syzbot has found a reproducer for the following issue on: HEAD commit: 4853c74bd7ab Merge tag 'parisc-for-6.5-rc7' of git://git.k.. git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=178eb2efa80000 kernel config: https://syzkaller.appspot.com/x/.config?x=aa796b6080b04102 dashboard link: https://syzkaller.appspot.com/bug?extid=38d04642cea49f3a3d2e compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=171242cfa80000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17934703a80000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/fef982ba26aa/disk-4853c74b.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/633875549882/vmlinux-4853c74b.xz kernel image: https://storage.googleapis.com/syzbot-assets/a1d2d81c82f6/bzImage-4853c74b.xz mounted in repro: https://storage.googleapis.com/syzbot-assets/45ecbb86ca49/mount_4.gz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+38d04642cea49f3a3d2e@xxxxxxxxxxxxxxxxxxxxxxxxx INFO: task syz-executor359:5018 blocked for more than 143 seconds. Not tainted 6.5.0-rc6-syzkaller-00036-g4853c74bd7ab #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor359 state:D stack:27216 pid:5018 ppid:5015 flags:0x00004002 Call Trace: <TASK> context_switch kernel/sched/core.c:5381 [inline] __schedule+0xee1/0x59f0 kernel/sched/core.c:6710 schedule+0xe7/0x1b0 kernel/sched/core.c:6786 wb_wait_for_completion+0x1ae/0x270 fs/fs-writeback.c:192 __writeback_inodes_sb_nr+0x1d8/0x270 fs/fs-writeback.c:2650 sync_filesystem fs/sync.c:54 [inline] sync_filesystem+0xb6/0x280 fs/sync.c:30 generic_shutdown_super+0x74/0x480 fs/super.c:472 kill_block_super+0x64/0xb0 fs/super.c:1417 deactivate_locked_super+0x9a/0x170 fs/super.c:330 deactivate_super+0xde/0x100 fs/super.c:361 cleanup_mnt+0x222/0x3d0 fs/namespace.c:1254 task_work_run+0x14d/0x240 kernel/task_work.c:179 ptrace_notify+0x10c/0x130 kernel/signal.c:2376 ptrace_report_syscall include/linux/ptrace.h:411 [inline] ptrace_report_syscall_exit include/linux/ptrace.h:473 [inline] syscall_exit_work kernel/entry/common.c:252 [inline] syscall_exit_to_user_mode_prepare+0x120/0x220 kernel/entry/common.c:279 __syscall_exit_to_user_mode_work kernel/entry/common.c:284 [inline] syscall_exit_to_user_mode+0xd/0x50 kernel/entry/common.c:297 do_syscall_64+0x44/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f497ef65487 RSP: 002b:00007ffdd57d4148 EFLAGS: 00000206 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f497ef65487 RDX: 0000000000000000 RSI: 000000000000000a RDI: 00007ffdd57d4200 RBP: 00007ffdd57d4200 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000206 R12: 00007ffdd57d5270 R13: 00005555566da6c0 R14: 431bde82d7b634db R15: 00007ffdd57d5290 </TASK> Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/13: #0: ffffffff8c9a67f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x2c/0xe20 kernel/rcu/tasks.h:522 1 lock held by rcu_tasks_trace/14: #0: ffffffff8c9a64f0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x2c/0xe20 kernel/rcu/tasks.h:522 1 lock held by khungtaskd/27: #0: ffffffff8c9a7400 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x340 kernel/locking/lockdep.c:6615 3 locks held by kworker/u4:2/34: 2 locks held by getty/4774: #0: ffff88802cdfa098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900015c02f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xfcb/0x1480 drivers/tty/n_tty.c:2187 1 lock held by syz-executor359/5018: #0: ffff88807b0e80e0 (&type->s_umount_key#42){+.+.}-{3:3}, at: deactivate_super+0xd6/0x100 fs/super.c:360 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 Comm: khungtaskd Not tainted 6.5.0-rc6-syzkaller-00036-g4853c74bd7ab #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 nmi_cpu_backtrace+0x277/0x380 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x2ac/0x310 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xf29/0x11b0 kernel/hung_task.c:379 kthread+0x33a/0x430 kernel/kthread.c:389 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 </TASK> Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 34 Comm: kworker/u4:2 Not tainted 6.5.0-rc6-syzkaller-00036-g4853c74bd7ab #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023 Workqueue: writeback wb_workfn (flush-7:0) RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:200 Code: a6 27 99 02 66 0f 1f 44 00 00 f3 0f 1e fa 48 8b be b0 01 00 00 e8 b0 ff ff ff 31 c0 c3 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 <f3> 0f 1e fa 65 8b 05 dd b0 7d 7e 89 c1 48 8b 34 24 81 e1 00 01 00 RSP: 0018:ffffc90000ab74e8 EFLAGS: 00000206 RAX: 0000000000000000 RBX: ffffea0001c90174 RCX: ffffffff81fa92f9 RDX: ffff8880136fbb80 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000003 R11: 1ffffffff1936441 R12: 0000000000000003 R13: 0000000000000200 R14: 0000000000000003 R15: ffffea0001c90140 FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055fded888928 CR3: 0000000028191000 CR4: 0000000000350ef0 Call Trace: <NMI> </NMI> <TASK> instrument_atomic_read_write include/linux/instrumented.h:96 [inline] atomic_dec_and_test include/linux/atomic/atomic-instrumented.h:1375 [inline] page_ref_dec_and_test include/linux/page_ref.h:210 [inline] put_page_testzero include/linux/mm.h:1028 [inline] folio_put_testzero include/linux/mm.h:1033 [inline] folio_put include/linux/mm.h:1439 [inline] grow_dev_page fs/buffer.c:1093 [inline] grow_buffers fs/buffer.c:1123 [inline] __getblk_slow+0x4b7/0x720 fs/buffer.c:1150 __getblk_gfp fs/buffer.c:1445 [inline] __bread_gfp+0x215/0x310 fs/buffer.c:1479 sb_bread include/linux/buffer_head.h:351 [inline] exfat_get_dentry_set+0x283/0xc10 fs/exfat/dir.c:878 __exfat_write_inode+0x2c0/0x9e0 fs/exfat/inode.c:45 exfat_write_inode+0xad/0x130 fs/exfat/inode.c:94 write_inode fs/fs-writeback.c:1456 [inline] __writeback_single_inode+0xa81/0xe70 fs/fs-writeback.c:1668 writeback_sb_inodes+0x599/0x1010 fs/fs-writeback.c:1894 wb_writeback+0x2a5/0xa90 fs/fs-writeback.c:2070 wb_do_writeback fs/fs-writeback.c:2217 [inline] wb_workfn+0x29c/0xfd0 fs/fs-writeback.c:2257 process_one_work+0xaa2/0x16f0 kernel/workqueue.c:2600 worker_thread+0x687/0x1110 kernel/workqueue.c:2751 kthread+0x33a/0x430 kernel/kthread.c:389 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 </TASK> INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.463 msecs --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.
