bisecting fixing commit since a1b977b49b66c75e6c51a515f6700371ae720217 building syzkaller on 4a77ae0bdc5cd75ebe88ce7c896aae6bbf457a29 testing commit a1b977b49b66c75e6c51a515f6700371ae720217 with gcc (GCC) 8.4.1 20210217 kernel signature: 37427370a8d57a594d8cb8dfaeaebe89b2550e4503773d3c460f3dc828fc2e1c all runs: crashed: INFO: task hung in __sync_dirty_buffer testing current HEAD 125222814e7b8f84df767d6ab622aff2a6d2f234 testing commit 125222814e7b8f84df767d6ab622aff2a6d2f234 with gcc (GCC) 8.4.1 20210217 kernel signature: 284058b298b5dc850a6ac6f749d8a611b75ead2f940f1a8cb1e270aebfe145b5 all runs: crashed: INFO: task hung in __sync_dirty_buffer revisions tested: 2, total time: 31m11.705999769s (build: 16m22.036704743s, test: 14m25.832957535s) the crash still happens on HEAD commit msg: Linux 4.19.182 crash: INFO: task hung in __sync_dirty_buffer Bluetooth: hci2: command 0x0406 tx timeout Bluetooth: hci0: command 0x0406 tx timeout Bluetooth: hci4: command 0x0406 tx timeout Bluetooth: hci3: command 0x0406 tx timeout Bluetooth: hci5: command 0x0406 tx timeout INFO: task syz-executor.3:7407 blocked for more than 140 seconds. Not tainted 4.19.182-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D25480 7407 5918 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 io_schedule+0x1c/0x70 kernel/sched/core.c:5181 bit_wait_io+0xf/0x90 kernel/sched/wait_bit.c:207 __wait_on_bit_lock+0xbb/0x160 kernel/sched/wait_bit.c:89 out_of_line_wait_on_bit_lock+0xde/0x110 kernel/sched/wait_bit.c:116 wait_on_bit_lock_io include/linux/wait_bit.h:208 [inline] __lock_buffer+0x3c/0x40 fs/buffer.c:65 lock_buffer include/linux/buffer_head.h:374 [inline] __sync_dirty_buffer+0x180/0x1f0 fs/buffer.c:3178 sync_dirty_buffer+0xe/0x10 fs/buffer.c:3204 __ext4_handle_dirty_metadata+0x17a/0x520 fs/ext4/ext4_jbd2.c:300 ext4_convert_inline_data_nolock+0x4f8/0xc40 fs/ext4/inline.c:1240 ext4_convert_inline_data+0x299/0x3c0 fs/ext4/inline.c:2027 ext4_fallocate+0xdb/0x1920 fs/ext4/extents.c:4956 vfs_fallocate+0x2b5/0x7c0 fs/open.c:308 ksys_fallocate+0x3c/0x80 fs/open.c:331 __do_sys_fallocate fs/open.c:339 [inline] __se_sys_fallocate fs/open.c:337 [inline] __x64_sys_fallocate+0x92/0xf0 fs/open.c:337 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465849 Code: Bad RIP value. RSP: 002b:00007f1cd4799188 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 000000000055bf00 RCX: 0000000000465849 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00000000004af675 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000ffe0 R11: 0000000000000246 R12: 000000000055bf00 R13: 00007fffb17d30cf R14: 00007f1cd4799300 R15: 0000000000022000 INFO: task syz-executor.5:7424 blocked for more than 140 seconds. Not tainted 4.19.182-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D25656 7424 5920 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 io_schedule+0x1c/0x70 kernel/sched/core.c:5181 bit_wait_io+0xf/0x90 kernel/sched/wait_bit.c:207 __wait_on_bit_lock+0xbb/0x160 kernel/sched/wait_bit.c:89 out_of_line_wait_on_bit_lock+0xde/0x110 kernel/sched/wait_bit.c:116 wait_on_bit_lock_io include/linux/wait_bit.h:208 [inline] __lock_buffer+0x3c/0x40 fs/buffer.c:65 lock_buffer include/linux/buffer_head.h:374 [inline] __sync_dirty_buffer+0x180/0x1f0 fs/buffer.c:3178 sync_dirty_buffer+0xe/0x10 fs/buffer.c:3204 __ext4_handle_dirty_metadata+0x17a/0x520 fs/ext4/ext4_jbd2.c:300 ext4_convert_inline_data_nolock+0x4f8/0xc40 fs/ext4/inline.c:1240 ext4_convert_inline_data+0x299/0x3c0 fs/ext4/inline.c:2027 ext4_fallocate+0xdb/0x1920 fs/ext4/extents.c:4956 vfs_fallocate+0x2b5/0x7c0 fs/open.c:308 ksys_fallocate+0x3c/0x80 fs/open.c:331 __do_sys_fallocate fs/open.c:339 [inline] __se_sys_fallocate fs/open.c:337 [inline] __x64_sys_fallocate+0x92/0xf0 fs/open.c:337 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465849 Code: Bad RIP value. RSP: 002b:00007f4c90a21188 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 000000000055bf00 RCX: 0000000000465849 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00000000004af675 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000ffe0 R11: 0000000000000246 R12: 000000000055bf00 R13: 00007ffeb361b0af R14: 00007f4c90a21300 R15: 0000000000022000 INFO: task syz-executor.1:7437 blocked for more than 140 seconds. Not tainted 4.19.182-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D25656 7437 5916 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 io_schedule+0x1c/0x70 kernel/sched/core.c:5181 bit_wait_io+0xf/0x90 kernel/sched/wait_bit.c:207 __wait_on_bit_lock+0xbb/0x160 kernel/sched/wait_bit.c:89 out_of_line_wait_on_bit_lock+0xde/0x110 kernel/sched/wait_bit.c:116 wait_on_bit_lock_io include/linux/wait_bit.h:208 [inline] __lock_buffer+0x3c/0x40 fs/buffer.c:65 lock_buffer include/linux/buffer_head.h:374 [inline] __sync_dirty_buffer+0x180/0x1f0 fs/buffer.c:3178 sync_dirty_buffer+0xe/0x10 fs/buffer.c:3204 __ext4_handle_dirty_metadata+0x17a/0x520 fs/ext4/ext4_jbd2.c:300 ext4_convert_inline_data_nolock+0x4f8/0xc40 fs/ext4/inline.c:1240 ext4_convert_inline_data+0x299/0x3c0 fs/ext4/inline.c:2027 ext4_fallocate+0xdb/0x1920 fs/ext4/extents.c:4956 vfs_fallocate+0x2b5/0x7c0 fs/open.c:308 ksys_fallocate+0x3c/0x80 fs/open.c:331 __do_sys_fallocate fs/open.c:339 [inline] __se_sys_fallocate fs/open.c:337 [inline] __x64_sys_fallocate+0x92/0xf0 fs/open.c:337 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465849 Code: Bad RIP value. RSP: 002b:00007ff17acca188 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 000000000055bf00 RCX: 0000000000465849 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00000000004af675 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000ffe0 R11: 0000000000000246 R12: 000000000055bf00 R13: 00007ffe3f884f0f R14: 00007ff17acca300 R15: 0000000000022000 INFO: task syz-executor.2:7443 blocked for more than 140 seconds. Not tainted 4.19.182-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D25656 7443 5912 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 io_schedule+0x1c/0x70 kernel/sched/core.c:5181 bit_wait_io+0xf/0x90 kernel/sched/wait_bit.c:207 __wait_on_bit_lock+0xbb/0x160 kernel/sched/wait_bit.c:89 out_of_line_wait_on_bit_lock+0xde/0x110 kernel/sched/wait_bit.c:116 wait_on_bit_lock_io include/linux/wait_bit.h:208 [inline] __lock_buffer+0x3c/0x40 fs/buffer.c:65 lock_buffer include/linux/buffer_head.h:374 [inline] __sync_dirty_buffer+0x180/0x1f0 fs/buffer.c:3178 sync_dirty_buffer+0xe/0x10 fs/buffer.c:3204 __ext4_handle_dirty_metadata+0x17a/0x520 fs/ext4/ext4_jbd2.c:300 ext4_convert_inline_data_nolock+0x4f8/0xc40 fs/ext4/inline.c:1240 ext4_convert_inline_data+0x299/0x3c0 fs/ext4/inline.c:2027 ext4_fallocate+0xdb/0x1920 fs/ext4/extents.c:4956 vfs_fallocate+0x2b5/0x7c0 fs/open.c:308 ksys_fallocate+0x3c/0x80 fs/open.c:331 __do_sys_fallocate fs/open.c:339 [inline] __se_sys_fallocate fs/open.c:337 [inline] __x64_sys_fallocate+0x92/0xf0 fs/open.c:337 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465849 Code: Bad RIP value. RSP: 002b:00007f821fe5e188 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 000000000055bf00 RCX: 0000000000465849 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00000000004af675 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000ffe0 R11: 0000000000000246 R12: 000000000055bf00 R13: 00007ffe6d6aabff R14: 00007f821fe5e300 R15: 0000000000022000 INFO: task syz-executor.0:7451 blocked for more than 140 seconds. Not tainted 4.19.182-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D25656 7451 5913 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 io_schedule+0x1c/0x70 kernel/sched/core.c:5181 bit_wait_io+0xf/0x90 kernel/sched/wait_bit.c:207 __wait_on_bit_lock+0xbb/0x160 kernel/sched/wait_bit.c:89 out_of_line_wait_on_bit_lock+0xde/0x110 kernel/sched/wait_bit.c:116 wait_on_bit_lock_io include/linux/wait_bit.h:208 [inline] __lock_buffer+0x3c/0x40 fs/buffer.c:65 lock_buffer include/linux/buffer_head.h:374 [inline] __sync_dirty_buffer+0x180/0x1f0 fs/buffer.c:3178 sync_dirty_buffer+0xe/0x10 fs/buffer.c:3204 __ext4_handle_dirty_metadata+0x17a/0x520 fs/ext4/ext4_jbd2.c:300 ext4_convert_inline_data_nolock+0x4f8/0xc40 fs/ext4/inline.c:1240 ext4_convert_inline_data+0x299/0x3c0 fs/ext4/inline.c:2027 ext4_fallocate+0xdb/0x1920 fs/ext4/extents.c:4956 vfs_fallocate+0x2b5/0x7c0 fs/open.c:308 ksys_fallocate+0x3c/0x80 fs/open.c:331 __do_sys_fallocate fs/open.c:339 [inline] __se_sys_fallocate fs/open.c:337 [inline] __x64_sys_fallocate+0x92/0xf0 fs/open.c:337 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465849 Code: Bad RIP value. RSP: 002b:00007f1095cab188 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 000000000055bf00 RCX: 0000000000465849 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00000000004af675 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000ffe0 R11: 0000000000000246 R12: 000000000055bf00 R13: 00007ffe3e1df01f R14: 00007f1095cab300 R15: 0000000000022000 INFO: task syz-executor.4:7459 blocked for more than 140 seconds. Not tainted 4.19.182-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D25656 7459 5919 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 io_schedule+0x1c/0x70 kernel/sched/core.c:5181 bit_wait_io+0xf/0x90 kernel/sched/wait_bit.c:207 __wait_on_bit_lock+0xbb/0x160 kernel/sched/wait_bit.c:89 out_of_line_wait_on_bit_lock+0xde/0x110 kernel/sched/wait_bit.c:116 wait_on_bit_lock_io include/linux/wait_bit.h:208 [inline] __lock_buffer+0x3c/0x40 fs/buffer.c:65 lock_buffer include/linux/buffer_head.h:374 [inline] __sync_dirty_buffer+0x180/0x1f0 fs/buffer.c:3178 sync_dirty_buffer+0xe/0x10 fs/buffer.c:3204 __ext4_handle_dirty_metadata+0x17a/0x520 fs/ext4/ext4_jbd2.c:300 ext4_convert_inline_data_nolock+0x4f8/0xc40 fs/ext4/inline.c:1240 ext4_convert_inline_data+0x299/0x3c0 fs/ext4/inline.c:2027 ext4_fallocate+0xdb/0x1920 fs/ext4/extents.c:4956 vfs_fallocate+0x2b5/0x7c0 fs/open.c:308 ksys_fallocate+0x3c/0x80 fs/open.c:331 __do_sys_fallocate fs/open.c:339 [inline] __se_sys_fallocate fs/open.c:337 [inline] __x64_sys_fallocate+0x92/0xf0 fs/open.c:337 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465849 Code: Bad RIP value. RSP: 002b:00007f3c5320c188 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 000000000055bf00 RCX: 0000000000465849 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00000000004af675 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000ffe0 R11: 0000000000000246 R12: 000000000055bf00 R13: 00007ffe71a4299f R14: 00007f3c5320c300 R15: 0000000000022000 Showing all locks held in the system: 3 locks held by kworker/u4:3/376: #0: 000000007395ed36 (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1824 [inline] #0: 000000007395ed36 (&rq->lock){-.-.}, at: __schedule+0x1f6/0x1f70 kernel/sched/core.c:3455 #1: 0000000002f365fe (rcu_read_lock){....}, at: trace_sched_stat_runtime include/trace/events/sched.h:428 [inline] #1: 0000000002f365fe (rcu_read_lock){....}, at: update_curr+0x2cf/0x870 kernel/sched/fair.c:857 #2: 00000000ef76047c (&wdev->mtx){+.+.}, at: sdata_lock net/mac80211/ieee80211_i.h:990 [inline] #2: 00000000ef76047c (&wdev->mtx){+.+.}, at: ieee80211_ibss_work+0x8b/0xdb0 net/mac80211/ibss.c:1675 1 lock held by khungtaskd/1096: #0: 0000000002f365fe (rcu_read_lock){....}, at: debug_show_all_locks+0x5b/0x27a kernel/locking/lockdep.c:4442 1 lock held by in:imklog/5594: 2 locks held by syz-executor.3/7407: #0: 000000005b29df0b (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2779 [inline] #0: 000000005b29df0b (sb_writers#3){.+.+}, at: vfs_fallocate+0x4df/0x7c0 fs/open.c:307 #1: 0000000006dba257 (&ei->xattr_sem){++++}, at: ext4_write_lock_xattr fs/ext4/xattr.h:141 [inline] #1: 0000000006dba257 (&ei->xattr_sem){++++}, at: ext4_convert_inline_data+0x1dc/0x3c0 fs/ext4/inline.c:2025 2 locks held by syz-executor.5/7424: #0: 0000000016b4c0ed (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2779 [inline] #0: 0000000016b4c0ed (sb_writers#3){.+.+}, at: vfs_fallocate+0x4df/0x7c0 fs/open.c:307 #1: 00000000135c4a6c (&ei->xattr_sem){++++}, at: ext4_write_lock_xattr fs/ext4/xattr.h:141 [inline] #1: 00000000135c4a6c (&ei->xattr_sem){++++}, at: ext4_convert_inline_data+0x1dc/0x3c0 fs/ext4/inline.c:2025 2 locks held by syz-executor.1/7437: #0: 00000000a7313237 (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2779 [inline] #0: 00000000a7313237 (sb_writers#3){.+.+}, at: vfs_fallocate+0x4df/0x7c0 fs/open.c:307 #1: 00000000b9f3d697 (&ei->xattr_sem){++++}, at: ext4_write_lock_xattr fs/ext4/xattr.h:141 [inline] #1: 00000000b9f3d697 (&ei->xattr_sem){++++}, at: ext4_convert_inline_data+0x1dc/0x3c0 fs/ext4/inline.c:2025 2 locks held by syz-executor.2/7443: #0: 00000000f2040163 (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2779 [inline] #0: 00000000f2040163 (sb_writers#3){.+.+}, at: vfs_fallocate+0x4df/0x7c0 fs/open.c:307 #1: 000000003e9dda17 (&ei->xattr_sem){++++}, at: ext4_write_lock_xattr fs/ext4/xattr.h:141 [inline] #1: 000000003e9dda17 (&ei->xattr_sem){++++}, at: ext4_convert_inline_data+0x1dc/0x3c0 fs/ext4/inline.c:2025 2 locks held by syz-executor.0/7451: #0: 000000006fc5d55c (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2779 [inline] #0: 000000006fc5d55c (sb_writers#3){.+.+}, at: vfs_fallocate+0x4df/0x7c0 fs/open.c:307 #1: 00000000b4c4139a (&ei->xattr_sem){++++}, at: ext4_write_lock_xattr fs/ext4/xattr.h:141 [inline] #1: 00000000b4c4139a (&ei->xattr_sem){++++}, at: ext4_convert_inline_data+0x1dc/0x3c0 fs/ext4/inline.c:2025 2 locks held by syz-executor.4/7459: #0: 0000000068af4bff (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2779 [inline] #0: 0000000068af4bff (sb_writers#3){.+.+}, at: vfs_fallocate+0x4df/0x7c0 fs/open.c:307 #1: 00000000c2fb1eab (&ei->xattr_sem){++++}, at: ext4_write_lock_xattr fs/ext4/xattr.h:141 [inline] #1: 00000000c2fb1eab (&ei->xattr_sem){++++}, at: ext4_convert_inline_data+0x1dc/0x3c0 fs/ext4/inline.c:2025 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1096 Comm: khungtaskd Not tainted 4.19.182-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x17c/0x226 lib/dump_stack.c:118 nmi_cpu_backtrace.cold.0+0x3c/0x78 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0xf5/0x120 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x5c3/0xb40 kernel/hung_task.c:287 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 376 Comm: kworker/u4:3 Not tainted 4.19.182-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: writeback wb_workfn (flush-7:0) RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline] RIP: 0010:debug_lockdep_rcu_enabled.part.0+0xf/0x60 kernel/rcu/update.c:254 Code: 40 00 48 8b 45 a0 e9 bc fd ff ff 48 8b 7d d0 e8 97 64 40 00 e9 95 fd ff ff 66 90 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 53 <65> 48 8b 1c 25 40 ee 01 00 48 8d bb 84 08 00 00 48 89 fa 48 c1 ea RSP: 0018:ffff8881f41ef500 EFLAGS: 00000202 RAX: dffffc0000000000 RBX: dffffc0000000000 RCX: 1ffff1103e83de95 RDX: 0000000000000004 RSI: 00000000000008e8 RDI: ffffffff88bd9120 RBP: ffff8881f41ef508 R08: ffff8881f46d0c78 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff87509f60 R14: 00000000000008e8 R15: ffff8881f41ef668 FS: 0000000000000000(0000) GS:ffff8881f6600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f055d0df000 CR3: 000000000866d005 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: debug_lockdep_rcu_enabled+0x77/0x90 kernel/rcu/update.c:253 ___might_sleep+0x1b/0x2b0 kernel/sched/core.c:6157 write_cache_pages+0x634/0xf70 mm/page-writeback.c:2280 generic_writepages mm/page-writeback.c:2329 [inline] generic_writepages+0xca/0x130 mm/page-writeback.c:2318 blkdev_writepages+0x9/0x10 fs/block_dev.c:1980 do_writepages+0xca/0x240 mm/page-writeback.c:2344 __writeback_single_inode+0xc6/0xc40 fs/fs-writeback.c:1380 writeback_sb_inodes+0x47b/0xd40 fs/fs-writeback.c:1642 __writeback_inodes_wb+0xec/0x1e0 fs/fs-writeback.c:1711 wb_writeback+0x593/0x910 fs/fs-writeback.c:1817 wb_check_old_data_flush fs/fs-writeback.c:1919 [inline] wb_do_writeback fs/fs-writeback.c:1972 [inline] wb_workfn+0x887/0xec0 fs/fs-writeback.c:2001 process_one_work+0x7b9/0x15a0 kernel/workqueue.c:2152 worker_thread+0x85/0xb60 kernel/workqueue.c:2295 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415