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BUG: KMSAN: uninit-value in pptp_xmit+0xc34/0x2720 drivers/net/ppp/pptp.c:193
 pptp_xmit+0xc34/0x2720 drivers/net/ppp/pptp.c:193
 ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2295 [inline]
 ppp_input+0x1d6/0xe60 drivers/net/ppp/ppp_generic.c:2319
 pppoe_rcv_core+0x1e8/0x760 drivers/net/ppp/pppoe.c:379
 sk_backlog_rcv+0x13f/0x420 include/net/sock.h:1132
 __release_sock+0x1d3/0x330 net/core/sock.c:3163
 release_sock+0x6b/0x270 net/core/sock.c:3717
 pppoe_sendmsg+0x15d/0xcb0 drivers/net/ppp/pppoe.c:904
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x330/0x3d0 net/socket.c:727
 ____sys_sendmsg+0x893/0xd80 net/socket.c:2566
 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2620
 __sys_sendmmsg+0x3c2/0x7d0 net/socket.c:2702
 __compat_sys_sendmmsg net/compat.c:360 [inline]
 __do_compat_sys_sendmmsg net/compat.c:367 [inline]
 __se_compat_sys_sendmmsg net/compat.c:364 [inline]
 __ia32_compat_sys_sendmmsg+0xd2/0x160 net/compat.c:364
 ia32_sys_call+0x3a66/0x42c0 arch/x86/include/generated/asm/syscalls_32.h:346
 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
 pskb_expand_head+0x207/0x1c90 net/core/skbuff.c:2247
 skb_realloc_headroom+0x152/0x2d0 net/core/skbuff.c:2327
 pptp_xmit+0x9d4/0x2720 drivers/net/ppp/pptp.c:181
 ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2295 [inline]
 ppp_input+0x1d6/0xe60 drivers/net/ppp/ppp_generic.c:2319
 pppoe_rcv_core+0x1e8/0x760 drivers/net/ppp/pppoe.c:379
 sk_backlog_rcv+0x13f/0x420 include/net/sock.h:1132
 __release_sock+0x1d3/0x330 net/core/sock.c:3163
 release_sock+0x6b/0x270 net/core/sock.c:3717
 pppoe_sendmsg+0x15d/0xcb0 drivers/net/ppp/pppoe.c:904
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x330/0x3d0 net/socket.c:727
 ____sys_sendmsg+0x893/0xd80 net/socket.c:2566
 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2620
 __sys_sendmmsg+0x3c2/0x7d0 net/socket.c:2702
 __compat_sys_sendmmsg net/compat.c:360 [inline]
 __do_compat_sys_sendmmsg net/compat.c:367 [inline]
 __se_compat_sys_sendmmsg net/compat.c:364 [inline]
 __ia32_compat_sys_sendmmsg+0xd2/0x160 net/compat.c:364
 ia32_sys_call+0x3a66/0x42c0 arch/x86/include/generated/asm/syscalls_32.h:346
 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

CPU: 1 UID: 0 PID: 8735 Comm: syz.9.610 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
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