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BUG: KASAN: slab-out-of-bounds in ifname_compare_aligned include/linux/netfilter/x_tables.h:411 [inline]
BUG: KASAN: slab-out-of-bounds in ip_packet_match net/ipv4/netfilter/ip_tables.c:64 [inline]
BUG: KASAN: slab-out-of-bounds in ipt_do_table+0x68d/0x1480 net/ipv4/netfilter/ip_tables.c:284
Read of size 8 at addr ffff888125b08000 by task syz.7.358/1591

CPU: 1 PID: 1591 Comm: syz.7.358 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 __dump_stack+0x21/0x24 lib/dump_stack.c:77
 dump_stack_lvl+0x1a7/0x208 lib/dump_stack.c:118
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0x100/0x140 mm/kasan/report.c:452
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:309
 ifname_compare_aligned include/linux/netfilter/x_tables.h:411 [inline]
 ip_packet_match net/ipv4/netfilter/ip_tables.c:64 [inline]
 ipt_do_table+0x68d/0x1480 net/ipv4/netfilter/ip_tables.c:284
 iptable_mangle_hook+0x200/0x540 net/ipv4/netfilter/iptable_mangle.c:82
 nf_hook_entry_hookfn include/linux/netfilter.h:137 [inline]
 nf_hook_slow+0xbc/0x1f0 net/netfilter/core.c:584
 nf_hook include/linux/netfilter.h:254 [inline]
 NF_HOOK_COND include/linux/netfilter.h:287 [inline]
 ip_mc_output+0x622/0x8e0 net/ipv4/ip_output.c:424
 dst_output include/net/dst.h:451 [inline]
 ip_local_out net/ipv4/ip_output.c:126 [inline]
 ip_send_skb+0xb2/0x140 net/ipv4/ip_output.c:1598
 udp_send_skb+0x8e6/0x10f0 net/ipv4/udp.c:977
 udp_sendmsg+0x17a6/0x2140 net/ipv4/udp.c:1265
 inet_sendmsg+0xa5/0xc0 net/ipv4/af_inet.c:830
 sock_sendmsg_nosec net/socket.c:652 [inline]
 __sock_sendmsg net/socket.c:664 [inline]
 ____sys_sendmsg+0x5be/0x8f0 net/socket.c:2377
 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2431
 __sys_sendmmsg+0x2ab/0x4c0 net/socket.c:2517
 __do_sys_sendmmsg net/socket.c:2546 [inline]
 __se_sys_sendmmsg net/socket.c:2543 [inline]
 __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2543
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fc58ab0c559
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:00007fc589544028 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007fc58ad94090 RCX: 00007fc58ab0c559
RDX: 000000000800001d RSI: 0000200000007fc0 RDI: 0000000000000005
RBP: 00007fc58aba38b0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000300 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc58ad94128 R14: 00007fc58ad94090 R15: 00007ffe29587d28

Allocated by task 1610:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:430 [inline]
 __kasan_slab_alloc+0xb7/0xe0 mm/kasan/common.c:463
 kasan_slab_alloc include/linux/kasan.h:244 [inline]
 slab_post_alloc_hook+0x5d/0x2f0 mm/slab.h:580
 slab_alloc_node mm/slub.c:2952 [inline]
 slab_alloc mm/slub.c:2960 [inline]
 kmem_cache_alloc+0x15a/0x2d0 mm/slub.c:2965
 shmem_alloc_inode+0x1a/0x30 mm/shmem.c:3816
 alloc_inode fs/inode.c:233 [inline]
 new_inode_pseudo+0x62/0x210 fs/inode.c:968
 new_inode+0x28/0x1e0 fs/inode.c:997
 shmem_get_inode+0x343/0x9d0 mm/shmem.c:2311
 __shmem_file_setup+0x113/0x2b0 mm/shmem.c:4187
 shmem_file_setup+0x2f/0x40 mm/shmem.c:4228
 __do_sys_memfd_create mm/memfd.c:323 [inline]
 __se_sys_memfd_create+0x1de/0x3a0 mm/memfd.c:266
 __x64_sys_memfd_create+0x5b/0x70 mm/memfd.c:266
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

The buggy address belongs to the object at ffff888125b08000
 which belongs to the cache shmem_inode_cache of size 800
The buggy address is located 0 bytes inside of
 800-byte region [ffff888125b08000, ffff888125b08320)
The buggy address belongs to the page:
page:ffffea000496c200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x125b08
head:ffffea000496c200 order:2 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 dead000000000100 dead000000000122 ffff88810018bc80
raw: 0000000000000000 0000000080110011 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 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 1603, ts 91834515942, free_ts 91801994124
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x176/0x190 mm/page_alloc.c:2462
 get_page_from_freelist+0x225f/0x23f0 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x29a/0x640 mm/page_alloc.c:5384
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1813 [inline]
 new_slab+0x84/0x3f0 mm/slub.c:1874
 new_slab_objects mm/slub.c:2632 [inline]
 ___slab_alloc+0x2f8/0x4c0 mm/slub.c:2796
 __slab_alloc+0x63/0xa0 mm/slub.c:2836
 slab_alloc_node mm/slub.c:2918 [inline]
 slab_alloc mm/slub.c:2960 [inline]
 kmem_cache_alloc+0x1a4/0x2d0 mm/slub.c:2965
 shmem_alloc_inode+0x1a/0x30 mm/shmem.c:3816
 alloc_inode fs/inode.c:233 [inline]
 new_inode_pseudo+0x62/0x210 fs/inode.c:968
 new_inode+0x28/0x1e0 fs/inode.c:997
 shmem_get_inode+0x343/0x9d0 mm/shmem.c:2311
 shmem_symlink+0x9e/0x4f0 mm/shmem.c:3118
 vfs_symlink+0x339/0x4c0 fs/namei.c:4149
 do_symlinkat+0x10e/0x3d0 fs/namei.c:4176
 __do_sys_symlinkat fs/namei.c:4190 [inline]
 __se_sys_symlinkat fs/namei.c:4187 [inline]
 __x64_sys_symlinkat+0x7b/0x90 fs/namei.c:4187
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1349 [inline]
 __free_pages_ok+0x80b/0x830 mm/page_alloc.c:1629
 free_the_page mm/page_alloc.c:5445 [inline]
 __free_pages+0xd8/0x390 mm/page_alloc.c:5454
 kfree+0x1e4/0x270 mm/slub.c:4193
 kvfree+0x35/0x40 mm/util.c:647
 netdev_freemem+0x3f/0x60 net/core/dev.c:10492
 netdev_release+0x7f/0xb0 net/core/net-sysfs.c:1886
 device_release+0x96/0x1c0 drivers/base/core.c:-1
 kobject_cleanup lib/kobject.c:713 [inline]
 kobject_release lib/kobject.c:744 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x18a/0x270 lib/kobject.c:761
 netdev_run_todo+0xc06/0xda0 net/core/dev.c:10363
 rtnl_unlock net/core/rtnetlink.c:112 [inline]
 rtnetlink_rcv_msg+0xa24/0xca0 net/core/rtnetlink.c:5623
 netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2508
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5640
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x86c/0xa30 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x949/0xb70 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:652 [inline]
 __sock_sendmsg net/socket.c:664 [inline]
 ____sys_sendmsg+0x5be/0x8f0 net/socket.c:2377
 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2431

Memory state around the buggy address:
 ffff888125b07f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888125b07f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888125b08000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                   ^
 ffff888125b08080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888125b08100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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