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KASAN: use-after-free Read in ieee80211_monitor_select_queue

Status: upstream: reported on 2026/01/29 16:08
Reported-by: syzbot+878643e0580bc580f883@syzkaller.appspotmail.com
First crash: 72d, last: 4d04h
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 KASAN: use-after-free Read in ieee80211_monitor_select_queue 19 C 37 2h07m 14d 0/3 upstream: reported C repro on 2026/03/28 06:14

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in ieee80211_monitor_select_queue+0x23a/0x240 net/mac80211/iface.c:764
Read of size 2 at addr ffff88805e4bac42 by task syz.0.762/8019

CPU: 1 PID: 8019 Comm: syz.0.762 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 ieee80211_monitor_select_queue+0x23a/0x240 net/mac80211/iface.c:764
 netdev_core_pick_tx+0x118/0x2e0 net/core/dev.c:4184
 __dev_queue_xmit+0x756/0x2f80 net/core/dev.c:4261
 packet_snd net/packet/af_packet.c:3089 [inline]
 packet_sendmsg+0x3dba/0x5060 net/packet/af_packet.c:3120
 sock_sendmsg_nosec net/socket.c:706 [inline]
 __sock_sendmsg net/socket.c:718 [inline]
 ____sys_sendmsg+0x5b7/0x8f0 net/socket.c:2445
 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2499
 __sys_sendmsg net/socket.c:2528 [inline]
 __do_sys_sendmsg net/socket.c:2537 [inline]
 __se_sys_sendmsg+0x1af/0x290 net/socket.c:2535
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fc5366c8819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 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:00007fc534922028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fc536941fa0 RCX: 00007fc5366c8819
RDX: 008bb3a321ef809b RSI: 0000200000000280 RDI: 0000000000000006
RBP: 00007fc53675ec91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc536942038 R14: 00007fc536941fa0 R15: 00007ffe99dbbaa8
 </TASK>

Allocated by task 5381:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522
 kmalloc_reserve net/core/skbuff.c:356 [inline]
 __alloc_skb+0x22c/0x750 net/core/skbuff.c:427
 __netdev_alloc_skb+0x110/0x4c0 net/core/skbuff.c:494
 netdev_alloc_skb include/linux/skbuff.h:3024 [inline]
 dev_alloc_skb include/linux/skbuff.h:3037 [inline]
 __ieee80211_beacon_get+0xaa1/0x2000 net/mac80211/tx.c:5088
 ieee80211_beacon_get_tim+0x48/0x840 net/mac80211/tx.c:5202
 ieee80211_beacon_get include/net/mac80211.h:4983 [inline]
 mac80211_hwsim_beacon_tx+0xf4/0x920 drivers/net/wireless/mac80211_hwsim.c:1812
 __iterate_interfaces+0x243/0x500 net/mac80211/util.c:793
 ieee80211_iterate_active_interfaces_atomic+0xb3/0x140 net/mac80211/util.c:829
 mac80211_hwsim_beacon+0x9b/0x180 drivers/net/wireless/mac80211_hwsim.c:1865
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4f2/0xb70 kernel/time/hrtimer.c:1749
 hrtimer_run_softirq+0x176/0x240 kernel/time/hrtimer.c:1766
 handle_softirqs+0x339/0x830 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676

Freed by task 5381:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1710 [inline]
 slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736
 slab_free mm/slub.c:3504 [inline]
 kfree+0xef/0x2a0 mm/slub.c:4564
 skb_free_head net/core/skbuff.c:655 [inline]
 skb_release_data+0x6b8/0x800 net/core/skbuff.c:677
 skb_release_all net/core/skbuff.c:742 [inline]
 __kfree_skb net/core/skbuff.c:756 [inline]
 consume_skb+0xa2/0x100 net/core/skbuff.c:914
 mac80211_hwsim_beacon_tx+0x4f3/0x920 drivers/net/wireless/mac80211_hwsim.c:1842
 __iterate_interfaces+0x243/0x500 net/mac80211/util.c:793
 ieee80211_iterate_active_interfaces_atomic+0xb3/0x140 net/mac80211/util.c:829
 mac80211_hwsim_beacon+0x9b/0x180 drivers/net/wireless/mac80211_hwsim.c:1865
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4f2/0xb70 kernel/time/hrtimer.c:1749
 hrtimer_run_softirq+0x176/0x240 kernel/time/hrtimer.c:1766
 handle_softirqs+0x339/0x830 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676

Last potentially related work creation:
 kasan_save_stack+0x35/0x60 mm/kasan/common.c:38
 kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348
 kvfree_call_rcu+0x105/0x7d0 kernel/rcu/tree.c:3600
 __ipv6_dev_mc_dec+0x2bf/0x320 net/ipv6/mcast.c:981
 addrconf_leave_solict net/ipv6/addrconf.c:2213 [inline]
 __ipv6_ifa_notify+0x75a/0xe60 net/ipv6/addrconf.c:6201
 addrconf_ifdown+0xdff/0x19c0 net/ipv6/addrconf.c:3899
 addrconf_notify+0x445/0xf00 net/ipv6/addrconf.c:-1
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391
 call_netdevice_notifiers_extack net/core/dev.c:2074 [inline]
 call_netdevice_notifiers net/core/dev.c:2088 [inline]
 dev_close_many+0x29f/0x400 net/core/dev.c:1663
 unregister_netdevice_many+0x481/0x19f0 net/core/dev.c:11136
 default_device_exit_batch+0x364/0x3c0 net/core/dev.c:11693
 ops_exit_list net/core/net_namespace.c:177 [inline]
 cleanup_net+0x791/0xba0 net/core/net_namespace.c:635
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

The buggy address belongs to the object at ffff88805e4bac00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 66 bytes inside of
 512-byte region [ffff88805e4bac00, ffff88805e4bae00)
The buggy address belongs to the page:
page:ffffea0001792e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5e4b8
head:ffffea0001792e00 order:2 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea00017ad300 0000000400000004 ffff888016c41c80
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x1d2a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 4186, ts 70627578223, free_ts 23743396471
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x1bbd/0x1ca0 mm/page_alloc.c:4192
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
 alloc_slab_page mm/slub.c:1780 [inline]
 allocate_slab mm/slub.c:1917 [inline]
 new_slab+0xc0/0x4b0 mm/slub.c:1980
 ___slab_alloc+0x80a/0xdd0 mm/slub.c:3013
 __slab_alloc mm/slub.c:3100 [inline]
 slab_alloc_node mm/slub.c:3191 [inline]
 __kmalloc_node_track_caller+0x1fc/0x3a0 mm/slub.c:4963
 kmalloc_reserve net/core/skbuff.c:356 [inline]
 __alloc_skb+0x22c/0x750 net/core/skbuff.c:427
 alloc_skb include/linux/skbuff.h:1162 [inline]
 ndisc_alloc_skb+0xa6/0x420 net/ipv6/ndisc.c:422
 ndisc_send_rs+0x291/0x730 net/ipv6/ndisc.c:691
 addrconf_rs_timer+0x2d1/0x630 net/ipv6/addrconf.c:3956
 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
 expire_timers kernel/time/timer.c:1699 [inline]
 __run_timers+0x53e/0x800 kernel/time/timer.c:1970
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
 handle_softirqs+0x339/0x830 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
 free_unref_page+0x8f/0x2a0 mm/page_alloc.c:3396
 free_contig_range+0x96/0xf0 mm/page_alloc.c:9428
 destroy_args+0xf0/0xa00 mm/debug_vm_pgtable.c:1018
 debug_vm_pgtable+0x321/0x380 mm/debug_vm_pgtable.c:1336
 do_one_initcall+0x272/0x730 init/main.c:1316
 do_initcall_level+0x137/0x1f0 init/main.c:1389
 do_initcalls+0x4b/0x90 init/main.c:1405
 kernel_init_freeable+0x3e9/0x570 init/main.c:1629
 kernel_init+0x19/0x1b0 init/main.c:1520
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Memory state around the buggy address:
 ffff88805e4bab00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88805e4bab80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88805e4bac00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff88805e4bac80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805e4bad00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (15):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/07 17:53 linux-5.15.y 91d48252ad4b 628666c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ieee80211_monitor_select_queue
2026/04/04 05:55 linux-5.15.y 91d48252ad4b 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ieee80211_monitor_select_queue
2026/04/04 03:18 linux-5.15.y 91d48252ad4b 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ieee80211_monitor_select_queue
2026/04/03 14:29 linux-5.15.y 91d48252ad4b 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ieee80211_monitor_select_queue
2026/04/01 01:46 linux-5.15.y 91d48252ad4b fb8b2c26 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ieee80211_monitor_select_queue
2026/03/30 17:06 linux-5.15.y 91d48252ad4b dcaebc52 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ieee80211_monitor_select_queue
2026/02/04 02:52 linux-5.15.y 9eec9a14ee10 42b01fab .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ieee80211_monitor_select_queue
2026/02/03 02:28 linux-5.15.y 9eec9a14ee10 d78927dd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ieee80211_monitor_select_queue
2026/01/29 16:08 linux-5.15.y 9eec9a14ee10 aeb6fdd5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in ieee80211_monitor_select_queue
2026/03/05 04:18 linux-5.15.y 91d48252ad4b a9fe5c9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in ieee80211_monitor_select_queue
2026/03/03 04:40 linux-5.15.y 3330a8d33e08 28b83e23 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in ieee80211_monitor_select_queue
2026/02/23 16:02 linux-5.15.y 3330a8d33e08 6beca497 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in ieee80211_monitor_select_queue
2026/02/03 02:27 linux-5.15.y 9eec9a14ee10 d78927dd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in ieee80211_monitor_select_queue
2026/02/03 01:36 linux-5.15.y 9eec9a14ee10 d78927dd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in ieee80211_monitor_select_queue
2026/02/02 13:32 linux-5.15.y 9eec9a14ee10 018ebef2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in ieee80211_monitor_select_queue
* Struck through repros no longer work on HEAD.