KASAN: use-after-free Read in hfsplus_btree_open (3)

Status: upstream: reported on 2026/07/28 01:25
Reported-by: syzbot+4b7bdbb7e31de0ef18d1@syzkaller.appspotmail.com
First crash: 8d11h, last: 8d11h
▶ ▼ Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 KASAN: use-after-free Read in hfsplus_btree_open 19 2 1030d 1103d 0/3 auto-obsoleted due to no activity on 2024/01/17 21:37
linux-5.15 KASAN: use-after-free Read in hfsplus_btree_open 19 5 984d 1225d 0/3 auto-obsoleted due to no activity on 2024/03/04 05:58
linux-6.1 KASAN: use-after-free Read in hfsplus_btree_open (5) 19 1 71d 71d 0/3 upstream: reported on 2026/05/26 09:45
linux-6.1 KASAN: use-after-free Read in hfsplus_btree_open (4) 19 1 188d 188d 0/3 auto-obsoleted due to no activity on 2026/05/09 12:26
linux-6.1 KASAN: use-after-free Read in hfsplus_btree_open (2) 19 2 915d 925d 0/3 auto-obsoleted due to no activity on 2024/05/12 07:07
linux-6.1 KASAN: use-after-free Read in hfsplus_btree_open (3) 19 1 713d 713d 0/3 auto-obsoleted due to no activity on 2024/11/30 09:06
upstream KASAN: use-after-free Read in hfsplus_btree_open hfs 19 8 1197d 1339d 0/29 auto-obsoleted due to no activity on 2023/08/23 09:08
linux-5.15 KASAN: use-after-free Read in hfsplus_btree_open (2) 19 2 446d 515d 0/3 auto-obsoleted due to no activity on 2025/08/24 11:57

Sample crash report:
loop1: detected capacity change from 0 to 1024
==================================================================
BUG: KASAN: use-after-free in hfsplus_btree_open+0xae6/0x1170 fs/hfsplus/btree.c:155
Read of size 4 at addr ffff88807479d3d4 by task syz.1.25748/2855

CPU: 1 PID: 2855 Comm: syz.1.25748 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 hfsplus_btree_open+0xae6/0x1170 fs/hfsplus/btree.c:155
 hfsplus_fill_super+0xa5d/0x1e20 fs/hfsplus/super.c:492
 mount_bdev+0x28a/0x3c0 fs/super.c:1400
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x247/0xa40 fs/namespace.c:3034
 do_mount fs/namespace.c:3377 [inline]
 __do_sys_mount fs/namespace.c:3585 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f4fbbeb610a
Code: 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4fba10ce58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f4fba10cee0 RCX: 00007f4fbbeb610a
RDX: 00002000000000c0 RSI: 0000200000000080 RDI: 00007f4fba10cea0
RBP: 00002000000000c0 R08: 00007f4fba10cee0 R09: 0000000000004800
R10: 0000000000004800 R11: 0000000000000246 R12: 0000200000000080
R13: 00007f4fba10cea0 R14: 00000000000006bb R15: 0000200000000340
 </TASK>

Allocated by task 24883:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 __kasan_slab_alloc+0x92/0xc0 mm/kasan/common.c:467
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519
 slab_alloc_node mm/slub.c:3225 [inline]
 slab_alloc mm/slub.c:3233 [inline]
 kmem_cache_alloc+0x15d/0x280 mm/slub.c:3238
 f2fs_kmem_cache_alloc fs/f2fs/f2fs.h:2648 [inline]
 f2fs_alloc_inode+0x149/0x5b0 fs/f2fs/super.c:1396
 alloc_inode fs/inode.c:261 [inline]
 iget_locked+0x18c/0x820 fs/inode.c:1308
 f2fs_iget+0x52/0x4bb0 fs/f2fs/inode.c:517
 f2fs_fill_super+0x4c33/0x7050 fs/f2fs/super.c:4309
 mount_bdev+0x28a/0x3c0 fs/super.c:1400
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x247/0xa40 fs/namespace.c:3034
 do_mount fs/namespace.c:3377 [inline]
 __do_sys_mount fs/namespace.c:3585 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Last potentially related work creation:
 kasan_save_stack+0x35/0x60 mm/kasan/common.c:38
 kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348
 __call_rcu kernel/rcu/tree.c:3011 [inline]
 call_rcu+0x189/0x900 kernel/rcu/tree.c:3091
 destroy_inode fs/inode.c:316 [inline]
 evict+0x810/0x8b0 fs/inode.c:662
 dispose_list fs/inode.c:680 [inline]
 evict_inodes+0x650/0x6e0 fs/inode.c:734
 generic_shutdown_super+0x93/0x300 fs/super.c:454
 kill_block_super+0x7c/0xe0 fs/super.c:1427
 kill_f2fs_super+0x310/0x3d0 fs/f2fs/super.c:4584
 deactivate_locked_super+0x93/0xf0 fs/super.c:335
 cleanup_mnt+0x426/0x4d0 fs/namespace.c:1148
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Second to last potentially related work creation:
 kasan_save_stack+0x35/0x60 mm/kasan/common.c:38
 kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348
 __call_rcu kernel/rcu/tree.c:3011 [inline]
 call_rcu+0x189/0x900 kernel/rcu/tree.c:3091
 destroy_inode fs/inode.c:316 [inline]
 evict+0x810/0x8b0 fs/inode.c:662
 f2fs_fill_super+0x59b1/0x7050 fs/f2fs/super.c:4505
 mount_bdev+0x28a/0x3c0 fs/super.c:1400
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x247/0xa40 fs/namespace.c:3034
 do_mount fs/namespace.c:3377 [inline]
 __do_sys_mount fs/namespace.c:3585 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff88807479cc00
 which belongs to the cache f2fs_inode_cache of size 2304
The buggy address is located 2004 bytes inside of
 2304-byte region [ffff88807479cc00, ffff88807479d500)
The buggy address belongs to the page:
page:ffffea0001d1e600 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888074798000 pfn:0x74798
head:ffffea0001d1e600 order:3 compound_mapcount:0 compound_pincount:0
memcg:ffff88802868b701
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000122 ffff88801e2af500
raw: ffff888074798000 00000000800d0009 00000001ffffffff ffff88802868b701
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Reclaimable, gfp_mask 0x1d2050(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL|__GFP_RECLAIMABLE), pid 5432, ts 121789671301, free_ts 120533783836
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x24f6/0x2670 mm/page_alloc.c:4192
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
 alloc_slab_page mm/slub.c:1780 [inline]
 allocate_slab mm/slub.c:1917 [inline]
 new_slab+0xc0/0x4b0 mm/slub.c:1980
 ___slab_alloc+0x807/0xdd0 mm/slub.c:3013
 __slab_alloc mm/slub.c:3100 [inline]
 slab_alloc_node mm/slub.c:3191 [inline]
 slab_alloc mm/slub.c:3233 [inline]
 kmem_cache_alloc+0xf0/0x280 mm/slub.c:3238
 f2fs_kmem_cache_alloc fs/f2fs/f2fs.h:2648 [inline]
 f2fs_alloc_inode+0x149/0x5b0 fs/f2fs/super.c:1396
 alloc_inode fs/inode.c:261 [inline]
 iget_locked+0x18c/0x820 fs/inode.c:1308
 f2fs_iget+0x52/0x4bb0 fs/f2fs/inode.c:517
 f2fs_fill_super+0x4063/0x7050 fs/f2fs/super.c:4193
 mount_bdev+0x28a/0x3c0 fs/super.c:1400
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x247/0xa40 fs/namespace.c:3034
 do_mount fs/namespace.c:3377 [inline]
 __do_sys_mount fs/namespace.c:3585 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
 free_unref_page+0x8f/0x2a0 mm/page_alloc.c:3396
 qlist_free_all+0x35/0x90 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x150/0x160 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0x2f/0xc0 mm/kasan/common.c:444
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519
 slab_alloc_node mm/slub.c:3225 [inline]
 slab_alloc mm/slub.c:3233 [inline]
 __kmalloc+0x189/0x340 mm/slub.c:4408
 kmalloc include/linux/slab.h:612 [inline]
 tomoyo_realpath_from_path+0xed/0x5e0 security/tomoyo/realpath.c:254
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x23f/0x5d0 security/tomoyo/file.c:822
 security_inode_getattr+0xcf/0x120 security/security.c:1349
 vfs_getattr+0x26/0x3a0 fs/stat.c:157
 vfs_fstat fs/stat.c:182 [inline]
 __do_sys_newfstat fs/stat.c:421 [inline]
 __se_sys_newfstat fs/stat.c:418 [inline]
 __x64_sys_newfstat+0x137/0x210 fs/stat.c:418
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff88807479d280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807479d300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807479d380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff88807479d400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807479d480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/28 01:25 linux-5.15.y 674f684f7c61 45ae1df4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in hfsplus_btree_open
* Struck through repros no longer work on HEAD.