[syzbot ci] Re: DEPT(DEPendency Tracker)

[syzbot ci]

syzbot ci has tested the following series

[v19] DEPT(DEPendency Tracker)
https://lore.kernel.org/all/20260706061928.6...@sk.com
* [PATCH v19 01/40] dept: implement DEPT(DEPendency Tracker)
* [PATCH v19 02/40] dept: add single event dependency tracker APIs
* [PATCH v19 03/40] dept: add lock dependency tracker APIs
* [PATCH v19 04/40] dept: tie to lockdep and IRQ tracing
* [PATCH v19 05/40] dept: add proc knobs to show stats and dependency graph
* [PATCH v19 06/40] dept: distinguish each kernel context from another
* [PATCH v19 07/40] dept: distinguish each work from another
* [PATCH v19 08/40] dept: add a mechanism to refill the internal memory pools on running out
* [PATCH v19 09/40] dept: record the latest one out of consecutive waits of the same class
* [PATCH v19 10/40] dept: apply sdt_might_sleep_{start,end}() to wait_for_completion()/complete()
* [PATCH v19 11/40] dept: apply sdt_might_sleep_{start,end}() to swait
* [PATCH v19 12/40] dept: apply sdt_might_sleep_{start,end}() to waitqueue wait
* [PATCH v19 13/40] dept: apply sdt_might_sleep_{start,end}() to hashed-waitqueue wait
* [PATCH v19 14/40] dept: apply sdt_might_sleep_{start,end}() to dma fence
* [PATCH v19 15/40] dept: track timeout waits separately with a new Kconfig
* [PATCH v19 16/40] dept: apply timeout consideration to wait_for_completion()/complete()
* [PATCH v19 17/40] dept: apply timeout consideration to swait
* [PATCH v19 18/40] dept: apply timeout consideration to waitqueue wait
* [PATCH v19 19/40] dept: apply timeout consideration to hashed-waitqueue wait
* [PATCH v19 20/40] dept: apply timeout consideration to dma fence wait
* [PATCH v19 21/40] dept: make dept able to work with an external wgen
* [PATCH v19 22/40] dept: track PG_locked with dept
* [PATCH v19 23/40] dept: print staged wait's stacktrace on report
* [PATCH v19 24/40] locking/lockdep: prevent various lockdep assertions when lockdep_off()'ed
* [PATCH v19 25/40] dept: add documents for dept
* [PATCH v19 26/40] cpu/hotplug: use a weaker annotation in AP thread
* [PATCH v19 27/40] dept: assign dept map to mmu notifier invalidation synchronization
* [PATCH v19 28/40] dept: assign unique dept_key to each distinct dma fence caller
* [PATCH v19 29/40] dept: make dept aware of lockdep_set_lock_cmp_fn() annotation
* [PATCH v19 30/40] dept: make dept stop from working on debug_locks_off()
* [PATCH v19 31/40] dept: assign unique dept_key to each distinct wait_for_completion() caller
* [PATCH v19 32/40] completion, dept: introduce init_completion_dmap() API
* [PATCH v19 33/40] dept: call dept_hardirqs_off() in local_irq_*() regardless of irq state
* [PATCH v19 34/40] rcu/update: fix same dept key collision between various types of RCU
* [PATCH v19 35/40] dept: introduce APIs to set page usage and use subclasses_evt for the usage
* [PATCH v19 36/40] dept: track PG_writeback with dept
* [PATCH v19 37/40] SUNRPC: relocate struct rcu_head to the first field of struct rpc_xprt
* [PATCH v19 38/40] mm: percpu: increase PERCPU_DYNAMIC_SIZE_SHIFT on DEPT and large PAGE_SIZE
* [PATCH v19 39/40] rust: completion: Add __rust_helper to rust_helper_wait_for_completion()
* [PATCH v19 40/40] dept: implement a basic unit test for dept

and found the following issue:
KASAN: slab-use-after-free Read in __dept_wait

Full report is available here:
https://ci.syzbot.org/series/bad70fd4-71dd-485d-92ef-f266796152e3

***

KASAN: slab-use-after-free Read in __dept_wait

tree: bpf-next
URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/bpf/bpf-next.git
base: 028ef9c96e96197026887c0f092424679298aae8
arch: amd64
compiler: Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
config: https://ci.syzbot.org/builds/e0007242-bbfe-42b9-ad3e-e15fe3f29261/config
syz repro: https://ci.syzbot.org/findings/1c2fe55b-5fa6-4b20-a73c-b9bbc70528f7/syz_repro

==================================================================
BUG: KASAN: slab-use-after-free in lockdep_cmp_fn kernel/dependency/dept.c:1647 [inline]
BUG: KASAN: slab-use-after-free in add_wait kernel/dependency/dept.c:1710 [inline]
BUG: KASAN: slab-use-after-free in __dept_wait+0xe66/0x1b70 kernel/dependency/dept.c:2422
Read of size 8 at addr ffff8881a7a30190 by task syz.1.18/5874

CPU: 1 UID: 0 PID: 5874 Comm: syz.1.18 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
<IRQ>
dump_stack_lvl+0xed/0x160 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xbe/0x230 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
lockdep_cmp_fn kernel/dependency/dept.c:1647 [inline]
add_wait kernel/dependency/dept.c:1710 [inline]
__dept_wait+0xe66/0x1b70 kernel/dependency/dept.c:2422
dept_wait+0x135/0x1a0 kernel/dependency/dept.c:2483
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
_raw_spin_lock_irqsave+0x5b/0xc0 kernel/locking/spinlock.c:162
debug_object_active_state+0x77/0x390 lib/debugobjects.c:1063
debug_rcu_head_unqueue kernel/rcu/rcu.h:246 [inline]
rcu_do_batch kernel/rcu/tree.c:2609 [inline]
rcu_core+0x6f9/0xff0 kernel/rcu/tree.c:2869
handle_softirqs+0x231/0x890 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x66/0x150 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+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x20b/0x2e0 kernel/locking/lockdep.c:5893
Code: e9 30 ff ff ff e8 c5 62 fd 09 f7 c3 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 d1 2e 84 11 48 3b 44 24 30 75 33 fb 48 83 c4 38 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d 6e 8d 82
RSP: 0018:ffffc900041e74a8 EFLAGS: 00000282
RAX: e0efb026e1546b00 RBX: 0000000000000246 RCX: 0000000000000046
RDX: 00000000279c9488 RSI: ffffffff8e150025 RDI: ffffffff8c281c40
RBP: 0000000000000000 R08: ffffffff81764955 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8e7da2a0 R12: 0000000000000002
R13: ffffffff8e7da2a0 R14: 0000000000000000 R15: 0000000000000000
rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
rcu_read_lock include/linux/rcupdate.h:850 [inline]
class_rcu_constructor include/linux/rcupdate.h:1193 [inline]
unwind_next_frame+0xb2/0x2380 arch/x86/kernel/unwind_orc.c:495
__unwind_start+0x4f2/0x640 arch/x86/kernel/unwind_orc.c:773
unwind_start arch/x86/include/asm/unwind.h:64 [inline]
arch_stack_walk+0xe3/0x150 arch/x86/kernel/stacktrace.c:24
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x40/0x50 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:2685 [inline]
slab_free mm/slub.c:6165 [inline]
kfree+0x1c5/0x640 mm/slub.c:6483
xfs_mountfs+0x1458/0x2350 fs/xfs/xfs_mount.c:1280
xfs_fs_fill_super+0x11a2/0x15f0 fs/xfs/xfs_super.c:1938
get_tree_bdev_flags+0x430/0x4f0 fs/super.c:1694
vfs_get_tree+0x92/0x2a0 fs/super.c:1754
fc_mount fs/namespace.c:1193 [inline]
do_new_mount_fc fs/namespace.c:3763 [inline]
do_new_mount+0x319/0xdd0 fs/namespace.c:3839
do_mount fs/namespace.c:4172 [inline]
__do_sys_mount fs/namespace.c:4361 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4338
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x175/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6977f9e0ca
Code: 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6978ec5e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f6978ec5ee0 RCX: 00007f6977f9e0ca
RDX: 0000200000000040 RSI: 00002000000000c0 RDI: 00007f6978ec5ea0
RBP: 0000200000000040 R08: 00007f6978ec5ee0 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000246 R12: 00002000000000c0
R13: 00007f6978ec5ea0 R14: 0000000000009888 R15: 0000200000000080
</TASK>

Allocated by task 5874:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
unpoison_slab_object mm/kasan/common.c:340 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4538 [inline]
slab_alloc_node mm/slub.c:4866 [inline]
kmem_cache_alloc_lru_noprof+0x2b4/0x640 mm/slub.c:4885
xfs_inode_alloc+0x7e/0x710 fs/xfs/xfs_icache.c:97
xfs_iget_cache_miss fs/xfs/xfs_icache.c:637 [inline]
xfs_iget+0xa6b/0x2ef0 fs/xfs/xfs_icache.c:808
xfs_mountfs+0x1165/0x2350 fs/xfs/xfs_mount.c:1073
xfs_fs_fill_super+0x11a2/0x15f0 fs/xfs/xfs_super.c:1938
get_tree_bdev_flags+0x430/0x4f0 fs/super.c:1694
vfs_get_tree+0x92/0x2a0 fs/super.c:1754
fc_mount fs/namespace.c:1193 [inline]
do_new_mount_fc fs/namespace.c:3763 [inline]
do_new_mount+0x319/0xdd0 fs/namespace.c:3839
do_mount fs/namespace.c:4172 [inline]
__do_sys_mount fs/namespace.c:4361 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4338
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x175/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5874:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x40/0x50 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:2685 [inline]
slab_free mm/slub.c:6165 [inline]
kmem_cache_free+0x18c/0x630 mm/slub.c:6295
rcu_do_batch kernel/rcu/tree.c:2617 [inline]
rcu_core+0x794/0xff0 kernel/rcu/tree.c:2869
handle_softirqs+0x231/0x890 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x66/0x150 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+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697

Last potentially related work creation:
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
kasan_record_aux_stack+0xcb/0xe0 mm/kasan/generic.c:556
__call_rcu_common kernel/rcu/tree.c:3131 [inline]
call_rcu+0xf7/0x890 kernel/rcu/tree.c:3251
xfs_reclaim_inode fs/xfs/xfs_icache.c:1049 [inline]
xfs_icwalk_process_inode fs/xfs/xfs_icache.c:1736 [inline]
xfs_icwalk_ag+0x1204/0x18c0 fs/xfs/xfs_icache.c:1818
xfs_icwalk fs/xfs/xfs_icache.c:1866 [inline]
xfs_reclaim_inodes+0x1b6/0x2b0 fs/xfs/xfs_icache.c:1082
xfs_unmount_flush_inodes+0xb1/0xd0 fs/xfs/xfs_mount.c:628
xfs_mountfs+0x1325/0x2350 fs/xfs/xfs_mount.c:1267
xfs_fs_fill_super+0x11a2/0x15f0 fs/xfs/xfs_super.c:1938
get_tree_bdev_flags+0x430/0x4f0 fs/super.c:1694
vfs_get_tree+0x92/0x2a0 fs/super.c:1754
fc_mount fs/namespace.c:1193 [inline]
do_new_mount_fc fs/namespace.c:3763 [inline]
do_new_mount+0x319/0xdd0 fs/namespace.c:3839
do_mount fs/namespace.c:4172 [inline]
__do_sys_mount fs/namespace.c:4361 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4338
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x175/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff8881a7a30000
which belongs to the cache xfs_inode of size 2672
The buggy address is located 400 bytes inside of
freed 2672-byte region [ffff8881a7a30000, ffff8881a7a30a70)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8881a7a30b00 pfn:0x1a7a30
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff8881a7a37901
flags: 0x57ff00000000240(workingset|head|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000240 ffff8881604168c0 ffff888163eabc88 ffff888163eabc88
raw: ffff8881a7a30b00 00000008000b0001 00000000f5000000 ffff8881a7a37901
raw: 0000000000000000 0000000000000000
head: 057ff00000000240 ffff8881604168c0 ffff888163eabc88 ffff888163eabc88
head: ffff8881a7a30b00 00000008000b0001 00000000f5000000 ffff8881a7a37901
head: 0000000000000000 0000000000000000 057ff00000000003 ffffea0008462f01
head: 00000000ffffffff 00000000ffffffff ffffffffffffffff 0000000000000000
head: 00000000ffffffff 0000000000000008 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Reclaimable, gfp_mask 0xd20d0(__GFP_RECLAIMABLE|__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5874, tgid 5873 (syz.1.18), ts 154889839111, free_ts 140490269358
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x239/0x290 mm/page_alloc.c:1889
prep_new_page mm/page_alloc.c:1897 [inline]
get_page_from_freelist+0x2541/0x25e0 mm/page_alloc.c:3962
__alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
alloc_slab_page mm/slub.c:3292 [inline]
allocate_slab+0x77/0x6a0 mm/slub.c:3481
new_slab mm/slub.c:3539 [inline]
refill_objects+0x331/0x3c0 mm/slub.c:7175
refill_sheaf mm/slub.c:2812 [inline]
alloc_full_sheaf mm/slub.c:2834 [inline]
__pcs_replace_empty_main+0x428/0x760 mm/slub.c:4626
alloc_from_pcs mm/slub.c:4717 [inline]
slab_alloc_node mm/slub.c:4851 [inline]
kmem_cache_alloc_lru_noprof+0x372/0x640 mm/slub.c:4885
xfs_inode_alloc+0x7e/0x710 fs/xfs/xfs_icache.c:97
xfs_iget_cache_miss fs/xfs/xfs_icache.c:637 [inline]
xfs_iget+0xa6b/0x2ef0 fs/xfs/xfs_icache.c:808
xfs_mountfs+0x1165/0x2350 fs/xfs/xfs_mount.c:1073
xfs_fs_fill_super+0x11a2/0x15f0 fs/xfs/xfs_super.c:1938
get_tree_bdev_flags+0x430/0x4f0 fs/super.c:1694
vfs_get_tree+0x92/0x2a0 fs/super.c:1754
fc_mount fs/namespace.c:1193 [inline]
do_new_mount_fc fs/namespace.c:3763 [inline]
do_new_mount+0x319/0xdd0 fs/namespace.c:3839
do_mount fs/namespace.c:4172 [inline]
__do_sys_mount fs/namespace.c:4361 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4338
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x175/0xf80 arch/x86/entry/syscall_64.c:94
page last free pid 5668 tgid 5668 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1433 [inline]
__free_frozen_pages+0xc81/0xe10 mm/page_alloc.c:2978
vfree+0x25b/0x400 mm/vmalloc.c:3479
kcov_put kernel/kcov.c:444 [inline]
kcov_close+0x2e/0x60 kernel/kcov.c:543
__fput+0x440/0xa80 fs/file_table.c:469
task_work_run+0x1d9/0x270 kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x73a/0x2470 kernel/exit.c:976
do_group_exit+0x22d/0x2f0 kernel/exit.c:1119
get_signal+0x121b/0x12c0 kernel/signal.c:3034
arch_do_signal_or_restart+0xbb/0x810 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
exit_to_user_mode_loop+0xa8/0x5f0 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:260 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
do_syscall_64+0x37e/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
ffff8881a7a30080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881a7a30100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881a7a30180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881a7a30200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881a7a30280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: e9 30 ff ff ff jmp 0xffffff35
5: e8 c5 62 fd 09 call 0x9fd62cf
a: f7 c3 00 02 00 00 test $0x200,%ebx
10: 0f 84 38 ff ff ff je 0xffffff4e
16: 65 48 8b 05 d1 2e 84 mov %gs:0x11842ed1(%rip),%rax # 0x11842eef
1d: 11
1e: 48 3b 44 24 30 cmp 0x30(%rsp),%rax
23: 75 33 jne 0x58
25: fb sti
26: 48 83 c4 38 add $0x38,%rsp
* 2a: 5b pop %rbx <-- trapping instruction
2b: 41 5c pop %r12
2d: 41 5d pop %r13
2f: 41 5e pop %r14
31: 41 5f pop %r15
33: 5d pop %rbp
34: c3 ret
35: cc int3
36: cc int3
37: cc int3
38: cc int3
39: cc int3
3a: 48 rex.W
3b: 8d .byte 0x8d
3c: 3d .byte 0x3d
3d: 6e outsb %ds:(%rsi),(%dx)
3e: 8d .byte 0x8d
3f: 82 .byte 0x82


***

If these findings have caused you to resend the series or submit a
separate fix, please add the following tag to your commit message:
Tested-by: syz...@syzkaller.appspotmail.com

---
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