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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+0x2dc/0x7d0 net/socket.c:2709
 __do_sys_sendmmsg net/socket.c:2736 [inline]
 __se_sys_sendmmsg net/socket.c:2733 [inline]
 __x64_sys_sendmmsg+0xc6/0x150 net/socket.c:2733
 x64_sys_call+0x3ce7/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:308
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x1b0 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:4153 [inline]
 slab_alloc_node mm/slub.c:4196 [inline]
 __do_kmalloc_node mm/slub.c:4326 [inline]
 __kmalloc_node_track_caller_noprof+0x96d/0x12f0 mm/slub.c:4346
 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+0x2dc/0x7d0 net/socket.c:2709
 __do_sys_sendmmsg net/socket.c:2736 [inline]
 __se_sys_sendmmsg net/socket.c:2733 [inline]
 __x64_sys_sendmmsg+0xc6/0x150 net/socket.c:2733
 x64_sys_call+0x3ce7/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:308
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x1b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 UID: 0 PID: 6760 Comm: syz.0.16 Not tainted 6.15.0-rc5-syzkaller-00300-g3ce9925823c7 #0 PREEMPT(undef) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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