[v6.1] KASAN: use-after-free Read in move_to_new_folio

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 50cbba13faa2 Linux 6.1.159
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11d43fb4580000
kernel config: https://syzkaller.appspot.com/x/.config?x=31ea1cecaf34f0db
dashboard link: https://syzkaller.appspot.com/bug?extid=6a7fd5db88b6f52348c5
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7ad0bd66715a/disk-50cbba13.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3284d626258e/vmlinux-50cbba13.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a1f92ca7bbfc/Image-50cbba13.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6a7fd5...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in move_to_new_folio+0x1c0/0xb5c mm/migrate.c:950
Read of size 8 at addr ffff0000f71ed430 by task syz.1.125/5061

CPU: 0 PID: 5061 Comm: syz.1.125 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
Call trace:
dump_backtrace+0x1c8/0x1f4 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+0xf8/0x160 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+0xa8/0x100 mm/kasan/report.c:524
__asan_report_load8_noabort+0x2c/0x38 mm/kasan/report_generic.c:351
move_to_new_folio+0x1c0/0xb5c mm/migrate.c:950
__migrate_folio_move mm/migrate.c:1199 [inline]
migrate_folio_move mm/migrate.c:1297 [inline]
migrate_pages_batch mm/migrate.c:1639 [inline]
migrate_pages+0x259c/0x3bbc mm/migrate.c:1843
compact_zone+0x2274/0x3c94 mm/compaction.c:2414
compact_node+0x1d8/0x370 mm/compaction.c:2691
compact_nodes mm/compaction.c:2707 [inline]
sysctl_compaction_handler+0x88/0x108 mm/compaction.c:2749
proc_sys_call_handler+0x3fc/0x69c fs/proc/proc_sysctl.c:602
proc_sys_write+0x2c/0x3c fs/proc/proc_sysctl.c:628
do_iter_readv_writev fs/read_write.c:-1 [inline]
do_iter_write+0x530/0x91c fs/read_write.c:861
vfs_writev fs/read_write.c:934 [inline]
do_writev+0x1e0/0x380 fs/read_write.c:977
__do_sys_writev fs/read_write.c:1050 [inline]
__se_sys_writev fs/read_write.c:1047 [inline]
__arm64_sys_writev+0x80/0x94 fs/read_write.c:1047
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x138 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 4449:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4c/0x80 mm/kasan/common.c:52
kasan_save_alloc_info+0x28/0x34 mm/kasan/generic.c:505
__kasan_slab_alloc+0x70/0x88 mm/kasan/common.c:328
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook+0x74/0x43c 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+0x234/0x318 mm/slub.c:3383
gfs2_glock_get+0x208/0xc60 fs/gfs2/glock.c:1180
gfs2_inode_lookup+0x1ec/0xab0 fs/gfs2/inode.c:135
gfs2_dir_search+0x148/0x204 fs/gfs2/dir.c:1664
gfs2_lookupi+0x3bc/0x58c fs/gfs2/inode.c:323
gfs2_jindex_hold fs/gfs2/ops_fstype.c:609 [inline]
init_journal+0x4a8/0x1e14 fs/gfs2/ops_fstype.c:753
init_inodes+0xe0/0x2d4 fs/gfs2/ops_fstype.c:889
gfs2_fill_super+0x122c/0x19ec fs/gfs2/ops_fstype.c:1246
get_tree_bdev+0x358/0x544 fs/super.c:1366
gfs2_get_tree+0x54/0x1b4 fs/gfs2/ops_fstype.c:1327
vfs_get_tree+0x90/0x274 fs/super.c:1573
do_new_mount+0x228/0x810 fs/namespace.c:3078
path_mount+0x5b4/0xe78 fs/namespace.c:3408
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/0x584 fs/namespace.c:3606
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x138 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

Last potentially related work creation:
kasan_save_stack+0x40/0x70 mm/kasan/common.c:45
__kasan_record_aux_stack+0xc0/0xdc mm/kasan/generic.c:486
kasan_record_aux_stack_noalloc+0x14/0x20 mm/kasan/generic.c:496
call_rcu+0x100/0x954 kernel/rcu/tree.c:2849
gfs2_glock_free+0x910/0xc20 fs/gfs2/glock.c:178
__gfs2_glock_put+0x254/0x51c fs/gfs2/glock.c:292
gfs2_glock_put+0x48/0x58 fs/gfs2/glock.c:314
gfs2_glock_put_eventually fs/gfs2/super.c:1257 [inline]
gfs2_evict_inode+0xb78/0xe20 fs/gfs2/super.c:1534
evict+0x3c8/0x810 fs/inode.c:705
iput_final fs/inode.c:1834 [inline]
iput+0x764/0x7f4 fs/inode.c:1860
gfs2_jindex_free+0x2d0/0x380 fs/gfs2/super.c:75
init_journal+0x7a0/0x1e14 fs/gfs2/ops_fstype.c:871
init_inodes+0xe0/0x2d4 fs/gfs2/ops_fstype.c:889
gfs2_fill_super+0x122c/0x19ec fs/gfs2/ops_fstype.c:1246
get_tree_bdev+0x358/0x544 fs/super.c:1366
gfs2_get_tree+0x54/0x1b4 fs/gfs2/ops_fstype.c:1327
vfs_get_tree+0x90/0x274 fs/super.c:1573
do_new_mount+0x228/0x810 fs/namespace.c:3078
path_mount+0x5b4/0xe78 fs/namespace.c:3408
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/0x584 fs/namespace.c:3606
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x138 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

Second to last potentially related work creation:
kasan_save_stack+0x40/0x70 mm/kasan/common.c:45
__kasan_record_aux_stack+0xc0/0xdc mm/kasan/generic.c:486
kasan_record_aux_stack_noalloc+0x14/0x20 mm/kasan/generic.c:496
insert_work+0x64/0x37c kernel/workqueue.c:1361
__queue_work+0xcbc/0x123c kernel/workqueue.c:1520
__queue_delayed_work kernel/workqueue.c:1668 [inline]
queue_delayed_work_on+0x204/0x314 kernel/workqueue.c:1704
queue_delayed_work include/linux/workqueue.h:527 [inline]
__gfs2_glock_queue_work fs/gfs2/glock.c:258 [inline]
gfs2_glock_queue_work fs/gfs2/glock.c:272 [inline]
do_xmote+0x688/0x1198 fs/gfs2/glock.c:871
run_queue+0x3b4/0x690 fs/gfs2/glock.c:905
glock_work_func+0x1fc/0x428 fs/gfs2/glock.c:1089
process_one_work+0x7f4/0x13a8 kernel/workqueue.c:2292
worker_thread+0x8c8/0xfbc kernel/workqueue.c:2439
kthread+0x250/0x2d8 kernel/kthread.c:376
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850

The buggy address belongs to the object at ffff0000f71ecfd8
which belongs to the cache gfs2_glock(aspace) of size 1224
The buggy address is located 1112 bytes inside of
1224-byte region [ffff0000f71ecfd8, ffff0000f71ed4a0)

The buggy address belongs to the physical page:
page:00000000844c2f7f refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff0000f71ec548 pfn:0x1371ec
head:00000000844c2f7f order:2 compound_mapcount:0 compound_pincount:0
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 0000000000000000 dead000000000122 ffff0000c6ccfb00
raw: ffff0000f71ec548 00000000800c0008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff0000f71ed300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff0000f71ed380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff0000f71ed400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff0000f71ed480: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
ffff0000f71ed500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


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