On 07/24/2014 05:45 PM, Borislav Petkov wrote:
On Thu, Jul 24, 2014 at 04:38:28PM -0400, Waiman Long wrote:
Borislav, can you apply the following patch on top of the lockdep
patch to see if it can fix the problem?
It is too late here for me to test anything but the ingridients to
reproduce are nothing special. Just grab a kvm guest and pick out the
locking or so options out of the .config I sent previously. Then boot it
a couple of times, it triggers pretty easy after a couple of tries.
Thank for the reply.
I was not able to reproduce the read_lock lockdep problem that you see
in your test machine. However, I saw the following lockdep warning on a
mutex when I enabled CONFIG_PROVE_LOCKING=y and CONFIG_LOCKDEP=y. My
virtual machine is based on RHEL 7 beta with xfs filesystem, and the
error happens for both plain 3.16-rc6 and tip/master+3.16-rc6.
[ 7.821723] ======================================================
[ 7.821725] [ INFO: possible circular locking dependency detected ]
[ 7.821727] 3.16.0-rc6 #4 Not tainted
[ 7.821727] -------------------------------------------------------
[ 7.821728] kworker/3:1/276 is trying to acquire lock:
[ 7.821747] (&qdev->release_mutex){+.+.+.}, at: [<ffffffffa0151a2c>]
qxl_alloc_release_reserved+0x6c/0x200 [qxl]
[ 7.821749]
[ 7.821749] but task is already holding lock:
[ 7.821763] (&fbdefio->lock){+.+.+.}, at: [<ffffffff8135ea65>]
fb_deferred_io_work+0x35/0xd0
[ 7.821765]
[ 7.821765] which lock already depends on the new lock.
[ 7.821765]
[ 7.821766]
[ 7.821766] the existing dependency chain (in reverse order) is:
[ 7.821770]
[ 7.821770] -> #4 (&fbdefio->lock){+.+.+.}:
[ 7.821781] [<ffffffff810b2078>] __lock_acquire+0x3a8/0xc40
[ 7.821785] [<ffffffff810b29c0>] lock_acquire+0xb0/0x140
[ 7.821793] [<ffffffff81636add>] mutex_lock_nested+0x5d/0x4d0
[ 7.821796] [<ffffffff8135e866>] fb_deferred_io_mkwrite+0x46/0x120
[ 7.821803] [<ffffffff8118534d>] do_page_mkwrite+0x3d/0x70
[ 7.821807] [<ffffffff81188376>]
do_shared_fault.isra.52+0x66/0x1d0
[ 7.821811] [<ffffffff81189524>] handle_mm_fault+0x474/0x1080
[ 7.821819] [<ffffffff81048ea1>] __do_page_fault+0x191/0x530
[ 7.821822] [<ffffffff810492f1>] trace_do_page_fault+0x41/0x100
[ 7.821828] [<ffffffff81043569>] do_async_page_fault+0x29/0xe0
[ 7.821834] [<ffffffff8163d608>] async_page_fault+0x28/0x30
[ 7.821841]
[ 7.821841] -> #3 (&mm->mmap_sem){++++++}:
[ 7.821844] [<ffffffff810b2078>] __lock_acquire+0x3a8/0xc40
[ 7.821846] [<ffffffff810b29c0>] lock_acquire+0xb0/0x140
[ 7.821849] [<ffffffff81185220>] might_fault+0x70/0xa0
[ 7.821858] [<ffffffff811e4ad1>] filldir+0x91/0x120
[ 7.821904] [<ffffffffa018253e>]
xfs_dir2_block_getdents.isra.12+0x1ae/0x200 [xfs]
[ 7.821916] [<ffffffffa01826f9>] xfs_readdir+0x109/0x150 [xfs]
[ 7.821928] [<ffffffffa018436b>] xfs_file_readdir+0x2b/0x40 [xfs]
[ 7.821931] [<ffffffff811e48be>] iterate_dir+0xae/0x140
[ 7.821933] [<ffffffff811e4dba>] SyS_getdents+0x8a/0x120
[ 7.821935] [<ffffffff8163b6e9>] system_call_fastpath+0x16/0x1b
[ 7.821937]
[ 7.821937] -> #2 (&xfs_dir_ilock_class){++++.+}:
[ 7.821940] [<ffffffff810b2078>] __lock_acquire+0x3a8/0xc40
[ 7.821942] [<ffffffff810b29c0>] lock_acquire+0xb0/0x140
[ 7.821945] [<ffffffff810abd74>] down_read_nested+0x44/0x90
[ 7.821965] [<ffffffffa01c8d82>] xfs_ilock+0xd2/0x100 [xfs]
[ 7.821982] [<ffffffffa01c8e24>]
xfs_ilock_attr_map_shared+0x34/0x40 [xfs]
[ 7.821997] [<ffffffffa019e5a7>] xfs_attr_get+0xb7/0x160 [xfs]
[ 7.822013] [<ffffffffa01986a7>] xfs_xattr_get+0x37/0x50 [xfs]
[ 7.822013] [<ffffffff811f6a7f>] generic_getxattr+0x4f/0x70
[ 7.822013] [<ffffffff8127ce60>]
inode_doinit_with_dentry+0x150/0x640
[ 7.822013] [<ffffffff8127d428>] sb_finish_set_opts+0xd8/0x270
[ 7.822013] [<ffffffff8127d84f>] selinux_set_mnt_opts+0x28f/0x5e0
[ 7.822013] [<ffffffff8127dc08>] superblock_doinit+0x68/0xd0
[ 7.822013] [<ffffffff8127dc80>] delayed_superblock_init+0x10/0x20
[ 7.822013] [<ffffffff811d45c2>] iterate_supers+0xb2/0x110
[ 7.822013] [<ffffffff8127e713>] selinux_complete_init+0x33/0x40
[ 7.822013] [<ffffffff8128cea4>] security_load_policy+0xf4/0x600
[ 7.822013] [<ffffffff8128008c>] sel_write_load+0xac/0x750
[ 7.822013] [<ffffffff811d0b9a>] vfs_write+0xba/0x1f0
[ 7.822013] [<ffffffff811d1749>] SyS_write+0x49/0xb0
[ 7.822013] [<ffffffff8163b6e9>] system_call_fastpath+0x16/0x1b
[ 7.822013]
[ 7.822013] -> #1 (&isec->lock){+.+.+.}:
[ 7.822013] [<ffffffff810b2078>] __lock_acquire+0x3a8/0xc40
[ 7.822013] [<ffffffff810b29c0>] lock_acquire+0xb0/0x140
[ 7.822013] [<ffffffff81636add>] mutex_lock_nested+0x5d/0x4d0
[ 7.822013] [<ffffffff8127cdb5>]
inode_doinit_with_dentry+0xa5/0x640
[ 7.822013] [<ffffffff8127defc>] selinux_d_instantiate+0x1c/0x20
[ 7.822013] [<ffffffff812732fb>] security_d_instantiate+0x1b/0x30
[ 7.822013] [<ffffffff811e8810>] d_instantiate+0x50/0x70
[ 7.822013] [<ffffffff811747f0>] __shmem_file_setup+0xe0/0x1d0
[ 7.822013] [<ffffffff811748f0>] shmem_file_setup+0x10/0x20
[ 7.822013] [<ffffffffa00d718b>] drm_gem_object_init+0x2b/0x40
[drm]
[ 7.822013] [<ffffffffa014cfce>] qxl_bo_create+0x7e/0x1a0 [qxl]
[ 7.822013] [<ffffffffa0151b50>]
qxl_alloc_release_reserved+0x190/0x200 [qxl]
[ 7.822013] [<ffffffffa014f6ec>] qxl_draw_opaque_fb+0x7c/0x390
[qxl]
[ 7.822013] [<ffffffffa014bc8e>]
qxl_fb_imageblit_internal+0x3e/0x40 [qxl]
[ 7.822013] [<ffffffffa014c17e>] qxl_fb_imageblit+0x6e/0x1a0 [qxl]
[ 7.822013] [<ffffffff813522a4>] soft_cursor+0x1b4/0x250
[ 7.822013] [<ffffffff81351b63>] bit_cursor+0x623/0x660
[ 7.822013] [<ffffffff8134df5b>] fbcon_cursor+0x13b/0x1c0
[ 7.822013] [<ffffffff813b5c98>] hide_cursor+0x28/0xa0
[ 7.822013] [<ffffffff813b77a8>] redraw_screen+0x168/0x240
[ 7.822013] [<ffffffff813b8181>] vc_do_resize+0x481/0x4b0
[ 7.822013] [<ffffffff813b81cf>] vc_resize+0x1f/0x30
[ 7.822013] [<ffffffff8134fb1c>] fbcon_init+0x35c/0x590
[ 7.822013] [<ffffffff813b5ef8>] visual_init+0xb8/0x120
[ 7.822013] [<ffffffff813b85a3>] do_bind_con_driver+0x163/0x330
[ 7.822013] [<ffffffff813b8d44>] do_take_over_console+0x114/0x1c0
[ 7.822013] [<ffffffff8134b3c3>] do_fbcon_takeover+0x63/0xd0
[ 7.822013] [<ffffffff813507a5>] fbcon_event_notify+0x6b5/0x800
[ 7.822013] [<ffffffff8108628c>] notifier_call_chain+0x4c/0x70
[ 7.822013] [<ffffffff81086553>]
__blocking_notifier_call_chain+0x53/0x70
[ 7.822013] [<ffffffff81086586>]
blocking_notifier_call_chain+0x16/0x20
[ 7.822013] [<ffffffff81356e0b>] fb_notifier_call_chain+0x1b/0x20
[ 7.822013] [<ffffffff8135905c>] register_framebuffer+0x1ec/0x330
[ 7.822013] [<ffffffffa013cb9e>]
drm_fb_helper_initial_config+0x2fe/0x4b0 [drm_kms_helper]
[ 7.822013] [<ffffffffa014ccfb>] qxl_fbdev_init+0xab/0xd0 [qxl]
[ 7.822013] [<ffffffffa014aded>] qxl_modeset_init+0x1fd/0x240
[qxl]
[ 7.822013] [<ffffffffa0148ca8>] qxl_driver_load+0x88/0xc0 [qxl]
[ 7.822013] [<ffffffffa00db90d>] drm_dev_register+0xad/0x100 [drm]
[ 7.822013] [<ffffffffa00de46f>] drm_get_pci_dev+0x8f/0x1f0 [drm]
[ 7.822013] [<ffffffffa01482ab>] qxl_pci_probe+0x1b/0x40 [qxl]
[ 7.822013] [<ffffffff8132ad65>] local_pci_probe+0x45/0xa0
[ 7.822013] [<ffffffff8132c031>] pci_device_probe+0xd1/0x130
[ 7.822013] [<ffffffff813e6f80>] driver_probe_device+0x90/0x3c0
[ 7.822013] [<ffffffff813e7383>] __driver_attach+0x93/0xa0
[ 7.822013] [<ffffffff813e4f2b>] bus_for_each_dev+0x6b/0xb0
[ 7.822013] [<ffffffff813e69ee>] driver_attach+0x1e/0x20
[ 7.822013] [<ffffffff813e65f8>] bus_add_driver+0x188/0x260
[ 7.822013] [<ffffffff813e7b54>] driver_register+0x64/0xf0
[ 7.822013] [<ffffffff8132a6f0>] __pci_register_driver+0x60/0x70
[ 7.822013] [<ffffffffa00de6da>] drm_pci_init+0x10a/0x140 [drm]
[ 7.822013] [<ffffffffa015b03e>]
cdrom_dummy_generic_packet+0x3e/0x40 [cdrom]
[ 7.822013] [<ffffffff810002fc>] do_one_initcall+0xbc/0x200
[ 7.822013] [<ffffffff810e714d>] load_module+0x162d/0x1a90
[ 7.822013] [<ffffffff810e7746>] SyS_finit_module+0x86/0xb0
[ 7.822013] [<ffffffff8163b6e9>] system_call_fastpath+0x16/0x1b
[ 7.822013]
[ 7.822013] -> #0 (&qdev->release_mutex){+.+.+.}:
[ 7.822013] [<ffffffff810b030c>]
validate_chain.isra.36+0x110c/0x11b0
[ 7.822013] [<ffffffff810b2078>] __lock_acquire+0x3a8/0xc40
[ 7.822013] [<ffffffff810b29c0>] lock_acquire+0xb0/0x140
[ 7.822013] [<ffffffff81636add>] mutex_lock_nested+0x5d/0x4d0
[ 7.822013] [<ffffffffa0151a2c>]
qxl_alloc_release_reserved+0x6c/0x200 [qxl]
[ 7.822013] [<ffffffffa014f6ec>] qxl_draw_opaque_fb+0x7c/0x390
[qxl]
[ 7.822013] [<ffffffffa014bdb1>]
qxl_fb_dirty_flush+0x121/0x160 [qxl]
[ 7.822013] [<ffffffffa014be90>] qxl_deferred_io+0xa0/0xb0 [qxl]
[ 7.822013] [<ffffffff8135eaae>] fb_deferred_io_work+0x7e/0xd0
[ 7.822013] [<ffffffff8107a0b5>] process_one_work+0x1f5/0x510
[ 7.822013] [<ffffffff8107ab4d>] worker_thread+0x11d/0x520
[ 7.822013] [<ffffffff81081760>] kthread+0xf0/0x110
[ 7.822013] [<ffffffff8163b63c>] ret_from_fork+0x7c/0xb0
[ 7.822013]
[ 7.822013] other info that might help us debug this:
[ 7.822013]
[ 7.822013] Chain exists of:
[ 7.822013] &qdev->release_mutex --> &mm->mmap_sem --> &fbdefio->lock
[ 7.822013]
[ 7.822013] Possible unsafe locking scenario:
[ 7.822013]
[ 7.822013] CPU0 CPU1
[ 7.822013] ---- ----
[ 7.822013] lock(&fbdefio->lock);
[ 7.822013] lock(&mm->mmap_sem);
[ 7.822013] lock(&fbdefio->lock);
[ 7.822013] lock(&qdev->release_mutex);
[ 7.822013]
[ 7.822013] *** DEADLOCK ***
[ 7.822013]
[ 7.822013] 3 locks held by kworker/3:1/276:
[ 7.822013] #0: ("events"){.+.+.+}, at: [<ffffffff8107a053>]
process_one_work+0x193/0x510
[ 7.822013] #1: ((&(&info->deferred_work)->work)){+.+.+.}, at:
[<ffffffff8107a053>] process_one_work+0x193/0x510
[ 7.822013] #2: (&fbdefio->lock){+.+.+.}, at: [<ffffffff8135ea65>]
fb_deferred_io_work+0x35/0xd0
[ 7.822013]
[ 7.822013] stack backtrace:
[ 7.822013] CPU: 3 PID: 276 Comm: kworker/3:1 Not tainted 3.16.0-rc6 #4
[ 7.822013] Hardware name: Red Hat KVM, BIOS Bochs 01/01/2011
[ 7.822013] Workqueue: events fb_deferred_io_work
[ 7.822013] ffffffff8268aa90 ffff8807df2ff8e8 ffffffff8163182a
ffffffff826ba5f0
[ 7.822013] ffff8807df2ff928 ffffffff8162b0d5 ffff8807df2ff960
ffff8807df2ddb50
[ 7.822013] ffff8807df2ddb50 0000000000000002 ffff8807df2dcec0
0000000000000003
[ 7.822013] Call Trace:
[ 7.822013] [<ffffffff8163182a>] dump_stack+0x45/0x56
[ 7.822013] [<ffffffff8162b0d5>] print_circular_bug+0x1f9/0x207
[ 7.822013] [<ffffffff810b030c>] validate_chain.isra.36+0x110c/0x11b0
[ 7.822013] [<ffffffff810ad89b>] ?
add_lock_to_list.isra.22.constprop.43+0x7b/0xf0
[ 7.822013] [<ffffffff8100c1b9>] ? sched_clock+0x9/0x10
[ 7.822013] [<ffffffff810b2078>] __lock_acquire+0x3a8/0xc40
[ 7.822013] [<ffffffff810b29c0>] lock_acquire+0xb0/0x140
[ 7.822013] [<ffffffffa0151a2c>] ?
qxl_alloc_release_reserved+0x6c/0x200 [qxl]
[ 7.822013] [<ffffffff81636add>] mutex_lock_nested+0x5d/0x4d0
[ 7.822013] [<ffffffffa0151a2c>] ?
qxl_alloc_release_reserved+0x6c/0x200 [qxl]
[ 7.822013] [<ffffffffa0151a2c>] ?
qxl_alloc_release_reserved+0x6c/0x200 [qxl]
[ 7.822013] [<ffffffff8163a957>] ? _raw_spin_unlock+0x27/0x30
[ 7.822013] [<ffffffffa0151598>] ? qxl_release_alloc+0x98/0x100 [qxl]
[ 7.822013] [<ffffffffa0151a2c>]
qxl_alloc_release_reserved+0x6c/0x200 [qxl]
[ 7.822013] [<ffffffffa014f6ec>] qxl_draw_opaque_fb+0x7c/0x390 [qxl]
[ 7.822013] [<ffffffffa014e3e3>] ? qxl_io_log+0x63/0x70 [qxl]
[ 7.822013] [<ffffffffa014bdb1>] qxl_fb_dirty_flush+0x121/0x160 [qxl]
[ 7.822013] [<ffffffffa014be90>] qxl_deferred_io+0xa0/0xb0 [qxl]
[ 7.822013] [<ffffffff8135eaae>] fb_deferred_io_work+0x7e/0xd0
[ 7.822013] [<ffffffff8107a0b5>] process_one_work+0x1f5/0x510
[ 7.822013] [<ffffffff8107a053>] ? process_one_work+0x193/0x510
[ 7.822013] [<ffffffff8107ab4d>] worker_thread+0x11d/0x520
[ 7.822013] [<ffffffff8107aa30>] ? create_and_start_worker+0x60/0x60
[ 7.822013] [<ffffffff81081760>] kthread+0xf0/0x110
[ 7.822013] [<ffffffff81081670>] ? kthread_create_on_node+0x220/0x220
[ 7.822013] [<ffffffff8163b63c>] ret_from_fork+0x7c/0xb0
[ 7.822013] [<ffffffff81081670>] ? kthread_create_on_node+0x220/0x220
[ 7.988039] hardirqs last enabled at (361): [<ffffffff81048f85>]
__do_page_fault+0x275/0x530
[ 7.988039] hardirqs last disabled at (360): [<ffffffff8163d826>]
error_sti+0x5/0x6
[ 7.988039] softirqs last enabled at (0): [<ffffffff8105ad8b>]
copy_process.part.22+0x66b/0x1d40
[ 7.988039] softirqs last disabled at (0): [<
(null)>] (null)
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