bisecting fixing commit since dafd634415a7f9892a6fcc99c540fe567ab42c92
building syzkaller on 2f661ec405cb3975128e9851c7a5979d92d001f1
testing commit dafd634415a7f9892a6fcc99c540fe567ab42c92 with gcc (GCC) 8.1.0
kernel signature: ca46f80d5b02fea00917440c3bbb800ffa26b5f8
all runs: crashed: WARNING in check_for_bios_corruption
testing current HEAD cb1f9a169a0e197f93816ace48a6520e8640809d
testing commit cb1f9a169a0e197f93816ace48a6520e8640809d with gcc (GCC) 8.1.0
kernel signature: 509f58b9ff380d47e000b688452bbd15610e9849
all runs: crashed: WARNING in check_for_bios_corruption
revisions tested: 2, total time: 24m17.102470073s (build: 16m46.682110187s, test: 6m42.488927933s)
the crash still happens on HEAD
commit msg: Linux 4.19.94
crash: WARNING in check_for_bios_corruption
Corrupted low memory at 0000000089a0bf6a (2900 phys) = 000000e8
------------[ cut here ]------------
Memory corruption detected in low memory
WARNING: CPU: 0 PID: 14 at arch/x86/kernel/check.c:157 check_for_bios_corruption+0x10c/0x1d0 arch/x86/kernel/check.c:157
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 14 Comm: kworker/0:1 Not tainted 4.19.94-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events check_corruption
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x123/0x177 lib/dump_stack.c:118
 panic+0x1cd/0x375 kernel/panic.c:186
 __warn.cold.8+0x1b/0x3e kernel/panic.c:541
 report_bug+0x1a4/0x200 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x200/0x350 arch/x86/kernel/traps.c:296
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1037
RIP: 0010:check_for_bios_corruption+0x10c/0x1d0 arch/x86/kernel/check.c:157
Code: c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d c3 c3 80 3d 9f e5 83 07 00 75 e7 48 c7 c7 40 5d c7 86 c6 05 8f e5 83 07 01 e8 c7 75 0f 00 <0f> 0b eb d0 48 89 df 89 55 d0 e8 05 3f 67 00 8b 55 d0 49 b8 00 00
RSP: 0018:ffff8880aa36fd08 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff888000010000 RCX: 0000000000000000
RDX: 0000000000000004 RSI: ffffffff86ff2420 RDI: ffffffff89a866a0
RBP: ffff8880aa36fd40 R08: ffffed1015d45079 R09: ffffed1015d45078
R10: ffffed1015d45078 R11: ffff8880aea283c7 R12: ffff888000010000
R13: dffffc0000000000 R14: 0000000000000001 R15: ffffffff88ea80a0
 check_corruption+0xd/0x63 arch/x86/kernel/check.c:165
 process_one_work+0x830/0x1670 kernel/workqueue.c:2153
 worker_thread+0x85/0xb60 kernel/workqueue.c:2296
 kthread+0x324/0x3e0 kernel/kthread.c:246
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Kernel Offset: disabled
Rebooting in 86400 seconds..