From: syzbot <syzbot+e91dc13b1b37759b3d9f@syzkaller.appspotmail.com>
To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com,
toke@toke.dk
Subject: Re: [syzbot] [wireless?] KASAN: slab-use-after-free Read in tasklet_action_common
Date: Wed, 21 Oct 2026 03:01:03 -0700 [thread overview]
Message-ID: <6ad88d5f.5c73e770.1a06c9.0142.GAE@google.com> (raw)
In-Reply-To: <877bjbtpi8.fsf@toke.dk>
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in tasklet_action_common
==================================================================
BUG: KASAN: slab-use-after-free in tasklet_action_common+0x103/0x490 kernel/softirq.c:954
Read of size 8 at addr ffff888032f6b158 by task ksoftirqd/1/23
CPU: 1 UID: 0 PID: 23 Comm: ksoftirqd/1 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
<IRQ>
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
tasklet_action_common+0x103/0x490 kernel/softirq.c:954
handle_softirqs+0x226/0x860 kernel/softirq.c:645
__do_softirq kernel/softirq.c:679 [inline]
invoke_softirq kernel/softirq.c:519 [inline]
__irq_exit_rcu+0xcb/0x220 kernel/softirq.c:758
irq_exit_rcu+0x9/0x30 kernel/softirq.c:775
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:finish_task_switch+0x413/0xc60 kernel/sched/core.c:5434
Code: 04 00 00 41 c7 84 24 20 0e 00 00 00 00 00 00 0f 1f 44 00 00 49 83 c4 48 4c 89 e7 e8 d7 61 56 0a e8 52 42 3a 00 fb 4c 8b 65 c8 <49> 8d bc 24 18 17 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0
RSP: 0018:ffffc900001d7aa0 EFLAGS: 00000206
RAX: 00000000008dcaf3 RBX: ffff8880b873cbe0 RCX: 8000000000000001
RDX: 0000000000000000 RSI: ffffffff8e41c2b1 RDI: ffffffff8c6dca80
RBP: ffffc900001d7af0 R08: ffffffff907a75bf R09: 1ffffffff20f4eb7
R10: dffffc0000000000 R11: fffffbfff20f4eb8 R12: ffff88801e688000
R13: ffff88801e688000 R14: dffffc0000000000 R15: 1ffff110170e797c
context_switch kernel/sched/core.c:5586 [inline]
__schedule+0x17e5/0x5820 kernel/sched/core.c:7382
preempt_schedule_common+0x7f/0xd0 kernel/sched/core.c:7561
preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12
smpboot_thread_fn+0x6ac/0xb30 kernel/smpboot.c:161
kthread+0x38b/0x480 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 5675:
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:409 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:426
kasan_kmalloc include/linux/kasan.h:263 [inline]
__kmalloc_cache_noprof+0x31c/0x600 mm/slub.c:5563
_kmalloc_noprof include/linux/slab.h:991 [inline]
_kzalloc_noprof include/linux/slab.h:1312 [inline]
ath9k_init_wmi+0x4f/0x2b0 drivers/net/wireless/ath/ath9k/wmi.c:95
ath9k_htc_probe_device+0x1e5/0x2370 drivers/net/wireless/ath/ath9k/htc_drv_init.c:956
ath9k_htc_hw_init+0x32/0x70 drivers/net/wireless/ath/ath9k/htc_hst.c:532
ath9k_hif_usb_firmware_cb+0x214/0x4b0 drivers/net/wireless/ath/ath9k/hif_usb.c:1255
request_firmware_work_func+0xf7/0x2d0 drivers/base/firmware_loader/main.c:1164
process_one_work kernel/workqueue.c:3396 [inline]
process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
kthread+0x38b/0x480 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
Freed by task 5675:
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:264 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:296
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2748 [inline]
slab_free mm/slub.c:6509 [inline]
kfree+0x1c5/0x650 mm/slub.c:6802
ath9k_htc_probe_device+0x11a9/0x2370 drivers/net/wireless/ath/ath9k/htc_drv_init.c:978
ath9k_htc_hw_init+0x32/0x70 drivers/net/wireless/ath/ath9k/htc_hst.c:532
ath9k_hif_usb_firmware_cb+0x214/0x4b0 drivers/net/wireless/ath/ath9k/hif_usb.c:1255
request_firmware_work_func+0xf7/0x2d0 drivers/base/firmware_loader/main.c:1164
process_one_work kernel/workqueue.c:3396 [inline]
process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
kthread+0x38b/0x480 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
The buggy address belongs to the object at ffff888032f6b000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 344 bytes inside of
freed 2048-byte region [ffff888032f6b000, ffff888032f6b800)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x32f68
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 ffff88801b042000 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801b042000 dead000000000100 dead000000000122
head: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
head: 00fff00000000003 fffffffffffffe01 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 203, tgid 203 (kworker/u8:6), ts 127967665812
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871
prep_new_page mm/page_alloc.c:1879 [inline]
get_page_from_freelist+0x2209/0x2280 mm/page_alloc.c:3943
__alloc_frozen_pages_noprof+0x217/0x5a0 mm/page_alloc.c:5436
alloc_slab_page mm/slub.c:3347 [inline]
allocate_slab+0x7d/0x620 mm/slub.c:3462
new_slab mm/slub.c:3513 [inline]
refill_objects+0x2d5/0x350 mm/slub.c:7418
refill_sheaf mm/slub.c:2885 [inline]
__pcs_replace_empty_main+0x2c8/0x6c0 mm/slub.c:4774
alloc_from_pcs mm/slub.c:4850 [inline]
slab_alloc_node mm/slub.c:4984 [inline]
__do_kmalloc_node mm/slub.c:5413 [inline]
__kmalloc_node_track_caller_noprof+0x543/0x720 mm/slub.c:5545
kmalloc_reserve net/core/skbuff.c:637 [inline]
__alloc_skb+0x2c1/0x7a0 net/core/skbuff.c:715
alloc_skb include/linux/skbuff.h:1384 [inline]
mld_newpack+0x165/0xcb0 net/ipv6/mcast.c:1810
add_grhead net/ipv6/mcast.c:1921 [inline]
add_grec+0x119f/0x19d0 net/ipv6/mcast.c:2060
mld_send_initial_cr+0x288/0x550 net/ipv6/mcast.c:2305
ipv6_mc_dad_complete+0x87/0x410 net/ipv6/mcast.c:2316
addrconf_dad_completed+0x8af/0xe60 net/ipv6/addrconf.c:4376
addrconf_dad_work+0xcf8/0x15c0 net/ipv6/addrconf.c:-1
process_one_work kernel/workqueue.c:3396 [inline]
process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
page last free pid 6268 tgid 6268 ts 124939507899 stack trace:
reset_page_owner include/linux/page_owner.h:26 [inline]
__free_pages_prepare mm/page_alloc.c:1418 [inline]
__free_frozen_pages+0xc93/0xd90 mm/page_alloc.c:2962
__slab_free+0x274/0x2c0 mm/slub.c:5823
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:361
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4683 [inline]
slab_alloc_node mm/slub.c:4996 [inline]
kmem_cache_alloc_noprof+0x2b4/0x600 mm/slub.c:5010
anon_vma_chain_alloc mm/rmap.c:142 [inline]
__anon_vma_prepare+0xbe/0x4d0 mm/rmap.c:194
__vmf_anon_prepare mm/memory.c:3961 [inline]
vmf_anon_prepare mm/internal.h:569 [inline]
do_anonymous_page mm/memory.c:5478 [inline]
do_pte_missing+0x2f18/0x34b0 mm/memory.c:4698
handle_pte_fault mm/memory.c:6558 [inline]
__handle_mm_fault mm/memory.c:6707 [inline]
handle_mm_fault+0x1a53/0x3750 mm/memory.c:6876
do_user_addr_fault+0xb35/0x1480 arch/x86/mm/fault.c:1343
handle_page_fault arch/x86/mm/fault.c:1483 [inline]
exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1536
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595
Memory state around the buggy address:
ffff888032f6b000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888032f6b080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888032f6b100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888032f6b180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888032f6b200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 00 00 add %al,(%rax)
2: 41 c7 84 24 20 0e 00 movl $0x0,0xe20(%r12)
9: 00 00 00 00 00
e: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
13: 49 83 c4 48 add $0x48,%r12
17: 4c 89 e7 mov %r12,%rdi
1a: e8 d7 61 56 0a call 0xa5661f6
1f: e8 52 42 3a 00 call 0x3a4276
24: fb sti
25: 4c 8b 65 c8 mov -0x38(%rbp),%r12
* 29: 49 8d bc 24 18 17 00 lea 0x1718(%r12),%rdi <-- trapping instruction
30: 00
31: 48 89 f8 mov %rdi,%rax
34: 48 c1 e8 03 shr $0x3,%rax
38: 42 0f b6 04 30 movzbl (%rax,%r14,1),%eax
3d: 84 c0 test %al,%al
Tested on:
commit: a804c574 Merge tag 'lsm-pr-20261016' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=104e4f01580000
kernel config: https://syzkaller.appspot.com/x/.config?x=5a37d7227c6a6352
dashboard link: https://syzkaller.appspot.com/bug?extid=e91dc13b1b37759b3d9f
compiler: Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.8
Note: no patches were applied.
next parent reply other threads:[~2026-10-21 10:01 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <877bjbtpi8.fsf@toke.dk>
2026-10-21 10:01 ` syzbot [this message]
[not found] <87y0brs1mv.fsf@toke.dk>
2026-10-21 12:47 ` syzbot
[not found] <871p9jthve.fsf@toke.dk>
2026-10-21 11:55 ` syzbot
[not found] <874ieftph3.fsf@toke.dk>
2026-10-21 10:26 ` syzbot
[not found] <20261002230851.103334-1-kartikey406@gmail.com>
2026-10-03 2:02 ` syzbot
[not found] <20261002230311.102330-1-kartikey406@gmail.com>
2026-10-03 1:36 ` syzbot
2026-10-02 17:14 syzbot
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