syzbot


KASAN: use-after-free Read in udf_free_inode

Status: upstream: reported on 2025/01/12 09:43
Reported-by: syzbot+ad6ac41722badfb6d0f2@syzkaller.appspotmail.com
First crash: 2d23h, last: 2d23h
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: use-after-free Read in udf_free_inode fs 1 750d 746d 0/28 auto-obsoleted due to no activity on 2023/03/26 23:00
linux-6.1 KASAN: use-after-free Read in udf_free_inode 1 197d 197d 0/3 auto-obsoleted due to no activity on 2024/10/09 09:17
upstream BUG: unable to handle kernel paging request in udf_free_inode udf 1 1175d 1171d 0/28 auto-closed as invalid on 2022/01/25 11:13
linux-6.1 BUG: unable to handle kernel paging request in udf_free_inode 1 70d 70d 0/3 upstream: reported on 2024/11/06 07:32

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in udf_free_inode+0x269/0x2d0
Read of size 4 at addr ffff88808f21eab0 by task syz.4.1101/9655

CPU: 0 PID: 9655 Comm: syz.4.1101 Not tainted 5.15.176-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 print_address_description+0x63/0x3b0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0x16b/0x1c0 mm/kasan/report.c:451
 udf_free_inode+0x269/0x2d0
 evict+0x529/0x930 fs/inode.c:622
 do_unlinkat+0x508/0x950 fs/namei.c:4355
 __do_sys_unlinkat fs/namei.c:4391 [inline]
 __se_sys_unlinkat fs/namei.c:4384 [inline]
 __x64_sys_unlinkat+0xca/0xf0 fs/namei.c:4384
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f7632c16d29
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7630a87038 EFLAGS: 00000246 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 00007f7632e06fa0 RCX: 00007f7632c16d29
RDX: 0000000000000000 RSI: 0000000020000140 RDI: ffffffffffffff9c
RBP: 00007f7632c92b08 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f7632e06fa0 R15: 00007fff6a72f6b8
 </TASK>

The buggy address belongs to the page:
page:ffffea00023c8780 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x8f21e
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea00023c8788 ffffea00023c8788 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:
 ffff88808f21e980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88808f21ea00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88808f21ea80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                     ^
 ffff88808f21eb00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88808f21eb80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/01/12 09:42 linux-5.15.y 4735586da88e 6dbc6a9b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_free_inode
* Struck through repros no longer work on HEAD.