syzbot

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BUG: KASAN: slab-use-after-free in z_erofs_decompress_kickoff+0x371/0x3d0 fs/erofs/zdata.c:1475
Read of size 4 at addr ffff888065039968 by task kworker/u8:13/5808

CPU: 1 UID: 0 PID: 5808 Comm: kworker/u8:13 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: wg-kex-wg2 wg_packet_handshake_send_worker
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 z_erofs_decompress_kickoff+0x371/0x3d0 fs/erofs/zdata.c:1475
 z_erofs_endio+0xb28/0xd40 fs/erofs/zdata.c:1655
 blk_update_request+0x57e/0xe60 block/blk-mq.c:1016
 blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1178
 blk_complete_reqs block/blk-mq.c:1253 [inline]
 blk_done_softirq+0x10a/0x160 block/blk-mq.c:1258
 handle_softirqs+0x1de/0x6d0 kernel/softirq.c:626
 __do_softirq kernel/softirq.c:660 [inline]
 __local_bh_enable_ip+0x170/0x2b0 kernel/softirq.c:302
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 spin_unlock_bh include/linux/spinlock_rt.h:116 [inline]
 wg_index_hashtable_insert+0x12e/0x8c0 drivers/net/wireguard/peerlookup.c:126
 wg_noise_handshake_create_initiation+0x64e/0x830 drivers/net/wireguard/noise.c:569
 wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:34 [inline]
 wg_packet_handshake_send_worker+0x18d/0x350 drivers/net/wireguard/send.c:51
 process_one_work+0x9a3/0x1710 kernel/workqueue.c:3312
 process_scheduled_works kernel/workqueue.c:3403 [inline]
 worker_thread+0xba8/0x11e0 kernel/workqueue.c:3489
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 10011:
 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+0x3a6/0x690 mm/slub.c:5427
 kmalloc_noprof include/linux/slab.h:950 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 erofs_init_fs_context+0x54/0x290 fs/erofs/super.c:897
 alloc_fs_context+0x9d5/0xd50 fs/fs_context.c:295
 do_new_mount+0x187/0xd30 fs/namespace.c:3814
 do_mount fs/namespace.c:4167 [inline]
 __do_sys_mount fs/namespace.c:4383 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4360
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5611:
 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:2700 [inline]
 slab_free mm/slub.c:6258 [inline]
 kfree+0x1c5/0x6c0 mm/slub.c:6573
 erofs_sb_free fs/erofs/super.c:875 [inline]
 erofs_kill_sb+0x26a/0x2a0 fs/erofs/super.c:939
 deactivate_locked_super+0xbc/0x130 fs/super.c:476
 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
 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:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888065039800
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 360 bytes inside of
 freed 1024-byte region [ffff888065039800, ffff888065039c00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x6503[  694.792263][    C1] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x65038
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88813fe15dc0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88813fe15dc0 dead000000000100 dead000000000122
head: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 0080000000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff
head: 0000000000002be4 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 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 30, tgid 30 (ktimers/1), ts 174831828958, free_ts 174792463503
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x27d6/0x2850 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5249
 alloc_slab_page mm/slub.c:3289 [inline]
 allocate_slab+0x74/0x5e0 mm/slub.c:3404
 new_slab mm/slub.c:3447 [inline]
 refill_objects+0x33c/0x3d0 mm/slub.c:7263
 refill_sheaf mm/slub.c:2827 [inline]
 __pcs_replace_empty_main+0x373/0x720 mm/slub.c:4659
 alloc_from_pcs mm/slub.c:4757 [inline]
 slab_alloc_node mm/slub.c:4891 [inline]
 __do_kmalloc_node mm/slub.c:5302 [inline]
 __kmalloc_noprof+0x530/0x7b0 mm/slub.c:5315
 kmalloc_noprof include/linux/slab.h:954 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 ieee802_11_parse_elems_full+0x159/0x2ab0 net/mac80211/parse.c:1051
 ieee802_11_parse_elems net/mac80211/ieee80211_i.h:2501 [inline]
 ieee80211_inform_bss+0x161/0x1160 net/mac80211/scan.c:79
 rdev_inform_bss net/wireless/rdev-ops.h:418 [inline]
 cfg80211_inform_single_bss_data+0xd2f/0x1b80 net/wireless/scan.c:2372
 cfg80211_inform_bss_data+0x266/0x3c40 net/wireless/scan.c:3226
 cfg80211_inform_bss_frame_data+0x3c7/0x730 net/wireless/scan.c:3317
 ieee80211_bss_info_update+0x794/0xa40 net/mac80211/scan.c:230
 ieee80211_scan_rx+0x552/0xa40 net/mac80211/scan.c:364
 __ieee80211_rx_handle_packet net/mac80211/rx.c:5353 [inline]
 ieee80211_rx_list+0x2a2f/0x37a0 net/mac80211/rx.c:5638
 ieee80211_rx_napi+0x1b1/0x3e0 net/mac80211/rx.c:5661
page last free pid 43 tgid 43 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0x1075/0x11b0 mm/page_alloc.c:2938
 skb_free_frag include/linux/skbuff.h:3534 [inline]
 skb_free_head net/core/skbuff.c:1085 [inline]
 skb_release_data+0x8a5/0xa60 net/core/skbuff.c:1114
 skb_release_all net/core/skbuff.c:1189 [inline]
 __kfree_skb+0x5d/0x210 net/core/skbuff.c:1203
 batadv_forw_packet_free+0x65/0x1f0 net/batman-adv/send.c:458
 process_one_work+0x9a3/0x1710 kernel/workqueue.c:3312
 process_scheduled_works kernel/workqueue.c:3403 [inline]
 worker_thread+0xba8/0x11e0 kernel/workqueue.c:3489
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff888065039800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888065039880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888065039900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                          ^
 ffff888065039980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888065039a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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