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: 100d, last: 12d
▶ ▼ Similar bugs (9)
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 1122d 1194d 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 1075d 1317d 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 162d 162d 0/3 auto-obsoleted due to no activity on 2026/09/03 09:45
linux-6.1 KASAN: use-after-free Read in hfsplus_btree_open (4) 19 1 279d 279d 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 1006d 1016d 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 804d 804d 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 1289d 1430d 0/29 auto-obsoleted due to no activity on 2023/08/23 09:08
linux-6.1 KASAN: use-after-free Read in hfsplus_btree_open (6) 19 1 54d 54d 0/3 upstream: reported on 2026/09/11 19:38
linux-5.15 KASAN: use-after-free Read in hfsplus_btree_open (2) 19 2 537d 607d 0/3 auto-obsoleted due to no activity on 2025/08/24 11:57

Sample crash report:
loop5: 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 ffff888051d091a4 by task syz.5.1229/8349

CPU: 0 PID: 8349 Comm: syz.5.1229 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
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:490
 mount_bdev+0x28a/0x3c0 fs/super.c:1411
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1541
 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: 0033:0x7f162bd4f7ca
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:00007f1629fa4e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f1629fa4ee0 RCX: 00007f162bd4f7ca
RDX: 0000200000000080 RSI: 0000200000000100 RDI: 00007f1629fa4ea0
RBP: 0000200000000080 R08: 00007f1629fa4ee0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000100
R13: 00007f1629fa4ea0 R14: 0000000000000638 R15: 0000200000000140
 </TASK>

Allocated by task 4887:
 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+0x4b53/0x7050 fs/f2fs/super.c:4301
 mount_bdev+0x28a/0x3c0 fs/super.c:1411
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1541
 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
 f2fs_fill_super+0x58ef/0x7050 fs/f2fs/super.c:4487
 mount_bdev+0x28a/0x3c0 fs/super.c:1411
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1541
 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 ffff888051d08980
 which belongs to the cache f2fs_inode_cache of size 2304
The buggy address is located 2084 bytes inside of
 2304-byte region [ffff888051d08980, ffff888051d09280)
The buggy address belongs to the page:
page:ffffea0001474200 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888051d08980 pfn:0x51d08
head:ffffea0001474200 order:3 compound_mapcount:0 compound_pincount:0
memcg:ffff888052996201
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000122 ffff88801efaa500
raw: ffff888051d08980 00000000800d000b 00000001ffffffff ffff888052996201
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 4887, ts 123870896817, free_ts 18164985643
 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:1411
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1541
 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
 free_contig_range+0x96/0xf0 mm/page_alloc.c:9428
 destroy_args+0xef/0xa00 mm/debug_vm_pgtable.c:1018
 debug_vm_pgtable+0x321/0x380 mm/debug_vm_pgtable.c:1336
 do_one_initcall+0x272/0x730 init/main.c:1276
 do_initcall_level+0x13d/0x1f0 init/main.c:1349
 do_initcalls+0x4b/0x90 init/main.c:1365
 kernel_init_freeable+0x3d5/0x560 init/main.c:1589
 kernel_init+0x19/0x1b0 init/main.c:1480
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Memory state around the buggy address:
 ffff888051d09080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888051d09100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888051d09180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff888051d09200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888051d09280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/23 10:31 linux-5.15.y 792fbe1537d8 d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in hfsplus_btree_open
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.