Re: [syzbot] [kernel?] INFO: rcu detected stall in kill

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Write in ath9k_hif_usb_reg_in_resubmit

==================================================================
BUG: KASAN: slab-use-after-free in ath9k_hif_usb_reg_in_resubmit+0x143/0x170 drivers/net/wireless/ath/ath9k/hif_usb.c:759
Write of size 8 at addr ffff8880282609b0 by task kworker/0:4/5926

CPU: 0 UID: 0 PID: 5926 Comm: kworker/0:4 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: events ath9k_hif_usb_reg_in_resubmit
Call Trace:
 <TASK>
 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
 ath9k_hif_usb_reg_in_resubmit+0x143/0x170 drivers/net/wireless/ath/ath9k/hif_usb.c:759
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 6436:
 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]
 __do_kmalloc_node mm/slub.c:5260 [inline]
 __kmalloc_noprof+0x35c/0x760 mm/slub.c:5272
 kmalloc_noprof include/linux/slab.h:954 [inline]
 usb_alloc_urb+0x46/0x150 drivers/usb/core/urb.c:75
 ath9k_hif_usb_alloc_reg_in_urbs drivers/net/wireless/ath/ath9k/hif_usb.c:1019 [inline]
 ath9k_hif_usb_alloc_urbs+0xb8c/0x1120 drivers/net/wireless/ath/ath9k/hif_usb.c:1085
 ath9k_hif_usb_dev_init drivers/net/wireless/ath/ath9k/hif_usb.c:1171 [inline]
 ath9k_hif_usb_firmware_cb+0x127/0x4c0 drivers/net/wireless/ath/ath9k/hif_usb.c:1304
 request_firmware_work_func+0x105/0x1c0 drivers/base/firmware_loader/main.c:1152
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 5926:
 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:2685 [inline]
 slab_free mm/slub.c:6165 [inline]
 kfree+0x1c1/0x630 mm/slub.c:6483
 urb_destroy drivers/usb/core/urb.c:27 [inline]
 kref_put include/linux/kref.h:65 [inline]
 usb_free_urb drivers/usb/core/urb.c:96 [inline]
 __usb_unanchor_urb drivers/usb/core/urb.c:153 [inline]
 usb_unanchor_urb+0x283/0x380 drivers/usb/core/urb.c:183
 ath9k_hif_usb_reg_in_resubmit+0xf4/0x170 drivers/net/wireless/ath/ath9k/hif_usb.c:755
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff888028260900
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 176 bytes inside of
 freed 192-byte region [ffff888028260900, ffff8880282609c0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x28260
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88813fea63c0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2c00(GFP_NOIO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 24, tgid 24 (kworker/1:0), ts 10584606067, free_ts 6626023302
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x24dc/0x2580 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+0x77/0x660 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]
 __pcs_replace_empty_main+0x2e6/0x730 mm/slub.c:4615
 alloc_from_pcs mm/slub.c:4717 [inline]
 slab_alloc_node mm/slub.c:4851 [inline]
 __do_kmalloc_node mm/slub.c:5259 [inline]
 __kmalloc_noprof+0x474/0x760 mm/slub.c:5272
 kmalloc_noprof include/linux/slab.h:954 [inline]
 usb_alloc_urb+0x46/0x150 drivers/usb/core/urb.c:75
 usb_internal_control_msg drivers/usb/core/message.c:110 [inline]
 usb_control_msg+0x118/0x3e0 drivers/usb/core/message.c:167
 get_port_status drivers/usb/core/hub.c:607 [inline]
 hub_ext_port_status+0x116/0x820 drivers/usb/core/hub.c:624
 usb_hub_port_status drivers/usb/core/hub.c:674 [inline]
 hub_activate+0x6eb/0x1a80 drivers/usb/core/hub.c:1185
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page last free pid 24 tgid 24 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978
 vfree+0x25a/0x400 mm/vmalloc.c:3479
 delayed_vfree_work+0x55/0x80 mm/vmalloc.c:3398
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 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:
 ffff888028260880: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff888028260900: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888028260980: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                                     ^
 ffff888028260a00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888028260a80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================


Tested on:

commit:         3aae9383 Merge tag 'input-for-v7.0-rc6' of git://git.k..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11424e06580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6754c86e8d9e4c91
dashboard link: https://syzkaller.appspot.com/bug?extid=9b95da55ba5146a60734
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=108bc1ca580000