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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 ffff888098a2c358 by task syz-executor.2/3377

CPU: 0 PID: 3377 Comm: syz-executor.2 Not tainted 5.7.0-rc7-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_sendmsg+0x308/0x7e0 net/socket.c:2362
 ___sys_sendmsg+0x100/0x170 net/socket.c:2416
 __sys_sendmmsg+0x195/0x480 net/socket.c:2506
 __do_sys_sendmmsg net/socket.c:2535 [inline]
 __se_sys_sendmmsg net/socket.c:2532 [inline]
 __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2532
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45ca29
Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f304f747c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00000000004fc580 RCX: 000000000045ca29
RDX: 00000000000000c6 RSI: 0000000020006d00 RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000008dd R14: 00000000004cba1f R15: 00007f304f7486d4

Allocated by task 3377:
 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
 ipv6_setsockopt+0xfb/0x180 net/ipv6/ipv6_sockglue.c:949
 udpv6_setsockopt+0x5d/0xa0 net/ipv6/udp.c:1567
 __sys_setsockopt+0x248/0x480 net/socket.c:2132
 __do_sys_setsockopt net/socket.c:2148 [inline]
 __se_sys_setsockopt net/socket.c:2145 [inline]
 __x64_sys_setsockopt+0xba/0x150 net/socket.c:2145
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

Freed by task 3015:
 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
 constrain_params_by_rules+0x824/0x1190 sound/core/pcm_native.c:436
 snd_pcm_hw_refine sound/core/pcm_native.c:507 [inline]
 snd_pcm_hw_refine+0xbe4/0xef0 sound/core/pcm_native.c:485
 snd_pcm_hw_param_first+0x34d/0x6f0 sound/core/pcm_lib.c:1629
 snd_pcm_hw_param_near.constprop.0+0x543/0x810 sound/core/oss/pcm_oss.c:442
 snd_pcm_oss_change_params_locked+0x1283/0x34b0 sound/core/oss/pcm_oss.c:930
 snd_pcm_oss_change_params+0x76/0xd0 sound/core/oss/pcm_oss.c:1084
 snd_pcm_oss_make_ready+0xb7/0x170 sound/core/oss/pcm_oss.c:1143
 snd_pcm_oss_sync.isra.0+0x1be/0x7d0 sound/core/oss/pcm_oss.c:1708
 snd_pcm_oss_release+0x210/0x280 sound/core/oss/pcm_oss.c:2546
 __fput+0x33e/0x880 fs/file_table.c:280
 task_work_run+0xf4/0x1b0 kernel/task_work.c:123
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0xb34/0x2dd0 kernel/exit.c:796
 do_group_exit+0x125/0x340 kernel/exit.c:894
 get_signal+0x47b/0x24e0 kernel/signal.c:2739
 do_signal+0x81/0x2240 arch/x86/kernel/signal.c:784
 exit_to_usermode_loop+0x26c/0x360 arch/x86/entry/common.c:161
 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 ffff888098a2c300
 which belongs to the cache kmalloc-96 of size 96
The buggy address is located 88 bytes inside of
 96-byte region [ffff888098a2c300, ffff888098a2c360)
The buggy address belongs to the page:
page:ffffea0002628b00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888098a2c480
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00025404c8 ffffea0002504a48 ffff8880aa000540
raw: ffff888098a2c480 ffff888098a2c000 000000010000001e 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888098a2c200: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff888098a2c280: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
>ffff888098a2c300: 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc
                                                    ^
 ffff888098a2c380: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc
 ffff888098a2c400: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
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