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BUG: KASAN: stack-out-of-bounds in ip6mr_ioctl+0xc54/0xcb0 net/ipv6/ip6mr.c:1917
Read of size 16 at addr ffffc9000fd3fb94 by task syz-executor.5/28862

CPU: 1 PID: 28862 Comm: syz-executor.5 Not tainted 6.4.0-rc6-syzkaller-01339-g4931062492c5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
 print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351
 print_report mm/kasan/report.c:462 [inline]
 kasan_report+0x11c/0x130 mm/kasan/report.c:572
 ip6mr_ioctl+0xc54/0xcb0 net/ipv6/ip6mr.c:1917
 rawv6_ioctl+0x4e/0x1e0 net/ipv6/raw.c:1143
 sock_ioctl_inout+0xc1/0x150 net/core/sock.c:4167
 ip6mr_sk_ioctl include/linux/mroute6.h:117 [inline]
 sk_ioctl+0x279/0x440 net/core/sock.c:4205
 inet6_ioctl+0x1b8/0x290 net/ipv6/af_inet6.c:582
 sock_do_ioctl+0xcc/0x230 net/socket.c:1189
 sock_ioctl+0x1f8/0x680 net/socket.c:1306
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __x64_sys_ioctl+0x197/0x210 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fcc12a8c389
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fcc13790168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fcc12babf80 RCX: 00007fcc12a8c389
RDX: 0000000020000000 RSI: 00000000000089e1 RDI: 0000000000000003
RBP: 00007fcc12ad7493 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffca0ce6a9f R14: 00007fcc13790300 R15: 0000000000022000
 </TASK>

The buggy address belongs to stack of task syz-executor.5/28862
 and is located at offset 84 in frame:
 sk_ioctl+0x0/0x440 net/core/sock.c:4172

This frame has 2 objects:
 [32, 36) 'karg'
 [48, 88) 'buffer'

The buggy address belongs to the virtual mapping at
 [ffffc9000fd38000, ffffc9000fd41000) created by:
 kernel_clone+0xeb/0x890 kernel/fork.c:2915

The buggy address belongs to the physical page:
page:ffffea000122c480 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x48b12
memcg:ffff8880222ad602
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff ffff8880222ad602
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x102dc2(GFP_HIGHUSER|__GFP_NOWARN|__GFP_ZERO), pid 28802, tgid 28802 (syz-executor.5), ts 1131768609049, free_ts 1131696675606
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x2db/0x350 mm/page_alloc.c:1731
 prep_new_page mm/page_alloc.c:1738 [inline]
 get_page_from_freelist+0xf41/0x2c00 mm/page_alloc.c:3502
 __alloc_pages+0x1cb/0x4a0 mm/page_alloc.c:4768
 alloc_pages+0x1aa/0x270 mm/mempolicy.c:2279
 vm_area_alloc_pages mm/vmalloc.c:3009 [inline]
 __vmalloc_area_node mm/vmalloc.c:3085 [inline]
 __vmalloc_node_range+0xb1c/0x14a0 mm/vmalloc.c:3257
 alloc_thread_stack_node kernel/fork.c:313 [inline]
 dup_task_struct kernel/fork.c:1116 [inline]
 copy_process+0x13bb/0x75c0 kernel/fork.c:2333
 kernel_clone+0xeb/0x890 kernel/fork.c:2915
 __do_sys_clone+0xba/0x100 kernel/fork.c:3058
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1302 [inline]
 free_unref_page_prepare+0x62e/0xcb0 mm/page_alloc.c:2564
 free_unref_page+0x33/0x370 mm/page_alloc.c:2659
 vfree+0x180/0x7e0 mm/vmalloc.c:2798
 delayed_vfree_work+0x57/0x70 mm/vmalloc.c:2719
 process_one_work+0x99a/0x15e0 kernel/workqueue.c:2405
 worker_thread+0x67d/0x10c0 kernel/workqueue.c:2552
 kthread+0x344/0x440 kernel/kthread.c:379
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

Memory state around the buggy address:
 ffffc9000fd3fa80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc9000fd3fb00: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 04 f2 00 00
>ffffc9000fd3fb80: 00 00 00 f3 f3 f3 f3 f3 00 00 00 00 00 00 00 00
                            ^
 ffffc9000fd3fc00: 00 00 00 f1 f1 f1 f1 f1 f1 00 00 00 00 00 00 00
 ffffc9000fd3fc80: 00 00 00 f3 f3 f3 f3 00 00 00 00 00 00 00 00 00
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