On Mon, Feb 19, 2024 at 7:54 PM syzbot wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: f735966ee23c Merge branches 'for-next/reorg-va-space' and .. > git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci > console output: https://syzkaller.appspot.com/x/log.txt?x=12dbb3dc180000 > kernel config: https://syzkaller.appspot.com/x/.config?x=d47605a39da2cf06 > dashboard link: https://syzkaller.appspot.com/bug?extid=c8166c541d3971bf6c87 > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 > userspace arch: arm64 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/bdea2316c4db/disk-f735966e.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/75ba7806a91c/vmlinux-f735966e.xz > kernel image: https://storage.googleapis.com/syzbot-assets/208f119d45ed/Image-f735966e.gz.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+c8166c541d3971bf6c87@xxxxxxxxxxxxxxxxxxxxxxxxx > > INFO: task segctord:26558 blocked for more than 143 seconds. > Not tainted 6.8.0-rc3-syzkaller-gf735966ee23c #0 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > task:segctord state:D stack:0 pid:26558 tgid:26558 ppid:2 flags:0x00000008 > Call trace: > __switch_to+0x314/0x560 arch/arm64/kernel/process.c:556 > context_switch kernel/sched/core.c:5400 [inline] > __schedule+0x1498/0x24b4 kernel/sched/core.c:6727 > __schedule_loop kernel/sched/core.c:6802 [inline] > schedule+0xb8/0x19c kernel/sched/core.c:6817 > schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:6874 > rwsem_down_write_slowpath+0xcfc/0x1aa0 kernel/locking/rwsem.c:1178 > __down_write_common kernel/locking/rwsem.c:1306 [inline] > __down_write kernel/locking/rwsem.c:1315 [inline] > down_write+0xb4/0xc0 kernel/locking/rwsem.c:1580 > nilfs_transaction_lock+0x178/0x33c fs/nilfs2/segment.c:357 > nilfs_segctor_thread_construct fs/nilfs2/segment.c:2523 [inline] > nilfs_segctor_thread+0x3cc/0xd78 fs/nilfs2/segment.c:2608 > kthread+0x288/0x310 kernel/kthread.c:388 > ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860 > > Showing all locks held in the system: > 1 lock held by khungtaskd/29: > #0: ffff80008ee43fc0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:297 > 2 locks held by getty/5931: > #0: ffff0000d82710a0 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340 > #1: ffff800093fe72f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41c/0x1228 drivers/tty/n_tty.c:2201 > 1 lock held by syz-executor.0/6205: > #0: ffff0000d6d12c68 (&pipe->mutex/1){+.+.}-{3:3}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:297 > 2 locks held by kworker/u4:26/13298: > 6 locks held by syz-executor.2/26553: > 1 lock held by segctord/26558: > #0: ffff00011fc2d2a0 > (&nilfs->ns_segctor_sem){++++}-{3:3}, at: nilfs_transaction_lock+0x178/0x33c fs/nilfs2/segment.c:357 > 1 lock held by syz-executor.3/11586: > #0: ffff0000c346f8b8 (&nft_net->commit_mutex){+.+.}-{3:3}, at: nf_tables_valid_genid+0x3c/0xd4 net/netfilter/nf_tables_api.c:10624 > 1 lock held by syz-executor.1/11588: > 1 lock held by syz-executor.2/11593: > #0: ffff0001485282b8 (&nft_net->commit_mutex){+.+.}-{3:3}, at: nf_tables_valid_genid+0x3c/0xd4 net/netfilter/nf_tables_api.c:10624 > 1 lock held by syz-executor.4/11594: > #0: ffff0000d343fcb8 (&nft_net->commit_mutex){+.+.}-{3:3}, at: nf_tables_valid_genid+0x3c/0xd4 net/netfilter/nf_tables_api.c:10624 > 4 locks held by syz-executor.0/11595: > #0: ffff0001b400ef58 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:559 [inline] > #0: ffff0001b400ef58 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock kernel/sched/sched.h:1385 [inline] > #0: ffff0001b400ef58 (&rq->__lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1699 [inline] > #0: ffff0001b400ef58 (&rq->__lock){-.-.}-{2:2}, at: __schedule+0x2e0/0x24b4 kernel/sched/core.c:6643 > #1: ffff0001b3ffac88 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x3c0/0x618 kernel/sched/psi.c:988 > #2: ffff0001b401cc88 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_change+0x100/0x234 kernel/sched/psi.c:912 > #3: ffff0001b401cc88 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_change+0x100/0x234 kernel/sched/psi.c:912 > > ============================================= > > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > If the report is already addressed, let syzbot know by replying with: > #syz fix: exact-commit-title > > If you want to overwrite report's subsystems, reply with: > #syz set subsystems: new-subsystem > (See the list of subsystem names on the web dashboard) > > If the report is a duplicate of another one, reply with: > #syz dup: exact-subject-of-another-report > > If you want to undo deduplication, reply with: > #syz undup This is difficult to handle as there is no reproducer and lack of information, but one of the fixes merged in 6.8-rc4 is related to this task hang, so I would like to see if it can be reproduced in 6.8-rc4 or later. Ryusuke Konishi
