Hello, When using Healer to fuzz the latest Linux kernel, the following crash was triggered. HEAD commit: 4b93c544e90e-thunderbolt: test: split up test cases git tree: upstream console output: https://drive.google.com/file/d/1gi1OlktAs3lQS5uGyqcOmFdGg-hb5ek8/view?usp=sharing kernel config: https://drive.google.com/file/d/1c0u2EeRDhRO-ZCxr9MP2VvAtJd6kfg-p/view?usp=sharing Similar repot: https://groups.google.com/g/syzkaller-bugs/c/N3_ECgVYE0c/m/ubwipYJ6AgAJ Sorry, I don't have a reproducer for this crash, hope the symbolized report can help. If you fix this issue, please add the following tag to the commit: Reported-by: Hao Sun <sunhao.th@xxxxxxxxx> INFO: task syz-executor:13124 blocked for more than 143 seconds. Not tainted 5.14.0+ #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:29232 pid:13124 ppid: 12323 flags:0x00404004 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xcd9/0x2530 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 rwsem_down_read_slowpath+0x4ee/0x9d0 kernel/locking/rwsem.c:993 __down_read_common kernel/locking/rwsem.c:1214 [inline] __down_read kernel/locking/rwsem.c:1223 [inline] down_read+0xe4/0x440 kernel/locking/rwsem.c:1464 iterate_supers+0xdb/0x290 fs/super.c:693 ksys_sync+0x86/0x150 fs/sync.c:114 __do_sys_sync+0xa/0x10 fs/sync.c:125 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x2000000a RSP: 002b:00007f38a62cbbb8 EFLAGS: 00000a83 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 000000002000000a RDX: 0000000000004c01 RSI: 0000000000000003 RDI: 000000000000001c RBP: 00000000000000ab R08: 0000000000000005 R09: 0000000000000006 R10: 0000000000000007 R11: 0000000000000a83 R12: 000000000000000b R13: 000000000000000c R14: 000000000000000d R15: 00007f38a62cbdc0 INFO: task syz-executor:13127 blocked for more than 143 seconds. Not tainted 5.14.0+ #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:27752 pid:13127 ppid: 12323 flags:0x00404004 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xcd9/0x2530 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 rwsem_down_read_slowpath+0x4ee/0x9d0 kernel/locking/rwsem.c:993 __down_read_common kernel/locking/rwsem.c:1214 [inline] __down_read kernel/locking/rwsem.c:1223 [inline] down_read+0xe4/0x440 kernel/locking/rwsem.c:1464 iterate_supers+0xdb/0x290 fs/super.c:693 ksys_sync+0x86/0x150 fs/sync.c:114 __do_sys_sync+0xa/0x10 fs/sync.c:125 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x2000000a RSP: 002b:00007f38a62aabb8 EFLAGS: 00000a83 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 000000002000000a RDX: 0000000000004c01 RSI: 0000000000000003 RDI: 000000000000001c RBP: 00000000000000ab R08: 0000000000000005 R09: 0000000000000006 R10: 0000000000000007 R11: 0000000000000a83 R12: 000000000000000b R13: 000000000000000c R14: 000000000000000d R15: 00007f38a62aadc0 Showing all locks held in the system: 1 lock held by khungtaskd/1360: #0: ffffffff8b97dde0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6446 1 lock held by in:imklog/8202: #0: ffff88801f4d7a70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990 1 lock held by syz-executor/11128: #0: ffff88810f7600e0 (&type->s_umount_key#69/1){+.+.}-{3:3}, at: alloc_super+0x1dd/0xab0 fs/super.c:229 1 lock held by syz-executor/11714: #0: ffff8880163760e0 (&type->s_umount_key#69/1){+.+.}-{3:3}, at: alloc_super+0x1dd/0xab0 fs/super.c:229 1 lock held by syz-executor/12302: #0: ffff888026ad60e0 (&type->s_umount_key#69/1){+.+.}-{3:3}, at: alloc_super+0x1dd/0xab0 fs/super.c:229 1 lock held by syz-executor/13124: #0: ffff88810f7600e0 (&type->s_umount_key#73){.+.+}-{3:3}, at: iterate_supers+0xdb/0x290 fs/super.c:693 1 lock held by syz-executor/13127: #0: ffff88810f7600e0 (&type->s_umount_key#73){.+.+}-{3:3}, at: iterate_supers+0xdb/0x290 fs/super.c:693 1 lock held by syz-executor/15012: #0: ffff88810f7600e0 (&type->s_umount_key#73){.+.+}-{3:3}, at: iterate_supers+0xdb/0x290 fs/super.c:693 1 lock held by syz-executor/15016: #0: ffff88810f7600e0 (&type->s_umount_key#73){.+.+}-{3:3}, at: iterate_supers+0xdb/0x290 fs/super.c:693 1 lock held by syz-executor/15627: #0: ffff88810f7600e0 (&type->s_umount_key#73){.+.+}-{3:3}, at: iterate_supers+0xdb/0x290 fs/super.c:693 1 lock held by syz-executor/15630: #0: ffff88810f7600e0 (&type->s_umount_key#73){.+.+}-{3:3}, at: iterate_supers+0xdb/0x290 fs/super.c:693 1 lock held by syz-executor/16215: #0: ffff88810f7600e0 (&type->s_umount_key#73){.+.+}-{3:3}, at: iterate_supers+0xdb/0x290 fs/super.c:693 1 lock held by syz-executor/16219: #0: ffff88810f7600e0 (&type->s_umount_key#73){.+.+}-{3:3}, at: iterate_supers+0xdb/0x290 fs/super.c:693 ============================================= NMI backtrace for cpu 3 CPU: 3 PID: 1360 Comm: khungtaskd Not tainted 5.14.0+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1e1/0x220 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline] watchdog+0xcc8/0x1010 kernel/hung_task.c:295 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 3 to CPUs 0-2: NMI backtrace for cpu 1 CPU: 1 PID: 4939 Comm: systemd-journal Not tainted 5.14.0+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: 0010:__sanitizer_cov_trace_pc+0x1a/0x40 kernel/kcov.c:197 Code: 00 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 65 48 8b 0c 25 40 f0 01 00 bf 02 00 00 00 48 89 ce 4c 8b 04 24 e8 76 ff ff ff <84> c0 74 20 48 8b 91 20 15 00 00 8b 89 1c 15 00 00 48 8b 02 48 83 RSP: 0018:ffffc9000112fd08 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000059 RCX: ffff888012bb5580 RDX: 0000000000000000 RSI: ffff888012bb5580 RDI: 0000000000000002 RBP: ffff8880125b8151 R08: ffffffff81c7243d R09: 0000000000000000 R10: 0000000000000007 R11: ffffed10024b7000 R12: ffff8880125b80f8 R13: 0000000000000001 R14: ffffea0000496e00 R15: ffffea0000496e00 FS: 00007f5f361678c0(0000) GS:ffff888135c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5f3364d000 CR3: 00000000233d6000 CR4: 0000000000350ee0 Call Trace: PageSlab include/linux/page-flags.h:345 [inline] check_heap_object mm/usercopy.c:238 [inline] __check_object_size mm/usercopy.c:286 [inline] __check_object_size+0x26d/0x450 mm/usercopy.c:256 check_object_size include/linux/thread_info.h:185 [inline] check_copy_size include/linux/thread_info.h:218 [inline] copy_to_user include/linux/uaccess.h:199 [inline] devkmsg_read+0x530/0x750 kernel/printk/printk.c:761 vfs_read+0x1b5/0x600 fs/read_write.c:483 ksys_read+0x12d/0x250 fs/read_write.c:623 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f5f356f7210 Code: 73 01 c3 48 8b 0d 98 7d 20 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d b9 c1 20 00 00 75 10 b8 00 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 4e fc ff ff 48 89 04 24 RSP: 002b:00007ffc1620fa58 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007ffc162124d0 RCX: 00007f5f356f7210 RDX: 0000000000002000 RSI: 00007ffc162102d0 RDI: 0000000000000009 RBP: 0000000000000000 R08: 0000000000000008 R09: 00007ffc162e60f0 R10: 0000000000012664 R11: 0000000000000246 R12: 00007ffc162102d0 R13: 00007ffc16212428 R14: 0000555f702f1958 R15: 0005cb9b366b0203 NMI backtrace for cpu 2 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] NMI backtrace for cpu 2 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] NMI backtrace for cpu 2 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:716 NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] NMI backtrace for cpu 0 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:716 ---------------- Code disassembly (best guess): 0: 00 c3 add %al,%bl 2: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1) 9: 00 00 00 00 d: 0f 1f 00 nopl (%rax) 10: 65 48 8b 0c 25 40 f0 mov %gs:0x1f040,%rcx 17: 01 00 19: bf 02 00 00 00 mov $0x2,%edi 1e: 48 89 ce mov %rcx,%rsi 21: 4c 8b 04 24 mov (%rsp),%r8 25: e8 76 ff ff ff callq 0xffffffa0 * 2a: 84 c0 test %al,%al <-- trapping instruction 2c: 74 20 je 0x4e 2e: 48 8b 91 20 15 00 00 mov 0x1520(%rcx),%rdx 35: 8b 89 1c 15 00 00 mov 0x151c(%rcx),%ecx 3b: 48 8b 02 mov (%rdx),%rax 3e: 48 rex.W 3f: 83 .byte 0x83
