/0x160
[<c109cca0>] sys_unlink+0x10/0x20
[<c1002c50>] sysenter_do_call+0x12/0x36
-> #0 (&REISERFS_SB(s)->lock){+.+.+.}:
[<c104fc68>] validate_chain+0xf68/0xf70
[<c1050155>] __lock_acquire+0x4e5/0xa70
[<c105075a>] lock_acquire+0x7a/0xa0
[<c134c76f>] mutex_lock_nested+0x5f/0x2b0
[<c1110708>] reiserfs_write_lock+0x28/0x40
[<c1103d6b>] search_by_key+0x1f7b/0x21b0
[<c10e73ef>] search_by_entry_key+0x1f/0x3b0
[<c10e77f7>] reiserfs_find_entry+0x77/0x400
[<c10e81e5>] reiserfs_lookup+0x85/0x130
[<c109a144>] __lookup_hash+0xb4/0x110
[<c109b763>] lookup_one_len+0xb3/0x100
[<c1110350>] reiserfs_for_each_xattr+0x120/0x380
[<c1110615>] reiserfs_delete_xattrs+0x15/0x50
[<c10ef57f>] reiserfs_delete_inode+0x8f/0x140
[<c10a565c>] generic_delete_inode+0x9c/0x150
[<c10a574d>] generic_drop_inode+0x3d/0x60
[<c10a4667>] iput+0x47/0x50
[<c10a1c4f>] dentry_iput+0x6f/0xf0
[<c10a1d74>] d_kill+0x24/0x50
[<c10a396b>] dput+0x5b/0x120
[<c109ca89>] sys_renameat+0x1b9/0x230
[<c109cb28>] sys_rename+0x28/0x30
[<c1002c50>] sysenter_do_call+0x12/0x36
other info that might help us debug this:
2 locks held by mv/18566:
#0: (&sb->s_type->i_mutex_key#5/1){+.+.+.}, at: [<c109b6ac>]
lock_rename+0xcc/0xd0
#1: (&sb->s_type->i_mutex_key#5/3){+.+.+.}, at: [<c111033c>]
reiserfs_for_each_xattr+0x10c/0x380
stack backtrace:
Pid: 18566, comm: mv Tainted: G C 2.6.32-06793-gf405425-dirty #2
Call Trace:
[<c134b252>] ? printk+0x18/0x1e
[<c104e790>] print_circular_bug+0xc0/0xd0
[<c104fc68>] validate_chain+0xf68/0xf70
[<c104c8cb>] ? trace_hardirqs_off+0xb/0x10
[<c1050155>] __lock_acquire+0x4e5/0xa70
[<c105075a>] lock_acquire+0x7a/0xa0
[<c1110708>] ? reiserfs_write_lock+0x28/0x40
[<c134c76f>] mutex_lock_nested+0x5f/0x2b0
[<c1110708>] ? reiserfs_write_lock+0x28/0x40
[<c1110708>] ? reiserfs_write_lock+0x28/0x40
[<c134b60a>] ? schedule+0x27a/0x440
[<c1110708>] reiserfs_write_lock+0x28/0x40
[<c1103d6b>] search_by_key+0x1f7b/0x21b0
[<c1050176>] ? __lock_acquire+0x506/0xa70
[<c1051267>] ? lock_release_non_nested+0x1e7/0x340
[<c1110708>] ? reiserfs_write_lock+0x28/0x40
[<c104e354>] ? trace_hardirqs_on_caller+0x124/0x170
[<c104e3ab>] ? trace_hardirqs_on+0xb/0x10
[<c1042a55>] ? T.316+0x15/0x1a0
[<c1042d2d>] ? sched_clock_cpu+0x9d/0x100
[<c10e73ef>] search_by_entry_key+0x1f/0x3b0
[<c134bf2a>] ? __mutex_unlock_slowpath+0x9a/0x120
[<c104e354>] ? trace_hardirqs_on_caller+0x124/0x170
[<c10e77f7>] reiserfs_find_entry+0x77/0x400
[<c10e81e5>] reiserfs_lookup+0x85/0x130
[<c1042d2d>] ? sched_clock_cpu+0x9d/0x100
[<c109a144>] __lookup_hash+0xb4/0x110
[<c109b763>] lookup_one_len+0xb3/0x100
[<c1110350>] reiserfs_for_each_xattr+0x120/0x380
[<c110ffe0>] ? delete_one_xattr+0x0/0x1c0
[<c1003342>] ? math_error+0x22/0x150
[<c1110708>] ? reiserfs_write_lock+0x28/0x40
[<c1110615>] reiserfs_delete_xattrs+0x15/0x50
[<c1110708>] ? reiserfs_write_lock+0x28/0x40
[<c10ef57f>] reiserfs_delete_inode+0x8f/0x140
[<c10a561f>] ? generic_delete_inode+0x5f/0x150
[<c10ef4f0>] ? reiserfs_delete_inode+0x0/0x140
[<c10a565c>] generic_delete_inode+0x9c/0x150
[<c10a574d>] generic_drop_inode+0x3d/0x60
[<c10a4667>] iput+0x47/0x50
[<c10a1c4f>] dentry_iput+0x6f/0xf0
[<c10a1d74>] d_kill+0x24/0x50
[<c10a396b>] dput+0x5b/0x120
[<c109ca89>] sys_renameat+0x1b9/0x230
[<c1042d2d>] ? sched_clock_cpu+0x9d/0x100
[<c104c8cb>] ? trace_hardirqs_off+0xb/0x10
[<c1042dde>] ? cpu_clock+0x4e/0x60
[<c1350825>] ? do_page_fault+0x155/0x370
[<c1041816>] ? up_read+0x16/0x30
[<c1350825>] ? do_page_fault+0x155/0x370
[<c109cb28>] sys_rename+0x28/0x30
[<c1002c50>] sysenter_do_call+0x12/0x36
Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
|
|
When we were using the bkl, we didn't care about dependencies against
other locks, but the mutex conversion created new ones, which is why
we have reiserfs_mutex_lock_safe(), which unlocks the reiserfs lock
before acquiring another mutex.
But this trick actually fails if we have acquired the reiserfs lock
recursively, as we try to unlock it to acquire the new mutex without
inverted dependency, but we eventually only decrease its depth.
This happens in the case of a nested inode creation/deletion.
Say we have no space left on the device, we create an inode
and tak the lock but fail to create its entry, then we release the
inode using iput(), which calls reiserfs_delete_inode() that takes
the reiserfs lock recursively. The path eventually ends up in
journal_begin() where we try to take the journal safely but we
fail because of the reiserfs lock recursion:
[ INFO: possible circular locking dependency detected ]
2.6.32-06486-g053fe57 #2
-------------------------------------------------------
vi/23454 is trying to acquire lock:
(&journal->j_mutex){+.+...}, at: [<c110dac4>] do_journal_begin_r+0x64/0x2f0
but task is already holding lock:
(&REISERFS_SB(s)->lock){+.+.+.}, at: [<c11106a8>] reiserfs_write_lock+0x28/0x40
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&REISERFS_SB(s)->lock){+.+.+.}:
[<c104f8f3>] validate_chain+0xa23/0xf70
[<c1050325>] __lock_acquire+0x4e5/0xa70
[<c105092a>] lock_acquire+0x7a/0xa0
[<c134c78f>] mutex_lock_nested+0x5f/0x2b0
[<c11106a8>] reiserfs_write_lock+0x28/0x40
[<c110dacb>] do_journal_begin_r+0x6b/0x2f0
[<c110ddcf>] journal_begin+0x7f/0x120
[<c10f76c2>] reiserfs_remount+0x212/0x4d0
[<c1093997>] do_remount_sb+0x67/0x140
[<c10a9ca6>] do_mount+0x436/0x6b0
[<c10a9f86>] sys_mount+0x66/0xa0
[<c1002c50>] sysenter_do_call+0x12/0x36
-> #0 (&journal->j_mutex){+.+...}:
[<c104fe38>] validate_chain+0xf68/0xf70
[<c1050325>] __lock_acquire+0x4e5/0xa70
[<c105092a>] lock_acquire+0x7a/0xa0
[<c134c78f>] mutex_lock_nested+0x5f/0x2b0
[<c110dac4>] do_journal_begin_r+0x64/0x2f0
[<c110ddcf>] journal_begin+0x7f/0x120
[<c10ef52f>] reiserfs_delete_inode+0x9f/0x140
[<c10a55fc>] generic_delete_inode+0x9c/0x150
[<c10a56ed>] generic_drop_inode+0x3d/0x60
[<c10a4607>] iput+0x47/0x50
[<c10e915c>] reiserfs_create+0x16c/0x1c0
[<c109a9c1>] vfs_create+0xc1/0x130
[<c109dbec>] do_filp_open+0x81c/0x920
[<c109004f>] do_sys_open+0x4f/0x110
[<c1090179>] sys_open+0x29/0x40
[<c1002c50>] sysenter_do_call+0x12/0x36
other info that might help us debug this:
2 locks held by vi/23454:
#0: (&sb->s_type->i_mutex_key#5){+.+.+.}, at: [<c109d64e>]
do_filp_open+0x27e/0x920
#1: (&REISERFS_SB(s)->lock){+.+.+.}, at: [<c11106a8>]
reiserfs_write_lock+0x28/0x40
stack backtrace:
Pid: 23454, comm: vi Not tainted 2.6.32-06486-g053fe57 #2
Call Trace:
[<c134b202>] ? printk+0x18/0x1e
[<c104e960>] print_circular_bug+0xc0/0xd0
[<c104fe38>] validate_chain+0xf68/0xf70
[<c104ca9b>] ? trace_hardirqs_off+0xb/0x10
[<c1050325>] __lock_acquire+0x4e5/0xa70
[<c105092a>] lock_acquire+0x7a/0xa0
[<c110dac4>] ? do_journal_begin_r+0x64/0x2f0
[<c134c78f>] mutex_lock_nested+0x5f/0x2b0
[<c110dac4>] ? do_journal_begin_r+0x64/0x2f0
[<c110dac4>] ? do_journal_begin_r+0x64/0x2f0
[<c110ff80>] ? delete_one_xattr+0x0/0x1c0
[<c110dac4>] do_journal_begin_r+0x64/0x2f0
[<c110ddcf>] journal_begin+0x7f/0x120
[<c11105b5>] ? reiserfs_delete_xattrs+0x15/0x50
[<c10ef52f>] reiserfs_delete_inode+0x9f/0x140
[<c10a55bf>] ? generic_delete_inode+0x5f/0x150
[<c10ef490>] ? reiserfs_delete_inode+0x0/0x140
[<c10a55fc>] generic_delete_inode+0x9c/0x150
[<c10a56ed>] generic_drop_inode+0x3d/0x60
[<c10a4607>] iput+0x47/0x50
[<c10e915c>] reiserfs_create+0x16c/0x1c0
[<c1099a5d>] ? inode_permission+0x7d/0xa0
[<c109a9c1>] vfs_create+0xc1/0x130
[<c10e8ff0>] ? reiserfs_create+0x0/0x1c0
[<c109dbec>] do_filp_open+0x81c/0x920
[<c104ca9b>] ? trace_hardirqs_off+0xb/0x10
[<c134dc0d>] ? _spin_unlock+0x1d/0x20
[<c10a6eea>] ? alloc_fd+0xba/0xf0
[<c109004f>] do_sys_open+0x4f/0x110
[<c1090179>] sys_open+0x29/0x40
[<c1002c50>] sysenter_do_call+0x12/0x36
To fix this, use reiserfs_lock_once() from reiserfs_delete_inode()
which prevents from adding reiserfs lock recursion.
Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
|
|
While allocating the bitmap using vmalloc, we hold the reiserfs lock,
which makes lockdep later reporting a possible deadlock as we may
swap out pages to allocate memory and then take the reiserfs lock
recursively:
inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage.
kswapd0/312 [HC0[0]:SC0[0]:HE1:SE1] takes:
(&REISERFS_SB(s)->lock){+.+.?.}, at: [<c11108a8>] reiserfs_write_lock+0x28/0x40
{RECLAIM_FS-ON-W} state was registered at:
[<c104e1c2>] mark_held_locks+0x62/0x90
[<c104e28a>] lockdep_trace_alloc+0x9a/0xc0
[<c108e396>] kmem_cache_alloc+0x26/0xf0
[<c10850ec>] __get_vm_area_node+0x6c/0xf0
[<c10857de>] __vmalloc_node+0x7e/0xa0
[<c108597b>] vmalloc+0x2b/0x30
[<c10e00b9>] reiserfs_init_bitmap_cache+0x39/0x70
[<c10f8178>] reiserfs_fill_super+0x2e8/0xb90
[<c1094345>] get_sb_bdev+0x145/0x180
[<c10f5a11>] get_super_block+0x21/0x30
[<c10931f0>] vfs_kern_mount+0x40/0xd0
[<c10932d9>] do_kern_mount+0x39/0xd0
[<c10a9857>] do_mount+0x2c7/0x6b0
[<c10a9ca6>] sys_mount+0x66/0xa0
[<c161589b>] mount_block_root+0xc4/0x245
[<c1615a75>] mount_root+0x59/0x5f
[<c1615b8c>] prepare_namespace+0x111/0x14b
[<c1615269>] kernel_init+0xcf/0xdb
[<c10031fb>] kernel_thread_helper+0x7/0x1c
This is actually fine for two reasons: we call vmalloc at mount time
then it's not in the swapping out path. Also the reiserfs lock can be
acquired recursively, but since its implementation depends on a mutex,
it's hard and not necessary worth it to teach that to lockdep.
The lock is useless at mount time anyway, at least until we replay the
journal. But let's remove it from this path later as this needs
more thinking and is a sensible change.
For now we can just relax the lock around vmalloc,
Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
|
|
Merge-reason: The tree was based 2.6.31. It's better to be up to date
with 2.6.32. Although no conflicting changes were made in between,
it gives benchmarking results closer to the lastest kernel behaviour.
|
|
|
|
request_region should be used with release_region, not request_mem_region.
Geert Uytterhoeven pointed out that in the case of drivers/video/gbefb.c,
the problem is actually the other way around; request_mem_region should be
used instead of request_region.
The semantic patch that finds/fixes this problem is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@r1@
expression start;
@@
request_region(start,...)
@b1@
expression r1.start;
@@
request_mem_region(start,...)
@depends on !b1@
expression r1.start;
expression E;
@@
- release_mem_region
+ release_region
(start,E)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
|
|
TXx9 SPI bit rate is calculated by:
fBR = (spi-baseclk) / (n + 1)
Fix calculation of min_speed_hz, max_speed_hz and n.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/sameo/mfd-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sameo/mfd-2.6:
mfd: Correct WM831X_MAX_ISEL_VALUE
|
|
These laptops often leave i8042 in a wierd state resulting in non-
operational touchpad and keyboard.
Signed-off-by: Anisse Astier <anisse@astier.eu>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
* 'for-linus' of git://neil.brown.name/md:
md: revert incorrect fix for read error handling in raid1.
|
|
Jon confirms that recent modprobe will look in /proc/cmdline, so these
cmdline options can still be used.
See http://bugzilla.kernel.org/show_bug.cgi?id=14164
Reported-by: Adam Williamson <awilliam@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus:
MIPS: RB532: Fix devices.c compilation.
MIPS: Fix MIPS I build.
|
|
* git://git.kernel.org/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog:
[PATCH] rc32434_wdt: fix compilation failure
[WATCHDOG] rc32434_wdt.c: use resource_size()
|
|
On the parisc architecture we face for each and every loaded kernel module
this kernel "badness warning":
sysfs: cannot create duplicate filename '/module/ac97_bus/sections/.text'
Badness at fs/sysfs/dir.c:487
Reason for that is, that on parisc all kernel modules do have multiple
.text sections due to the usage of the -ffunction-sections compiler flag
which is needed to reach all jump targets on this platform.
An objdump on such a kernel module gives:
Sections:
Idx Name Size VMA LMA File off Algn
0 .note.gnu.build-id 00000024 00000000 00000000 00000034 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
1 .text 00000000 00000000 00000000 00000058 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
2 .text.ac97_bus_match 0000001c 00000000 00000000 00000058 2**2
CONTENTS, ALLOC, LOAD, READONLY, CODE
3 .text 00000000 00000000 00000000 000000d4 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
...
Since the .text sections are empty (size of 0 bytes) and won't be
loaded by the kernel module loader anyway, I don't see a reason
why such sections need to be listed under
/sys/module/<module_name>/sections/<section_name> either.
The attached patch does solve this issue by not exporting section
names which are empty.
This fixes bugzilla http://bugzilla.kernel.org/show_bug.cgi?id=14703
Signed-off-by: Helge Deller <deller@gmx.de>
CC: rusty@rustcorp.com.au
CC: akpm@linux-foundation.org
CC: James.Bottomley@HansenPartnership.com
CC: roland@redhat.com
CC: dave@hiauly1.hia.nrc.ca
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/lrg/voltage-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lrg/voltage-2.6:
regulator: Initialise wm831x structure pointor for ISINK driver
|
|
The version that made it into mainline missed the initialisation of the
chip handle.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
|
|
We should now use dev_set_drvdata to set the driver driver_data field.
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/747/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
|
|
Broken by d63c63e889bbeeaa461a8addf1245f89f3ce4ece (lmo) rsp.
f1e39a4a616cd9981a9decfd5332fd07a01abb8b (kernel.org).
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Patchwork: http://patchwork.linux-mips.org/patch/746/
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/ycmiao/pxa-linux-2.6
* 'fix' of git://git.kernel.org/pub/scm/linux/kernel/git/ycmiao/pxa-linux-2.6:
[ARM] pxamci: call mmc_remove_host() before freeing resources
|
|
mmc_remove_host() will cause the mmc core to switch off the bus power by
eventually calling pxamci_set_ios(). This function uses the regulator or
the GPIO which have been freed already.
This causes the following Oops on module unload.
[ 49.519649] Unable to handle kernel paging request at virtual address 30303a70
[ 49.526878] pgd = c7084000
[ 49.529563] [30303a70] *pgd=00000000
[ 49.533136] Internal error: Oops: 5 [#1]
[ 49.537025] last sysfs file: /sys/devices/platform/pxa27x-ohci/usb1/1-1/1-1:1.0/host0/target0:0:0/0:0:0:0/scsi_level
[ 49.547471] Modules linked in: pxamci(-) eeti_ts
[ 49.552061] CPU: 0 Not tainted (2.6.32-rc8 #322)
[ 49.557001] PC is at regulator_is_enabled+0x3c/0xbc
[ 49.561846] LR is at regulator_is_enabled+0x30/0xbc
[ 49.566691] pc : [<c01a2448>] lr : [<c01a243c>] psr: 60000013
[ 49.566702] sp : c7083e70 ip : 30303a30 fp : 00000000
[ 49.578093] r10: c705e200 r9 : c7082000 r8 : c705e2e0
[ 49.583280] r7 : c7061340 r6 : c7061340 r5 : c7083e70 r4 : 00000000
[ 49.589759] r3 : c04dc434 r2 : c04dc434 r1 : c03eecea r0 : 00000047
[ 49.596241] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
[ 49.603329] Control: 0000397f Table: a7084018 DAC: 00000015
[ 49.609031] Process rmmod (pid: 1101, stack limit = 0xc7082278)
[ 49.614908] Stack: (0xc7083e70 to 0xc7084000)
[ 49.619238] 3e60: c7082000 c703c4f8 c705ea00 c04f4074
[ 49.627366] 3e80: 00000000 c705e3a0 ffffffff c0247ddc c70361a0 00000000 c705e3a0 ffffffff
[ 49.635499] 3ea0: c705e200 bf006400 c78c4f00 c705e200 c705e3a0 ffffffff c705e200 ffffffff
[ 49.643633] 3ec0: c04d8ac8 c02476d0 ffffffff c0247c60 c705e200 c0248678 c705e200 c0249064
[ 49.651765] 3ee0: ffffffff bf006204 c04d8ad0 c04d8ad0 c04d8ac8 bf007490 00000880 c00440c4
[ 49.659898] 3f00: 0000b748 c01c5708 bf007490 c01c44c8 c04d8ac8 c04d8afc bf007490 c01c4570
[ 49.668031] 3f20: bf007490 bf00750c c04f4258 c01c37a4 00000000 bf00750c c7083f44 c007b014
[ 49.676162] 3f40: 4000d000 6d617870 08006963 00000001 00000000 c7085000 00000001 00000000
[ 49.684287] 3f60: 4000d000 c7083f8c 00000001 bea01a54 00005401 c7ab1400 c00440c4 00082000
[ 49.692420] 3f80: bf00750c 00000880 c7083f8c 00000000 4000cfa8 00000000 00000880 bea01cc8
[ 49.700552] 3fa0: 00000081 c0043f40 00000000 00000880 bea01cc8 00000880 00000006 00000000
[ 49.708677] 3fc0: 00000000 00000880 bea01cc8 00000081 00000097 0000cca4 0000b748 00000000
[ 49.716802] 3fe0: 4001a4f0 bea01cc0 00018bf4 4001a4fc 20000010 bea01cc8 a063e021 a063e421
[ 49.724958] [<c01a2448>] (regulator_is_enabled+0x3c/0xbc) from [<c0247ddc>] (mmc_regulator_set_ocr+0x14/0xd8)
[ 49.734836] [<c0247ddc>] (mmc_regulator_set_ocr+0x14/0xd8) from [<bf006400>] (pxamci_set_ios+0xd8/0x17c [pxamci])
[ 49.745044] [<bf006400>] (pxamci_set_ios+0xd8/0x17c [pxamci]) from [<c02476d0>] (mmc_power_off+0x50/0x58)
[ 49.754555] [<c02476d0>] (mmc_power_off+0x50/0x58) from [<c0247c60>] (mmc_detach_bus+0x68/0xc4)
[ 49.763207] [<c0247c60>] (mmc_detach_bus+0x68/0xc4) from [<c0248678>] (mmc_stop_host+0xd4/0x1bc)
[ 49.771944] [<c0248678>] (mmc_stop_host+0xd4/0x1bc) from [<c0249064>] (mmc_remove_host+0xc/0x20)
[ 49.780681] [<c0249064>] (mmc_remove_host+0xc/0x20) from [<bf006204>] (pxamci_remove+0xc8/0x174 [pxamci])
[ 49.790211] [<bf006204>] (pxamci_remove+0xc8/0x174 [pxamci]) from [<c01c5708>] (platform_drv_remove+0x1c/0x24)
[ 49.800164] [<c01c5708>] (platform_drv_remove+0x1c/0x24) from [<c01c44c8>] (__device_release_driver+0x7c/0xc4)
[ 49.810110] [<c01c44c8>] (__device_release_driver+0x7c/0xc4) from [<c01c4570>] (driver_detach+0x60/0x8c)
[ 49.819535] [<c01c4570>] (driver_detach+0x60/0x8c) from [<c01c37a4>] (bus_remove_driver+0x90/0xcc)
[ 49.828452] [<c01c37a4>] (bus_remove_driver+0x90/0xcc) from [<c007b014>] (sys_delete_module+0x1d8/0x254)
[ 49.837891] [<c007b014>] (sys_delete_module+0x1d8/0x254) from [<c0043f40>] (ret_fast_syscall+0x0/0x28)
[ 49.847145] Code: eb06c53a e596c030 e1a0500d e59f106c (e59c0040)
[ 49.853566] ---[ end trace b5fa66a00cea142f ]---
Signed-off-by: Daniel Mack <daniel@caiaq.de>
Reported-by: Sven Neumann <s.neumann@raumfeld.com>
Cc: Pierre Ossman <pierre@ossman.eu>
Cc: linux-mmc@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: stable@kernel.org
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
|
|
This patch fixes the compilation failure of
rc32434 due to a bad module parameter description.
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
|
|
The size value passed to ioremap_nocache() is not correct.
Use resource_size() to get the correct value.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Phil Sutter <n0-1@freewrt.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
|
|
The SYSFS_DEPRECATED_V2 says "remove" older, deprecated features, but it
actually enables them, so correct this confusing, backwards text.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
When detecting power failure, the probe function would reset the clock
time to defined state.
However, the clock's _date_ might still be bogus and a subsequent probe
fails when sanity-checking these values.
Change the power-failure fixup code to do a full setting of rtc_time,
including a valid date.
Signed-off-by: Johannes Weiner <jw@emlix.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Paul Gortmaker <p_gortmaker@yahoo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
The possible CCR_Y2K register values are 19 or 20 and struct rtc_time's
tm_year is in years since 1900.
The function translating rtc_time to register values assumes tm_year to be
years since first christmas, though, and we end up storing 0 or 1 in the
CCR_Y2K register, which the hardware does not refuse to do.
A subsequent probing of the clock fails due to the invalid value range in
the register, though.
[ And if it didn't, reading the clock would yield a bogus year because
the function translating registers to tm_year is assuming a register
value of 19 or 20. ]
This fixes the conversion from years since 1900 in tm_year to the
corresponding CCR_Y2K value of 19 or 20.
Signed-off-by: Johannes Weiner <jw@emlix.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Paul Gortmaker <p_gortmaker@yahoo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Prevent the AoE block driver from creating cache aliases of page cache
pages on machines with virtually indexed caches.
Building kernels on an AT91SAM9G20 board without this patch fails with
segmentation faults after a couple of passes.
Signed-off-by: Peter Horton <zero@colonel-panic.org>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
- Remove wrong and unnecessary unmask operation
- Remove extra GEDR reading
This fixes the loss of interrupts which occurs when two or more pins are
triggered in close succession.
Signed-off-by: Alek Du <alek.du@intel.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
It has been fun but the last year or more it has been a duty and a burden.
So I leave it open for others to take over.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Anibal Monsalve Salazar <anibal@debian.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Michal Marek <mmarek@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Following issues have been addressed on DA8XX/OMAP-L1XX:
a. Screen misalignment during booting when frame buffer console is
enabled.
b. Driver was configured always in PSEUDOCOLOR mode. This patch
dynamically configures the driver either in PSEUDOCOLOUR or TRUECOLOR
mode depending on bpp.
c. The RED and BLUE offsets were interchanged resulting in wrong
bootup logo colour.
This patch has been tested on DA830/OMAP-L137 and DA850/OMAP-L138 EVMs.
Signed-off-by: Sudhakar Rajashekhara <sudhakar.raj@ti.com>
Cc: Steve Chen <schen@mvista.com>
Cc: Pavel Kiryukhin <pkiryukhin@ru.mvista.com>
Cc: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
"rtc" is freed and then dereferenced on the next line. This patch fixes
that.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Cc: Paul Gortmaker <p_gortmaker@yahoo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Fixes:
v4l/dvb_frontend.c: In function 'dvb_frontend_stop':
v4l/dvb_frontend.c:707: error: implicit declaration of function 'init_MUTEX'
Addresses http://bugzilla.kernel.org/show_bug.cgi?id=14609
Reported-by: <tstrelar@gmail.com>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging-2.6:
Staging: update TODO files
Staging: hv: Fix some missing author names
Staging: hv: Fix vmbus event handler bug
Staging: hv: Fix argument order in incorrect memset invocations in hyperv driver.
|
|
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6:
USB: Add support for Mobilcom Debitel USB UMTS Surf-Stick to option driver
USB: work around for EHCI with quirky periodic schedules
USB: musb: Fix CPPI IRQs not being signaled
USB: musb: respect usb_request->zero in control requests
USB: musb: fix ISOC Tx programming for CPPI DMAs
USB: musb: Remove unwanted message in boot log
usb: amd5536udc: fixed shared interrupt bug and warning oops
USB: ftdi_sio: Keep going when write errors are encountered.
USB: musb_gadget: fix STALL handling
USB: EHCI: don't send Clear-TT-Buffer following a STALL
|
|
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6:
tty/of_serial: add missing ns16550a id
bcm63xx_uart: Fix serial driver compile breakage.
tty_port: handle the nonblocking open of a dead port corner case
|
|
* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus:
MIPS: Loongson: Switch from flatmem to sparsemem
MIPS: Loongson: Disallow 4kB pages
MIPS: Add missing definition for MADV_HWPOISON.
MIPS: Fix build error if __xchg() is not getting inlined.
MIPS: IP22/IP28 Disable early printk to fix boot problems on some systems.
|
|
With flatmem hibernation for Loongson will fail, and there are also some
other problems such as broken files when using NFS or CIFS / Samba.
The config help of sparsemem says:
"This option provides some potential performance benefits, along with
decreased code complexity."
So to avoid the potential problems of FLATMEM, we disable FLATMEM directly
and use SPARSEMEM instead.
Related email thread:
http://groups.google.com/group/loongson-dev/browse_thread/thread/b6b65890ec2b0f24/feb43e5aa7f55d9b?show_docid=feb43e5aa7f55d9b
Reported-by: Tatu Kilappa <tatu.kilappa@gmail.com>
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Patchwork: http://patchwork.linux-mips.org/patch/737/
Cc: linux-mips@linux-mips.org
Cc: zhangfx@lemote.com
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
|
|
Currently, with PAGE_SIZE_4KB, the kernel for loongson will hang on:
Kernel panic - not syncing: Attempted to kill init!
The possible reason is the cache aliases problem:
Loongson 2F has 64kb, 4 way L1 Cache, the way size is 16kb, which is bigger
then 4kb. so, If using 4kb page size, there is cache aliases problem.
To avoid this kind of problem, extra cache flushing. The 2nd possible
solution is 16kb page size which avoids cache aliases without the need for
extra cache flushes. So we disable 4kB pages until the aliasing issue is
solved.
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Patchwork: http://patchwork.linux-mips.org/patch/736/
Cc: linux-mips@linux-mips.org
Cc: zhangfx@lemote.com
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
|
|
Thanks to Joseph S. Myers for reporting this.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: "Joseph S. Myers" <joseph@codesourcery.com>
Patchwork: http://patchwork.linux-mips.org/patch/723/
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If __xchg() is not getting inlined the outline version of the function
will have a reference to __xchg_called_with_bad_pointer() which does not
exist remaining. Fixed by using BUILD_BUG_ON() to check for allowable
operand sizes.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Patchwork: http://patchwork.linux-mips.org/patch/705/
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Some Debian users have reported that the kernel hangs early during boot on
some IP22 systems. Thomas Bogendoerfer found that this is due to a "bad
interaction between CONFIG_EARLY_PRINTK and overwritten prom memory during
early boot". Since there's no fix yet, disable CONFIG_EARLY_PRINTK for now.
Signed-off-by: Martin Michlmayr <tbm@cyrius.com>
Cc: linux-mips@linux-mips.org
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Dmitri Vorobiev <dmitri.vorobiev@gmail.com>
Patchwork: http://patchwork.linux-mips.org/patch/702/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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Move slow_work's debugging proc file to debugfs.
Signed-off-by: David Howells <dhowells@redhat.com>
Requested-and-acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/mattst88/alpha-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mattst88/alpha-2.6:
alpha: Fixup last users of irq_chip->typename
Alpha: Rearrange thread info flags fixing two regressions
arch/alpha/kernel: Add kmalloc NULL tests
arch/alpha/kernel/sys_ruffian.c: Use DIV_ROUND_CLOSEST
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When IMA is active, using dentry_open without updating the
IMA counters will result in free/open imbalance errors when
fput is eventually called.
Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Frederic Weisbecker
Linus Torvalds
Julia Lawall
Atsushi Nemoto
Anisse Astier
Rusty Russell
Helge Deller
Mark Brown
Florian Fainelli
Ralf Baechle
Daniel Mack
H Hartley Sweeten
Randy Dunlap
Johannes Weiner
Peter Horton
Alek Du
Sam Ravnborg
Sudhakar Rajashekhara
Dan Carpenter
Andrew Morton
Wu Zhangjin
Martin Michlmayr
David Howells
Marc Dionne