==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:96 [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 ffff88807b6a4b68 by task syz.1.869/9779
CPU: 1 UID: 0 PID: 9779 Comm: syz.1.869 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
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_write include/linux/instrumented.h:96 [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:2605 [inline]
rcu_core+0xd70/0x1870 kernel/rcu/tree.c:2857
handle_softirqs+0x27d/0x850 kernel/softirq.c:626
__do_softirq kernel/softirq.c:660 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x1f0 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:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202
Code: 90 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 ea ff 3e f6 48 89 df e8 22 77 3f f6 e8 ed ff 69 f6 fb bf 01 00 00 00 a2 6b 31 f6 65 8b 05 db 8f 3f 07 85 c0 74 07 5b e9 c1 4b 00 00
RSP: 0018:ffffc9000bde75d8 EFLAGS: 00000286
RAX: ffd11aa580260100 RBX: ffff8880799e64b0 RCX: ffd11aa580260100
RDX: 0000000000000006 RSI: ffffffff8d99597b RDI: 0000000000000001
RBP: ffffc9000bde79f0 R08: ffffffff8fa20e77 R09: 1ffffffff1f441ce
R10: dffffc0000000000 R11: fffffbfff1f441cf R12: dffffc0000000000
R13: 1ffff1100f33cc95 R14: ffff8880799e64a8 R15: ffff8880799e64b0
spin_unlock_irq include/linux/spinlock.h:401 [inline]
filemap_remove_folio+0xee/0x1f0 mm/filemap.c:258
truncate_inode_folio+0x5d/0x70 mm/truncate.c:176
shmem_undo_range+0x3a9/0x1490 mm/shmem.c:1133
shmem_truncate_range mm/shmem.c:1249 [inline]
shmem_evict_inode+0x26e/0xa70 mm/shmem.c:1379
evict+0x5f4/0xae0 fs/inode.c:837
__dentry_kill+0x209/0x660 fs/dcache.c:670
finish_dput+0xc9/0x480 fs/dcache.c:879
__fput+0x68e/0xa70 fs/file_table.c:476
task_work_run+0x1d4/0x260 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:44 [inline]
exit_to_user_mode_loop+0xff/0x4f0 kernel/entry/common.c:75
__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+0x2d0/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5cba98e3aa
Code: 48 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c 24 0c e8 43 91 02 00 8b 7c 24 0c 89 c2 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 36 89 d7 89 44 24 0c e8 a3 91 02 00 8b 44 24
RSP: 002b:00007f5cbb7d8e50 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: ffffffffffffffff RCX: 00007f5cba98e3aa
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000001000800
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000005
R13: 00007f5cbb7d8eb0 R14: 000000000001258b R15: 0000200000000180
Allocated by task 9779:
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+0x3e2/0x700 mm/slub.c:5780
kmalloc_noprof include/linux/slab.h:957 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
init_sbd fs/gfs2/ops_fstype.c:79 [inline]
gfs2_fill_super+0x11f/0x21b0 fs/gfs2/ops_fstype.c:1121
get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691
gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1332
vfs_get_tree+0x92/0x2a0 fs/super.c:1751
fc_mount fs/namespace.c:1199 [inline]
do_new_mount_fc fs/namespace.c:3636 [inline]
do_new_mount+0x302/0xa10 fs/namespace.c:3712
do_mount fs/namespace.c:4035 [inline]
__do_sys_mount fs/namespace.c:4224 [inline]
__se_sys_mount+0x313/0x410 fs/namespace.c:4201
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 9779:
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:2540 [inline]
slab_free mm/slub.c:6674 [inline]
kfree+0x1c0/0x660 mm/slub.c:6882
free_sbd fs/gfs2/ops_fstype.c:72 [inline]
gfs2_fill_super+0x14ef/0x21b0 fs/gfs2/ops_fstype.c:1316
get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691
gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1332
vfs_get_tree+0x92/0x2a0 fs/super.c:1751
fc_mount fs/namespace.c:1199 [inline]
do_new_mount_fc fs/namespace.c:3636 [inline]
do_new_mount+0x302/0xa10 fs/namespace.c:3712
do_mount fs/namespace.c:4035 [inline]
__do_sys_mount fs/namespace.c:4224 [inline]
__se_sys_mount+0x313/0x410 fs/namespace.c:4201
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff88807b6a4000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 2920 bytes inside of
freed 8192-byte region [ffff88807b6a4000, ffff88807b6a6000)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7b6a0
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
ksm flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88813fea7280 ffffea00015a7e00 dead000000000003
raw: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813fea7280 ffffea00015a7e00 dead000000000003
head: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0001eda801 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 8348, tgid 8344 (syz.4.590), ts 307021214886, free_ts 306992471355
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x234/0x290 mm/page_alloc.c:1857
prep_new_page mm/page_alloc.c:1865 [inline]
get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3915
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486
alloc_slab_page mm/slub.c:3075 [inline]
allocate_slab+0x86/0x3b0 mm/slub.c:3248
new_slab mm/slub.c:3302 [inline]
___slab_alloc+0xf2b/0x1960 mm/slub.c:4656
__slab_alloc+0x65/0x100 mm/slub.c:4779
__slab_alloc_node mm/slub.c:4855 [inline]
slab_alloc_node mm/slub.c:5255 [inline]
__kmalloc_cache_noprof+0x41e/0x700 mm/slub.c:5775
kmalloc_noprof include/linux/slab.h:957 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
hfs_mdb_get+0x10a0/0x1ff0 fs/hfs/mdb.c:175
hfs_fill_super+0x401/0x6a0 fs/hfs/super.c:341
get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691
vfs_get_tree+0x92/0x2a0 fs/super.c:1751
fc_mount fs/namespace.c:1199 [inline]
do_new_mount_fc fs/namespace.c:3636 [inline]
do_new_mount+0x302/0xa10 fs/namespace.c:3712
do_mount fs/namespace.c:4035 [inline]
__do_sys_mount fs/namespace.c:4224 [inline]
__se_sys_mount+0x313/0x410 fs/namespace.c:4201
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 8348 tgid 8344 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1406 [inline]
__free_frozen_pages+0xbc8/0xd30 mm/page_alloc.c:2943
discard_slab mm/slub.c:3346 [inline]
__put_partials+0x146/0x170 mm/slub.c:3886
put_cpu_partial+0x1f2/0x2d0 mm/slub.c:3961
__slab_free+0x288/0x2a0 mm/slub.c:5956
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:4953 [inline]
slab_alloc_node mm/slub.c:5267 [inline]
__kmalloc_cache_noprof+0x37c/0x700 mm/slub.c:5775
kmalloc_noprof include/linux/slab.h:957 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
kobject_uevent_env+0x28c/0x9f0 lib/kobject_uevent.c:540
loop_configure+0xb88/0xe50 drivers/block/loop.c:1093
lo_ioctl+0x806/0x1c50 drivers/block/loop.c:-1
blkdev_ioctl+0x60e/0x710 block/ioctl.c:791
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Memory state around the buggy address:
ffff88807b6a4a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807b6a4a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807b6a4b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88807b6a4b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807b6a4c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: 90 nop
1: f3 0f 1e fa endbr64
5: 53 push %rbx
6: 48 89 fb mov %rdi,%rbx
9: 48 83 c7 18 add $0x18,%rdi
d: 48 8b 74 24 08 mov 0x8(%rsp),%rsi
12: e8 ea ff 3e f6 call 0xf63f0001
17: 48 89 df mov %rbx,%rdi
1a: e8 22 77 3f f6 call 0xf63f7741
1f: e8 ed ff 69 f6 call 0xf66a0011
24: fb sti
25: bf 01 00 00 00 mov $0x1,%edi
* 2a: e8 a2 6b 31 f6 call 0xf6316bd1 <-- trapping instruction
2f: 65 8b 05 db 8f 3f 07 mov %gs:0x73f8fdb(%rip),%eax # 0x73f9011
36: 85 c0 test %eax,%eax
38: 74 07 je 0x41
3a: 5b pop %rbx
3b: e9 c1 4b 00 00 jmp 0x4c01