syzbot


KASAN: slab-out-of-bounds Write in udf_write_aext (2)

Status: upstream: reported on 2025/07/15 07:05
Subsystems: udf
[Documentation on labels]
Reported-by: syzbot+4e1da0d327b65949fe1b@syzkaller.appspotmail.com
First crash: 104d, last: 1d21h
Discussions (3)
Title Replies (including bot) Last reply
[syzbot] Monthly udf report (Sep 2025) 0 (1) 2025/09/26 05:14
[syzbot] Monthly udf report (Jul 2025) 0 (1) 2025/07/26 20:43
[syzbot] [udf?] KASAN: slab-out-of-bounds Write in udf_write_aext (2) 0 (1) 2025/07/15 07:05
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 KASAN: slab-out-of-bounds Write in udf_write_aext origin:lts-only 24 C error 7050 365d 956d 0/3 auto-obsoleted due to no activity on 2025/01/22 09:20
linux-6.1 KASAN: slab-out-of-bounds Write in udf_write_aext origin:lts-only 24 C done 5821 367d 956d 0/3 upstream: reported C repro on 2023/03/11 14:12
linux-4.14 KASAN: slab-out-of-bounds Write in udf_write_aext udf f2fs tmpfs 23 C 17 962d 1124d 0/1 upstream: reported C repro on 2022/09/25 01:59
upstream KASAN: slab-out-of-bounds Write in udf_write_aext udf 24 C error error 674 962d 1122d 0/29 auto-obsoleted due to no activity on 2023/07/26 07:31
linux-4.19 KASAN: slab-out-of-bounds Write in udf_write_aext udf tmpfs erofs 23 C error 67 962d 1453d 0/1 upstream: reported C repro on 2021/10/31 06:20

Sample crash report:
loop0: detected capacity change from 2048 to 64
==================================================================
BUG: KASAN: slab-out-of-bounds in udf_write_aext+0x69d/0x7b0 fs/udf/inode.c:2167
Write of size 4 at addr ffff8880433a15d8 by task syz.0.0/5320

CPU: 0 UID: 0 PID: 5320 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
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_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 udf_write_aext+0x69d/0x7b0 fs/udf/inode.c:2167
 __udf_add_aext+0x2b9/0x6d0 fs/udf/inode.c:2092
 udf_table_free_blocks fs/udf/balloc.c:481 [inline]
 udf_free_blocks+0x1466/0x17f0 fs/udf/balloc.c:677
 extent_trunc+0x35c/0x450 fs/udf/truncate.c:52
 udf_truncate_extents+0x5b0/0xec0 fs/udf/truncate.c:271
 udf_setsize+0x972/0x1000 fs/udf/inode.c:1324
 udf_setattr+0x3a1/0x5a0 fs/udf/file.c:236
 notify_change+0xc1a/0xf40 fs/attr.c:546
 do_truncate+0x1a4/0x220 fs/open.c:68
 vfs_truncate+0x493/0x520 fs/open.c:118
 do_sys_truncate+0xdb/0x190 fs/open.c:141
 __do_sys_truncate fs/open.c:153 [inline]
 __se_sys_truncate fs/open.c:151 [inline]
 __x64_sys_truncate+0x5b/0x70 fs/open.c:151
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0d5cd8efc9
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:00007f0d5dc5f038 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007f0d5cfe6090 RCX: 00007f0d5cd8efc9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00002000000013c0
RBP: 00007f0d5ce11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0d5cfe6128 R14: 00007f0d5cfe6090 R15: 00007ffd3d347878
 </TASK>

Allocated by task 5319:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417
 kasan_kmalloc include/linux/kasan.h:262 [inline]
 __do_kmalloc_node mm/slub.c:5634 [inline]
 __kmalloc_noprof+0x411/0x7f0 mm/slub.c:5646
 kmalloc_noprof include/linux/slab.h:961 [inline]
 udf_alloc_i_data fs/udf/inode.c:1668 [inline]
 udf_read_inode fs/udf/inode.c:1480 [inline]
 __udf_iget+0xc66/0x3ae0 fs/udf/inode.c:1974
 udf_iget_special fs/udf/udfdecl.h:147 [inline]
 udf_fill_partdesc_info+0x773/0x1320 fs/udf/super.c:1162
 udf_load_partdesc fs/udf/super.c:1321 [inline]
 udf_process_sequence+0x111c/0x47e0 fs/udf/super.c:1846
 udf_load_sequence fs/udf/super.c:1884 [inline]
 udf_check_anchor_block+0x28e/0x550 fs/udf/super.c:1919
 udf_scan_anchors fs/udf/super.c:1973 [inline]
 udf_load_vrs+0x96d/0xf20 fs/udf/super.c:2033
 udf_fill_super+0x5ad/0x17a0 fs/udf/super.c:2201
 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691
 vfs_get_tree+0x92/0x2b0 fs/super.c:1751
 fc_mount fs/namespace.c:1208 [inline]
 do_new_mount_fc fs/namespace.c:3651 [inline]
 do_new_mount+0x302/0xa10 fs/namespace.c:3727
 do_mount fs/namespace.c:4050 [inline]
 __do_sys_mount fs/namespace.c:4238 [inline]
 __se_sys_mount+0x313/0x410 fs/namespace.c:4215
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff8880433a1400
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 0 bytes to the right of
 allocated 472-byte region [ffff8880433a1400, ffff8880433a15d8)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x433a0
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000040 ffff88801a441c80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
head: 04fff00000000040 ffff88801a441c80 dead000000000100 dead000000000122
head: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
head: 04fff00000000001 ffffea00010ce801 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5296, tgid 5296 (sh), ts 72146847167, free_ts 61885960983
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850
 prep_new_page mm/page_alloc.c:1858 [inline]
 get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3884
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:3046 [inline]
 allocate_slab+0x96/0x3a0 mm/slub.c:3219
 new_slab mm/slub.c:3273 [inline]
 ___slab_alloc+0xe94/0x18a0 mm/slub.c:4643
 __slab_alloc+0x65/0x100 mm/slub.c:4762
 __slab_alloc_node mm/slub.c:4838 [inline]
 slab_alloc_node mm/slub.c:5260 [inline]
 __do_kmalloc_node mm/slub.c:5633 [inline]
 __kmalloc_noprof+0x471/0x7f0 mm/slub.c:5646
 kmalloc_noprof include/linux/slab.h:961 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 tomoyo_init_log+0x1a6e/0x1f70 security/tomoyo/audit.c:275
 tomoyo_supervisor+0x340/0x1480 security/tomoyo/common.c:2198
 tomoyo_audit_path_log security/tomoyo/file.c:168 [inline]
 tomoyo_path_permission+0x25a/0x380 security/tomoyo/file.c:587
 tomoyo_check_open_permission+0x24d/0x3b0 security/tomoyo/file.c:777
 security_file_open+0xb1/0x270 security/security.c:3183
 do_dentry_open+0x384/0x13f0 fs/open.c:942
 vfs_open+0x3b/0x340 fs/open.c:1097
 do_open fs/namei.c:3975 [inline]
 path_openat+0x2ee5/0x3830 fs/namei.c:4134
page last free pid 5255 tgid 5255 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1394 [inline]
 __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2906
 discard_slab mm/slub.c:3317 [inline]
 __put_partials+0x146/0x170 mm/slub.c:3864
 put_cpu_partial+0x1f2/0x2e0 mm/slub.c:3939
 __slab_free+0x2b9/0x390 mm/slub.c:5913
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:352
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4962 [inline]
 slab_alloc_node mm/slub.c:5272 [inline]
 kmem_cache_alloc_noprof+0x367/0x6e0 mm/slub.c:5279
 getname_flags+0xb8/0x540 fs/namei.c:146
 getname include/linux/fs.h:2922 [inline]
 do_sys_openat2+0xbc/0x1c0 fs/open.c:1431
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_openat fs/open.c:1468 [inline]
 __se_sys_openat fs/open.c:1463 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1463
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8880433a1480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880433a1500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880433a1580: 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc
                                                    ^
 ffff8880433a1600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880433a1680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (16):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/10/21 15:05 upstream 6548d364a3e8 9832ed61 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Write in udf_write_aext
2025/10/12 19:32 upstream 67029a49db6c ff1712fe .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Write in udf_write_aext
2025/10/12 09:58 upstream 98906f9d850e ff1712fe .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Write in udf_write_aext
2025/10/12 02:25 upstream 98906f9d850e ff1712fe .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Write in udf_write_aext
2025/10/11 01:23 upstream 917167ed1211 ff1712fe .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Write in udf_write_aext
2025/10/05 09:21 upstream 6093a688a07d 49379ee0 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Write in udf_write_aext
2025/09/28 16:30 upstream 51a24b7deaae 001c9061 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Write in udf_write_aext
2025/09/24 02:10 upstream cec1e6e5d1ab e667a34f .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Write in udf_write_aext
2025/07/27 10:29 upstream ec2df4364666 fb8f743d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Write in udf_write_aext
2025/07/26 20:47 upstream 302f88ff3584 fb8f743d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Write in udf_write_aext
2025/07/24 10:06 upstream f9af7b5d9349 0c1d6ded .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Write in udf_write_aext
2025/07/23 04:56 upstream 89be9a83ccf1 e1dd4f22 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Write in udf_write_aext
2025/07/13 13:02 upstream 3f31a806a62e 3cda49cf .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Write in udf_write_aext
2025/07/11 20:25 upstream 40f92e79b0aa 3cda49cf .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Write in udf_write_aext
2025/07/11 12:38 upstream bc9ff192a6c9 3cda49cf .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Write in udf_write_aext
2025/07/10 23:38 upstream bc9ff192a6c9 3cda49cf .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Write in udf_write_aext
* Struck through repros no longer work on HEAD.