KASAN: use-after-free Read in hfsplus_btree_open (5)

Status: upstream: reported on 2026/05/26 09:45
Reported-by: syzbot+1451d091c9fe1d03697d@syzkaller.appspotmail.com
First crash: 60d, last: 60d
▶ ▼ Similar bugs (7)
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 1020d 1092d 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 973d 1215d 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 (4) 19 1 177d 177d 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 904d 914d 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 702d 702d 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 1187d 1328d 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 435d 505d 0/3 auto-obsoleted due to no activity on 2025/08/24 11:57

Sample crash report:
loop2: detected capacity change from 0 to 1024
==================================================================
BUG: KASAN: use-after-free in hfsplus_btree_open+0x92e/0xd30 fs/hfsplus/btree.c:155
Read of size 4 at addr ffff888071b72274 by task syz.2.1120/7543

CPU: 1 PID: 7543 Comm: syz.2.1120 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:420
 kasan_report+0x10b/0x140 mm/kasan/report.c:524
 hfsplus_btree_open+0x92e/0xd30 fs/hfsplus/btree.c:155
 hfsplus_fill_super+0xa67/0x1e70 fs/hfsplus/super.c:492
 mount_bdev+0x287/0x3c0 fs/super.c:1443
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:632
 vfs_get_tree+0x88/0x270 fs/super.c:1573
 do_new_mount+0x24a/0xa40 fs/namespace.c:3078
 do_mount fs/namespace.c:3421 [inline]
 __do_sys_mount fs/namespace.c:3629 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3606
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9bcfb9e0ca
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:00007f9bd0985e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f9bd0985ee0 RCX: 00007f9bcfb9e0ca
RDX: 00002000000000c0 RSI: 0000200000000980 RDI: 00007f9bd0985ea0
RBP: 00002000000000c0 R08: 00007f9bd0985ee0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000980
R13: 00007f9bd0985ea0 R14: 00000000000006a4 R15: 0000200000000640
 </TASK>

Allocated by task 6712:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 __kasan_slab_alloc+0x6b/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x4b/0x480 mm/slab.h:737
 slab_alloc_node mm/slub.c:3359 [inline]
 slab_alloc mm/slub.c:3367 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3374 [inline]
 kmem_cache_alloc_lru+0x11a/0x2e0 mm/slub.c:3390
 alloc_inode_sb include/linux/fs.h:3245 [inline]
 f2fs_alloc_inode+0x151/0x610 fs/f2fs/super.c:1419
 alloc_inode fs/inode.c:261 [inline]
 iget_locked+0x1a9/0x830 fs/inode.c:1373
 f2fs_iget+0x52/0x4b30 fs/f2fs/inode.c:489
 f2fs_fill_super+0x4487/0x6b40 fs/f2fs/super.c:4414
 mount_bdev+0x287/0x3c0 fs/super.c:1443
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:632
 vfs_get_tree+0x88/0x270 fs/super.c:1573
 do_new_mount+0x24a/0xa40 fs/namespace.c:3078
 do_mount fs/namespace.c:3421 [inline]
 __do_sys_mount fs/namespace.c:3629 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3606
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46
 __kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486
 call_rcu+0x14f/0x990 kernel/rcu/tree.c:2849
 destroy_inode fs/inode.c:316 [inline]
 evict+0x834/0x8d0 fs/inode.c:720
 f2fs_put_super+0x63a/0xbf0 fs/f2fs/super.c:1650
 generic_shutdown_super+0x130/0x340 fs/super.c:501
 kill_block_super+0x7c/0xe0 fs/super.c:1470
 kill_f2fs_super+0x309/0x3c0 fs/f2fs/super.c:4694
 deactivate_locked_super+0x93/0xf0 fs/super.c:332
 cleanup_mnt+0x42c/0x4b0 fs/namespace.c:1191
 task_work_run+0x1d0/0x260 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Second to last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46
 __kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486
 call_rcu+0x14f/0x990 kernel/rcu/tree.c:2849
 destroy_inode fs/inode.c:316 [inline]
 evict+0x834/0x8d0 fs/inode.c:720
 f2fs_fill_super+0x51ea/0x6b40 fs/f2fs/super.c:4600
 mount_bdev+0x287/0x3c0 fs/super.c:1443
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:632
 vfs_get_tree+0x88/0x270 fs/super.c:1573
 do_new_mount+0x24a/0xa40 fs/namespace.c:3078
 do_mount fs/namespace.c:3421 [inline]
 __do_sys_mount fs/namespace.c:3629 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3606
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff888071b71b18
 which belongs to the cache f2fs_inode_cache of size 2184
The buggy address is located 1884 bytes inside of
 2184-byte region [ffff888071b71b18, ffff888071b723a0)

The buggy address belongs to the physical page:
page:ffffea0001c6dc00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888071b74840 pfn:0x71b70
head:ffffea0001c6dc00 order:3 compound_mapcount:0 compound_pincount:0
memcg:ffff88802675e501
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000122 ffff88801b7f9780
raw: ffff888071b74840 00000000800e0007 00000001ffffffff ffff88802675e501
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 4454, tgid 4453 (syz.3.33), ts 73495432403, free_ts 73218121162
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2559
 prep_new_page mm/page_alloc.c:2566 [inline]
 get_page_from_freelist+0x1a1e/0x1ab0 mm/page_alloc.c:4357
 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5657
 alloc_slab_page+0x5d/0x160 mm/slub.c:1799
 allocate_slab mm/slub.c:1944 [inline]
 new_slab+0x87/0x2c0 mm/slub.c:1997
 ___slab_alloc+0xbc6/0x1240 mm/slub.c:3154
 __slab_alloc mm/slub.c:3240 [inline]
 slab_alloc_node mm/slub.c:3325 [inline]
 slab_alloc mm/slub.c:3367 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3374 [inline]
 kmem_cache_alloc_lru+0x1ae/0x2e0 mm/slub.c:3390
 alloc_inode_sb include/linux/fs.h:3245 [inline]
 f2fs_alloc_inode+0x151/0x610 fs/f2fs/super.c:1419
 alloc_inode fs/inode.c:261 [inline]
 iget_locked+0x1a9/0x830 fs/inode.c:1373
 f2fs_iget+0x52/0x4b30 fs/f2fs/inode.c:489
 f2fs_fill_super+0x3a83/0x6b40 fs/f2fs/super.c:4312
 mount_bdev+0x287/0x3c0 fs/super.c:1443
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:632
 vfs_get_tree+0x88/0x270 fs/super.c:1573
 do_new_mount+0x24a/0xa40 fs/namespace.c:3078
 do_mount fs/namespace.c:3421 [inline]
 __do_sys_mount fs/namespace.c:3629 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3606
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1486 [inline]
 free_pcp_prepare mm/page_alloc.c:1536 [inline]
 free_unref_page_prepare+0x8b4/0x9a0 mm/page_alloc.c:3413
 free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3508
 free_slab mm/slub.c:2036 [inline]
 discard_slab mm/slub.c:2042 [inline]
 __unfreeze_partials+0x1a5/0x200 mm/slub.c:2591
 put_cpu_partial+0x17c/0x250 mm/slub.c:2667
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:306
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x4b/0x480 mm/slab.h:737
 slab_alloc_node mm/slub.c:3359 [inline]
 slab_alloc mm/slub.c:3367 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3374 [inline]
 kmem_cache_alloc+0x123/0x2f0 mm/slub.c:3383
 mt_alloc_one lib/maple_tree.c:154 [inline]
 mas_alloc_nodes+0x2ec/0x890 lib/maple_tree.c:1279
 mas_node_count_gfp lib/maple_tree.c:1361 [inline]
 mas_preallocate+0x161/0x3c0 lib/maple_tree.c:5809
 vma_expand+0x27a/0x880 mm/mmap.c:544
 __mmap_region mm/mmap.c:2740 [inline]
 mmap_region+0xbd2/0x1ca0 mm/mmap.c:2916
 do_mmap+0x964/0xfd0 mm/mmap.c:1436
 vm_mmap_pgoff+0x1c1/0x2d0 mm/util.c:520
 ksys_mmap_pgoff+0x516/0x6f0 mm/mmap.c:1482

Memory state around the buggy address:
 ffff888071b72100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888071b72180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888071b72200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                             ^
 ffff888071b72280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888071b72300: 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
2026/05/26 09:44 linux-6.1.y dcbcab9d7079 a3e47276 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in hfsplus_btree_open
* Struck through repros no longer work on HEAD.