bisecting fixing commit since a1b977b49b66c75e6c51a515f6700371ae720217 building syzkaller on 4a77ae0bdc5cd75ebe88ce7c896aae6bbf457a29 testing commit a1b977b49b66c75e6c51a515f6700371ae720217 with gcc (GCC) 8.1.0 kernel signature: c9203197143fb5762cc6b179f0a2bf19ed0527a15b1f36ed0a1a69183f0ffacb all runs: crashed: INFO: task hung in __sync_dirty_buffer testing current HEAD 4143d798313fffa39f05bf24dd560ace42225c26 testing commit 4143d798313fffa39f05bf24dd560ace42225c26 with gcc (GCC) 8.1.0 kernel signature: de59f575b58faae3adb1ff1de68cc9fab709e411d1db23f31530b156d983b745 all runs: crashed: INFO: task hung in __sync_dirty_buffer revisions tested: 2, total time: 33m15.789881317s (build: 18m32.838037324s, test: 14m5.603920353s) the crash still happens on HEAD commit msg: Linux 4.19.165 crash: INFO: task hung in __sync_dirty_buffer Bluetooth: hci2: command 0x0406 tx timeout Bluetooth: hci3: command 0x0406 tx timeout Bluetooth: hci5: command 0x0406 tx timeout Bluetooth: hci1: command 0x0406 tx timeout Bluetooth: hci4: command 0x0406 tx timeout INFO: task syz-executor.0:7483 blocked for more than 140 seconds. Not tainted 4.19.165-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D25488 7483 5994 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+0x299/0x3b1 fs/ext4/inline.c:2027 ext4_fallocate+0xdb/0x1920 fs/ext4/extents.c:4960 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: 0033:0x45de59 Code: Bad RIP value. RSP: 002b:00007fda9fcf9c78 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 0000000000002ec0 RCX: 000000000045de59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 000000000118bf68 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000ffe0 R11: 0000000000000246 R12: 000000000118bf2c R13: 00007ffcbfd45eaf R14: 00007fda9fcfa9c0 R15: 000000000118bf2c INFO: task syz-executor.1:7510 blocked for more than 140 seconds. Not tainted 4.19.165-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D25656 7510 5997 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+0x299/0x3b1 fs/ext4/inline.c:2027 ext4_fallocate+0xdb/0x1920 fs/ext4/extents.c:4960 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: 0033:0x45de59 Code: Bad RIP value. RSP: 002b:00007f93ccc9dc78 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 0000000000002ec0 RCX: 000000000045de59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 000000000118bf68 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000ffe0 R11: 0000000000000246 R12: 000000000118bf2c R13: 00007ffe3c782a3f R14: 00007f93ccc9e9c0 R15: 000000000118bf2c INFO: task syz-executor.5:7519 blocked for more than 140 seconds. Not tainted 4.19.165-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D25656 7519 5996 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+0x299/0x3b1 fs/ext4/inline.c:2027 ext4_fallocate+0xdb/0x1920 fs/ext4/extents.c:4960 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: 0033:0x45de59 Code: Bad RIP value. RSP: 002b:00007fbb3c590c78 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 0000000000002ec0 RCX: 000000000045de59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 000000000118bf68 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000ffe0 R11: 0000000000000246 R12: 000000000118bf2c R13: 00007ffc6e6416af R14: 00007fbb3c5919c0 R15: 000000000118bf2c INFO: task syz-executor.4:7527 blocked for more than 140 seconds. Not tainted 4.19.165-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D25656 7527 5998 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+0x299/0x3b1 fs/ext4/inline.c:2027 ext4_fallocate+0xdb/0x1920 fs/ext4/extents.c:4960 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: 0033:0x45de59 Code: Bad RIP value. RSP: 002b:00007fcee2735c78 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 0000000000002ec0 RCX: 000000000045de59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 000000000118bf68 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000ffe0 R11: 0000000000000246 R12: 000000000118bf2c R13: 00007ffe10dde1df R14: 00007fcee27369c0 R15: 000000000118bf2c INFO: task syz-executor.3:7535 blocked for more than 140 seconds. Not tainted 4.19.165-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D25656 7535 5992 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+0x299/0x3b1 fs/ext4/inline.c:2027 ext4_fallocate+0xdb/0x1920 fs/ext4/extents.c:4960 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: 0033:0x45de59 Code: Bad RIP value. RSP: 002b:00007f2f57346c78 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 0000000000002ec0 RCX: 000000000045de59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 000000000118bf68 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000ffe0 R11: 0000000000000246 R12: 000000000118bf2c R13: 00007fffd229533f R14: 00007f2f573479c0 R15: 000000000118bf2c INFO: task syz-executor.2:7542 blocked for more than 140 seconds. Not tainted 4.19.165-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D25656 7542 5990 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+0x299/0x3b1 fs/ext4/inline.c:2027 ext4_fallocate+0xdb/0x1920 fs/ext4/extents.c:4960 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: 0033:0x45de59 Code: Bad RIP value. RSP: 002b:00007f0ff9b1dc78 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 0000000000002ec0 RCX: 000000000045de59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 000000000118bf68 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000ffe0 R11: 0000000000000246 R12: 000000000118bf2c R13: 00007ffcd973919f R14: 00007f0ff9b1e9c0 R15: 000000000118bf2c Showing all locks held in the system: 1 lock held by khungtaskd/1097: #0: 00000000ee1abb6e (rcu_read_lock){....}, at: debug_show_all_locks+0x5b/0x27a kernel/locking/lockdep.c:4442 2 locks held by syz-executor.0/7483: #0: 0000000023e7819d (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2780 [inline] #0: 0000000023e7819d (sb_writers#3){.+.+}, at: vfs_fallocate+0x4df/0x7c0 fs/open.c:307 #1: 00000000caf49b2a (&ei->xattr_sem){++++}, at: ext4_write_lock_xattr fs/ext4/xattr.h:141 [inline] #1: 00000000caf49b2a (&ei->xattr_sem){++++}, at: ext4_convert_inline_data+0x1dc/0x3b1 fs/ext4/inline.c:2025 2 locks held by syz-executor.1/7510: #0: 000000003d107cfc (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2780 [inline] #0: 000000003d107cfc (sb_writers#3){.+.+}, at: vfs_fallocate+0x4df/0x7c0 fs/open.c:307 #1: 0000000099f129ba (&ei->xattr_sem){++++}, at: ext4_write_lock_xattr fs/ext4/xattr.h:141 [inline] #1: 0000000099f129ba (&ei->xattr_sem){++++}, at: ext4_convert_inline_data+0x1dc/0x3b1 fs/ext4/inline.c:2025 2 locks held by syz-executor.5/7519: #0: 0000000014ba3698 (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2780 [inline] #0: 0000000014ba3698 (sb_writers#3){.+.+}, at: vfs_fallocate+0x4df/0x7c0 fs/open.c:307 #1: 00000000fb6c6829 (&ei->xattr_sem){++++}, at: ext4_write_lock_xattr fs/ext4/xattr.h:141 [inline] #1: 00000000fb6c6829 (&ei->xattr_sem){++++}, at: ext4_convert_inline_data+0x1dc/0x3b1 fs/ext4/inline.c:2025 2 locks held by syz-executor.4/7527: #0: 0000000002f67072 (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2780 [inline] #0: 0000000002f67072 (sb_writers#3){.+.+}, at: vfs_fallocate+0x4df/0x7c0 fs/open.c:307 #1: 0000000022a2f595 (&ei->xattr_sem){++++}, at: ext4_write_lock_xattr fs/ext4/xattr.h:141 [inline] #1: 0000000022a2f595 (&ei->xattr_sem){++++}, at: ext4_convert_inline_data+0x1dc/0x3b1 fs/ext4/inline.c:2025 2 locks held by syz-executor.3/7535: #0: 0000000023f9cf15 (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2780 [inline] #0: 0000000023f9cf15 (sb_writers#3){.+.+}, at: vfs_fallocate+0x4df/0x7c0 fs/open.c:307 #1: 00000000f6b80f57 (&ei->xattr_sem){++++}, at: ext4_write_lock_xattr fs/ext4/xattr.h:141 [inline] #1: 00000000f6b80f57 (&ei->xattr_sem){++++}, at: ext4_convert_inline_data+0x1dc/0x3b1 fs/ext4/inline.c:2025 2 locks held by syz-executor.2/7542: #0: 00000000cf6f1b79 (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2780 [inline] #0: 00000000cf6f1b79 (sb_writers#3){.+.+}, at: vfs_fallocate+0x4df/0x7c0 fs/open.c:307 #1: 00000000bb13c242 (&ei->xattr_sem){++++}, at: ext4_write_lock_xattr fs/ext4/xattr.h:141 [inline] #1: 00000000bb13c242 (&ei->xattr_sem){++++}, at: ext4_convert_inline_data+0x1dc/0x3b1 fs/ext4/inline.c:2025 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1097 Comm: khungtaskd Not tainted 4.19.165-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/0x22a lib/dump_stack.c:118 nmi_cpu_backtrace.cold.0+0x3c/0x78 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0xf5/0x119 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 6680 Comm: kworker/u4:5 Not tainted 4.19.165-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:789 [inline] RIP: 0010:lock_acquire+0x1db/0x3a0 kernel/locking/lockdep.c:3910 Code: bb 01 00 00 48 c7 c7 88 fa 71 88 48 b8 00 00 00 00 00 fc ff df c7 83 84 08 00 00 00 00 00 00 48 89 fa 48 c1 ea 03 80 3c 02 00 <0f> 85 99 01 00 00 48 83 3d ff 17 26 07 00 0f 84 1c 01 00 00 48 8b RSP: 0018:ffff8881d1067cb0 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffff8881d060e280 RCX: 1ffff1103a0c1d6f RDX: 1ffffffff10e3f51 RSI: 0000000000000000 RDI: ffffffff8871fa88 RBP: ffff8881d1067cf8 R08: ffff8881d060eb78 R09: 0000000000000002 R10: ffff8881d060eb58 R11: 0000000000000001 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: ffff8881d060e280 FS: 0000000000000000(0000) GS:ffff8881f6700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9344af1000 CR3: 000000000866d005 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_lock_acquire include/linux/rcupdate.h:242 [inline] rcu_read_lock include/linux/rcupdate.h:627 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:419 [inline] batadv_nc_worker+0xec/0x630 net/batman-adv/network-coding.c:730 process_one_work+0x7b9/0x15a0 kernel/workqueue.c:2155 worker_thread+0x85/0xb60 kernel/workqueue.c:2298 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415