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BUG: KMSAN: kernel-infoleak-after-free in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
BUG: KMSAN: kernel-infoleak-after-free in copy_to_user_iter lib/iov_iter.c:24 [inline]
BUG: KMSAN: kernel-infoleak-after-free in iterate_ubuf include/linux/iov_iter.h:30 [inline]
BUG: KMSAN: kernel-infoleak-after-free in iterate_and_advance2 include/linux/iov_iter.h:302 [inline]
BUG: KMSAN: kernel-infoleak-after-free in iterate_and_advance include/linux/iov_iter.h:330 [inline]
BUG: KMSAN: kernel-infoleak-after-free in _copy_to_iter+0xef3/0x33f0 lib/iov_iter.c:185
 instrument_copy_to_user include/linux/instrumented.h:114 [inline]
 copy_to_user_iter lib/iov_iter.c:24 [inline]
 iterate_ubuf include/linux/iov_iter.h:30 [inline]
 iterate_and_advance2 include/linux/iov_iter.h:302 [inline]
 iterate_and_advance include/linux/iov_iter.h:330 [inline]
 _copy_to_iter+0xef3/0x33f0 lib/iov_iter.c:185
 copy_to_iter include/linux/uio.h:220 [inline]
 simple_copy_to_iter net/core/datagram.c:521 [inline]
 __skb_datagram_iter+0x196/0x12c0 net/core/datagram.c:402
 skb_copy_datagram_iter+0x5b/0x1e0 net/core/datagram.c:535
 tun_put_user drivers/net/tun.c:2105 [inline]
 tun_do_read+0x3a71/0x4100 drivers/net/tun.c:2184
 tun_chr_read_iter+0x393/0x6b0 drivers/net/tun.c:2208
 new_sync_read fs/read_write.c:491 [inline]
 vfs_read+0x8ed/0xf90 fs/read_write.c:572
 ksys_read fs/read_write.c:715 [inline]
 __do_sys_read fs/read_write.c:724 [inline]
 __se_sys_read fs/read_write.c:722 [inline]
 __ia32_sys_read+0x1f9/0x4d0 fs/read_write.c:722
 ia32_sys_call+0x18b8/0x4310 arch/x86/include/generated/asm/syscalls_32.h:4
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0xb0/0x150 arch/x86/entry/syscall_32.c:306
 do_fast_syscall_32+0x38/0x80 arch/x86/entry/syscall_32.c:331
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/syscall_32.c:369
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Uninit was created at:
 slab_free_hook mm/slub.c:2348 [inline]
 slab_free mm/slub.c:4695 [inline]
 kfree+0x252/0xec0 mm/slub.c:4894
 skb_kfree_head net/core/skbuff.c:1047 [inline]
 skb_free_head+0x1b5/0x3a0 net/core/skbuff.c:1059
 skb_release_data+0x9f7/0xac0 net/core/skbuff.c:1086
 skb_release_all net/core/skbuff.c:1151 [inline]
 __kfree_skb+0x6b/0x260 net/core/skbuff.c:1165
 sk_skb_reason_drop+0x126/0x440 net/core/skbuff.c:1203
 kfree_skb_reason include/linux/skbuff.h:1275 [inline]
 __skb_queue_purge_reason include/linux/skbuff.h:3378 [inline]
 skb_queue_purge_reason+0x44f/0x640 net/core/skbuff.c:3946
 skb_queue_purge include/linux/skbuff.h:3391 [inline]
 packet_release+0x1402/0x19c0 net/packet/af_packet.c:3231
 __sock_release net/socket.c:649 [inline]
 sock_close+0xd6/0x2e0 net/socket.c:1439
 __fput+0x608/0x1040 fs/file_table.c:468
 ____fput+0x25/0x30 fs/file_table.c:496
 task_work_run+0x206/0x2b0 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0x2a6/0x330 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 __do_fast_syscall_32+0x12a/0x150 arch/x86/entry/syscall_32.c:309
 do_fast_syscall_32+0x38/0x80 arch/x86/entry/syscall_32.c:331
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/syscall_32.c:369
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Bytes 38-41 of 1000 are uninitialized
Memory access of size 1000 starts at ffff88802fec5880
Data copied to user address 00000000ffe71078

CPU: 0 UID: 0 PID: 9130 Comm: syz-executor Tainted: G        W           syzkaller #0 PREEMPT(none) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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