FYI, we noticed the below changes on https://git.kernel.org/pub/scm/linux/kernel/git/sergeh/linux-security 2016-01-04/cgroupns commit 2f37bb12d30f69cd692933c4646dee73fc58eb43 ("cgroup: introduce cgroup namespaces") +-----------------------------------------------------------------------------+------------+------------+ | | f2a74e2f95 | 2f37bb12d3 | +-----------------------------------------------------------------------------+------------+------------+ | boot_successes | 10 | 0 | | boot_failures | 0 | 4 | | INFO:suspicious_RCU_usage | 0 | 4 | | BUG:sleeping_function_called_from_invalid_context_at_kernel/locking/mutex.c | 0 | 4 | | INFO:lockdep_is_turned_off | 0 | 4 | | WARNING:at_kernel/softirq.c:#__local_bh_enable_ip() | 0 | 4 | | backtrace:do_mount | 0 | 4 | | backtrace:SyS_mount | 0 | 4 | +-----------------------------------------------------------------------------+------------+------------+ [ 24.723231] Freeing unused kernel memory: 3412K (ffffffff823d1000 - ffffffff82726000) [ 29.889139] [ 29.890258] =============================== [ 29.894865] [ INFO: suspicious RCU usage. ] [ 29.896444] 4.4.0-rc1-00024-g2f37bb1 #1 Not tainted [ 29.903005] ------------------------------- [ 29.904342] include/linux/rcupdate.h:560 Illegal context switch in RCU read-side critical section! [ 29.913573] [ 29.913573] other info that might help us debug this: [ 29.913573] [ 29.929253] [ 29.929253] rcu_scheduler_active = 1, debug_locks = 0 [ 29.931806] 5 locks held by mount/2358: [ 29.939337] #0: (&bdev->bd_mutex){+.+.+.}, at: [] __blkdev_get+0xa3/0x3dc [ 29.942861] #1: (floppy_mutex){+.+.+.}, at: [] floppy_open+0x38/0x315 [ 29.946213] #2: (open_lock){+.+.+.}, at: [] floppy_open+0x46/0x315 [ 29.967575] #3: (floppy_lock){......}, at: [] cfq_set_request+0x5c/0x31e [ 29.970999] #4: (rcu_read_lock){......}, at: [] cfq_get_queue+0x5/0x480 [ 29.992419] [ 29.992419] stack backtrace: [ 29.994609] CPU: 0 PID: 2358 Comm: mount Not tainted 4.4.0-rc1-00024-g2f37bb1 #1 [ 30.015336] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 [ 30.018272] 0000000000000000 ffff88000b4c3670 ffffffff81505649 ffff88000ba90000 [ 30.021369] ffff88000b4c36a0 ffffffff810d85d6 ffffffff82079d47 0000000000000269 [ 30.076584] 0000000000000000 0000000000000000 ffff88000b4c36c8 ffffffff810b83de [ 30.079859] Call Trace: [ 30.102171] [] dump_stack+0x4b/0x63 [ 30.103881] [] lockdep_rcu_suspicious+0xf7/0x100 [ 30.105797] [] ___might_sleep+0x58/0x200 [ 30.107581] [] __might_sleep+0x75/0x7c [ 30.109284] [] mutex_lock_nested+0x3e/0x35f [ 30.111037] [] ? __lock_is_held+0x3c/0x57 [ 30.130858] [] ? cfq_get_queue+0x2b2/0x480 [ 30.132710] [] cgroup_path_ns+0x2c/0x72 [ 30.134475] [] ? cgroup_path_ns+0x2c/0x72 [ 30.136232] [] cgroup_path+0x15/0x17 [ 30.150820] [] cfq_get_queue+0x368/0x480 [ 30.152607] [] ? lock_acquire+0x113/0x1a1 [ 30.154395] [] ? cfq_set_request+0x5c/0x31e [ 30.156149] [] ? cfq_set_request+0x5c/0x31e [ 30.157899] [] cfq_set_request+0x134/0x31e [ 30.159750] [] ? mark_held_locks+0x5e/0x74 [ 30.161524] [] ? _raw_spin_unlock_irq+0x2c/0x3d [ 30.163320] [] ? trace_hardirqs_on_caller+0x17d/0x199 [ 30.165231] [] ? trace_hardirqs_on+0xd/0xf [ 30.166978] [] ? _raw_spin_unlock_irq+0x2c/0x3d [ 30.168768] [] elv_set_request+0x1c/0x21 [ 30.170555] [] get_request+0x516/0x933 [ 30.198310] [] ? wake_up_bit+0x2a/0x2a [ 30.200009] [] blk_queue_bio+0x19c/0x3c6 [ 30.201711] [] generic_make_request+0xc0/0x15e [ 30.203530] [] submit_bio+0x109/0x114 [ 30.205177] [] __floppy_read_block_0+0xcb/0x116 [ 30.206959] [] ? mark_held_locks+0x5e/0x74 [ 30.208701] [] ? _raw_spin_unlock_irqrestore+0x47/0x5d [ 30.214879] [] ? trace_hardirqs_on_caller+0x17d/0x199 [ 30.216775] [] ? floppy_resume+0x3f/0x3f [ 30.218558] [] floppy_revalidate+0x155/0x18b [ 30.220221] [] check_disk_change+0x52/0x5e [ 30.221972] [] floppy_open+0x2a6/0x315 [ 30.223641] [] __blkdev_get+0x115/0x3dc [ 30.225392] [] ? blkdev_get+0x2bc/0x2fd [ 30.240248] [] blkdev_get+0x1c6/0x2fd [ 30.241977] [] ? mntput_no_expire+0xdd/0x34d [ 30.243742] [] ? mntput+0x2d/0x2f [ 30.245364] [] ? path_put+0x1e/0x21 [ 30.247008] [] blkdev_get_by_path+0x38/0x71 [ 30.260842] [] mount_bdev+0x48/0x19f [ 30.262569] [] ? ext4_calculate_overhead+0x2bd/0x2bd [ 30.264552] [] ext4_mount+0x15/0x17 [ 30.266201] [] mount_fs+0x14/0x8c [ 30.267820] [] vfs_kern_mount+0x6c/0x13a [ 30.281895] [] do_mount+0xa45/0xbcf [ 30.283599] [] ? strndup_user+0x3f/0x8c [ 30.285307] [] SyS_mount+0x75/0xa1 [ 30.286895] [] entry_SYSCALL_64_fastpath+0x12/0x76 [ 30.288636] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:617 [ 30.291763] in_atomic(): 1, irqs_disabled(): 1, pid: 2358, name: mount [ 30.302833] INFO: lockdep is turned off. [ 30.304377] irq event stamp: 2146 [ 30.305789] hardirqs last enabled at (2145): [] _raw_spin_unlock_irq+0x2c/0x3d [ 30.308833] hardirqs last disabled at (2146): [] _raw_spin_lock_irq+0x1b/0x77 [ 30.325015] softirqs last enabled at (2096): [] __do_softirq+0x2ce/0x3bc [ 30.328158] softirqs last disabled at (2015): [] irq_exit+0x47/0x9b [ 30.331157] CPU: 0 PID: 2358 Comm: mount Not tainted 4.4.0-rc1-00024-g2f37bb1 #1 [ 30.333870] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 [ 30.349550] 0000000000000000 ffff88000b4c36a0 ffffffff81505649 ffff88000ba90000 [ 30.352376] ffff88000b4c36c8 ffffffff810b857f ffffffff82079d47 0000000000000269 [ 30.355309] 0000000000000000 ffff88000b4c36f0 ffffffff810b85fb ffffffff8227c4a0 [ 30.358186] Call Trace: [ 30.359444] [] dump_stack+0x4b/0x63 [ 30.360947] [] ___might_sleep+0x1f9/0x200 [ 30.374649] [] __might_sleep+0x75/0x7c [ 30.376366] [] mutex_lock_nested+0x3e/0x35f [ 30.377975] [] ? __lock_is_held+0x3c/0x57 [ 30.392669] [] ? cfq_get_queue+0x2b2/0x480 [ 30.394349] [] cgroup_path_ns+0x2c/0x72 [ 30.395795] [] ? cgroup_path_ns+0x2c/0x72 [ 30.397342] [] cgroup_path+0x15/0x17 [ 30.399137] [] cfq_get_queue+0x368/0x480 [ 30.400768] [] ? lock_acquire+0x113/0x1a1 [ 30.402242] [] ? cfq_set_request+0x5c/0x31e [ 30.412934] [] ? cfq_set_request+0x5c/0x31e [ 30.414461] [] cfq_set_request+0x134/0x31e [ 30.416314] [] ? mark_held_locks+0x5e/0x74 [ 30.418029] [] ? _raw_spin_unlock_irq+0x2c/0x3d [ 30.419557] [] ? trace_hardirqs_on_caller+0x17d/0x199 [ 30.421169] [] ? trace_hardirqs_on+0xd/0xf [ 30.433999] [] ? _raw_spin_unlock_irq+0x2c/0x3d [ 30.435841] [] elv_set_request+0x1c/0x21 [ 30.437539] [] get_request+0x516/0x933 [ 30.439329] [] ? wake_up_bit+0x2a/0x2a [ 30.441085] [] blk_queue_bio+0x19c/0x3c6 [ 30.442784] [] generic_make_request+0xc0/0x15e [ 30.444593] [] submit_bio+0x109/0x114 [ 30.459403] [] __floppy_read_block_0+0xcb/0x116 [ 30.461273] [] ? mark_held_locks+0x5e/0x74 [ 30.462849] [] ? _raw_spin_unlock_irqrestore+0x47/0x5d [ 30.464706] [] ? trace_hardirqs_on_caller+0x17d/0x199 [ 30.466616] [] ? floppy_resume+0x3f/0x3f [ 30.468094] [] floppy_revalidate+0x155/0x18b [ 30.469713] [] check_disk_change+0x52/0x5e [ 30.484430] [] floppy_open+0x2a6/0x315 [ 30.486076] [] __blkdev_get+0x115/0x3dc [ 30.487619] [] ? blkdev_get+0x2bc/0x2fd [ 30.489073] [] blkdev_get+0x1c6/0x2fd [ 30.490473] [] ? mntput_no_expire+0xdd/0x34d [ 30.492040] [] ? mntput+0x2d/0x2f [ 30.493508] [] ? path_put+0x1e/0x21 [ 30.494967] [] blkdev_get_by_path+0x38/0x71 [ 30.496443] [] mount_bdev+0x48/0x19f [ 30.497838] [] ? ext4_calculate_overhead+0x2bd/0x2bd [ 30.499568] [] ext4_mount+0x15/0x17 [ 30.514205] [] mount_fs+0x14/0x8c [ 30.515769] [] vfs_kern_mount+0x6c/0x13a [ 30.517471] [] do_mount+0xa45/0xbcf [ 30.519125] [] ? strndup_user+0x3f/0x8c [ 30.520873] [] SyS_mount+0x75/0xa1 [ 30.522380] [] entry_SYSCALL_64_fastpath+0x12/0x76 [ 30.523969] ------------[ cut here ]------------ [ 30.525353] WARNING: CPU: 0 PID: 2358 at kernel/softirq.c:150 __local_bh_enable_ip+0x45/0xb4() [ 30.541542] Modules linked in: [ 30.542882] CPU: 0 PID: 2358 Comm: mount Not tainted 4.4.0-rc1-00024-g2f37bb1 #1 [ 30.545260] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 [ 30.547707] 0000000000000000 ffff88000b4c36e8 ffffffff81505649 0000000000000000 [ 30.550543] ffff88000b4c3720 ffffffff810939e9 ffffffff81098485 0000000000000201 [ 30.553777] ffffffff81124687 ffff88000b4f6000 0000000000000000 ffff88000b4c3730 [ 30.570022] Call Trace: [ 30.571191] [] dump_stack+0x4b/0x63 [ 30.572786] [] warn_slowpath_common+0x99/0xb2 [ 30.574587] [] ? __local_bh_enable_ip+0x45/0xb4 [ 30.576425] [] ? cgroup_path_ns+0x5b/0x72 [ 30.578230] [] warn_slowpath_null+0x1a/0x1c [ 30.580107] [] __local_bh_enable_ip+0x45/0xb4 [ 30.595125] [] _raw_spin_unlock_bh+0x35/0x38 [ 30.597009] [] cgroup_path_ns+0x5b/0x72 [ 30.611039] [] cgroup_path+0x15/0x17 [ 30.612817] [] cfq_get_queue+0x368/0x480 [ 30.614661] [] ? lock_acquire+0x113/0x1a1 [ 30.616302] [] ? cfq_set_request+0x5c/0x31e [ 30.617786] [] ? cfq_set_request+0x5c/0x31e [ 30.619521] [] cfq_set_request+0x134/0x31e [ 30.621283] [] ? mark_held_locks+0x5e/0x74 [ 30.632111] [] ? _raw_spin_unlock_irq+0x2c/0x3d [ 30.633862] [] ? trace_hardirqs_on_caller+0x17d/0x199 [ 30.635700] [] ? trace_hardirqs_on+0xd/0xf [ 30.637368] [] ? _raw_spin_unlock_irq+0x2c/0x3d [ 30.639112] [] elv_set_request+0x1c/0x21 [ 30.640741] [] get_request+0x516/0x933 [ 30.654149] [] ? wake_up_bit+0x2a/0x2a [ 30.655765] [] blk_queue_bio+0x19c/0x3c6 [ 30.657479] [] generic_make_request+0xc0/0x15e [ 30.659366] [] submit_bio+0x109/0x114 [ 30.661102] [] __floppy_read_block_0+0xcb/0x116 [ 30.662903] [] ? mark_held_locks+0x5e/0x74 [ 30.664513] [] ? _raw_spin_unlock_irqrestore+0x47/0x5d [ 30.679590] [] ? trace_hardirqs_on_caller+0x17d/0x199 [ 30.681598] [] ? floppy_resume+0x3f/0x3f [ 30.683253] [] floppy_revalidate+0x155/0x18b [ 30.684989] [] check_disk_change+0x52/0x5e [ 30.686809] [] floppy_open+0x2a6/0x315 [ 30.688465] [] __blkdev_get+0x115/0x3dc [ 30.690014] [] ? blkdev_get+0x2bc/0x2fd [ 30.704620] [] blkdev_get+0x1c6/0x2fd [ 30.706161] [] ? mntput_no_expire+0xdd/0x34d [ 30.707903] [] ? mntput+0x2d/0x2f [ 30.738650] [] ? path_put+0x1e/0x21 [ 30.740474] [] blkdev_get_by_path+0x38/0x71 [ 30.742381] [] mount_bdev+0x48/0x19f [ 30.757122] [] ? ext4_calculate_overhead+0x2bd/0x2bd [ 30.759164] [] ext4_mount+0x15/0x17 [ 30.760866] [] mount_fs+0x14/0x8c [ 30.775089] [] vfs_kern_mount+0x6c/0x13a [ 30.776919] [] do_mount+0xa45/0xbcf [ 30.778657] [] ? strndup_user+0x3f/0x8c [ 30.780462] [] SyS_mount+0x75/0xa1 [ 30.782210] [] entry_SYSCALL_64_fastpath+0x12/0x76 [ 30.797259] ---[ end trace 7afed05606c6b402 ]--- [ 30.859656] blk_update_request: I/O error, dev fd0, sector 0 Thanks, Kernel Test Robot