Re: [syzbot] [wireless?] KASAN: slab-use-after-free Read in tasklet_action_common

Re: [syzbot] [wireless?] KASAN: slab-use-after-free Read in tasklet_action_common

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
INFO: task hung in ath9k_hif_usb_disconnect

INFO: task kworker/1:4:5768 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:4     state:D stack:24512 pid:5768  tgid:5768  ppid:2      task_flags:0x4288060 flags:0x00080000
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5533 [inline]
 __schedule+0x17db/0x58f0 kernel/sched/core.c:7284
 __schedule_loop kernel/sched/core.c:7361 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7376
 schedule_timeout+0xc0/0x2c0 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:100 [inline]
 __wait_for_common kernel/sched/completion.c:121 [inline]
 wait_for_common kernel/sched/completion.c:132 [inline]
 wait_for_completion+0x2ca/0x5e0 kernel/sched/completion.c:153
 ath9k_hif_usb_disconnect+0xb8/0x250 drivers/net/wireless/ath/ath9k/hif_usb.c:1419
 usb_unbind_interface+0x295/0x9f0 drivers/usb/core/driver.c:461
 device_remove drivers/base/dd.c:618 [inline]
 __device_release_driver drivers/base/dd.c:1349 [inline]
 device_release_driver_internal+0x4f5/0x880 drivers/base/dd.c:1372
 bus_remove_device+0x444/0x560 drivers/base/bus.c:664
 device_del+0x524/0x8f0 drivers/base/core.c:3965
 usb_disable_device+0x3d4/0x8d0 drivers/usb/core/message.c:1478
 usb_disconnect+0x346/0x9a0 drivers/usb/core/hub.c:2350
 hub_port_connect drivers/usb/core/hub.c:5420 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5720 [inline]
 port_event drivers/usb/core/hub.c:5884 [inline]
 hub_event+0x1bbb/0x4d30 drivers/usb/core/hub.c:5966
 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
 </TASK>

Showing all locks held in the system:
locks held by kworker/0:1/10: 4, on CPU#0:
 #0: ffff88801b06b140 ((wq_completion)events){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff88801b06b140 ((wq_completion)events){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff88801b06b140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #0: ffff88801b06b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #1: ffffc900000f7c40 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc900000f7c40 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc900000f7c40 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #1: ffffc900000f7c40 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #2: ffff8880b863bb20 (&rq->__lock){-.-.}-{2:2}, at: sched_submit_work kernel/sched/core.c:7319 [inline]
 #2: ffff8880b863bb20 (&rq->__lock){-.-.}-{2:2}, at: schedule+0x90/0x2b0 kernel/sched/core.c:7375
 #3: ffff8880b8624408 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x57/0x7d0 kernel/sched/psi.c:933
locks held by ksoftirqd/0/15: 2, last CPU#0:
 #0: ffff8880b863bb20 (&rq->__lock){-.-.}-{2:2}, at: finish_lock_switch kernel/sched/core.c:5261 [inline]
 #0: ffff8880b863bb20 (&rq->__lock){-.-.}-{2:2}, at: finish_task_switch+0x159/0xc60 kernel/sched/core.c:5382
 #1: ffff8880b8624408 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x57/0x7d0 kernel/sched/psi.c:933
locks held by khungtaskd/33: 1, last CPU#1:
 #0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by getty/5372: 2, on CPU#1:
 #0: ffff8880328b10a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by kworker/1:4/5768: 5, on CPU#1:
 #0: ffff888022aaf540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff888022aaf540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff888022aaf540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #0: ffff888022aaf540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #1: ffffc90003b9fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc90003b9fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc90003b9fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #1: ffffc90003b9fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #2: ffff88802a1b51d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
 #2: ffff88802a1b51d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30 drivers/usb/core/hub.c:5912
 #3: ffff88807bbca1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
 #3: ffff88807bbca1d8 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0xfc/0x9a0 drivers/usb/core/hub.c:2341
 #4: ffff88807f7b41a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
 #4: ffff88807f7b41a0 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1171 [inline]
 #4: ffff88807f7b41a0 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb9/0x880 drivers/base/dd.c:1369

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 33 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
 nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66
 trigger_all_cpu_backtrace include/linux/nmi.h:164 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
 watchdog+0xfd7/0x1030 kernel/hung_task.c:561
 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>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 15 Comm: ksoftirqd/0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:check_preemption_disabled+0x19/0xd0 lib/smp_processor_id.c:53
Code: 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41 56 53 65 8b 05 1b 4d ae 07 65 48 8b 0d eb 4c ae 07 85 c9 74 0c <5b> 41 5e 41 5f 5d c3 cc cc cc cc cc 9c 59 f7 c1 00 02 00 00 74 ea
RSP: 0018:ffffc90000147bf8 EFLAGS: 00000006
RAX: 0000000000000000 RBX: ffff88801e299f40 RCX: 8000000000000100
RDX: 0000000000000000 RSI: ffffffff8e69f5c6 RDI: ffffffff8c6dad80
RBP: dffffc0000000000 R08: ffffffff907a627f R09: 1ffffffff20f4c4f
R10: dffffc0000000000 R11: fffffbfff20f4c50 R12: ffff8880b8624080
R13: 0000000000000286 R14: ffff8880b8624088 R15: ffff88807c9cd158
FS:  0000000000000000(0000) GS:ffff888124cc7000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f74059872c0 CR3: 000000000eb48000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 lockdep_recursion_finish kernel/locking/lockdep.c:470 [inline]
 lockdep_hardirqs_on_prepare+0x19f/0x270 kernel/locking/lockdep.c:4455
 trace_hardirqs_on+0x28/0x40 kernel/trace/trace_preemptirq.c:78
 __tasklet_schedule_common+0xc9/0x110 kernel/softirq.c:858
 tasklet_action_common+0x2d7/0x490 kernel/softirq.c:961
 handle_softirqs+0x226/0x860 kernel/softirq.c:645
 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1099
 smpboot_thread_fn+0x565/0xa70 kernel/smpboot.c:160
 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>


Tested on:

commit:         ff47652a Merge tag 'cifs-fixes-7.3-rc6' of https://git..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=172edbf5580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=23e5acac5c98285f
dashboard link: https://syzkaller.appspot.com/bug?extid=e91dc13b1b37759b3d9f
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=137c1725580000

Re: [syzbot] [wireless?] KASAN: slab-use-after-free Read in tasklet_action_common

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+e91dc13b1b37759b3d9f@syzkaller.appspotmail.com
Tested-by: syzbot+e91dc13b1b37759b3d9f@syzkaller.appspotmail.com

Tested on:

commit:         ff47652a Merge tag 'cifs-fixes-7.3-rc6' of https://git..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11921035580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=23e5acac5c98285f
dashboard link: https://syzkaller.appspot.com/bug?extid=e91dc13b1b37759b3d9f
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1556db15580000

Note: testing is done by a robot and is best-effort only.

[syzbot] [wireless?] KASAN: slab-use-after-free Read in tasklet_action_common

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    d24e8ac715de Merge tag 'net-7.3-rc6' of git://git.kernel.o..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14361b15580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9d4242cb1c54cdf7
dashboard link: https://syzkaller.appspot.com/bug?extid=e91dc13b1b37759b3d9f
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12361b15580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=155bc725580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4ccd4fb94f0b/disk-d24e8ac7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/701ac3e3f73b/vmlinux-d24e8ac7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/976b7d839ef2/bzImage-d24e8ac7.xz

The issue was bisected to:

commit 1af8dc9ca726cf53767f9c0661171396f95c146a
Author: Toke Høiland-Jørgensen <toke@redhat.com>
Date:   Tue Sep 8 17:05:18 2026 +0000

    wifi: ath9k: Clean up device initialisation guards

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=145e5b15580000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=165e5b15580000
console output: https://syzkaller.appspot.com/x/log.txt?x=125e5b15580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e91dc13b1b37759b3d9f@syzkaller.appspotmail.com
Fixes: 1af8dc9ca726 ("wifi: ath9k: Clean up device initialisation guards")

==================================================================
BUG: KASAN: slab-use-after-free in tasklet_action_common+0x103/0x490 kernel/softirq.c:954
Read of size 8 at addr ffff888035947158 by task syz-executor/5756

CPU: 0 UID: 0 PID: 5756 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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+0x77/0xd0 kernel/softirq.c:546
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x100/0x140 kernel/softirq.c:473
 spin_unlock_bh include/linux/spinlock.h:407 [inline]
 tun_flow_delete_by_queue drivers/net/tun.c:379 [inline]
 __tun_detach+0xccc/0x1900 drivers/net/tun.c:614
 tun_detach drivers/net/tun.c:653 [inline]
 tun_chr_close+0x10a/0x1c0 drivers/net/tun.c:3587
 __fput+0x418/0xa50 fs/file_table.c:512
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x73a/0x2360 kernel/exit.c:986
 do_group_exit+0x22d/0x2f0 kernel/exit.c:1129
 __do_sys_exit_group kernel/exit.c:1140 [inline]
 __se_sys_exit_group kernel/exit.c:1138 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1138
 x64_sys_call+0x18c6/0x18d0 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f558db9e159
Code: Unable to access opcode bytes at 0x7f558db9e12f.
RSP: 002b:00007ffc01d96c68 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007f558dc35fb3 RCX: 00007f558db9e159
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000043
RBP: 00007f558dc35fc5 R08: 0000000000000000 R09: 00000000000927c0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000006
R13: 00000000000927c0 R14: 0000000000015771 R15: 00007ffc01d96e10
 </TASK>

Allocated by task 9:
 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+0x321/0x600 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 9:
 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:6508 [inline]
 kfree+0x1c5/0x650 mm/slub.c:6801
 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 ffff888035947000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 344 bytes inside of
 freed 2048-byte region [ffff888035947000, ffff888035947800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x35940
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 1225, tgid 1225 (kworker/0:2), ts 87487181723
 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:7417
 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+0x548/0x720 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
 mld_dad_work+0x3d/0x480 net/ipv6/mcast.c:2331
 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
page last free pid 5650 tgid 5650 ts 85122206691 stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 __free_pages_prepare mm/page_alloc.c:1418 [inline]
 free_pages_prepare+0x9eb/0xaf0 mm/page_alloc.c:1463
 __free_contig_range_common+0x174/0x340 mm/page_alloc.c:7072
 __free_contig_range mm/page_alloc.c:7117 [inline]
 free_pages_bulk+0x48/0x120 mm/page_alloc.c:5322
 vm_area_free_pages mm/vmalloc.c:3461 [inline]
 vfree+0x231/0x490 mm/vmalloc.c:3510
 delayed_vfree_work+0x55/0x80 mm/vmalloc.c:3414
 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

Memory state around the buggy address:
 ffff888035947000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888035947080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888035947100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff888035947180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888035947200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


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