INFO: task hung in sync_inodes_sb

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syzbot

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Feb 3, 2020, 12:26:11 PM2/3/20
to syzkaller...@googlegroups.com
Hello,

syzbot found the following crash on:

HEAD commit: 9fa690a2 Linux 4.14.169
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=103a1bf1e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=eb55b601e76e3476
dashboard link: https://syzkaller.appspot.com/bug?extid=af03214457b32b28a28b
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+af0321...@syzkaller.appspotmail.com

INFO: task syz-executor.1:29500 blocked for more than 140 seconds.
Not tainted 4.14.169-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1 D30000 29500 7262 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2808 [inline]
__schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
schedule+0x92/0x1c0 kernel/sched/core.c:3428
wb_wait_for_completion fs/fs-writeback.c:221 [inline]
wb_wait_for_completion+0x133/0x190 fs/fs-writeback.c:217
sync_inodes_sb+0x170/0x9b0 fs/fs-writeback.c:2461
sync_inodes_one_sb+0x48/0x60 fs/sync.c:74
iterate_supers+0x130/0x250 fs/super.c:613
sys_sync+0x7a/0x130 fs/sync.c:113
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45b399
RSP: 002b:00007f41cba61c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f41cba626d4 RCX: 000000000045b399
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000b72 R14: 00000000004c953f R15: 000000000075bf2c
INFO: task syz-executor.1:29534 blocked for more than 140 seconds.
Not tainted 4.14.169-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1 D29120 29534 7262 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2808 [inline]
__schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
schedule+0x92/0x1c0 kernel/sched/core.c:3428
__rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:588 [inline]
rwsem_down_write_failed+0x5ce/0xb50 kernel/locking/rwsem-xadd.c:617
call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:105
__down_write arch/x86/include/asm/rwsem.h:126 [inline]
down_write+0x53/0x90 kernel/locking/rwsem.c:56
bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:336 [inline]
sync_inodes_sb+0x150/0x9b0 fs/fs-writeback.c:2459
sync_inodes_one_sb+0x48/0x60 fs/sync.c:74
iterate_supers+0x130/0x250 fs/super.c:613
sys_sync+0x7a/0x130 fs/sync.c:113
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45b399
RSP: 002b:00007f41cba40c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f41cba416d4 RCX: 000000000045b399
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000b72 R14: 00000000004c953f R15: 000000000075bfd4

Showing all locks held in the system:
1 lock held by khungtaskd/1057:
#0: (tasklist_lock){.+.+}, at: [<ffffffff81488cf8>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4544
1 lock held by rsyslogd/7093:
#0: (&f->f_pos_lock){+.+.}, at: [<ffffffff8196346b>] __fdget_pos+0xab/0xd0 fs/file.c:769
2 locks held by getty/7215:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff86692003>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834c3816>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7216:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff86692003>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834c3816>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7217:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff86692003>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834c3816>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7218:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff86692003>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834c3816>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7219:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff86692003>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834c3816>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7220:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff86692003>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834c3816>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7221:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff86692003>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834c3816>] n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by syz-executor.2/11316:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
1 lock held by syz-executor.2/11494:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
1 lock held by syz-executor.2/11701:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
2 locks held by syz-executor.2/11773:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
2 locks held by syz-executor.2/11932:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
2 locks held by syz-executor.2/12060:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
2 locks held by syz-executor.2/12123:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
1 lock held by syz-executor.2/12194:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
2 locks held by syz-executor.2/12232:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
2 locks held by syz-executor.3/12307:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
1 lock held by syz-executor.2/12316:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
2 locks held by syz-executor.3/12363:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
2 locks held by syz-executor.2/12370:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
1 lock held by syz-executor.2/12426:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
1 lock held by syz-executor.3/12502:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
2 locks held by syz-executor.2/12513:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
1 lock held by syz-executor.3/12580:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
1 lock held by syz-executor.2/12592:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
1 lock held by syz-executor.3/12652:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
2 locks held by syz-executor.3/12724:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
2 locks held by syz-executor.2/12830:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
1 lock held by syz-executor.3/12911:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
2 locks held by syz-executor.4/12912:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
2 locks held by syz-executor.5/12925:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
2 locks held by syz-executor.2/12944:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&rq->lock){-.-.}, at: [<ffffffff8668004a>] rq_lock kernel/sched/sched.h:1741 [inline]
#1: (&rq->lock){-.-.}, at: [<ffffffff8668004a>] __schedule+0x1da/0x1cd0 kernel/sched/core.c:3321
2 locks held by syz-executor.4/13028:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&rq->lock){-.-.}, at: [<ffffffff8668004a>] rq_lock kernel/sched/sched.h:1741 [inline]
#1: (&rq->lock){-.-.}, at: [<ffffffff8668004a>] __schedule+0x1da/0x1cd0 kernel/sched/core.c:3321
2 locks held by syz-executor.2/13042:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
2 locks held by syz-executor.0/13115:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
1 lock held by syz-executor.4/13128:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
1 lock held by syz-executor.2/13138:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
2 locks held by syz-executor.5/13142:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
1 lock held by syz-executor.5/13238:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
1 lock held by syz-executor.2/13273:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
1 lock held by syz-executor.4/13280:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
1 lock held by syz-executor.0/13365:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
2 locks held by syz-executor.5/13382:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
1 lock held by syz-executor.4/13877:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
1 lock held by syz-executor.2/13928:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
1 lock held by syz-executor.3/14308:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
1 lock held by syz-executor.5/14337:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
2 locks held by syz-executor.0/14458:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
2 locks held by syz-executor.3/14489:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
2 locks held by syz-executor.4/14752:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
1 lock held by syz-executor.5/14952:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
2 locks held by syz-executor.0/15131:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
2 locks held by syz-executor.3/16091:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
2 locks held by syz-executor.3/16727:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
1 lock held by syz-executor.2/16774:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
1 lock held by syz-executor.3/16787:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
2 locks held by syz-executor.3/16844:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
2 locks held by syz-executor.5/16985:
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] file_start_write include/linux/fs.h:2707 [inline]
#0: (sb_writers#4){.+.+}, at: [<ffffffff818f7442>] do_sendfile+0x912/0xbd0 fs/read_write.c:1440
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] inode_trylock include/linux/fs.h:738 [inline]
#1: (&sb->s_type->i_mutex_key#9){++++}, at: [<ffffffff81c19584>] ext4_file_write_iter+0x1f4/0xe90 fs/ext4/file.c:234
4 locks held by kworker/u4:0/11795:
#0: ("writeback"){+.+.}, at: [<ffffffff813d223e>] work_static include/linux/workqueue.h:199 [inline]
#0: ("writeback"){+.+.}, at: [<ffffffff813d223e>] set_work_data kernel/workqueue.c:619 [inline]
#0: ("writeback"){+.+.}, at: [<ffffffff813d223e>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
#0: ("writeback"){+.+.}, at: [<ffffffff813d223e>] process_one_work+0x76e/0x1600 kernel/workqueue.c:2085
#1: ((&(&wb->dwork)->work)){+.+.}, at: [<ffffffff813d227b>] process_one_work+0x7ab/0x1600 kernel/workqueue.c:2089
#2: (&type->s_umount_key#45){++++}, at: [<ffffffff81900cf0>] trylock_super+0x20/0xf0 fs/super.c:402
#3: (&sbi->s_journal_flag_rwsem){.+.+}, at: [<ffffffff817432c0>] do_writepages+0xd0/0x250 mm/page-writeback.c:2361
2 locks held by syz-executor.1/29500:
#0: (&type->s_umount_key#45){++++}, at: [<ffffffff81901301>] iterate_supers+0xe1/0x250 fs/super.c:611
#1: (&bdi->wb_switch_rwsem){+.+.}, at: [<ffffffff819978b0>] bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:336 [inline]
#1: (&bdi->wb_switch_rwsem){+.+.}, at: [<ffffffff819978b0>] sync_inodes_sb+0x150/0x9b0 fs/fs-writeback.c:2459
2 locks held by syz-executor.1/29534:
#0: (&type->s_umount_key#45){++++}, at: [<ffffffff81901301>] iterate_supers+0xe1/0x250 fs/super.c:611
#1: (&bdi->wb_switch_rwsem){+.+.}, at: [<ffffffff819978b0>] bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:336 [inline]
#1: (&bdi->wb_switch_rwsem){+.+.}, at: [<ffffffff819978b0>] sync_inodes_sb+0x150/0x9b0 fs/fs-writeback.c:2459

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 1057 Comm: khungtaskd Not tainted 4.14.169-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x142/0x197 lib/dump_stack.c:58
nmi_cpu_backtrace.cold+0x57/0x94 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x141/0x189 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:140 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
watchdog+0x5e7/0xb90 kernel/hung_task.c:274
kthread+0x319/0x430 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 12370 Comm: syz-executor.2 Not tainted 4.14.169-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff888055c5e340 task.stack: ffff88803ed68000
RIP: 0010:radix_tree_load_root lib/radix-tree.c:608 [inline]
RIP: 0010:__radix_tree_lookup+0x86/0x2f0 lib/radix-tree.c:1040
RSP: 0018:ffff88803ed6f6e8 EFLAGS: 00000286
RAX: 0000000000000000 RBX: ffff88807f3ca401 RCX: ffff88803ed6f778
RDX: 0000000000000000 RSI: 000000000000017d RDI: ffff88809434fac0
RBP: ffff88803ed6f748 R08: 0000000000000000 R09: ffff888055c5ec08
R10: ffff888055c5ebe8 R11: ffff888055c5e340 R12: ffff88807f3ca400
R13: 000000000000017d R14: dffffc0000000000 R15: dffffc0000000000
FS: 00007fd618295700(0000) GS:ffff8880aec00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c428d5cb00 CR3: 0000000090f6a000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
radix_tree_lookup_slot+0x63/0xa0 lib/radix-tree.c:1079
find_get_entry+0x8c/0x680 mm/filemap.c:1355
pagecache_get_page+0x4a/0x9e0 mm/filemap.c:1465
find_get_page include/linux/pagemap.h:276 [inline]
generic_file_buffered_read mm/filemap.c:1999 [inline]
generic_file_read_iter+0x66a/0x28d0 mm/filemap.c:2273
ext4_file_read_iter+0x14e/0x340 fs/ext4/file.c:75
call_read_iter include/linux/fs.h:1771 [inline]
generic_file_splice_read+0x37d/0x600 fs/splice.c:307
do_splice_to+0x105/0x170 fs/splice.c:880
splice_direct_to_actor+0x222/0x7b0 fs/splice.c:952
do_splice_direct+0x18d/0x230 fs/splice.c:1061
do_sendfile+0x4db/0xbd0 fs/read_write.c:1441
SYSC_sendfile64 fs/read_write.c:1496 [inline]
SyS_sendfile64+0x9d/0x110 fs/read_write.c:1488
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45b399
RSP: 002b:00007fd618294c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007fd6182956d4 RCX: 000000000045b399
RDX: 0000000020d83ff8 RSI: 0000000000000007 RDI: 0000000000000005
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 00008000fffffffb R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000008ca R14: 00000000004ca24d R15: 000000000075bf2c
Code: 83 e0 03 48 83 f8 01 0f 85 d9 01 00 00 e8 f3 7e f9 fa 48 89 d8 48 89 da 49 89 dc 48 c1 e8 03 83 e2 06 49 83 e4 fe 42 0f b6 04 30 <38> d0 7f 08 84 c0 0f 85 28 02 00 00 41 0f b6 0c 24 41 bc 40 00


---
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unread,
Jun 2, 2020, 1:26:10 PM6/2/20
to syzkaller...@googlegroups.com
Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.
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