Hello, syzbot found the following crash on: HEAD commit: 2821e26f Merge tag 'for-linus' of git://git.armlinux.org.u.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=150b15c9e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=f1c1f9c2d5c6ce1b dashboard link: https://syzkaller.appspot.com/bug?extid=518c54e255b5031adde4 compiler: gcc (GCC) 9.0.0 20181231 (experimental) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+518c54e255b5031adde4@xxxxxxxxxxxxxxxxxxxxxxxxx INFO: task syz-executor.3:10862 blocked for more than 143 seconds. Not tainted 5.5.0-rc7-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D24888 10862 10588 0x00004004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 io_schedule+0x1c/0x70 kernel/sched/core.c:5799 wait_on_page_bit_common+0x3b6/0xf20 mm/filemap.c:1175 wait_on_page_bit mm/filemap.c:1224 [inline] wait_on_page_locked include/linux/pagemap.h:527 [inline] wait_on_page_read mm/filemap.c:2747 [inline] do_read_cache_page+0x1019/0x1700 mm/filemap.c:2790 read_cache_page+0x5e/0x70 mm/filemap.c:2874 read_mapping_page include/linux/pagemap.h:396 [inline] read_dev_sector+0x71/0x400 block/partition-generic.c:592 read_part_sector block/partitions/check.h:38 [inline] adfspart_check_ICS+0x12d/0xf50 block/partitions/acorn.c:361 check_partition+0x3bc/0x6ce block/partitions/check.c:167 blk_add_partitions+0xf8/0x6e2 block/partition-generic.c:525 bdev_disk_changed+0x13c/0x2c0 fs/block_dev.c:1531 __blkdev_get+0x140c/0x1650 fs/block_dev.c:1669 blkdev_get+0x47/0x2c0 fs/block_dev.c:1736 blkdev_open+0x205/0x290 fs/block_dev.c:1875 do_dentry_open+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3356 [inline] path_openat+0x118b/0x3180 fs/namei.c:3473 do_filp_open+0x1a1/0x280 fs/namei.c:3503 do_sys_open+0x3fe/0x5d0 fs/open.c:1097 __do_sys_open fs/open.c:1115 [inline] __se_sys_open fs/open.c:1110 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1110 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4150e1 Code: cc cc cc cc cc cc cc cc cc 48 83 ec 38 48 89 6c 24 30 48 8d 6c 24 30 64 48 8b 04 25 f8 ff ff ff 48 8b 40 30 48 8b 80 d0 00 00 <00> 48 89 44 24 28 84 00 48 8b 4c 24 58 48 89 ca 48 c1 e9 03 48 c1 RSP: 002b:00007f113d2747a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 00000000004150e1 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007f113d274850 RBP: 000000000075bf20 R08: 00007f113d2747b0 R09: 000000000075bf20 R10: 0000000000000000 R11: 0000000000000293 R12: 00000000ffffffff R13: 0000000000000bbe R14: 00000000004cca19 R15: 000000000075bf2c INFO: task syz-executor.3:10867 blocked for more than 143 seconds. Not tainted 5.5.0-rc7-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D27768 10867 10588 0x00004004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 blkdev_put+0x34/0x560 fs/block_dev.c:1916 blkdev_close+0x8b/0xb0 fs/block_dev.c:1965 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x316/0x380 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath arch/x86/entry/common.c:278 [inline] do_syscall_64+0x676/0x790 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45b349 Code: 80 00 00 0f 83 b2 00 00 00 48 3d f8 03 00 00 77 7a 48 83 c0 07 48 c1 e8 03 48 3d 81 00 00 00 0f 83 df 00 00 00 48 8d 15 d5 91 <9f> 00 0f b6 04 10 48 83 f8 43 0f 83 c0 00 00 00 48 8d 0d 00 93 9f RSP: 002b:00007f113d253c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: 0000000000000000 RBX: 00007f113d2546d4 RCX: 000000000045b349 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000003fd R14: 00000000004c549d R15: 000000000075bfd4 INFO: task syz-executor.3:10896 blocked for more than 143 seconds. Not tainted 5.5.0-rc7-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28592 10896 10588 0x00000004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 __blkdev_get+0x19b/0x1650 fs/block_dev.c:1588 blkdev_get+0x47/0x2c0 fs/block_dev.c:1736 blkdev_open+0x205/0x290 fs/block_dev.c:1875 do_dentry_open+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3356 [inline] path_openat+0x118b/0x3180 fs/namei.c:3473 do_filp_open+0x1a1/0x280 fs/namei.c:3503 do_sys_open+0x3fe/0x5d0 fs/open.c:1097 __do_sys_open fs/open.c:1115 [inline] __se_sys_open fs/open.c:1110 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1110 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4150e1 Code: cc cc cc cc cc cc cc cc cc 48 83 ec 38 48 89 6c 24 30 48 8d 6c 24 30 64 48 8b 04 25 f8 ff ff ff 48 8b 40 30 48 8b 80 d0 00 00 <00> 48 89 44 24 28 84 00 48 8b 4c 24 58 48 89 ca 48 c1 e9 03 48 c1 RSP: 002b:00007f113d2327a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 00000000004150e1 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007f113d232850 RBP: 000000000075c070 R08: 000000000000000f R09: 0000000000000000 R10: 00007f113d2339d0 R11: 0000000000000293 R12: 00000000ffffffff R13: 0000000000000bbe R14: 00000000004cca19 R15: 000000000075c07c Showing all locks held in the system: 1 lock held by khungtaskd/1027: #0: ffffffff899a3dc0 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5333 1 lock held by rsyslogd/10415: #0: ffff8880a8f916a0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/10537: #0: ffff888084fdc090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90001a1b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10538: #0: ffff8880a06c2090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900019fb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10539: #0: ffff8880968b9090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90001a6b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10540: #0: ffff88809ffa6090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900019eb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10541: #0: ffff8880a41aa090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90001a4b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10542: #0: ffff8880945f8090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90001a5b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/10543: #0: ffff888096f83090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900019ab2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.3/10862: #0: ffff8880904db738 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x1650 fs/block_dev.c:1588 1 lock held by syz-executor.3/10867: #0: ffff8880904db738 (&bdev->bd_mutex){+.+.}, at: blkdev_put+0x34/0x560 fs/block_dev.c:1916 1 lock held by syz-executor.3/10896: #0: ffff8880904db738 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x1650 fs/block_dev.c:1588 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1027 Comm: khungtaskd Not tainted 5.5.0-rc7-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+0x197/0x210 lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b 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:205 [inline] watchdog+0xb11/0x10c0 kernel/hung_task.c:289 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60 --- This bug is generated by a bot. 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