KASAN: stack-out-of-bounds Write in dev_map_redirect

ID	Workflow	Result	Correct	Bug	Created	Started	Finished	Revision	Error
e14aee67-24be-4294-8837-6ceb19f52d0c	repro		❓	KASAN: stack-out-of-bounds Write in dev_map_redirect_multi	2026/03/10 13:37	2026/03/10 23:49	2026/03/11 01:22	86914af9098a80da53c3c5d46be980c572ee29f8

repro

❓

KASAN: stack-out-of-bounds Write in dev_map_redirect_multi

2026/03/10 13:37

2026/03/10 23:49

2026/03/11 01:22

86914af9098a80da53c3c5d46be980c572ee29f8

Title	Replies (including bot)	Last reply
[PATCH v4 bpf] bpf: devmap: fix stack-out-of-bounds write in get_upper_ifindexes()	2 (2)	2026/02/26 19:30
[PATCH v3 bpf] bpf: devmap: fix stack-out-of-bounds write in get_upper_ifindexes()	3 (3)	2026/02/24 10:58
[PATCH v2 bpf] bpf: devmap: fix stack-out-of-bounds write in get_upper_ifindexes()	3 (3)	2026/02/23 13:32
[PATCH v1 bpf] bpf: devmap: fix stack-out-of-bounds write in get_upper_ifindexes()	2 (2)	2026/02/20 02:44
[syzbot] [bpf?] [net?] KASAN: stack-out-of-bounds Write in dev_map_redirect_multi	0 (1)	2026/02/11 09:33

================================================================== BUG: KASAN: stack-out-of-bounds in get_upper_ifindexes kernel/bpf/devmap.c:601 [inline] BUG: KASAN: stack-out-of-bounds in dev_map_redirect_multi+0x1bb/0xa00 kernel/bpf/devmap.c:736 Write of size 4 at addr ffffc900039f7164 by task syz.1.4880/24782 CPU: 1 UID: 0 PID: 24782 Comm: syz.1.4880 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 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 get_upper_ifindexes kernel/bpf/devmap.c:601 [inline] dev_map_redirect_multi+0x1bb/0xa00 kernel/bpf/devmap.c:736 xdp_do_generic_redirect_map net/core/filter.c:4556 [inline] xdp_do_generic_redirect+0x669/0x820 net/core/filter.c:4619 do_xdp_generic+0xcf7/0x12e0 net/core/dev.c:5617 __netif_receive_skb_core+0x10e5/0x31a0 net/core/dev.c:5966 __netif_receive_skb_one_core net/core/dev.c:6154 [inline] __netif_receive_skb net/core/dev.c:6269 [inline] netif_receive_skb_internal net/core/dev.c:6355 [inline] netif_receive_skb+0x1fe/0xc50 net/core/dev.c:6414 tun_rx_batched+0x1de/0x790 drivers/net/tun.c:1485 tun_get_user+0x2a78/0x3dd0 drivers/net/tun.c:1953 tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:1999 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x61d/0xb90 fs/read_write.c:688 ksys_write+0x150/0x270 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f71c515cece Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08 RSP: 002b:00007f71c607ffb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f71c60806c0 RCX: 00007f71c515cece RDX: 000000000000006e RSI: 0000200000000040 RDI: 00000000000000c8 RBP: 00007f71c5232b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f71c5416038 R14: 00007f71c5415fa0 R15: 00007ffcc237dd98 </TASK> The buggy address belongs to stack of task syz.1.4880/24782 and is located at offset 100 in frame: dev_map_redirect_multi+0x0/0xa00 include/linux/skbuff.h:2833 This frame has 2 objects: [32, 40) 'iter.i' [64, 100) 'excluded_devices' The buggy address belongs to a 8-page vmalloc region starting at 0xffffc900039f0000 allocated at copy_process+0x508/0x3cf0 kernel/fork.c:2050 The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x63a37 memcg:ffff888033a20902 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000000000 00000001ffffffff ffff888033a20902 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x29c2(GFP_NOWAIT|__GFP_HIGHMEM|__GFP_IO|__GFP_FS|__GFP_ZERO), pid 24774, tgid 24774 (syz.1.4877), ts 628925626739, free_ts 628905835634 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_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2485 alloc_frozen_pages_noprof mm/mempolicy.c:2556 [inline] alloc_pages_noprof+0xa8/0x190 mm/mempolicy.c:2576 vm_area_alloc_pages mm/vmalloc.c:3662 [inline] __vmalloc_area_node mm/vmalloc.c:3876 [inline] __vmalloc_node_range_noprof+0x79b/0x1730 mm/vmalloc.c:4064 __vmalloc_node_noprof+0xc2/0x100 mm/vmalloc.c:4124 alloc_thread_stack_node kernel/fork.c:355 [inline] dup_task_struct+0x228/0x9a0 kernel/fork.c:924 copy_process+0x508/0x3cf0 kernel/fork.c:2050 kernel_clone+0x248/0x8e0 kernel/fork.c:2654 __do_sys_clone3 kernel/fork.c:2956 [inline] __se_sys_clone3+0x33c/0x360 kernel/fork.c:2935 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 5808 tgid 5808 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 __slab_free+0x263/0x2b0 mm/slub.c:5532 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4501 [inline] slab_alloc_node mm/slub.c:4830 [inline] kmem_cache_alloc_node_noprof+0x384/0x690 mm/slub.c:4882 __alloc_skb+0x1d0/0x7d0 net/core/skbuff.c:702 alloc_skb_fclone include/linux/skbuff.h:1433 [inline] tcp_stream_alloc_skb+0x3f/0x580 net/ipv4/tcp.c:944 tcp_sendmsg_locked+0x1375/0x5490 net/ipv4/tcp.c:1269 tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1464 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] sock_write_iter+0x421/0x550 net/socket.c:1195 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x61d/0xb90 fs/read_write.c:688 ksys_write+0x150/0x270 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffffc900039f7000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffc900039f7080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffffc900039f7100: f1 f1 f1 f1 00 f2 f2 f2 00 00 00 00 04 f3 f3 f3 ^ ffffc900039f7180: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 ffffc900039f7200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================

Crashes (2):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2026/02/22 21:28	net-next	8bf22c33e7a1	6e7b5511	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci-upstream-net-kasan-gce	KASAN: stack-out-of-bounds Write in dev_map_redirect_multi
2026/02/07 00:29	net-next	24cf78c73831	f20fc9f9	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci-upstream-net-kasan-gce	KASAN: stack-out-of-bounds Write in dev_map_redirect_multi

Crashes (2):

Assets (help?)