bisecting fixing commit since cb95712138ec5e480db5160b41172bbc6f6494cc
building syzkaller on cef5ae6814696260ff58c538a1b6044af90c5979
testing commit cb95712138ec5e480db5160b41172bbc6f6494cc with gcc (GCC) 8.1.0
kernel signature: 292fa100968031ef86b631f6b7bcc248fdf05f248f6765662fbb3dd9b8132f00
all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in bdev_read_page
testing current HEAD 40f78232f97344afbbeb5b0008615f17c4b93466
testing commit 40f78232f97344afbbeb5b0008615f17c4b93466 with gcc (GCC) 8.1.0
kernel signature: 776d18e9c38a1990b355b1606c7a75e4a4519bb2700bb6c0450ded2e31e4a748
all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in bdev_read_page
revisions tested: 2, total time: 15m26.767385242s (build: 9m32.153962693s, test: 5m11.768281799s)
the crash still happens on HEAD
commit msg: Merge tag 'pci-v5.11-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci
crash: BUG: unable to handle kernel NULL pointer dereference in bdev_read_page
BUG: kernel NULL pointer dereference, address: 0000000000000628
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0 
Oops: 0000 [#1] PREEMPT SMP
CPU: 0 PID: 7521 Comm: systemd-udevd Not tainted 5.10.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:bdev_read_page+0xa/0x90 fs/block_dev.c:708
Code: ff ff 49 8b 7e 28 bd fa ff ff ff e8 50 e2 fc ff e9 33 fe ff ff 90 66 2e 0f 1f 84 00 00 00 00 00 41 55 41 54 55 53 48 83 ec 08 <48> 8b 87 28 06 00 00 4c 8b 68 40 49 83 7d 18 00 74 68 48 8b 48 48
RSP: 0018:ffffc900022e3998 EFLAGS: 00010292
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000014
RDX: ffffea000457b740 RSI: a000457b74000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 000000000000001d
R13: 0000000000000000 R14: a000457b74000000 R15: ffffc900022e3a90
FS:  00007ffb3a8598c0(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000628 CR3: 00000001161d4003 CR4: 00000000001706f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 do_mpage_readpage+0x648/0x900 fs/mpage.c:302
 mpage_readahead+0xf3/0x220 fs/mpage.c:391
 read_pages+0x8a/0x3f0 mm/readahead.c:130
 page_cache_ra_unbounded+0x142/0x270 mm/readahead.c:238
 page_cache_sync_readahead include/linux/pagemap.h:839 [inline]
 generic_file_buffered_read_get_pages+0x168/0x880 mm/filemap.c:2361
 generic_file_buffered_read+0xfd/0x410 mm/filemap.c:2481
 call_read_iter include/linux/fs.h:1895 [inline]
 new_sync_read+0x110/0x190 fs/read_write.c:415
 vfs_read+0x118/0x1b0 fs/read_write.c:496
 ksys_read+0x5a/0xd0 fs/read_write.c:634
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7ffb399a0210
Code: 73 01 c3 48 8b 0d 98 7d 20 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d b9 c1 20 00 00 75 10 b8 00 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 4e fc ff ff 48 89 04 24
RSP: 002b:00007fffde425d38 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00005626dda20ca0 RCX: 00007ffb399a0210
RDX: 0000000000000400 RSI: 00005626dda20cc8 RDI: 000000000000000f
RBP: 00005626dda226a0 R08: 00007ffb3998af48 R09: 0000000000000430
R10: 00005626dda20cb8 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000400 R14: 00005626dda226f0 R15: 0000000000000400
Modules linked in:
CR2: 0000000000000628
---[ end trace 87280f59feb1bce6 ]---
RIP: 0010:bdev_read_page+0xa/0x90 fs/block_dev.c:708
Code: ff ff 49 8b 7e 28 bd fa ff ff ff e8 50 e2 fc ff e9 33 fe ff ff 90 66 2e 0f 1f 84 00 00 00 00 00 41 55 41 54 55 53 48 83 ec 08 <48> 8b 87 28 06 00 00 4c 8b 68 40 49 83 7d 18 00 74 68 48 8b 48 48
RSP: 0018:ffffc900022e3998 EFLAGS: 00010292
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000014
RDX: ffffea000457b740 RSI: a000457b74000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 000000000000001d
R13: 0000000000000000 R14: a000457b74000000 R15: ffffc900022e3a90
FS:  00007ffb3a8598c0(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000628 CR3: 00000001161d4003 CR4: 00000000001706f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400