bisecting fixing commit since 01fd1694b93c92ad54fa684dac9c8068ecda8288
building syzkaller on 040fda588472da50749a3f605e183ad5c02104f4
testing commit 01fd1694b93c92ad54fa684dac9c8068ecda8288 with gcc (GCC) 8.1.0
kernel signature: 0e4e24984dae4a2d650daf862d87da05a1fbee7012356f6eaea9fe4a184eb159
run #0: crashed: WARNING in untrack_pfn
run #1: crashed: WARNING in corrupted
run #2: crashed: WARNING in untrack_pfn
run #3: crashed: WARNING in untrack_pfn
run #4: crashed: WARNING in untrack_pfn
run #5: crashed: WARNING in untrack_pfn
run #6: crashed: WARNING in untrack_pfn
run #7: crashed: WARNING in untrack_pfn
run #8: crashed: WARNING in untrack_pfn
run #9: crashed: WARNING in untrack_pfn
testing current HEAD 98db2bf27b9ed2d5ed0b6c9c8a4bfcb127a19796
testing commit 98db2bf27b9ed2d5ed0b6c9c8a4bfcb127a19796 with gcc (GCC) 8.1.0
kernel signature: 4e94bb2d9d7e6625911c0fc96c37b4c406e62cfa57bf8ade9ae4f16f6dd8bfc7
run #0: crashed: WARNING in untrack_pfn
run #1: crashed: WARNING in untrack_pfn
run #2: crashed: WARNING in corrupted
run #3: crashed: WARNING in untrack_pfn
run #4: crashed: WARNING in untrack_pfn
run #5: crashed: WARNING in untrack_pfn
run #6: crashed: WARNING in untrack_pfn
run #7: crashed: WARNING in untrack_pfn
run #8: crashed: WARNING in corrupted
run #9: crashed: WARNING in untrack_pfn
revisions tested: 2, total time: 24m4.585755408s (build: 16m48.605580789s, test: 6m22.136587692s)
the crash still happens on HEAD
commit msg: Linux 4.14.171
crash: WARNING in untrack_pfn
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f8f5f3be6d4
R13: 00000000004bfd46 R14: 00000000004d1af8 R15: 0000000000000004
------------[ cut here ]------------
WARNING: CPU: 1 PID: 7002 at arch/x86/mm/pat.c:1020 untrack_pfn+0x1ab/0x210 arch/x86/mm/pat.c:1027
device hsr_slave_0 entered promiscuous mode
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 7002 Comm: syz-executor.2 Not tainted 4.14.171-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xf7/0x13b lib/dump_stack.c:58
 panic+0x1b0/0x358 kernel/panic.c:183
 __warn.cold.8+0x25/0x2c kernel/panic.c:547
 report_bug+0x1a4/0x1f3 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:177 [inline]
 do_error_trap+0x1bd/0x310 arch/x86/kernel/traps.c:295
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:963
RIP: 0010:untrack_pfn+0x1ab/0x210 arch/x86/mm/pat.c:1020
RSP: 0018:ffff88809b94f8f8 EFLAGS: 00010282
RAX: 00000000ffffffea RBX: ffff8880a8089568 RCX: 0000000000000000
RDX: 0000000000000004 RSI: 0000000000000001 RDI: ffffffff89383840
RBP: ffff88809b94f9c8 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: ffff8880a3d901c0 R12: 1ffff11013729f21
R13: 0000000000000000 R14: ffff88809b94f9a8 R15: ffff88809b94fa98
 unmap_single_vma+0x144/0x300 mm/memory.c:1539
 unmap_vmas+0xe2/0x190 mm/memory.c:1590
 exit_mmap+0x249/0x450 mm/mmap.c:3056
 __mmput kernel/fork.c:930 [inline]
 mmput+0xed/0x3c0 kernel/fork.c:951
 dup_mm kernel/fork.c:1215 [inline]
 copy_mm kernel/fork.c:1254 [inline]
 copy_process.part.37+0x5d6f/0x66e0 kernel/fork.c:1771
 copy_process kernel/fork.c:1586 [inline]
 _do_fork+0x155/0xbb0 kernel/fork.c:2070
 SYSC_clone kernel/fork.c:2180 [inline]
 SyS_clone+0x14/0x20 kernel/fork.c:2174
 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459879
RSP: 002b:00007f8f5f3bdc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007f8f5f3bdc90 RCX: 0000000000459879
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f8f5f3be6d4
R13: 00000000004bfd46 R14: 00000000004d1af8 R15: 0000000000000004
Kernel Offset: disabled
Rebooting in 86400 seconds..