================================================================== BUG: KASAN: slab-out-of-bounds in pskb_expand_head+0x1c4/0x1064 net/core/skbuff.c:1714 Write of size 48 at addr ffff0000c1c3e1c0 by task kworker/0:0/7 CPU: 0 PID: 7 Comm: kworker/0:0 Not tainted 5.15.99-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023 Workqueue: mld mld_ifc_work Call trace: dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106 print_address_description+0x7c/0x3f0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:434 [inline] kasan_report+0x174/0x1e4 mm/kasan/report.c:451 kasan_check_range+0x274/0x2b4 mm/kasan/generic.c:189 memcpy+0xb4/0xe8 mm/kasan/shadow.c:66 pskb_expand_head+0x1c4/0x1064 net/core/skbuff.c:1714 __skb_cow include/linux/skbuff.h:3364 [inline] skb_cow_head include/linux/skbuff.h:3398 [inline] batadv_skb_head_push+0x158/0x1e8 net/batman-adv/soft-interface.c:73 batadv_interface_tx+0xb74/0x12d8 net/batman-adv/soft-interface.c:330 __netdev_start_xmit include/linux/netdevice.h:5017 [inline] netdev_start_xmit include/linux/netdevice.h:5031 [inline] xmit_one net/core/dev.c:3590 [inline] dev_hard_start_xmit+0x3a0/0xc50 net/core/dev.c:3606 __dev_queue_xmit+0x1500/0x2c20 net/core/dev.c:4221 dev_queue_xmit+0x24/0x34 net/core/dev.c:4254 neigh_hh_output include/net/neighbour.h:500 [inline] neigh_output include/net/neighbour.h:514 [inline] ip6_finish_output2+0x1310/0x1c48 net/ipv6/ip6_output.c:126 __ip6_finish_output+0x518/0x67c net/ipv6/ip6_output.c:191 ip6_finish_output+0x40/0x218 net/ipv6/ip6_output.c:201 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip6_output+0x270/0x594 net/ipv6/ip6_output.c:224 dst_output include/net/dst.h:449 [inline] NF_HOOK+0x160/0x4ec include/linux/netfilter.h:307 mld_sendpack+0x828/0x1264 net/ipv6/mcast.c:1820 mld_send_cr net/ipv6/mcast.c:2121 [inline] mld_ifc_work+0x85c/0xb9c net/ipv6/mcast.c:2653 process_one_work+0x84c/0x14b8 kernel/workqueue.c:2306 worker_thread+0x910/0x1034 kernel/workqueue.c:2453 kthread+0x37c/0x45c kernel/kthread.c:319 ret_from_fork+0x10/0x20 :870 Allocated by task 1: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc+0xbc/0xfc mm/kasan/common.c:513 __kasan_kmalloc+0x10/0x1c mm/kasan/common.c:522 kasan_kmalloc include/linux/kasan.h:264 [inline] kmem_cache_alloc_trace+0x248/0x3b4 mm/slub.c:3247 kmalloc include/linux/slab.h:591 [inline] kzalloc include/linux/slab.h:721 [inline] call_usermodehelper_setup+0xa8/0x254 kernel/umh.c:365 kobject_uevent_env+0x660/0x898 lib/kobject_uevent.c:614 kobject_uevent+0x2c/0x3c lib/kobject_uevent.c:642 kernel_add_sysfs_param+0x104/0x138 kernel/params.c:816 param_sysfs_builtin+0x180/0x1ec kernel/params.c:851 param_sysfs_init+0x70/0x80 kernel/params.c:970 do_one_initcall+0x2e4/0xc68 init/main.c:1306 do_initcall_level+0x154/0x214 init/main.c:1379 do_initcalls+0x58/0xac init/main.c:1395 do_basic_setup+0x8c/0xa0 init/main.c:1414 kernel_init_freeable+0x470/0x650 init/main.c:1619 kernel_init+0x24/0x294 init/main.c:1510 ret_from_fork+0x10/0x20 :870 The buggy address belongs to the object at ffff0000c1c3e000 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 192 bytes to the right of 256-byte region [ffff0000c1c3e000, ffff0000c1c3e100) The buggy address belongs to the page: page:0000000069d69f6d refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x101c3e head:0000000069d69f6d order:1 compound_mapcount:0 flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000010200 dead000000000100 dead000000000122 ffff0000c0002480 raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000c1c3e080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000c1c3e100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff0000c1c3e180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff0000c1c3e200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff0000c1c3e280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ================================================================== Unable to handle kernel paging request at virtual address dfff800000000000 Mem abort info: ESR = 0x0000000096000006 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x06: level 2 translation fault Data abort info: ISV = 0, ISS = 0x00000006 CM = 0, WnR = 0 [dfff800000000000] address between user and kernel address ranges Internal error: Oops: 96000006 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 7 Comm: kworker/0:0 Tainted: G B 5.15.99-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023 Workqueue: mld mld_ifc_work pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : _compound_head include/linux/page-flags.h:196 [inline] pc : put_page+0x2c/0x21c include/linux/mm.h:1233 lr : put_page+0x24/0x21c include/linux/mm.h:1232 sp : ffff8000189a7050 x29: ffff8000189a7050 x28: ffff0001c1c3e1f0 x27: 1fffe0001b4eb00f x26: dfff800000000000 x25: ffffffffffffffff x24: 1fffe00038387c38 x23: ffff0001c1c3e1f0 x22: 0000000000000000 x21: dfff800000000000 x20: 0000000000000007 x19: ffffffffffffffff x18: 0000000000000402 x17: ff808000083386a0 x16: ffff800011a08b18 x15: ffff8000083386a0 x14: 00000000ffffffff x13: ffffffffffffffff x12: 0000000000000000 x11: ff8080000fdc8df0 x10: 0000000000000000 x9 : ffff80000fdc8df0 x8 : 0000000000000000 x7 : 0000000000000000 x6 : ffff80000fdbd374 x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff80000fdb3d58 x2 : 0000000000000001 x1 : 0000000000000000 x0 : ffffffffffffffff Call trace: _compound_head include/linux/page-flags.h:196 [inline] put_page+0x2c/0x21c include/linux/mm.h:1233 __skb_frag_unref include/linux/skbuff.h:3218 [inline] skb_release_data+0x2e4/0x5fc net/core/skbuff.c:672 skb_release_all net/core/skbuff.c:742 [inline] __kfree_skb net/core/skbuff.c:756 [inline] consume_skb+0xa0/0x18c net/core/skbuff.c:914 batadv_send_bcast_packet+0x44/0x58 net/batman-adv/send.c:999 batadv_interface_tx+0xcec/0x12d8 net/batman-adv/soft-interface.c:351 __netdev_start_xmit include/linux/netdevice.h:5017 [inline] netdev_start_xmit include/linux/netdevice.h:5031 [inline] xmit_one net/core/dev.c:3590 [inline] dev_hard_start_xmit+0x3a0/0xc50 net/core/dev.c:3606 __dev_queue_xmit+0x1500/0x2c20 net/core/dev.c:4221 dev_queue_xmit+0x24/0x34 net/core/dev.c:4254 neigh_hh_output include/net/neighbour.h:500 [inline] neigh_output include/net/neighbour.h:514 [inline] ip6_finish_output2+0x1310/0x1c48 net/ipv6/ip6_output.c:126 __ip6_finish_output+0x518/0x67c net/ipv6/ip6_output.c:191 ip6_finish_output+0x40/0x218 net/ipv6/ip6_output.c:201 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip6_output+0x270/0x594 net/ipv6/ip6_output.c:224 dst_output include/net/dst.h:449 [inline] NF_HOOK+0x160/0x4ec include/linux/netfilter.h:307 mld_sendpack+0x828/0x1264 net/ipv6/mcast.c:1820 mld_send_cr net/ipv6/mcast.c:2121 [inline] mld_ifc_work+0x85c/0xb9c net/ipv6/mcast.c:2653 process_one_work+0x84c/0x14b8 kernel/workqueue.c:2306 worker_thread+0x910/0x1034 kernel/workqueue.c:2453 kthread+0x37c/0x45c kernel/kthread.c:319 ret_from_fork+0x10/0x20 :870 Code: f2fbfff5 961bf75c 91002274 d343fe88 (38756908) ---[ end trace e2058ed71e43c7ab ]--- ---------------- Code disassembly (best guess): 0: f2fbfff5 movk x21, #0xdfff, lsl #48 4: 961bf75c bl 0xfffffffff86fdd74 8: 91002274 add x20, x19, #0x8 c: d343fe88 lsr x8, x20, #3 * 10: 38756908 ldrb w8, [x8, x21] <-- trapping instruction