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UBSAN: shift-out-of-bounds in net/core/gen_estimator.c:83:38
shift exponent -1 is negative
CPU: 1 PID: 8656 Comm: syz-executor.5 Not tainted 5.10.0-next-20201218-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:120
 ubsan_epilogue+0xb/0x5a lib/ubsan.c:148
 __ubsan_handle_shift_out_of_bounds.cold+0xb1/0x181 lib/ubsan.c:395
 est_timer.cold+0xbb/0x12d net/core/gen_estimator.c:83
 call_timer_fn+0x1a5/0x710 kernel/time/timer.c:1417
 expire_timers kernel/time/timer.c:1462 [inline]
 __run_timers.part.0+0x692/0xa80 kernel/time/timer.c:1731
 __run_timers kernel/time/timer.c:1712 [inline]
 run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1744
 __do_softirq+0x2bc/0xa77 kernel/softirq.c:343
 asm_call_irq_on_stack+0xf/0x20
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline]
 do_softirq_own_stack+0xaa/0xd0 arch/x86/kernel/irq_64.c:77
 invoke_softirq kernel/softirq.c:226 [inline]
 __irq_exit_rcu+0x17f/0x200 kernel/softirq.c:420
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:432
 sysvec_apic_timer_interrupt+0x4d/0x100 arch/x86/kernel/apic/apic.c:1096
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:628
RIP: 0010:check_kcov_mode+0x7/0x40 kernel/kcov.c:163
Code: fe ff ff 48 89 df e8 c8 58 43 00 e9 a1 fe ff ff 48 8b 3c 24 e8 ba 58 43 00 e9 18 fe ff ff cc cc cc cc cc 65 8b 05 d9 ac 8e 7e <89> c2 81 e2 00 01 00 00 a9 00 01 ff 00 74 10 31 c0 85 d2 74 15 8b
RSP: 0018:ffffc90001b1fb10 EFLAGS: 00000246
RAX: 0000000080000001 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 1ffff92000363fae RSI: ffff888017531b00 RDI: 0000000000000003
RBP: ffffc90001b1fd24 R08: 0000000000000000 R09: ffffffff8b40a083
R10: ffffffff8143b100 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffff888021be0000 R15: ffff888021be04ec
 write_comp_data kernel/kcov.c:218 [inline]
 __sanitizer_cov_trace_const_cmp4+0x1c/0x70 kernel/kcov.c:284
 wait_task_stopped kernel/exit.c:1165 [inline]
 wait_consider_task+0x3f0/0x3d10 kernel/exit.c:1369
 do_wait_thread kernel/exit.c:1395 [inline]
 do_wait+0x376/0xa20 kernel/exit.c:1466
 kernel_wait4+0x14c/0x260 kernel/exit.c:1628
 __do_sys_wait4+0x13f/0x150 kernel/exit.c:1656
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x417d3b
Code: 54 55 41 89 d4 53 48 89 f5 89 fb 48 83 ec 10 e8 7b f9 ff ff 45 31 d2 41 89 c0 49 63 d4 48 89 ee 48 63 fb b8 3d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 19 44 89 c7 89 44 24 0c e8 b1 f9 ff ff 8b 44
RSP: 002b:00007ffd92b07c90 EFLAGS: 00000246 ORIG_RAX: 000000000000003d
RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 0000000000417d3b
RDX: 0000000040000001 RSI: 00007ffd92b07cf0 RDI: ffffffffffffffff
RBP: 00007ffd92b07cf0 R08: 0000000000000000 R09: 0000000002192940
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000040000001
R13: 00007ffd92b07cf0 R14: 00007ffd92b07d00 R15: 000000000005c8e5
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