==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:112 [inline]
BUG: KASAN: slab-use-after-free in atomic_dec_and_test include/linux/atomic/atomic-instrumented.h:1383 [inline]
BUG: KASAN: slab-use-after-free in gfs2_qd_dealloc+0x81/0xe0 fs/gfs2/quota.c:112
Write of size 4 at addr ffff88807fa9cb68 by task syz.8.1033/11621
CPU: 0 UID: 0 PID: 11621 Comm: syz.8.1033 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xba/0x230 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200
instrument_atomic_read_write include/linux/instrumented.h:112 [inline]
atomic_dec_and_test include/linux/atomic/atomic-instrumented.h:1383 [inline]
gfs2_qd_dealloc+0x81/0xe0 fs/gfs2/quota.c:112
rcu_do_batch kernel/rcu/tree.c:2617 [inline]
rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869
handle_softirqs+0x22a/0x7c0 kernel/softirq.c:626
__do_softirq kernel/softirq.c:660 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x5f/0x150 kernel/softirq.c:727
irq_exit_rcu+0x9/0x30 kernel/softirq.c:743
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:arch_xor_unlock_is_negative_byte arch/x86/include/asm/bitops.h:101 [inline]
RIP: 0010:xor_unlock_is_negative_byte include/asm-generic/bitops/instrumented-lock.h:80 [inline]
RIP: 0010:folio_xor_flags_has_waiters include/linux/page-flags.h:772 [inline]
RIP: 0010:folio_unlock+0xcf/0x160 mm/filemap.c:1505
Code: 89 f6 48 83 e6 01 31 ff e8 de 65 c6 ff 49 83 e6 01 0f 85 83 00 00 00 48 89 df be 08 00 00 00 e8 c7 81 2e 00 31 f6 f0 80 33 01 <40> 0f 98 c5 40 0f 98 c6 bf 02 00 00 00 e8 cf 63 c6 ff 40 84 ed 74
RSP: 0018:ffffc9000fff7628 EFLAGS: 00000202
RAX: ffffffff81fc7101 RBX: ffffea0001a94500 RCX: ffffffff81fc7139
RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffffea0001a94500
RBP: ffffc9000fff7a10 R08: ffffea0001a94507 R09: 1ffffd40003528a0
R10: dffffc0000000000 R11: fffff940003528a1 R12: 1ffffd40003528a1
R13: 00fff6000002002d R14: 0000000000000000 R15: dffffc0000000000
shmem_undo_range+0x494/0x1670 mm/shmem.c:1147
shmem_truncate_range mm/shmem.c:1273 [inline]
shmem_evict_inode+0x240/0x9e0 mm/shmem.c:1403
evict+0x61e/0xb10 fs/inode.c:837
__dentry_kill+0x209/0x660 fs/dcache.c:670
finish_dput+0xc9/0x480 fs/dcache.c:879
__fput+0x691/0xa70 fs/file_table.c:476
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5fd535b58e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007f5fd6176df8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 00007f5fd61776c0 RCX: 00007f5fd535b58e
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000005
R13: 00007f5fd6176ea0 R14: 00000000000125c7 R15: 0000200000000180
Allocated by task 11621:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5244
kmalloc_noprof include/linux/slab.h:962 [inline]
kzalloc_noprof include/linux/slab.h:1204 [inline]
init_sbd fs/gfs2/ops_fstype.c:79 [inline]
gfs2_fill_super+0x128/0x21d0 fs/gfs2/ops_fstype.c:1121
get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1694
gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1332
vfs_get_tree+0x92/0x2a0 fs/super.c:1754
fc_mount fs/namespace.c:1193 [inline]
do_new_mount_fc fs/namespace.c:3760 [inline]
do_new_mount+0x341/0xd30 fs/namespace.c:3836
do_mount fs/namespace.c:4159 [inline]
__do_sys_mount fs/namespace.c:4348 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4325
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 11621:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2621 [inline]
slab_free mm/slub.c:6026 [inline]
kfree+0x1c1/0x610 mm/slub.c:6339
free_sbd fs/gfs2/ops_fstype.c:72 [inline]
gfs2_fill_super+0x150e/0x21d0 fs/gfs2/ops_fstype.c:1316
get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1694
gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1332
vfs_get_tree+0x92/0x2a0 fs/super.c:1754
fc_mount fs/namespace.c:1193 [inline]
do_new_mount_fc fs/namespace.c:3760 [inline]
do_new_mount+0x341/0xd30 fs/namespace.c:3836
do_mount fs/namespace.c:4159 [inline]
__do_sys_mount fs/namespace.c:4348 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4325
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff88807fa9c000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 2920 bytes inside of
freed 8192-byte region [ffff88807fa9c000, ffff88807fa9e000)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7fa98
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801b027280 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801b027280 dead000000000100 dead000000000122
head: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0001fea601 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 7155, tgid 7150 (syz.3.238), ts 253881188359, free_ts 253873668197
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x231/0x280 mm/page_alloc.c:1883
prep_new_page mm/page_alloc.c:1891 [inline]
get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3956
__alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5244
alloc_slab_page mm/slub.c:3189 [inline]
allocate_slab+0x7b/0x660 mm/slub.c:3362
new_slab mm/slub.c:3420 [inline]
refill_objects+0x33a/0x3d0 mm/slub.c:7028
refill_sheaf mm/slub.c:2738 [inline]
__pcs_replace_empty_main+0x2b9/0x620 mm/slub.c:4483
alloc_from_pcs mm/slub.c:4586 [inline]
slab_alloc_node mm/slub.c:4720 [inline]
__kmalloc_cache_noprof+0x392/0x660 mm/slub.c:5239
kmalloc_noprof include/linux/slab.h:962 [inline]
kzalloc_noprof include/linux/slab.h:1204 [inline]
xfs_init_fs_context+0x54/0x500 fs/xfs/xfs_super.c:2216
alloc_fs_context+0x49c/0x590 fs/fs_context.c:295
do_new_mount+0x187/0xd30 fs/namespace.c:3816
do_mount fs/namespace.c:4159 [inline]
__do_sys_mount fs/namespace.c:4348 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4325
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 7155 tgid 7150 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1432 [inline]
__free_frozen_pages+0xbb9/0xd10 mm/page_alloc.c:2972
__slab_free+0x263/0x2b0 mm/slub.c:5437
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4406 [inline]
slab_alloc_node mm/slub.c:4735 [inline]
kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4742
alloc_filename fs/namei.c:142 [inline]
do_getname+0x2e/0x250 fs/namei.c:182
getname include/linux/fs.h:2512 [inline]
class_filename_constructor include/linux/fs.h:2539 [inline]
do_sys_openat2+0xca/0x200 fs/open.c:1365
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1383
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Memory state around the buggy address:
ffff88807fa9ca00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807fa9ca80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807fa9cb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88807fa9cb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807fa9cc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: 89 f6 mov %esi,%esi
2: 48 83 e6 01 and $0x1,%rsi
6: 31 ff xor %edi,%edi
8: e8 de 65 c6 ff call 0xffc665eb
d: 49 83 e6 01 and $0x1,%r14
11: 0f 85 83 00 00 00 jne 0x9a
17: 48 89 df mov %rbx,%rdi
1a: be 08 00 00 00 mov $0x8,%esi
1f: e8 c7 81 2e 00 call 0x2e81eb
24: 31 f6 xor %esi,%esi
26: f0 80 33 01 lock xorb $0x1,(%rbx)
* 2a: 40 0f 98 c5 sets %bpl <-- trapping instruction
2e: 40 0f 98 c6 sets %sil
32: bf 02 00 00 00 mov $0x2,%edi
37: e8 cf 63 c6 ff call 0xffc6640b
3c: 40 84 ed test %bpl,%bpl
3f: 74 .byte 0x74