==================================================================
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+0x7a/0xf0 fs/gfs2/quota.c:112
Write of size 4 at addr ffff888050e00b68 by task syz.7.1314/9843
CPU: 0 UID: 0 PID: 9843 Comm: syz.7.1314 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xcd/0x630 mm/kasan/report.c:482
kasan_report+0xe0/0x110 mm/kasan/report.c:595
check_region_inline mm/kasan/generic.c:194 [inline]
kasan_check_range+0x100/0x1b0 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+0x7a/0xf0 fs/gfs2/quota.c:112
rcu_do_batch kernel/rcu/tree.c:2605 [inline]
rcu_core+0x79c/0x15f0 kernel/rcu/tree.c:2857
handle_softirqs+0x219/0x950 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x109/0x170 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:unset_current_in_page_owner mm/page_owner.c:79 [inline]
RIP: 0010:save_stack+0x1a6/0x1f0 mm/page_owner.c:169
Code: e8 cf 95 8c ff 8b 2d 59 d0 92 18 e8 c4 95 8c ff 48 b8 00 00 00 00 00 fc ff df 65 4c 8b 25 5a 7a 80 11 49 8d bc 24 d0 05 00 00 <48> 89 fa 48 c1 ea 03 0f b6 04 02 84 c0 74 04 3c 03 7e 27 41 80 a4
RSP: 0018:ffffc900039af3d8 EFLAGS: 00000246
RAX: dffffc0000000000 RBX: 1ffff92000735e7b RCX: ffffc9000c90c000
RDX: 0000000000080000 RSI: ffffffff823255ac RDI: ffff88802e406150
RBP: 0000000007ea0277 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000007ea0277 R11: 000000000000a72d R12: ffff88802e405b80
R13: 0000000000002000 R14: dffffc0000000000 R15: 00000000044c01b0
__reset_page_owner+0x84/0x1a0 mm/page_owner.c:320
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1406 [inline]
free_unref_folios+0xa22/0x1610 mm/page_alloc.c:3000
folios_put_refs+0x4be/0x750 mm/swap.c:1002
folio_batch_release include/linux/pagevec.h:101 [inline]
shmem_undo_range+0x58f/0x1140 mm/shmem.c:1137
shmem_truncate_range mm/shmem.c:1249 [inline]
shmem_evict_inode+0x39e/0xbe0 mm/shmem.c:1379
evict+0x3c2/0xad0 fs/inode.c:837
iput_final fs/inode.c:1954 [inline]
iput.part.0+0x621/0x1190 fs/inode.c:2006
iput+0x35/0x40 fs/inode.c:1969
dentry_unlink_inode+0x29c/0x480 fs/dcache.c:467
__dentry_kill+0x1d0/0x600 fs/dcache.c:670
finish_dput+0x76/0x480 fs/dcache.c:879
dput.part.0+0x451/0x570 fs/dcache.c:928
dput+0x1f/0x30 fs/dcache.c:920
__fput+0x51c/0xb70 fs/file_table.c:476
task_work_run+0x150/0x240 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+0xfb/0x540 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+0x4ee/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff95a58e3aa
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:00007ff95b33fe50 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: ffffffffffffffff RCX: 00007ff95a58e3aa
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000005
R13: 00007ff95b33feb0 R14: 00000000000125c7 R15: 0000200000000180
Allocated by task 9843:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
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+0x148/0x2f90 fs/gfs2/ops_fstype.c:1121
get_tree_bdev_flags+0x38c/0x620 fs/super.c:1691
gfs2_get_tree+0x4e/0x280 fs/gfs2/ops_fstype.c:1332
vfs_get_tree+0x8e/0x330 fs/super.c:1751
fc_mount fs/namespace.c:1199 [inline]
do_new_mount_fc fs/namespace.c:3636 [inline]
do_new_mount fs/namespace.c:3712 [inline]
path_mount+0x7bf/0x23a0 fs/namespace.c:4022
do_mount fs/namespace.c:4035 [inline]
__do_sys_mount fs/namespace.c:4224 [inline]
__se_sys_mount fs/namespace.c:4201 [inline]
__x64_sys_mount+0x293/0x310 fs/namespace.c:4201
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 9843:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5f/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:6670 [inline]
kfree+0x2f8/0x6e0 mm/slub.c:6878
free_sbd fs/gfs2/ops_fstype.c:72 [inline]
gfs2_fill_super+0x15a3/0x2f90 fs/gfs2/ops_fstype.c:1316
get_tree_bdev_flags+0x38c/0x620 fs/super.c:1691
gfs2_get_tree+0x4e/0x280 fs/gfs2/ops_fstype.c:1332
vfs_get_tree+0x8e/0x330 fs/super.c:1751
fc_mount fs/namespace.c:1199 [inline]
do_new_mount_fc fs/namespace.c:3636 [inline]
do_new_mount fs/namespace.c:3712 [inline]
path_mount+0x7bf/0x23a0 fs/namespace.c:4022
do_mount fs/namespace.c:4035 [inline]
__do_sys_mount fs/namespace.c:4224 [inline]
__se_sys_mount fs/namespace.c:4201 [inline]
__x64_sys_mount+0x293/0x310 fs/namespace.c:4201
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff888050e00000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 2920 bytes inside of
freed 8192-byte region [ffff888050e00000, ffff888050e02000)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x50e00
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 ffff88813ff27280 ffffea0001e4a400 dead000000000002
raw: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813ff27280 ffffea0001e4a400 dead000000000002
head: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0001438001 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 0x528c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP), pid 8410, tgid 8409 (syz.0.814), ts 247704810667, free_ts 247681378362
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1af/0x220 mm/page_alloc.c:1857
prep_new_page mm/page_alloc.c:1865 [inline]
get_page_from_freelist+0xd0b/0x31a0 mm/page_alloc.c:3915
__alloc_frozen_pages_noprof+0x25f/0x2430 mm/page_alloc.c:5210
alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2486
alloc_slab_page mm/slub.c:3075 [inline]
allocate_slab mm/slub.c:3248 [inline]
new_slab+0x2c3/0x430 mm/slub.c:3302
___slab_alloc+0xe18/0x1c90 mm/slub.c:4656
__slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4779
__slab_alloc_node mm/slub.c:4855 [inline]
slab_alloc_node mm/slub.c:5251 [inline]
__do_kmalloc_node mm/slub.c:5656 [inline]
__kvmalloc_node_noprof+0x592/0xa40 mm/slub.c:7136
alloc_heuristic_ws fs/btrfs/compression.c:713 [inline]
alloc_workspace+0xf4/0x350 fs/btrfs/compression.c:745
alloc_workspace_manager+0x18e/0x600 fs/btrfs/compression.c:795
btrfs_alloc_compress_wsm+0x18/0xe0 fs/btrfs/compression.c:1117
open_ctree+0x1de8/0x7790 fs/btrfs/disk-io.c:3408
btrfs_fill_super fs/btrfs/super.c:981 [inline]
btrfs_get_tree_super fs/btrfs/super.c:1944 [inline]
btrfs_get_tree_subvol fs/btrfs/super.c:2087 [inline]
btrfs_get_tree+0x12e2/0x2710 fs/btrfs/super.c:2121
vfs_get_tree+0x8e/0x330 fs/super.c:1751
fc_mount fs/namespace.c:1199 [inline]
do_new_mount_fc fs/namespace.c:3636 [inline]
do_new_mount fs/namespace.c:3712 [inline]
path_mount+0x7bf/0x23a0 fs/namespace.c:4022
do_mount fs/namespace.c:4035 [inline]
__do_sys_mount fs/namespace.c:4224 [inline]
__se_sys_mount fs/namespace.c:4201 [inline]
__x64_sys_mount+0x293/0x310 fs/namespace.c:4201
page last free pid 7327 tgid 7327 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1406 [inline]
__free_frozen_pages+0x7df/0x1170 mm/page_alloc.c:2943
discard_slab mm/slub.c:3346 [inline]
__put_partials+0x130/0x170 mm/slub.c:3886
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x4c/0xf0 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x69/0x90 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:5263 [inline]
__kmalloc_cache_noprof+0x282/0x800 mm/slub.c:5771
kmalloc_noprof include/linux/slab.h:957 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
nsim_fib6_rt_create drivers/net/netdevsim/fib.c:547 [inline]
nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline]
nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline]
nsim_fib_event_work+0x199a/0x65f0 drivers/net/netdevsim/fib.c:1493
process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Memory state around the buggy address:
ffff888050e00a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888050e00a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888050e00b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888050e00b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888050e00c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: e8 cf 95 8c ff call 0xff8c95d4
5: 8b 2d 59 d0 92 18 mov 0x1892d059(%rip),%ebp # 0x1892d064
b: e8 c4 95 8c ff call 0xff8c95d4
10: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
17: fc ff df
1a: 65 4c 8b 25 5a 7a 80 mov %gs:0x11807a5a(%rip),%r12 # 0x11807a7c
21: 11
22: 49 8d bc 24 d0 05 00 lea 0x5d0(%r12),%rdi
29: 00
* 2a: 48 89 fa mov %rdi,%rdx <-- trapping instruction
2d: 48 c1 ea 03 shr $0x3,%rdx
31: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax
35: 84 c0 test %al,%al
37: 74 04 je 0x3d
39: 3c 03 cmp $0x3,%al
3b: 7e 27 jle 0x64
3d: 41 rex.B
3e: 80 .byte 0x80
3f: a4 movsb %ds:(%rsi),%es:(%rdi)