general protection fault, probably for non-canonical address 0xdffffc00000000b2: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000590-0x0000000000000597] CPU: 0 PID: 10131 Comm: syz-executor.1 Not tainted 5.14.0-rc6-next-20210817-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:latency_exceeded block/blk-wbt.c:237 [inline] RIP: 0010:wb_timer_fn+0x149/0x1740 block/blk-wbt.c:360 Code: 03 80 3c 02 00 0f 85 68 13 00 00 48 8b 9b c8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d bb 90 05 00 00 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 35 13 00 00 48 8b 9b 90 05 00 00 48 b8 00 00 00 RSP: 0018:ffffc90000007cd8 EFLAGS: 00010206 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000100 RDX: 00000000000000b2 RSI: ffffffff83d23d1d RDI: 0000000000000590 RBP: ffff88801b3f0c00 R08: 0000000000000003 R09: ffff88801b3f0d83 R10: ffffffff83d23d12 R11: 0000000000000000 R12: 0000000000000003 R13: 0000000000000000 R14: ffff88801b334a80 R15: ffff88801b3f0cd0 FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000005670f0 CR3: 0000000083caf000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers.part.0+0x675/0xa20 kernel/time/timer.c:1734 __run_timers kernel/time/timer.c:1715 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:636 irq_exit_rcu+0x5/0x20 kernel/softirq.c:648 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:memset_erms+0xb/0x10 arch/x86/lib/memset_64.S:65 Code: 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 f3 aa <4c> 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 01 01 RSP: 0018:ffffc9000457f700 EFLAGS: 00000202 RAX: 0000000000000000 RBX: ffffc9000457f7e0 RCX: 0000000000000000 RDX: 0000000000000060 RSI: 0000000000000000 RDI: ffffc9000457f7b8 RBP: ffff8880786cd580 R08: 0000000000000001 R09: ffffc9000457f758 R10: fffff520008afef6 R11: 000000000000003f R12: 0000000000000000 R13: ffffc9000457f780 R14: ffff8880786cd580 R15: ffffc9000457f758 memset include/linux/fortify-string.h:175 [inline] __unwind_start+0x2a/0x800 arch/x86/kernel/unwind_orc.c:627 unwind_start arch/x86/include/asm/unwind.h:60 [inline] arch_stack_walk+0x5c/0xe0 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:121 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free mm/kasan/common.c:328 [inline] __kasan_slab_free+0xfb/0x130 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1681 [inline] slab_free_freelist_hook+0x7e/0x190 mm/slub.c:1706 slab_free mm/slub.c:3463 [inline] kmem_cache_free+0x8a/0x5a0 mm/slub.c:3479 free_fs_struct fs/fs_struct.c:92 [inline] exit_fs+0x123/0x170 fs/fs_struct.c:108 do_exit+0xb7c/0x2a30 kernel/exit.c:821 do_group_exit+0x125/0x310 kernel/exit.c:922 get_signal+0x47f/0x2160 kernel/signal.c:2846 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:865 handle_signal_work kernel/entry/common.c:148 [inline] exit_to_user_mode_loop kernel/entry/common.c:172 [inline] exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:209 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665e9 Code: Unable to access opcode bytes at RIP 0x4665bf. RSP: 002b:00007f27f469c188 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: fffffffffffffe00 RBX: 000000000056bf80 RCX: 00000000004665e9 RDX: 0000000000000001 RSI: 0000000020000600 RDI: 0000000000000005 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 R13: 00007ffe8fcdd51f R14: 00007f27f469c300 R15: 0000000000022000 Modules linked in: ---[ end trace c674d97716085674 ]--- RIP: 0010:latency_exceeded block/blk-wbt.c:237 [inline] RIP: 0010:wb_timer_fn+0x149/0x1740 block/blk-wbt.c:360 Code: 03 80 3c 02 00 0f 85 68 13 00 00 48 8b 9b c8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d bb 90 05 00 00 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 35 13 00 00 48 8b 9b 90 05 00 00 48 b8 00 00 00 RSP: 0018:ffffc90000007cd8 EFLAGS: 00010206 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000100 RDX: 00000000000000b2 RSI: ffffffff83d23d1d RDI: 0000000000000590 RBP: ffff88801b3f0c00 R08: 0000000000000003 R09: ffff88801b3f0d83 R10: ffffffff83d23d12 R11: 0000000000000000 R12: 0000000000000003 R13: 0000000000000000 R14: ffff88801b334a80 R15: ffff88801b3f0cd0 FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000005670f0 CR3: 0000000083caf000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 03 80 3c 02 00 0f add 0xf00023c(%rax),%eax 6: 85 68 13 test %ebp,0x13(%rax) 9: 00 00 add %al,(%rax) b: 48 8b 9b c8 00 00 00 mov 0xc8(%rbx),%rbx 12: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 19: fc ff df 1c: 48 8d bb 90 05 00 00 lea 0x590(%rbx),%rdi 23: 48 89 fa mov %rdi,%rdx 26: 48 c1 ea 03 shr $0x3,%rdx 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction 2e: 0f 85 35 13 00 00 jne 0x1369 34: 48 8b 9b 90 05 00 00 mov 0x590(%rbx),%rbx 3b: 48 rex.W 3c: b8 .byte 0xb8 3d: 00 00 add %al,(%rax)