Hello, When using Healer to fuzz the latest Linux kernel, the following crash was triggered. HEAD commit: 0513e464f900 Merge tag 'perf-tools-fixes-for-v5.15-2021-09-27' git tree: upstream console output: https://drive.google.com/file/d/1EUGmGiPEMh6IuR3fukiHWFlCBR8flhyB/view?usp=sharing kernel config: https://drive.google.com/file/d/1Jqhc4DpCVE8X7d-XBdQnrMoQzifTG5ho/view?usp=sharing 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> rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...0: (2 ticks this GP) idle=437/1/0x4000000000000000 softirq=7937/7937 fqs=2360 rcu: 2-...0: (123 ticks this GP) idle=e27/1/0x4000000000000000 softirq=8738/8738 fqs=2360 (detected by 1, t=10530 jiffies, g=9469, q=85) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 9701 Comm: syz-executor Not tainted 5.15.0-rc3+ #21 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 RIP: 0010:kvm_wait+0x4a/0x70 arch/x86/kernel/kvm.c:893 Code: 5d c3 89 f3 48 89 fd 9c 58 fa f6 c4 02 75 30 0f b6 45 00 38 c3 74 16 e8 f4 81 25 00 fb 5b 5d c3 eb 07 0f 00 2d 15 c4 6d 03 f4 <5b> 5d c3 e8 de 81 25 00 eb 07 0f 00 2d 03 c4 6d 03 fb f4 eb c0 e8 RSP: 0018:ffffc90000003e00 EFLAGS: 00000046 RAX: 0000000000000003 RBX: ffff8881019e0338 RCX: 0000000000000008 RDX: 0000000000000000 RSI: 0000000000000003 RDI: ffff8881019e0338 RBP: ffff88807dc2a600 R08: 0000000000000000 R09: 0000000000000001 R10: ffffc90000003d20 R11: 0000000000000005 R12: 0000000000000001 R13: 0000000000000100 R14: 0000000000000000 R15: 0000000000040000 FS: 00007fdb8fc96700(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe208c8f010 CR3: 000000010b7ef000 CR4: 0000000000750ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <IRQ> pv_wait arch/x86/include/asm/paravirt.h:597 [inline] pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline] __pv_queued_spin_lock_slowpath+0x262/0x330 kernel/locking/qspinlock.c:508 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline] queued_spin_lock include/asm-generic/qspinlock.h:85 [inline] do_raw_spin_lock+0xb6/0xc0 kernel/locking/spinlock_debug.c:115 spin_lock include/linux/spinlock.h:363 [inline] drm_handle_vblank+0x86/0x530 drivers/gpu/drm/drm_vblank.c:1951 vkms_vblank_simulate+0x5a/0x190 drivers/gpu/drm/vkms/vkms_crtc.c:29 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0xb8/0x610 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0xfe/0x280 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x9c/0x2c0 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x99/0xc0 arch/x86/kernel/apic/apic.c:1097 </IRQ> asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:clear_page_erms+0x7/0x10 arch/x86/lib/clear_page_64.S:49 Code: 48 89 47 18 48 89 47 20 48 89 47 28 48 89 47 30 48 89 47 38 48 8d 7f 40 75 d9 90 c3 0f 1f 80 00 00 00 00 b9 00 10 00 00 31 c0 <f3> aa c3 cc cc cc cc cc cc 41 57 41 56 41 55 41 54 55 53 48 89 fb RSP: 0018:ffffc9000358f4c8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000241e80 RCX: 0000000000001000 RDX: ffff88800ed3a280 RSI: 0000000000000001 RDI: ffff88800907a000 RBP: 0000000000241ec0 R08: 0000000000001000 R09: 0000000000000001 R10: ffffc9000358f4a8 R11: 0000000000000003 R12: ffff888000000000 R13: 0000000000012c50 R14: 0000000000000000 R15: ffff88807fffb700 clear_page arch/x86/include/asm/page_64.h:49 [inline] clear_highpage include/linux/highmem.h:181 [inline] kernel_init_free_pages.part.95+0x67/0xa0 mm/page_alloc.c:1278 kernel_init_free_pages mm/page_alloc.c:1267 [inline] post_alloc_hook+0x70/0x110 mm/page_alloc.c:2414 prep_new_page+0x16/0x50 mm/page_alloc.c:2424 get_page_from_freelist+0x64d/0x29a0 mm/page_alloc.c:4153 __alloc_pages+0xde/0x2a0 mm/page_alloc.c:5375 alloc_pages+0x85/0x150 mm/mempolicy.c:2197 alloc_slab_page mm/slub.c:1763 [inline] allocate_slab mm/slub.c:1900 [inline] new_slab+0x2ce/0x4f0 mm/slub.c:1963 ___slab_alloc+0x90e/0xec0 mm/slub.c:2994 __slab_alloc.isra.91+0x4f/0xb0 mm/slub.c:3081 slab_alloc_node mm/slub.c:3172 [inline] slab_alloc mm/slub.c:3214 [inline] kmem_cache_alloc+0x25f/0x280 mm/slub.c:3219 kmem_cache_zalloc include/linux/slab.h:711 [inline] alloc_buffer_head+0x1c/0xa0 fs/buffer.c:3309 alloc_page_buffers+0x155/0x390 fs/buffer.c:832 create_empty_buffers+0x24/0x310 fs/buffer.c:1560 ext4_block_write_begin+0x6ec/0x980 fs/ext4/inode.c:1060 ext4_da_write_begin+0x275/0x610 fs/ext4/inode.c:3021 generic_perform_write+0xce/0x220 mm/filemap.c:3770 ext4_buffered_write_iter+0xd6/0x190 fs/ext4/file.c:269 ext4_file_write_iter+0x80/0x940 fs/ext4/file.c:680 call_write_iter include/linux/fs.h:2163 [inline] do_iter_readv_writev+0x1e8/0x2b0 fs/read_write.c:729 do_iter_write+0xaf/0x250 fs/read_write.c:855 vfs_iter_write+0x38/0x60 fs/read_write.c:896 iter_file_splice_write+0x2d8/0x450 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0x4a/0x80 fs/splice.c:936 splice_direct_to_actor+0x123/0x2d0 fs/splice.c:891 do_splice_direct+0xc3/0x110 fs/splice.c:979 do_sendfile+0x338/0x740 fs/read_write.c:1249 __do_sys_sendfile64 fs/read_write.c:1314 [inline] __se_sys_sendfile64 fs/read_write.c:1300 [inline] __x64_sys_sendfile64+0xc7/0xe0 fs/read_write.c:1300 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x34/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x46ae99 Code: f7 d8 64 89 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fdb8fc95c48 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 000000000078c0a0 RCX: 000000000046ae99 RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000003 RBP: 00000000004e4809 R08: 0000000000000000 R09: 0000000000000000 R10: 00008400fffffffb R11: 0000000000000246 R12: 000000000078c0a0 R13: 0000000000000000 R14: 000000000078c0a0 R15: 00007fffa528c490 Sending NMI from CPU 1 to CPUs 2: NMI backtrace for cpu 2 CPU: 2 PID: 27 Comm: ksoftirqd/2 Not tainted 5.15.0-rc3+ #21 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 RIP: 0010:__lock_acquire+0x7de/0x1d60 kernel/locking/lockdep.c:5010 Code: f0 09 00 00 0f 8d 0e 03 00 00 49 63 c4 48 89 ee 48 8d 04 80 49 8d 3c c6 e8 1f 37 f9 02 85 c0 74 d8 4c 8b 34 24 44 8b 64 24 44 <44> 8b 05 d3 36 e2 04 45 85 c0 75 51 8b 7c 24 08 85 ff 0f 85 18 05 RSP: 0018:ffffc90000727b28 EFLAGS: 00010046 RAX: 0000000000000000 RBX: ffff888009900a70 RCX: 000000000b087fe1 RDX: 0000000000000008 RSI: 0000000000000000 RDI: ffff888009900000 RBP: 0000000000000057 R08: ffffffff8816e4e0 R09: 0000000000000001 R10: ffffc90000727b28 R11: 0000000000000003 R12: 0000000000000000 R13: ffff888009900000 R14: ffff8880099009f8 R15: 10b087fec69640ce FS: 0000000000000000(0000) GS:ffff88807dd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000736090 CR3: 000000000588a000 CR4: 0000000000750ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: lock_acquire+0x1f9/0x340 kernel/locking/lockdep.c:5625 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x38/0x50 kernel/locking/spinlock.c:162 lock_hrtimer_base+0x2f/0x70 kernel/time/hrtimer.c:173 hrtimer_try_to_cancel+0x6d/0x270 kernel/time/hrtimer.c:1331 hrtimer_cancel+0x12/0x30 kernel/time/hrtimer.c:1443 __disable_vblank drivers/gpu/drm/drm_vblank.c:434 [inline] drm_vblank_disable_and_save+0xca/0x130 drivers/gpu/drm/drm_vblank.c:478 vblank_disable_fn+0x83/0xa0 drivers/gpu/drm/drm_vblank.c:495 call_timer_fn+0xcb/0x3f0 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers kernel/time/timer.c:1734 [inline] run_timer_softirq+0x6bd/0x820 kernel/time/timer.c:1747 __do_softirq+0xe9/0x561 kernel/softirq.c:558 run_ksoftirqd+0x2d/0x60 kernel/softirq.c:920 smpboot_thread_fn+0x225/0x320 kernel/smpboot.c:164 kthread+0x178/0x1b0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 ---------------- Code disassembly (best guess): 0: 5d pop %rbp 1: c3 retq 2: 89 f3 mov %esi,%ebx 4: 48 89 fd mov %rdi,%rbp 7: 9c pushfq 8: 58 pop %rax 9: fa cli a: f6 c4 02 test $0x2,%ah d: 75 30 jne 0x3f f: 0f b6 45 00 movzbl 0x0(%rbp),%eax 13: 38 c3 cmp %al,%bl 15: 74 16 je 0x2d 17: e8 f4 81 25 00 callq 0x258210 1c: fb sti 1d: 5b pop %rbx 1e: 5d pop %rbp 1f: c3 retq 20: eb 07 jmp 0x29 22: 0f 00 2d 15 c4 6d 03 verw 0x36dc415(%rip) # 0x36dc43e 29: f4 hlt * 2a: 5b pop %rbx <-- trapping instruction 2b: 5d pop %rbp 2c: c3 retq 2d: e8 de 81 25 00 callq 0x258210 32: eb 07 jmp 0x3b 34: 0f 00 2d 03 c4 6d 03 verw 0x36dc403(%rip) # 0x36dc43e 3b: fb sti 3c: f4 hlt 3d: eb c0 jmp 0xffffffff 3f: e8 .byte 0xe8
