syzbot


KASAN: use-after-free Read in ieee80211_monitor_select_queue

Status: upstream: reported on 2026/03/28 06:14
Reported-by: syzbot+610e40369bc02181bad0@syzkaller.appspotmail.com
First crash: 1d22h, last: 1d03h
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 KASAN: use-after-free Read in ieee80211_monitor_select_queue 19 9 24d 59d 0/3 upstream: reported on 2026/01/29 16:08

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in ieee80211_monitor_select_queue+0x20c/0x210 net/mac80211/iface.c:909
Read of size 2 at addr ffff0000f5a739fb by task syz.0.2180/11904

CPU: 1 PID: 11904 Comm: syz.0.2180 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/26/2026
Call trace:
 dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
 print_address_description+0x88/0x218 mm/kasan/report.c:316
 print_report+0x50/0x68 mm/kasan/report.c:420
 kasan_report+0xa8/0xfc mm/kasan/report.c:524
 __asan_report_load2_noabort+0x2c/0x38 mm/kasan/report_generic.c:349
 ieee80211_monitor_select_queue+0x20c/0x210 net/mac80211/iface.c:909
 netdev_core_pick_tx+0x130/0x320 net/core/dev.c:4233
 __dev_queue_xmit+0x738/0x3118 net/core/dev.c:4319
 dev_queue_xmit+0x24/0x34 include/linux/netdevice.h:3051
 packet_snd net/packet/af_packet.c:3127 [inline]
 packet_sendmsg+0x2f9c/0x3fd0 net/packet/af_packet.c:3158
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5c8/0x938 net/socket.c:2518
 ___sys_sendmsg net/socket.c:2572 [inline]
 __sys_sendmsg+0x288/0x374 net/socket.c:2601
 __do_sys_sendmsg net/socket.c:2610 [inline]
 __se_sys_sendmsg net/socket.c:2608 [inline]
 __arm64_sys_sendmsg+0x80/0x94 net/socket.c:2608
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Allocated by task 10250:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
 kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505
 ____kasan_kmalloc mm/kasan/common.c:375 [inline]
 __kasan_kmalloc+0xa0/0xb8 mm/kasan/common.c:384
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 kmalloc_trace+0x7c/0x94 mm/slab_common.c:1031
 kmalloc include/linux/slab.h:563 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 squashfs_fill_super+0xb0/0x18b4 fs/squashfs/super.c:135
 get_tree_bdev+0x358/0x544 fs/super.c:1366
 squashfs_get_tree+0x28/0x38 fs/squashfs/super.c:404
 vfs_get_tree+0x90/0x274 fs/super.c:1573
 do_new_mount+0x228/0x810 fs/namespace.c:3078
 path_mount+0x5bc/0xe80 fs/namespace.c:3408
 do_mount fs/namespace.c:3421 [inline]
 __do_sys_mount fs/namespace.c:3629 [inline]
 __se_sys_mount fs/namespace.c:3606 [inline]
 __arm64_sys_mount+0x49c/0x59c fs/namespace.c:3606
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x1fc/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to the object at ffff0000f5a73800
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 507 bytes inside of
 512-byte region [ffff0000f5a73800, ffff0000f5a73a00)

The buggy address belongs to the physical page:
page:000000002befc8c1 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff0000f5a73800 pfn:0x135a70
head:000000002befc8c1 order:2 compound_mapcount:0 compound_pincount:0
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 fffffc0003d2ef08 fffffc0003d69a08 ffff0000c0002600
raw: ffff0000f5a73800 0000000000100003 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000f5a73880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000f5a73900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff0000f5a73980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                                ^
 ffff0000f5a73a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000f5a73a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/29 01:10 linux-6.1.y 1989cd3d56e2 b5ceaad2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in ieee80211_monitor_select_queue
2026/03/28 19:25 linux-6.1.y 1989cd3d56e2 b5ceaad2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in ieee80211_monitor_select_queue
2026/03/28 06:13 linux-6.1.y 1989cd3d56e2 356bdfc9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: use-after-free Read in ieee80211_monitor_select_queue
* Struck through repros no longer work on HEAD.