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BUG: KASAN: null-ptr-deref in instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
BUG: KASAN: null-ptr-deref in atomic_dec_return include/asm-generic/atomic-instrumented.h:251 [inline]
BUG: KASAN: null-ptr-deref in dst_release net/core/dst.c:174 [inline]
BUG: KASAN: null-ptr-deref in dst_release+0x26/0xe0 net/core/dst.c:169
Write of size 4 at addr 00000000000003e8 by task kworker/u4:7/10948

CPU: 0 PID: 10948 Comm: kworker/u4:7 Tainted: G        W         5.13.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:96
 __kasan_report mm/kasan/report.c:423 [inline]
 kasan_report.cold+0x66/0xdf mm/kasan/report.c:436
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
 instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
 atomic_dec_return include/asm-generic/atomic-instrumented.h:251 [inline]
 dst_release net/core/dst.c:174 [inline]
 dst_release+0x26/0xe0 net/core/dst.c:169
 dst_cache_destroy net/core/dst_cache.c:160 [inline]
 dst_cache_destroy+0xcb/0x190 net/core/dst_cache.c:152
 ip_tunnel_dev_free+0x21/0x60 net/ipv4/ip_tunnel.c:1001
 netdev_run_todo+0x6b4/0xa80 net/core/dev.c:10609
 ip_tunnel_delete_nets+0x3f0/0x5b0 net/ipv4/ip_tunnel.c:1114
 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:178
 cleanup_net+0x4ea/0xb10 net/core/net_namespace.c:595
 process_one_work+0x98d/0x1630 kernel/workqueue.c:2276
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2422
 kthread+0x3e5/0x4d0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
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