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BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
BUG: KMSAN: kernel-infoleak in copy_to_user_iter lib/iov_iter.c:24 [inline]
BUG: KMSAN: kernel-infoleak in iterate_ubuf include/linux/iov_iter.h:30 [inline]
BUG: KMSAN: kernel-infoleak in iterate_and_advance2 include/linux/iov_iter.h:302 [inline]
BUG: KMSAN: kernel-infoleak in iterate_and_advance include/linux/iov_iter.h:330 [inline]
BUG: KMSAN: kernel-infoleak 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]
 __x64_sys_read+0x1fb/0x4d0 fs/read_write.c:722
 x64_sys_call+0x2f9c/0x3e20 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4197 [inline]
 slab_alloc_node mm/slub.c:4240 [inline]
 __do_kmalloc_node mm/slub.c:4375 [inline]
 __kmalloc_node_track_caller_noprof+0x96d/0x12f0 mm/slub.c:4395
 kmalloc_reserve+0x22f/0x4b0 net/core/skbuff.c:600
 __alloc_skb+0x347/0x7d0 net/core/skbuff.c:669
 alloc_skb include/linux/skbuff.h:1336 [inline]
 igmpv3_newpack+0x142/0x1540 net/ipv4/igmp.c:365
 add_grhead+0x8f/0x450 net/ipv4/igmp.c:446
 add_grec+0x1cd4/0x1fe0 net/ipv4/igmp.c:580
 igmpv3_send_cr net/ipv4/igmp.c:678 [inline]
 igmp_ifc_timer_expire+0x431/0x1cc0 net/ipv4/igmp.c:816
 call_timer_fn+0x4c/0x520 kernel/time/timer.c:1747
 expire_timers kernel/time/timer.c:1798 [inline]
 __run_timers kernel/time/timer.c:2372 [inline]
 __run_timer_base+0x80f/0xd90 kernel/time/timer.c:2384
 run_timer_base kernel/time/timer.c:2393 [inline]
 run_timer_softirq+0x3a/0x80 kernel/time/timer.c:2403
 handle_softirqs+0x169/0x6e0 kernel/softirq.c:579
 run_ksoftirqd+0x29/0x50 kernel/softirq.c:968
 smpboot_thread_fn+0x56c/0xa30 kernel/smpboot.c:160
 kthread+0xd5c/0xf00 kernel/kthread.c:463
 ret_from_fork+0x233/0x380 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Bytes 38-41 of 104 are uninitialized
Memory access of size 104 starts at ffff88804e208880
Data copied to user address 00007ffce4f327c0

CPU: 0 UID: 0 PID: 10997 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(none) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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