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BUG: KASAN: slab-out-of-bounds in fl6_update_dst+0x2bb/0x2c0 net/ipv6/exthdrs.c:1356
Read of size 16 at addr ffff8880a0f19368 by task syz-executor.0/7510

CPU: 0 PID: 7510 Comm: syz-executor.0 Not tainted 5.7.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x188/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd3/0x413 mm/kasan/report.c:382
 __kasan_report.cold+0x20/0x38 mm/kasan/report.c:511
 kasan_report+0x33/0x50 mm/kasan/common.c:625
 fl6_update_dst+0x2bb/0x2c0 net/ipv6/exthdrs.c:1356
 udpv6_sendmsg+0x1866/0x2b50 net/ipv6/udp.c:1431
 inet6_sendmsg+0x99/0xe0 net/ipv6/af_inet6.c:577
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 __sys_sendto+0x220/0x330 net/socket.c:2000
 __do_sys_sendto net/socket.c:2012 [inline]
 __se_sys_sendto net/socket.c:2008 [inline]
 __ia32_sys_sendto+0xdb/0x1b0 net/socket.c:2008
 do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline]
 do_fast_syscall_32+0x270/0xe90 arch/x86/entry/common.c:396
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

Allocated by task 7511:
 save_stack+0x1b/0x40 mm/kasan/common.c:49
 set_track mm/kasan/common.c:57 [inline]
 __kasan_kmalloc mm/kasan/common.c:495 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:468
 __do_kmalloc mm/slab.c:3656 [inline]
 __kmalloc+0x161/0x7a0 mm/slab.c:3665
 kmalloc include/linux/slab.h:560 [inline]
 sock_kmalloc net/core/sock.c:2166 [inline]
 sock_kmalloc+0xb5/0x100 net/core/sock.c:2157
 ipv6_renew_options+0x274/0x940 net/ipv6/exthdrs.c:1275
 do_ipv6_setsockopt.isra.0+0x2eaf/0x42f0 net/ipv6/ipv6_sockglue.c:435
 compat_ipv6_setsockopt net/ipv6/ipv6_sockglue.c:980 [inline]
 compat_ipv6_setsockopt+0x115/0x210 net/ipv6/ipv6_sockglue.c:961
 compat_udpv6_setsockopt+0x5d/0xa0 net/ipv6/udp.c:1577
 compat_sock_common_setsockopt+0xaa/0x120 net/core/sock.c:3182
 __compat_sys_setsockopt+0x15d/0x310 net/compat.c:400
 __do_compat_sys_setsockopt net/compat.c:413 [inline]
 __se_compat_sys_setsockopt net/compat.c:410 [inline]
 __ia32_compat_sys_setsockopt+0xb9/0x150 net/compat.c:410
 do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline]
 do_fast_syscall_32+0x270/0xe90 arch/x86/entry/common.c:396
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

Freed by task 6967:
 save_stack+0x1b/0x40 mm/kasan/common.c:49
 set_track mm/kasan/common.c:57 [inline]
 kasan_set_free_info mm/kasan/common.c:317 [inline]
 __kasan_slab_free+0xf7/0x140 mm/kasan/common.c:456
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x109/0x2b0 mm/slab.c:3757
 kernfs_fop_release+0xe7/0x190 fs/kernfs/file.c:779
 __fput+0x33e/0x880 fs/file_table.c:280
 task_work_run+0xf4/0x1b0 kernel/task_work.c:123
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x2fa/0x360 arch/x86/entry/common.c:165
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
 do_syscall_64+0x6b1/0x7d0 arch/x86/entry/common.c:305
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

The buggy address belongs to the object at ffff8880a0f19300
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 104 bytes inside of
 128-byte region [ffff8880a0f19300, ffff8880a0f19380)
The buggy address belongs to the page:
page:ffffea000283c640 refcount:1 mapcount:0 mapping:00000000eb87a825 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00027eb808 ffffea00029e6188 ffff8880aa000700
raw: 0000000000000000 ffff8880a0f19000 0000000100000010 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a0f19200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a0f19280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880a0f19300: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc
                                                          ^
 ffff8880a0f19380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a0f19400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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