syzbot

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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_enqueue_multi+0x1ad/0x1290 kernel/bpf/devmap.c:618
Write of size 4 at addr ffffc9011bd176e4 by task syz.2.633/8311

CPU: 0 UID: 0 PID: 8311 Comm: syz.2.633 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_enqueue_multi+0x1ad/0x1290 kernel/bpf/devmap.c:618
 __xdp_do_redirect_frame net/core/filter.c:4466 [inline]
 xdp_do_redirect+0x82e/0xaf0 net/core/filter.c:4509
 tun_xdp_act+0xe3/0xbb0 drivers/net/tun.c:1565
 tun_build_skb drivers/net/tun.c:1658 [inline]
 tun_get_user+0x2dc3/0x3dd0 drivers/net/tun.c:1770
 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: 0033:0x7f0aa115cfce
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:00007f0aa20a0fb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f0aa20a16c0 RCX: 00007f0aa115cfce
RDX: 000000000000001e RSI: 0000200000000040 RDI: 00000000000000c8
RBP: 00007f0aa1232bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0aa1416038 R14: 00007f0aa1415fa0 R15: 00007fff41442a98
 </TASK>

The buggy address belongs to stack of task syz.2.633/8311
 and is located at offset 100 in frame:
 dev_map_enqueue_multi+0x0/0x1290 include/net/xdp.h:-1

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 0xffffc9011bd10000 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:0x33d17
memcg:ffff8880344a0882
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 ffffea0000cf45c8 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff ffff8880344a0882
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 8231, tgid 8231 (syz.4.611), ts 139055909827, free_ts 139048832520
 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:2484
 alloc_frozen_pages_noprof mm/mempolicy.c:2555 [inline]
 alloc_pages_noprof+0xa8/0x190 mm/mempolicy.c:2575
 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 8238 tgid 8231 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
 kmalloc_reserve net/core/skbuff.c:613 [inline]
 __alloc_skb+0x27d/0x7d0 net/core/skbuff.c:713
 netlink_sendmsg+0x5d4/0xb40 net/netlink/af_netlink.c:1869
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 ____sys_sendmsg+0x972/0x9f0 net/socket.c:2592
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646
 __sys_sendmsg net/socket.c:2678 [inline]
 __do_sys_sendmsg net/socket.c:2683 [inline]
 __se_sys_sendmsg net/socket.c:2681 [inline]
 __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681
 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:
 ffffc9011bd17580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc9011bd17600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc9011bd17680: f1 f1 f1 f1 00 f2 f2 f2 00 00 00 00 04 f3 f3 f3
                                                       ^
 ffffc9011bd17700: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc9011bd17780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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