bisecting fixing commit since f4d51dffc6c01a9e94650d95ce0104964f8ae822
building syzkaller on abf9ba4fc75d9b29af15625d44dcfc1360fad3b7
testing commit f4d51dffc6c01a9e94650d95ce0104964f8ae822 with gcc (GCC) 8.1.0
kernel signature: 03843cb8e7fb124bff29e63e6c98263e466cf82567f0b8417054828df09e9a8c
all runs: crashed: BUG: unable to handle kernel paging request in cfb_imageblit
testing current HEAD b5fc7a89e58bcc059a3d5e4db79c481fb437de59
testing commit b5fc7a89e58bcc059a3d5e4db79c481fb437de59 with gcc (GCC) 8.1.0
kernel signature: e49362afc973b0f48d8f266d42cce349988fb5e2a41484a26661b8e3c4320bc5
all runs: crashed: BUG: unable to handle kernel paging request in cfb_imageblit
revisions tested: 2, total time: 16m39.509229882s (build: 10m4.638321966s, test: 6m11.377055057s)
the crash still happens on HEAD
commit msg: Merge tag 'overflow-v5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
crash: BUG: unable to handle kernel paging request in cfb_imageblit
BUG: unable to handle page fault for address: ffff888001000000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0003) - permissions violation
PGD 6c01067 P4D 6c01067 PUD 6c02067 PMD 80000000010001e1 
Oops: 0003 [#1] PREEMPT SMP
CPU: 1 PID: 8375 Comm: syz-executor.5 Not tainted 5.9.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__writel arch/x86/include/asm/io.h:71 [inline]
RIP: 0010:slow_imageblit drivers/video/fbdev/core/cfbimgblt.c:178 [inline]
RIP: 0010:cfb_imageblit+0x188/0x4c0 drivers/video/fbdev/core/cfbimgblt.c:302
Code: c9 41 d3 fa 89 d1 41 83 e2 01 44 8b 54 24 18 44 0f 45 54 24 14 45 89 d5 41 d3 e5 44 09 e8 41 39 d6 4d 89 c5 77 1d 49 83 c5 04 <41> 89 00 b9 20 00 00 00 b8 00 00 00 00 29 d1 41 d3 ea 41 39 d6 41
RSP: 0018:ffffc9000296fb50 EFLAGS: 00010282
RAX: 0000000070707070 RBX: ffff888001000000 RCX: 000000000000001c
RDX: 000000000000001c RSI: 000000000000000f RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff888001000000 R09: 0000000000000000
R10: 0000000000000007 R11: ffff88812b130fd0 R12: ffff888001000000
R13: ffff888001000004 R14: 000000000000001c R15: ffff88812b130fd0
FS:  0000000000000000(0000) GS:ffff88812c100000(0063) knlGS:00000000f7774b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: ffff888001000000 CR3: 000000010e40c000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 bit_putcs_unaligned drivers/video/fbdev/core/bitblit.c:139 [inline]
 bit_putcs+0x27f/0x500 drivers/video/fbdev/core/bitblit.c:188
 fbcon_putcs+0xe4/0x100 drivers/video/fbdev/core/fbcon.c:1308
 con_flush drivers/tty/vt/vt.c:2575 [inline]
 vc_con_write_normal drivers/tty/vt/vt.c:2803 [inline]
 do_con_write+0x2db/0x9b0 drivers/tty/vt/vt.c:2910
 con_write+0xa/0x40 drivers/tty/vt/vt.c:3250
 process_output_block drivers/tty/n_tty.c:595 [inline]
 n_tty_write+0x1a9/0x4e0 drivers/tty/n_tty.c:2333
 do_tty_write drivers/tty/tty_io.c:962 [inline]
 tty_write+0x15f/0x320 drivers/tty/tty_io.c:1046
 vfs_write+0xc7/0x230 fs/read_write.c:584
 ksys_write+0x5a/0xd0 fs/read_write.c:639
 do_syscall_32_irqs_on arch/x86/entry/common.c:78 [inline]
 __do_fast_syscall_32+0x56/0x80 arch/x86/entry/common.c:137
 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:160
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7f9b549
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000f77740cc EFLAGS: 00000296 ORIG_RAX: 0000000000000004
RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 0000000020001440
RDX: 0000000000001006 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
CR2: ffff888001000000
---[ end trace b1d0192999d8f392 ]---
RIP: 0010:__writel arch/x86/include/asm/io.h:71 [inline]
RIP: 0010:slow_imageblit drivers/video/fbdev/core/cfbimgblt.c:178 [inline]
RIP: 0010:cfb_imageblit+0x188/0x4c0 drivers/video/fbdev/core/cfbimgblt.c:302
Code: c9 41 d3 fa 89 d1 41 83 e2 01 44 8b 54 24 18 44 0f 45 54 24 14 45 89 d5 41 d3 e5 44 09 e8 41 39 d6 4d 89 c5 77 1d 49 83 c5 04 <41> 89 00 b9 20 00 00 00 b8 00 00 00 00 29 d1 41 d3 ea 41 39 d6 41
RSP: 0018:ffffc9000296fb50 EFLAGS: 00010282
RAX: 0000000070707070 RBX: ffff888001000000 RCX: 000000000000001c
RDX: 000000000000001c RSI: 000000000000000f RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff888001000000 R09: 0000000000000000
R10: 0000000000000007 R11: ffff88812b130fd0 R12: ffff888001000000
R13: ffff888001000004 R14: 000000000000001c R15: ffff88812b130fd0
FS:  0000000000000000(0000) GS:ffff88812c100000(0063) knlGS:00000000f7774b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: ffff888001000000 CR3: 000000010e40c000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400