bisecting fixing commit since a1b977b49b66c75e6c51a515f6700371ae720217
building syzkaller on 6e262c73cd452097096f0b4d5d96f5ae496bc021
testing commit a1b977b49b66c75e6c51a515f6700371ae720217 with gcc (GCC) 8.1.0
kernel signature: 915a8f82abb86bdf59417821368eca4dc20fbfdf77fa3b21a074f0d7a2f422a0
all runs: crashed: KASAN: use-after-free Read in reiserfs_fill_super
testing current HEAD 31acccdc877486a649a86d37725a15175fcd5ed6
testing commit 31acccdc877486a649a86d37725a15175fcd5ed6 with gcc (GCC) 8.1.0
kernel signature: 2c54c8a14187bed364a1328117dc80cf2b128583b434e72cbdba83b3206fd8e4
all runs: crashed: KASAN: use-after-free Read in reiserfs_fill_super
revisions tested: 2, total time: 24m32.497342553s (build: 17m56.277538289s, test: 5m51.421463517s)
the crash still happens on HEAD
commit msg: Linux 4.19.157
crash: KASAN: use-after-free Read in reiserfs_fill_super
REISERFS warning (device loop2): vs-13075 reiserfs_read_locked_inode: dead inode read from disk [1 2 0x0 SD]. This is likely to be race with knfsd. Ignore
REISERFS (device loop0): checking transaction log (loop0)
REISERFS (device loop2): Using r5 hash to sort names
REISERFS (device loop2): using 3.5.x disk format
==================================================================
BUG: KASAN: use-after-free in init_inode fs/reiserfs/inode.c:1327 [inline]
BUG: KASAN: use-after-free in reiserfs_read_locked_inode+0x273b/0x2800 fs/reiserfs/inode.c:1576
Read of size 4 at addr ffff88807fe73000 by task syz-executor.4/8407

CPU: 0 PID: 8407 Comm: syz-executor.4 Not tainted 4.19.157-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x17c/0x22a lib/dump_stack.c:118
 print_address_description.cold.6+0x9/0x211 mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0x242/0x307 mm/kasan/report.c:412
REISERFS warning (device loop1): vs-13075 reiserfs_read_locked_inode: dead inode read from disk [1 2 0x0 SD]. This is likely to be race with knfsd. Ignore
REISERFS (device loop1): Using r5 hash to sort names
 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/report.c:443
 init_inode fs/reiserfs/inode.c:1327 [inline]
 reiserfs_read_locked_inode+0x273b/0x2800 fs/reiserfs/inode.c:1576
 reiserfs_fill_super+0x1403/0x26b0 fs/reiserfs/super.c:2084
 mount_bdev+0x26f/0x330 fs/super.c:1158
 get_super_block+0x10/0x20 fs/reiserfs/super.c:2609
 mount_fs+0x7f/0x2a2 fs/super.c:1261
 vfs_kern_mount.part.11+0x58/0x3d0 fs/namespace.c:961
 vfs_kern_mount fs/namespace.c:951 [inline]
 do_new_mount fs/namespace.c:2469 [inline]
 do_mount+0x376/0x2710 fs/namespace.c:2799
 ksys_mount+0xba/0xe0 fs/namespace.c:3015
 __do_sys_mount fs/namespace.c:3029 [inline]
 __se_sys_mount fs/namespace.c:3026 [inline]
 __x64_sys_mount+0xb9/0x150 fs/namespace.c:3026
 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293
REISERFS (device loop1): using 3.5.x disk format
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4608aa
Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 ad 89 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 8a 89 fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007f4cd41f6a88 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f4cd41f6b20 RCX: 00000000004608aa
REISERFS warning (device loop3): vs-13075 reiserfs_read_locked_inode: dead inode read from disk [1 2 0x0 SD]. This is likely to be race with knfsd. Ignore
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f4cd41f6ae0
RBP: 00007f4cd41f6ae0 R08: 00007f4cd41f6b20 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000020000000
R13: 0000000020000100 R14: 0000000020000200 R15: 0000000020011100

The buggy address belongs to the page:
page:ffffea0001ff9cc0 count:0 mapcount:0 mapping:0000000000000000 index:0x1
flags: 0xfffe0000000000()
raw: 00fffe0000000000 ffffea0001ff9d08 ffff8880ba42fd88 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88807fe72f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88807fe72f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88807fe73000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88807fe73080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88807fe73100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================