Kernel bug: KASAN: use-after-free Read in __ocfs2_flush_truncate_log
Subsystem: ocfs2
Status: open

Crash report:
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BUG: KASAN: use-after-free in ocfs2_replay_truncate_records fs/ocfs2/alloc.c:5959 [inline]
BUG: KASAN: use-after-free in __ocfs2_flush_truncate_log+0x824/0x1240 fs/ocfs2/alloc.c:6054
Read of size 4 at addr ffff88804a142ac0 by task syz-executor176/5299

CPU: 0 UID: 0 PID: 5299 Comm: syz-executor176 Not tainted 6.13.0-rc3-syzkaller-00209-g499551201b5f #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:489
 kasan_report+0x143/0x180 mm/kasan/report.c:602
 ocfs2_replay_truncate_records fs/ocfs2/alloc.c:5959 [inline]
 __ocfs2_flush_truncate_log+0x824/0x1240 fs/ocfs2/alloc.c:6054
 ocfs2_flush_truncate_log+0x4f/0x70 fs/ocfs2/alloc.c:6076
 ocfs2_sync_fs+0x125/0x390 fs/ocfs2/super.c:402
 sync_filesystem+0x1c8/0x230 fs/sync.c:66
 generic_shutdown_super+0x72/0x2d0 fs/super.c:621
 kill_block_super+0x44/0x90 fs/super.c:1710
 deactivate_locked_super+0xc4/0x130 fs/super.c:473
 cleanup_mnt+0x41f/0x4b0 fs/namespace.c:1373
 task_work_run+0x24f/0x310 kernel/task_work.c:239
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcc3027d9a7
Code: 07 00 48 83 c4 08 5b 5d c3 66 2e 0f 1f 84 00 00 00 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 b8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffe09a23458 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fcc3027d9a7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe09a23510
RBP: 00007ffe09a23510 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000202 R12: 00007ffe09a24580
R13: 000055559072a7c0 R14: 431bde82d7b634db R15: 00007ffe09a245a0
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4a142
flags: 0x4fff00000000000(node=1|zone=1|lastcpupid=0x7ff)
raw: 04fff00000000000 ffffea00012850c8 ffffea000115ce08 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
 ffff88804a142980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88804a142a00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88804a142a80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                           ^
 ffff88804a142b00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88804a142b80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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