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BUG: KASAN: slab-out-of-bounds in ethnl_update_bitset32+0x17d7/0x1850
Read of size 4 at addr ffff8881eb47383c by task syz-executor.3/4464

CPU: 0 PID: 4464 Comm: syz-executor.3 Not tainted 5.6.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 dump_stack+0x191/0x20f
 print_address_description.constprop.0.cold+0x72/0x369
 __kasan_report.cold+0x1b/0x32
 kasan_report+0x12/0x20
 __asan_report_load4_noabort+0x14/0x20
 ethnl_update_bitset32+0x17d7/0x1850
 ethnl_update_bitset+0x41/0x50
 ethnl_set_linkmodes+0x50d/0xc40
 genl_rcv_msg+0x71f/0xf80
 netlink_rcv_skb+0x186/0x470
 genl_rcv+0x28/0x40
 netlink_unicast+0x589/0x880
 netlink_sendmsg+0x922/0xe90
 sock_sendmsg+0xd2/0x120
 ____sys_sendmsg+0x679/0x880
 ___sys_sendmsg+0x11d/0x1b0
 __x64_sys_sendmsg+0x149/0x230
 do_syscall_64+0xf6/0x240
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f4ec0f4df69
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4ec02ce0c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f4ec107bf80 RCX: 00007f4ec0f4df69
RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000003
RBP: 00007f4ec0f9a4a4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f4ec107bf80 R15: 00007ffdc4541628

Allocated by task 4400:
 save_stack+0x21/0x80
 __kasan_kmalloc.constprop.0+0xea/0x100
 kasan_kmalloc+0x9/0x10
 __kmalloc_node+0x4d/0x70
 kvmalloc_node+0x65/0xf0
 seq_read+0x82e/0x1160
 kernfs_fop_read+0xf2/0x570
 __vfs_read+0x88/0x110
 vfs_read+0x1f5/0x440
 ksys_read+0x151/0x290
 __x64_sys_read+0x72/0xb0
 do_syscall_64+0xf6/0x240
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 4400:
 save_stack+0x21/0x80
 __kasan_slab_free+0xfe/0x140
 kasan_slab_free+0xe/0x10
 kfree+0x104/0x2c0
 kvfree+0x4c/0x60
 seq_release+0x51/0x80
 kernfs_fop_release+0xf6/0x1a0
 __fput+0x2ef/0x880
 ____fput+0x15/0x20
 task_work_run+0x152/0x1d0
 prepare_exit_to_usermode+0x663/0x700
 syscall_return_slowpath+0xfe/0x7e0
 do_syscall_64+0x128/0x240
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8881eb472000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 2108 bytes to the right of
 4096-byte region [ffff8881eb472000, ffff8881eb473000)
The buggy address belongs to the page:
page:ffffea0007ad1c80 refcount:1 mapcount:0 mapping:ffff8881f5402000 index:0x0 compound_mapcount: 0
flags: 0x17ffe0000010200(slab|head)
raw: 017ffe0000010200 ffffea0007acf808 ffffea0007651208 ffff8881f5402000
raw: 0000000000000000 ffff8881eb472000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881eb473700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881eb473780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8881eb473800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                        ^
 ffff8881eb473880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881eb473900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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