syzbot has found a reproducer for the following issue on: HEAD commit: bb2281fb05e5 Merge tag 'x86_microcode_for_v6.14_rc6' of gi.. git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=159144b7980000 kernel config: https://syzkaller.appspot.com/x/.config?x=523d3ff8e053340a dashboard link: https://syzkaller.appspot.com/bug?extid=6983c03a6a28616e362f compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12cf7078580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10197da8580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/7f163a5da7e8/disk-bb2281fb.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/6841e1105518/vmlinux-bb2281fb.xz kernel image: https://storage.googleapis.com/syzbot-assets/3295ae6e86c0/bzImage-bb2281fb.xz mounted in repro: https://storage.googleapis.com/syzbot-assets/8d22fecc87c0/mount_0.gz fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=17e97da8580000) IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+6983c03a6a28616e362f@xxxxxxxxxxxxxxxxxxxxxxxxx INFO: task syz-executor399:5826 blocked for more than 143 seconds. Not tainted 6.14.0-rc5-syzkaller-00023-gbb2281fb05e5 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor399 state:D stack:27224 pid:5826 tgid:5823 ppid:5821 task_flags:0x400040 flags:0x00004006 Call Trace: <TASK> context_switch kernel/sched/core.c:5378 [inline] __schedule+0x18bc/0x4c40 kernel/sched/core.c:6765 __schedule_loop kernel/sched/core.c:6842 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6857 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6914 rwsem_down_write_slowpath+0xeee/0x13b0 kernel/locking/rwsem.c:1176 __down_write_common kernel/locking/rwsem.c:1304 [inline] __down_write kernel/locking/rwsem.c:1313 [inline] down_write+0x1d7/0x220 kernel/locking/rwsem.c:1578 inode_lock include/linux/fs.h:877 [inline] vfs_unlink+0xe4/0x650 fs/namei.c:4514 do_unlinkat+0x4ae/0x830 fs/namei.c:4589 __do_sys_unlink fs/namei.c:4637 [inline] __se_sys_unlink fs/namei.c:4635 [inline] __x64_sys_unlink+0x47/0x50 fs/namei.c:4635 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb1339de6f9 RSP: 002b:00007fb133974218 EFLAGS: 00000246 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 00007fb133a665f8 RCX: 00007fb1339de6f9 RDX: 00007fb1339b7dc6 RSI: 0000000000000000 RDI: 0000400000000100 RBP: 00007fb133a665f0 R08: 00007ffcb7766927 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0031656c69662f2e R13: 0000400000000100 R14: 0000400000000080 R15: 0000400000000240 </TASK> Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8eb392e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8eb392e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8eb392e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6746 2 locks held by getty/5580: #0: ffff88814e4bb0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900033332f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x616/0x1770 drivers/tty/n_tty.c:2211 2 locks held by syz-executor399/5825: 3 locks held by syz-executor399/5826: #0: ffff888076078420 (sb_writers#10){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:547 #1: ffff888073c182a0 (&sb->s_type->i_mutex_key#14/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:912 [inline] #1: ffff888073c182a0 (&sb->s_type->i_mutex_key#14/1){+.+.}-{4:4}, at: do_unlinkat+0x26a/0x830 fs/namei.c:4576 #2: ffff888073c18910 (&sb->s_type->i_mutex_key#14){++++}-{4:4}, at: inode_lock include/linux/fs.h:877 [inline] #2: ffff888073c18910 (&sb->s_type->i_mutex_key#14){++++}-{4:4}, at: vfs_unlink+0xe4/0x650 fs/namei.c:4514 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.14.0-rc5-syzkaller-00023-gbb2281fb05e5 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:236 [inline] watchdog+0x1058/0x10a0 kernel/hung_task.c:399 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK> Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 5825 Comm: syz-executor399 Not tainted 6.14.0-rc5-syzkaller-00023-gbb2281fb05e5 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:210 Code: 89 fb e8 23 00 00 00 48 8b 3d a4 04 92 0c 48 89 de 5b e9 23 5e 59 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 00 d5 03 00 65 8b 15 30 06 RSP: 0018:ffffc900040c78e8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff888023a2ce00 RCX: ffffffff824af6cf RDX: ffff8880330e5a00 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: ffffffff824af6f1 R09: 1ffff1100f76b200 R10: dffffc0000000000 R11: ffffed100f76b201 R12: 0000000000000008 R13: ffff888023a2c500 R14: 0000000000000200 R15: ffff88807bb59000 FS: 00007fb1339956c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005592141bc600 CR3: 0000000035948000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <NMI> </NMI> <TASK> __bread_gfp+0xca/0x400 fs/buffer.c:1487 sb_bread include/linux/buffer_head.h:346 [inline] __exfat_ent_get fs/exfat/fatent.c:48 [inline] exfat_ent_get+0x14d/0x400 fs/exfat/fatent.c:97 exfat_find_last_cluster+0x15d/0x380 fs/exfat/fatent.c:263 exfat_cont_expand fs/exfat/file.c:40 [inline] exfat_setattr+0xa8d/0x1a90 fs/exfat/file.c:295 notify_change+0xbca/0xe90 fs/attr.c:552 do_truncate+0x220/0x310 fs/open.c:65 vfs_truncate+0x492/0x530 fs/open.c:115 do_sys_truncate+0xdb/0x190 fs/open.c:138 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb1339de6f9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 81 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fb133995218 EFLAGS: 00000246 ORIG_RAX: 000000000000004c RAX: ffffffffffffffda RBX: 00007fb133a665e8 RCX: 00007fb1339de6f9 RDX: ffffffffffffffb0 RSI: 000000000000f000 RDI: 0000400000000080 RBP: 00007fb133a665e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0031656c69662f2e R13: 0000400000000100 R14: 0000400000000080 R15: 0000400000000240 </TASK> --- 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.
