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KASAN: slab-use-after-free Read in move_to_new_folio (4)

Status: upstream: reported syz repro on 2025/07/08 11:20
Subsystems: gfs2
[Documentation on labels]
Reported-by: syzbot+9f0d09a59e1e92ee7b43@syzkaller.appspotmail.com
First crash: 357d, last: 103d
▶ ▼ ✨ AI Jobs (5)
ID Workflow Result Correct Bug Created Started Finished Revision Error
4118ab93-8f7b-4b8c-931e-61a51fd120ce assessment-security 💥 KASAN: slab-use-after-free Read in move_to_new_folio (4) 2026/06/22 01:30 2026/06/22 01:30 2026/06/22 01:31 43bfcdb07c3552e4664e1029672054ac0924d543 
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/eb2ccb3a3e7cca1e94...
truncated to first 200 bytes; open job for full error
0d1d1254-c15b-4040-8988-e6a472d679ff assessment-security 💥 KASAN: slab-use-after-free Read in move_to_new_folio (4) 2026/06/14 01:19 2026/06/14 01:19 2026/06/14 01:20 4f06757f683a802254a4c8edbfe67ff801904c5e 
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/eb2ccb3a3e7cca1e94...
truncated to first 200 bytes; open job for full error
fdf37d38-e1b6-4881-84b3-f7b19357f5f9 assessment-security 💥 KASAN: slab-use-after-free Read in move_to_new_folio (4) 2026/06/09 16:25 2026/06/09 16:25 2026/06/09 16:26 c36c07f6c1f2230a36374cbd22235f635e8f9284 
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/eb2ccb3a3e7cca1e94...
truncated to first 200 bytes; open job for full error
36a974e4-6bb1-405b-8308-2e3453e3b8d8 assessment-security 💥 KASAN: slab-use-after-free Read in move_to_new_folio (4) 2026/06/02 11:10 2026/06/02 11:10 2026/06/02 11:13 1095583bae1d2729a3b4be301cb6ddc85ced9e38 
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/eb2ccb3a3e7cca1e94...
truncated to first 200 bytes; open job for full error
46c962cb-8d01-4b3d-9304-db896105fa0b assessment-security 💥 KASAN: slab-use-after-free Read in move_to_new_folio (4) 2026/05/24 09:18 2026/05/24 09:18 2026/05/24 09:21 c69befb30ac10e158cc9d1557b508ee3f0eca1de 
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/eb2ccb3a3e7cca1e94...
truncated to first 200 bytes; open job for full error
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [gfs2] KASAN: slab-use-after-free Read in move_to_new_folio (4) 1 (2) 2025/07/08 12:41
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-use-after-free Read in move_to_new_folio (2) nilfs 19 8 729d 732d 0/29 closed as dup on 2024/07/21 08:13
upstream KASAN: slab-use-after-free Read in move_to_new_folio (3) mm 19 81 455d 602d 0/29 auto-obsoleted due to no activity on 2025/06/05 04:43
upstream KASAN: slab-use-after-free Read in move_to_new_folio mm 19 1 1086d 1081d 0/29 auto-obsoleted due to no activity on 2023/10/13 09:28
linux-6.1 KASAN: use-after-free Read in move_to_new_folio 19 1 174d 174d 0/3 auto-obsoleted due to no activity on 2026/04/12 00:15
▶ ▼ Last patch testing requests (9)
Created Duration User Patch Repo Result
2026/05/22 19:57 22m retest repro upstream error
2026/05/22 19:57 22m retest repro upstream error
2026/03/13 19:06 18m retest repro upstream error
2026/03/13 19:06 17m retest repro upstream report log
2026/01/02 18:26 12m retest repro upstream report log
2026/01/02 18:26 11m retest repro upstream report log
2025/10/24 17:11 14m retest repro upstream report log
2025/10/24 17:11 14m retest repro upstream report log
2025/08/15 06:25 15m retest repro upstream report log

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read include/linux/instrumented.h:68 [inline]
BUG: KASAN: slab-use-after-free in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
BUG: KASAN: slab-use-after-free in mapping_inaccessible include/linux/pagemap.h:338 [inline]
BUG: KASAN: slab-use-after-free in move_to_new_folio+0x145/0x490 mm/migrate.c:1092
Read of size 8 at addr ffff888050c393a0 by task kcompactd1/30

CPU: 0 UID: 0 PID: 30 Comm: kcompactd1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x2b0/0x2c0 mm/kasan/generic.c:200
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 mapping_inaccessible include/linux/pagemap.h:338 [inline]
 move_to_new_folio+0x145/0x490 mm/migrate.c:1092
 migrate_folio_move mm/migrate.c:1365 [inline]
 migrate_folios_move mm/migrate.c:1713 [inline]
 migrate_pages_batch+0x1d5f/0x35e0 mm/migrate.c:1969
 migrate_pages_sync mm/migrate.c:1999 [inline]
 migrate_pages+0x1bcc/0x2930 mm/migrate.c:2108
 compact_zone+0x23e1/0x4ab0 mm/compaction.c:2647
 kcompactd_do_work mm/compaction.c:3098 [inline]
 kcompactd+0x97d/0x1290 mm/compaction.c:3192
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 5713:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 unpoison_slab_object mm/kasan/common.c:342 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:368
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4947 [inline]
 slab_alloc_node mm/slub.c:5246 [inline]
 kmem_cache_alloc_noprof+0x367/0x6e0 mm/slub.c:5253
 gfs2_glock_get+0x263/0xec0 fs/gfs2/glock.c:1167
 gfs2_inode_lookup+0x215/0xb10 fs/gfs2/inode.c:135
 gfs2_dir_search+0x168/0x220 fs/gfs2/dir.c:1665
 gfs2_lookupi+0x3d9/0x5a0 fs/gfs2/inode.c:340
 gfs2_jindex_hold fs/gfs2/ops_fstype.c:574 [inline]
 init_journal+0x54a/0x2260 fs/gfs2/ops_fstype.c:716
 init_inodes+0xdb/0x320 fs/gfs2/ops_fstype.c:851
 gfs2_fill_super+0x1923/0x20d0 fs/gfs2/ops_fstype.c:1255
 get_tree_bdev_flags+0x40b/0x4d0 fs/super.c:1691
 gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1337
 vfs_get_tree+0x8f/0x2b0 fs/super.c:1751
 fc_mount fs/namespace.c:1208 [inline]
 do_new_mount_fc fs/namespace.c:3651 [inline]
 do_new_mount+0x302/0xa10 fs/namespace.c:3727
 do_mount fs/namespace.c:4050 [inline]
 __do_sys_mount fs/namespace.c:4238 [inline]
 __se_sys_mount+0x313/0x410 fs/namespace.c:4215
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 15:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587
 kasan_save_free_info mm/kasan/kasan.h:406 [inline]
 poison_slab_object mm/kasan/common.c:252 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2515 [inline]
 slab_free mm/slub.c:6574 [inline]
 kmem_cache_free+0x19b/0x690 mm/slub.c:6684
 rcu_do_batch kernel/rcu/tree.c:2605 [inline]
 rcu_core+0xca8/0x1770 kernel/rcu/tree.c:2861
 handle_softirqs+0x283/0x870 kernel/softirq.c:622
 run_ksoftirqd+0x9b/0x100 kernel/softirq.c:1063
 smpboot_thread_fn+0x53f/0xa60 kernel/smpboot.c:160
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:56
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:559
 __call_rcu_common kernel/rcu/tree.c:3123 [inline]
 call_rcu+0x157/0x9c0 kernel/rcu/tree.c:3243
 __gfs2_glock_free+0xb44/0xc90 fs/gfs2/glock.c:172
 gfs2_glock_free+0x3c/0xa0 fs/gfs2/glock.c:178
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Second to last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:56
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:559
 insert_work+0x3d/0x330 kernel/workqueue.c:2186
 __queue_work+0xcd2/0xfb0 kernel/workqueue.c:2341
 queue_delayed_work_on+0x18b/0x280 kernel/workqueue.c:2561
 queue_delayed_work include/linux/workqueue.h:684 [inline]
 gfs2_glock_queue_work fs/gfs2/glock.c:250 [inline]
 do_xmote+0xa0d/0x1060 fs/gfs2/glock.c:814
 glock_work_func+0x2a8/0x580 fs/gfs2/glock.c:1080
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff888050c38fd8
 which belongs to the cache gfs2_glock(aspace) of size 1224
The buggy address is located 968 bytes inside of
 freed 1224-byte region [ffff888050c38fd8, ffff888050c394a0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x50c38
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000040 ffff888032b11780 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800c000c 00000000f5000000 0000000000000000
head: 04fff00000000040 ffff888032b11780 dead000000000122 0000000000000000
head: 0000000000000000 00000000800c000c 00000000f5000000 0000000000000000
head: 04fff00000000002 ffffea0001430e01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5659, tgid 5657 (syz.0.17), ts 122704993495, free_ts 106109051890
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850
 prep_new_page mm/page_alloc.c:1858 [inline]
 get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3884
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:3031 [inline]
 allocate_slab+0x96/0x3a0 mm/slub.c:3204
 new_slab mm/slub.c:3258 [inline]
 ___slab_alloc+0xe94/0x18a0 mm/slub.c:4628
 __slab_alloc+0x65/0x100 mm/slub.c:4747
 __slab_alloc_node mm/slub.c:4823 [inline]
 slab_alloc_node mm/slub.c:5234 [inline]
 kmem_cache_alloc_noprof+0x3f9/0x6e0 mm/slub.c:5253
 gfs2_glock_get+0x263/0xec0 fs/gfs2/glock.c:1167
 gfs2_inode_lookup+0x215/0xb10 fs/gfs2/inode.c:135
 gfs2_lookup_root fs/gfs2/ops_fstype.c:425 [inline]
 init_sb+0xa30/0x12c0 fs/gfs2/ops_fstype.c:494
 gfs2_fill_super+0x15ef/0x20d0 fs/gfs2/ops_fstype.c:1222
 get_tree_bdev_flags+0x40b/0x4d0 fs/super.c:1691
 gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1337
 vfs_get_tree+0x8f/0x2b0 fs/super.c:1751
 fc_mount fs/namespace.c:1208 [inline]
 do_new_mount_fc fs/namespace.c:3651 [inline]
 do_new_mount+0x302/0xa10 fs/namespace.c:3727
page last free pid 5371 tgid 5371 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1394 [inline]
 __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2906
 vfree+0x25a/0x400 mm/vmalloc.c:3440
 kcov_put kernel/kcov.c:439 [inline]
 kcov_close+0x28/0x50 kernel/kcov.c:535
 __fput+0x449/0xa70 fs/file_table.c:468
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x6b5/0x2300 kernel/exit.c:966
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1107
 get_signal+0x1285/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x72/0x130 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888050c39280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888050c39300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888050c39380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff888050c39400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888050c39480: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (21):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/10/10 16:17 upstream 5472d60c129f ff1712fe .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in move_to_new_folio
2025/07/08 11:19 upstream d7b8f8e20813 4f67c4ae .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in move_to_new_folio
2025/08/01 06:23 upstream f2d282e1dfb3 0c075d67 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root KASAN: slab-use-after-free Read in move_to_new_folio
2025/07/29 17:46 upstream ced1b9e0392d f8f2b4da .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root KASAN: slab-use-after-free Read in move_to_new_folio
2025/07/29 17:45 upstream ced1b9e0392d f8f2b4da .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root KASAN: slab-use-after-free Read in move_to_new_folio
2025/07/24 15:33 upstream 25fae0b93d1d fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root KASAN: slab-use-after-free Read in move_to_new_folio
2025/07/22 17:38 upstream 89be9a83ccf1 85deaf45 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root KASAN: slab-use-after-free Read in move_to_new_folio
2025/07/16 09:29 upstream 155a3c003e55 c118d736 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root KASAN: slab-use-after-free Read in move_to_new_folio
2025/07/04 15:10 upstream 4c06e63b9203 76ad128c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: slab-use-after-free Read in move_to_new_folio
2025/07/03 04:07 upstream b4911fb0b060 0cd59a8f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root KASAN: slab-use-after-free Read in move_to_new_folio
2025/07/03 04:05 upstream b4911fb0b060 0cd59a8f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root KASAN: slab-use-after-free Read in move_to_new_folio
2025/09/08 08:09 upstream 76eeb9b8de98 d291dd2d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in move_to_new_folio
2025/09/23 20:27 linux-next ce7f1a983b07 0abd0691 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: slab-use-after-free Read in move_to_new_folio
2025/09/23 18:05 linux-next ce7f1a983b07 0ac7291c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: slab-use-after-free Read in move_to_new_folio
2025/09/23 18:05 linux-next ce7f1a983b07 0ac7291c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: slab-use-after-free Read in move_to_new_folio
2025/09/07 15:33 linux-next be5d4872e528 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: slab-use-after-free Read in move_to_new_folio
2025/08/22 12:18 linux-next 7fa4d8dc380f bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: slab-use-after-free Read in move_to_new_folio
2025/08/18 22:08 linux-next 3ac864c2d9bb 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: slab-use-after-free Read in move_to_new_folio
2025/08/15 13:38 linux-next 931e46dcbc7e 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: slab-use-after-free Read in move_to_new_folio
2025/07/15 13:26 linux-next 0be23810e32e 03fcfc4b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: slab-use-after-free Read in move_to_new_folio
2025/07/12 10:51 linux-next a62b7a37e6fc 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: slab-use-after-free Read in move_to_new_folio
* Struck through repros no longer work on HEAD.