syzbot

bn = 0, index = 0
bn = 72c, index = 96
bn = 0, index = 0
bn = 0, index = 0
==================================================================
BUG: KASAN: use-after-free in drop_metapage fs/jfs/jfs_metapage.c:223 [inline]
BUG: KASAN: use-after-free in release_metapage+0x718/0xc6c fs/jfs/jfs_metapage.c:757
Read of size 8 at addr ffff0000db3eb028 by task syz.0.55/4679

CPU: 0 PID: 4679 Comm: syz.0.55 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
Call trace:
 dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
 print_address_description+0x88/0x218 mm/kasan/report.c:316
 print_report+0x50/0x68 mm/kasan/report.c:420
 kasan_report+0xa8/0xfc mm/kasan/report.c:524
 __asan_report_load8_noabort+0x2c/0x38 mm/kasan/report_generic.c:351
 drop_metapage fs/jfs/jfs_metapage.c:223 [inline]
 release_metapage+0x718/0xc6c fs/jfs/jfs_metapage.c:757
 dtSearch+0x169c/0x1b18 fs/jfs/jfs_dtree.c:793
 jfs_symlink+0x64c/0xdb0 fs/jfs/namei.c:1016
 vfs_symlink+0x238/0x3b0 fs/namei.c:4479
 do_symlinkat+0x178/0x35c fs/namei.c:4508
 __do_sys_symlinkat fs/namei.c:4525 [inline]
 __se_sys_symlinkat fs/namei.c:4522 [inline]
 __arm64_sys_symlinkat+0xa4/0xbc fs/namei.c:4522
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Allocated by task 4679:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
 kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505
 __kasan_slab_alloc+0x70/0x88 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x74/0x430 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+0x22c/0x308 mm/slub.c:3383
 mempool_alloc_slab+0x58/0x74 mm/mempool.c:532
 mempool_alloc+0x150/0x3fc mm/mempool.c:412
 alloc_metapage fs/jfs/jfs_metapage.c:176 [inline]
 __get_metapage+0x5c4/0xfac fs/jfs/jfs_metapage.c:651
 dtSplitRoot+0x178/0x1174 fs/jfs/jfs_dtree.c:1910
 dtSplitUp fs/jfs/jfs_dtree.c:993 [inline]
 dtInsert+0xb44/0x5720 fs/jfs/jfs_dtree.c:871
 jfs_create+0x5e4/0x920 fs/jfs/namei.c:137
 lookup_open fs/namei.c:3490 [inline]
 open_last_lookups fs/namei.c:3558 [inline]
 path_openat+0xe18/0x26bc fs/namei.c:3788
 do_filp_open+0x194/0x384 fs/namei.c:3818
 do_sys_openat2+0x134/0x3f4 fs/open.c:1320
 do_sys_open fs/open.c:1336 [inline]
 __do_sys_openat fs/open.c:1352 [inline]
 __se_sys_openat fs/open.c:1347 [inline]
 __arm64_sys_openat+0x118/0x14c fs/open.c:1347
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Freed by task 4688:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
 kasan_save_free_info+0x38/0x5c mm/kasan/generic.c:516
 ____kasan_slab_free+0x148/0x1b0 mm/kasan/common.c:237
 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:245
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1729 [inline]
 slab_free_freelist_hook+0x16c/0x1e8 mm/slub.c:1755
 slab_free mm/slub.c:3687 [inline]
 kmem_cache_free+0x118/0x314 mm/slub.c:3709
 mempool_free_slab+0x28/0x38 mm/mempool.c:539
 mempool_free+0xbc/0x2e0 mm/mempool.c:521
 free_metapage fs/jfs/jfs_metapage.c:191 [inline]
 metapage_release_folio+0x44c/0x5b4 fs/jfs/jfs_metapage.c:551
 metapage_invalidate_folio+0x140/0x1d8 fs/jfs/jfs_metapage.c:563
 folio_invalidate mm/truncate.c:158 [inline]
 truncate_cleanup_folio+0x1b4/0x32c mm/truncate.c:178
 truncate_inode_folio mm/truncate.c:194 [inline]
 truncate_inode_pages_range+0x8c8/0xd68 mm/truncate.c:450
 truncate_inode_pages+0x2c/0x3c mm/truncate.c:476
 jfs_remount+0x284/0x490 fs/jfs/super.c:451
 legacy_reconfigure+0xf8/0x110 fs/fs_context.c:655
 reconfigure_super+0x1d4/0x79c fs/super.c:977
 do_remount fs/namespace.c:2741 [inline]
 path_mount+0xbdc/0xe80 fs/namespace.c:3400
 do_mount fs/namespace.c:3421 [inline]
 __do_sys_mount fs/namespace.c:3629 [inline]
 __se_sys_mount fs/namespace.c:3606 [inline]
 __arm64_sys_mount+0x49c/0x59c fs/namespace.c:3606
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to the object at ffff0000db3eb000
 which belongs to the cache jfs_mp of size 184
The buggy address is located 40 bytes inside of
 184-byte region [ffff0000db3eb000, ffff0000db3eb0b8)

The buggy address belongs to the physical page:
page:00000000b331ed16 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11b3eb
flags: 0x5ffc00000000200(slab|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000200 0000000000000000 dead000000000122 ffff0000c4e4fc80
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000db3eaf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0000db3eaf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0000db3eb000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff0000db3eb080: fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc fa
 ffff0000db3eb100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================