On Sun, Oct 16, 2022 at 4:22 AM syzbot wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: bbed346d5a96 Merge branch 'for-next/core' into for-kernelci > 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=12497f8a880000 > kernel config: https://syzkaller.appspot.com/x/.config?x=3a4a45d2d827c1e > dashboard link: https://syzkaller.appspot.com/bug?extid=3a94da2c82ba4f401b9e > compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2 > userspace arch: arm64 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/e8e91bc79312/disk-bbed346d.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/c1cb3fb3b77e/vmlinux-bbed346d.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+3a94da2c82ba4f401b9e@xxxxxxxxxxxxxxxxxxxxxxxxx > > WARNING: possible circular locking dependency detected > 6.0.0-rc7-syzkaller-18095-gbbed346d5a96 #0 Not tainted > ------------------------------------------------------ > syz-executor.5/28633 is trying to acquire lock: > ffff0001126ee890 (&nilfs->ns_sem){++++}-{3:3}, at: nilfs_set_error fs/nilfs2/super.c:92 [inline] > ffff0001126ee890 (&nilfs->ns_sem){++++}-{3:3}, at: __nilfs_error+0xb4/0x284 fs/nilfs2/super.c:137 > > but task is already holding lock: > ffff000123b51e70 (&dat_lock_key > ){.+.+}-{3:3}, at: nilfs_get_block+0x64/0x364 fs/nilfs2/inode.c:84 > > which lock already depends on the new lock. > > > the existing dependency chain (in reverse order) is: > > -> #1 (&dat_lock_key){.+.+}-{3:3}: > down_read+0x5c/0x78 kernel/locking/rwsem.c:1499 > nilfs_count_free_blocks+0x2c/0x6c fs/nilfs2/the_nilfs.c:693 > nilfs_set_log_cursor fs/nilfs2/super.c:236 [inline] > nilfs_cleanup_super+0x118/0x1f0 fs/nilfs2/super.c:318 > nilfs_put_super+0x54/0x9c fs/nilfs2/super.c:472 > generic_shutdown_super+0x8c/0x190 fs/super.c:491 > kill_block_super+0x30/0x78 fs/super.c:1427 > deactivate_locked_super+0x70/0xe8 fs/super.c:332 > deactivate_super+0xd0/0xd4 fs/super.c:363 > cleanup_mnt+0x1f8/0x234 fs/namespace.c:1186 > __cleanup_mnt+0x20/0x30 fs/namespace.c:1193 > task_work_run+0xc4/0x14c kernel/task_work.c:177 > resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] > do_notify_resume+0x174/0x1f0 arch/arm64/kernel/signal.c:1127 > prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline] > exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline] > el0_svc+0x9c/0x150 arch/arm64/kernel/entry-common.c:637 > el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:654 > el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581 > > -> #0 (&nilfs->ns_sem){++++}-{3:3}: > check_prev_add kernel/locking/lockdep.c:3095 [inline] > check_prevs_add kernel/locking/lockdep.c:3214 [inline] > validate_chain kernel/locking/lockdep.c:3829 [inline] > __lock_acquire+0x1530/0x30a4 kernel/locking/lockdep.c:5053 > lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5666 > down_write+0x5c/0xcc kernel/locking/rwsem.c:1552 > nilfs_set_error fs/nilfs2/super.c:92 [inline] > __nilfs_error+0xb4/0x284 fs/nilfs2/super.c:137 > nilfs_bmap_convert_error fs/nilfs2/bmap.c:35 [inline] > nilfs_bmap_lookup_contig+0x98/0xc0 fs/nilfs2/bmap.c:95 > nilfs_get_block+0x7c/0x364 fs/nilfs2/inode.c:85 > block_truncate_page+0x1b4/0xab4 fs/buffer.c:2583 > nilfs_truncate+0xb8/0x178 fs/nilfs2/inode.c:857 > nilfs_setattr+0xf8/0x164 fs/nilfs2/inode.c:955 > notify_change+0x758/0x7f0 fs/attr.c:420 > do_truncate+0x108/0x150 fs/open.c:65 > vfs_truncate+0x1dc/0x24c fs/open.c:111 > do_sys_truncate+0x94/0x140 fs/open.c:134 > __do_sys_truncate fs/open.c:146 [inline] > __se_sys_truncate fs/open.c:144 [inline] > __arm64_sys_truncate+0x20/0x30 fs/open.c:144 > __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] > invoke_syscall arch/arm64/kernel/syscall.c:52 [inline] > el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142 > do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206 > el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:636 > el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:654 > el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581 > > other info that might help us debug this: > > Possible unsafe locking scenario: > > CPU0 CPU1 > ---- ---- > lock(&dat_lock_key); > lock(&nilfs->ns_sem); > lock(&dat_lock_key); > lock(&nilfs->ns_sem); > > *** DEADLOCK *** > > 5 locks held by syz-executor.5/28633: > #0: ffff0001199e2460 (sb_writers#16){.+.+}-{0:0}, at: mnt_want_write+0x20/0x64 fs/namespace.c:393 > #1: ffff0001128b2648 (&sb->s_type->i_mutex_key#26){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline] > #1: ffff0001128b2648 (&sb->s_type->i_mutex_key#26){+.+.}-{3:3}, at: do_truncate+0xf4/0x150 fs/open.c:63 > #2: ffff0001199e2650 (sb_internal#3){.+.+}-{0:0}, at: nilfs_setattr+0x84/0x164 fs/nilfs2/inode.c:947 > #3: ffff0001126eeaa0 (&nilfs->ns_segctor_sem){++++}-{3:3}, at: nilfs_transaction_begin+0x214/0x384 fs/nilfs2/segment.c:223 > #4: ffff000123b51e70 (&dat_lock_key){.+.+}-{3:3}, at: nilfs_get_block+0x64/0x364 fs/nilfs2/inode.c:84 > > stack backtrace: > CPU: 1 PID: 28633 Comm: syz-executor.5 Not tainted 6.0.0-rc7-syzkaller-18095-gbbed346d5a96 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/30/2022 > Call trace: > dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:156 > show_stack+0x2c/0x54 arch/arm64/kernel/stacktrace.c:163 > __dump_stack lib/dump_stack.c:88 [inline] > dump_stack_lvl+0x104/0x16c lib/dump_stack.c:106 > dump_stack+0x1c/0x58 lib/dump_stack.c:113 > print_circular_bug+0x2c4/0x2c8 kernel/locking/lockdep.c:2053 > check_noncircular+0x14c/0x154 kernel/locking/lockdep.c:2175 > check_prev_add kernel/locking/lockdep.c:3095 [inline] > check_prevs_add kernel/locking/lockdep.c:3214 [inline] > validate_chain kernel/locking/lockdep.c:3829 [inline] > __lock_acquire+0x1530/0x30a4 kernel/locking/lockdep.c:5053 > lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5666 > down_write+0x5c/0xcc kernel/locking/rwsem.c:1552 > nilfs_set_error fs/nilfs2/super.c:92 [inline] > __nilfs_error+0xb4/0x284 fs/nilfs2/super.c:137 > nilfs_bmap_convert_error fs/nilfs2/bmap.c:35 [inline] > nilfs_bmap_lookup_contig+0x98/0xc0 fs/nilfs2/bmap.c:95 > nilfs_get_block+0x7c/0x364 fs/nilfs2/inode.c:85 > block_truncate_page+0x1b4/0xab4 fs/buffer.c:2583 > nilfs_truncate+0xb8/0x178 fs/nilfs2/inode.c:857 > nilfs_setattr+0xf8/0x164 fs/nilfs2/inode.c:955 > notify_change+0x758/0x7f0 fs/attr.c:420 > do_truncate+0x108/0x150 fs/open.c:65 > vfs_truncate+0x1dc/0x24c fs/open.c:111 > do_sys_truncate+0x94/0x140 fs/open.c:134 > __do_sys_truncate fs/open.c:146 [inline] > __se_sys_truncate fs/open.c:144 [inline] > __arm64_sys_truncate+0x20/0x30 fs/open.c:144 > __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] > invoke_syscall arch/arm64/kernel/syscall.c:52 [inline] > el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142 > do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206 > el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:636 > el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:654 > el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581 > Remounting filesystem read-only > NILFS (loop5): bad btree node (ino=16, blocknr=15): level = 0, flags = 0x0, nchildren = 0 > NILFS error (device loop5): nilfs_bmap_last_key: broken bmap (inode number=16) > NILFS (loop5): error -5 truncating bmap (ino=16) > > > --- > 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. According to the stack trace, this looks like the same issue as below: #syz dup: possible deadlock in nilfs_count_free_blocks Ryusuke Konishi
