===================================================== 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:300 [inline] BUG: KMSAN: kernel-infoleak in iterate_and_advance include/linux/iov_iter.h:328 [inline] BUG: KMSAN: kernel-infoleak in _copy_to_iter+0xf0e/0x32f0 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:300 [inline] iterate_and_advance include/linux/iov_iter.h:328 [inline] _copy_to_iter+0xf0e/0x32f0 lib/iov_iter.c:185 copy_to_iter include/linux/uio.h:220 [inline] simple_copy_to_iter net/core/datagram.c:524 [inline] __skb_datagram_iter+0x18f/0x1250 net/core/datagram.c:401 skb_copy_datagram_iter+0x5b/0x1e0 net/core/datagram.c:538 tun_put_user drivers/net/tun.c:2082 [inline] tun_do_read+0x26d8/0x30f0 drivers/net/tun.c:2161 tun_chr_read_iter+0x393/0x6b0 drivers/net/tun.c:2185 new_sync_read fs/read_write.c:489 [inline] vfs_read+0x845/0xef0 fs/read_write.c:570 ksys_read fs/read_write.c:713 [inline] __do_sys_read fs/read_write.c:722 [inline] __se_sys_read fs/read_write.c:720 [inline] __ia32_sys_read+0x1f9/0x4d0 fs/read_write.c:720 ia32_sys_call+0x184c/0x42c0 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+0xb0/0x110 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 stored to memory at: pskb_expand_head+0x313/0x1c90 net/core/skbuff.c:2255 skb_expand_head+0x499/0x8e0 net/core/skbuff.c:2419 ip_finish_output2+0xe48/0x1d50 net/ipv4/ip_output.c:216 __ip_finish_output+0x284/0x860 net/ipv4/ip_output.c:-1 ip_finish_output+0x4a/0x640 net/ipv4/ip_output.c:323 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip_mc_output+0x60c/0xdb0 net/ipv4/ip_output.c:420 dst_output include/net/dst.h:459 [inline] ip_local_out net/ipv4/ip_output.c:129 [inline] __ip_queue_xmit+0x1f06/0x1fa0 net/ipv4/ip_output.c:527 sctp_v4_xmit+0x684/0x1120 net/sctp/protocol.c:1091 sctp_packet_transmit+0x4215/0x4560 net/sctp/output.c:653 sctp_packet_singleton+0x2e3/0x450 net/sctp/outqueue.c:783 sctp_outq_flush_ctrl net/sctp/outqueue.c:914 [inline] sctp_outq_flush+0x71c/0x67c0 net/sctp/outqueue.c:1212 sctp_outq_uncork+0x9e/0xc0 net/sctp/outqueue.c:764 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:-1 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1198 [inline] sctp_do_sm+0x8c8e/0x9720 net/sctp/sm_sideeffect.c:1169 sctp_primitive_ASSOCIATE+0xd4/0x100 net/sctp/primitive.c:73 sctp_sendmsg_to_asoc+0x1a6a/0x2260 net/sctp/socket.c:1842 sctp_sendmsg+0x3910/0x49f0 net/sctp/socket.c:2032 inet_sendmsg+0x269/0x2a0 net/ipv4/af_inet.c:851 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x278/0x3d0 net/socket.c:727 ____sys_sendmsg+0x7e0/0xd80 net/socket.c:2566 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2620 __sys_sendmsg+0x1aa/0x300 net/socket.c:2652 __compat_sys_sendmsg net/compat.c:346 [inline] __do_compat_sys_sendmsg net/compat.c:353 [inline] __se_compat_sys_sendmsg net/compat.c:350 [inline] __ia32_compat_sys_sendmsg+0xa4/0x100 net/compat.c:350 ia32_sys_call+0x3692/0x42c0 arch/x86/include/generated/asm/syscalls_32.h:371 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xb0/0x110 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_post_alloc_hook mm/slub.c:4167 [inline] slab_alloc_node mm/slub.c:4210 [inline] __do_kmalloc_node mm/slub.c:4340 [inline] __kmalloc_node_track_caller_noprof+0x96d/0x12f0 mm/slub.c:4360 kmalloc_reserve+0x22f/0x4b0 net/core/skbuff.c:599 __alloc_skb+0x347/0x7d0 net/core/skbuff.c:668 alloc_skb include/linux/skbuff.h:1340 [inline] sctp_packet_transmit+0x44b/0x4560 net/sctp/output.c:598 sctp_packet_singleton+0x2e3/0x450 net/sctp/outqueue.c:783 sctp_outq_flush_ctrl net/sctp/outqueue.c:914 [inline] sctp_outq_flush+0x71c/0x67c0 net/sctp/outqueue.c:1212 sctp_outq_uncork+0x9e/0xc0 net/sctp/outqueue.c:764 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:-1 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1198 [inline] sctp_do_sm+0x8c8e/0x9720 net/sctp/sm_sideeffect.c:1169 sctp_primitive_ASSOCIATE+0xd4/0x100 net/sctp/primitive.c:73 sctp_sendmsg_to_asoc+0x1a6a/0x2260 net/sctp/socket.c:1842 sctp_sendmsg+0x3910/0x49f0 net/sctp/socket.c:2032 inet_sendmsg+0x269/0x2a0 net/ipv4/af_inet.c:851 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x278/0x3d0 net/socket.c:727 ____sys_sendmsg+0x7e0/0xd80 net/socket.c:2566 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2620 __sys_sendmsg+0x1aa/0x300 net/socket.c:2652 __compat_sys_sendmsg net/compat.c:346 [inline] __do_compat_sys_sendmsg net/compat.c:353 [inline] __se_compat_sys_sendmsg net/compat.c:350 [inline] __ia32_compat_sys_sendmsg+0xa4/0x100 net/compat.c:350 ia32_sys_call+0x3692/0x42c0 arch/x86/include/generated/asm/syscalls_32.h:371 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xb0/0x110 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 Bytes 38-41 of 572 are uninitialized Memory access of size 572 starts at ffff8880492fb8b0 Data copied to user address 00000000fff84b68 CPU: 1 UID: 0 PID: 12052 Comm: syz-executor Not tainted 6.15.0-rc3-syzkaller-00094-g02ddfb981de8 #0 PREEMPT(undef) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 =====================================================