bisecting fixing commit since 01fd1694b93c92ad54fa684dac9c8068ecda8288
building syzkaller on 040fda588472da50749a3f605e183ad5c02104f4
testing commit 01fd1694b93c92ad54fa684dac9c8068ecda8288 with gcc (GCC) 8.1.0
kernel signature: 66db826a1ee09427c056c6ef521d37068a86a788168d6eabf5ca1fbf6d9d2a2b
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 12cd844a39ed16aa183a820a54fe6f9a0bb4cd14
testing commit 12cd844a39ed16aa183a820a54fe6f9a0bb4cd14 with gcc (GCC) 8.1.0
kernel signature: 63c985ba747af27ee7da83f86d065e7421173b9cc87ae07b11e16f702547ea01
all runs: crashed: WARNING in untrack_pfn
revisions tested: 2, total time: 24m27.634749361s (build: 16m45.530733608s, test: 6m30.907390942s)
the crash still happens on HEAD
commit msg: Linux 4.14.173
crash: WARNING in untrack_pfn
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f0d0ab4f6d4
R13: 00000000004bfd46 R14: 00000000004d1af8 R15: 0000000000000004
------------[ cut here ]------------
WARNING: CPU: 1 PID: 7021 at arch/x86/mm/pat.c:1020 untrack_pfn+0x1ab/0x210 arch/x86/mm/pat.c:1027
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 7021 Comm: syz-executor.0 Not tainted 4.14.173-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:ffff8880779ff8f8 EFLAGS: 00010282
RAX: 00000000ffffffea RBX: ffff888076e7c880 RCX: 0000000000000000
RDX: 0000000000000004 RSI: 0000000000000001 RDI: ffffffff89383800
RBP: ffff8880779ff9c8 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: ffff8880a1994040 R12: 1ffff1100ef3ff21
R13: 0000000000000000 R14: ffff8880779ff9a8 R15: ffff8880779ffa98
 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:00007f0d0ab4ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007f0d0ab4ec90 RCX: 0000000000459879
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f0d0ab4f6d4
R13: 00000000004bfd46 R14: 00000000004d1af8 R15: 0000000000000004
Kernel Offset: disabled
Rebooting in 86400 seconds..