Hello, syzbot found the following crash on: HEAD commit: 8632e9b5 Merge tag 'hyperv-fixes-signed' of git://git.kern.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=11ac6be0100000 kernel config: https://syzkaller.appspot.com/x/.config?x=5d351a1019ed81a2 dashboard link: https://syzkaller.appspot.com/bug?extid=a923008018a2d298247b compiler: gcc (GCC) 9.0.0 20181231 (experimental) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+a923008018a2d298247b@xxxxxxxxxxxxxxxxxxxxxxxxx raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: VM_BUG_ON_PAGE(page_ref_count(page) == 0) ------------[ cut here ]------------ kernel BUG at include/linux/mm.h:699! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 14511 Comm: syz-executor.4 Not tainted 5.7.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:put_page_testzero include/linux/mm.h:699 [inline] RIP: 0010:put_page_testzero include/linux/mm.h:697 [inline] RIP: 0010:release_pages+0x799/0x19b0 mm/swap.c:823 Code: c7 f9 ff ff e8 38 9d dd ff 48 89 ef e8 20 ac ff ff e9 96 fe ff ff e8 26 9d dd ff 48 c7 c6 c0 44 33 88 48 89 ef e8 87 86 09 00 <0f> 0b e8 10 9d dd ff 49 8d 6c 24 ff e9 c5 f9 ff ff 4c 8d 6d 08 31 RSP: 0018:ffffc90007fb7640 EFLAGS: 00010293 RAX: ffff8880a19f4280 RBX: 0000000000000000 RCX: ffffffff819f2d28 RDX: 0000000000000000 RSI: ffffffff819596e9 RDI: ffffea0000000038 RBP: ffffea0000000000 R08: ffff8880a19f4280 R09: ffffed1015cc66a9 R10: ffff8880ae633547 R11: ffffed1015cc66a8 R12: ffffea0000000034 R13: 0000000000000000 R14: dffffc0000000000 R15: 00000000000000c6 FS: 00007fc0946fc700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2142ba1db8 CR3: 000000008859f000 CR4: 00000000001426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: tlb_batch_pages_flush mm/mmu_gather.c:49 [inline] tlb_flush_mmu_free mm/mmu_gather.c:242 [inline] tlb_flush_mmu+0x8d/0x610 mm/mmu_gather.c:249 zap_pte_range mm/memory.c:1158 [inline] zap_pmd_range mm/memory.c:1196 [inline] zap_pud_range mm/memory.c:1225 [inline] zap_p4d_range mm/memory.c:1246 [inline] unmap_page_range+0x198d/0x25d0 mm/memory.c:1267 unmap_single_vma+0x196/0x300 mm/memory.c:1312 unmap_vmas+0x16f/0x2f0 mm/memory.c:1344 exit_mmap+0x2aa/0x510 mm/mmap.c:3150 __mmput kernel/fork.c:1085 [inline] mmput+0x168/0x4b0 kernel/fork.c:1106 exit_mm kernel/exit.c:479 [inline] do_exit+0xa51/0x2dd0 kernel/exit.c:782 do_group_exit+0x125/0x340 kernel/exit.c:893 get_signal+0x47b/0x24e0 kernel/signal.c:2739 do_signal+0x81/0x2240 arch/x86/kernel/signal.c:784 exit_to_usermode_loop+0x26c/0x360 arch/x86/entry/common.c:161 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x6b1/0x7d0 arch/x86/entry/common.c:305 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45c6f7 Code: 48 83 c4 08 48 89 d8 5b 5d c3 66 0f 1f 84 00 00 00 00 00 48 89 e8 48 f7 d8 48 39 c3 0f 92 c0 eb 92 66 90 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 0d b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fc0946fa068 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 000000000045c6f7 RDX: 00007fc0946fa510 RSI: 000000004020ae46 RDI: 0000000000000004 RBP: 0000000020000000 R08: 00007fc0946fa070 R09: 000000000076bfa0 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000fec00000 R13: 0000000000000004 R14: 00000000004cdf60 R15: 000000000076bfac Modules linked in: ---[ end trace 56c4701a85e32af3 ]--- RIP: 0010:put_page_testzero include/linux/mm.h:699 [inline] RIP: 0010:put_page_testzero include/linux/mm.h:697 [inline] RIP: 0010:release_pages+0x799/0x19b0 mm/swap.c:823 Code: c7 f9 ff ff e8 38 9d dd ff 48 89 ef e8 20 ac ff ff e9 96 fe ff ff e8 26 9d dd ff 48 c7 c6 c0 44 33 88 48 89 ef e8 87 86 09 00 <0f> 0b e8 10 9d dd ff 49 8d 6c 24 ff e9 c5 f9 ff ff 4c 8d 6d 08 31 RSP: 0018:ffffc90007fb7640 EFLAGS: 00010293 RAX: ffff8880a19f4280 RBX: 0000000000000000 RCX: ffffffff819f2d28 RDX: 0000000000000000 RSI: ffffffff819596e9 RDI: ffffea0000000038 RBP: ffffea0000000000 R08: ffff8880a19f4280 R09: ffffed1015cc66a9 R10: ffff8880ae633547 R11: ffffed1015cc66a8 R12: ffffea0000000034 R13: 0000000000000000 R14: dffffc0000000000 R15: 00000000000000c6 FS: 00007fc0946fc700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9347e2b000 CR3: 000000004d8bb000 CR4: 00000000001426e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 --- This bug is generated by a bot. 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