=====================================================
BUG: KMSAN: uninit-value in ppp_async_encode drivers/net/ppp/ppp_async.c:548 [inline]
BUG: KMSAN: uninit-value in ppp_async_push+0xc05/0x2660 drivers/net/ppp/ppp_async.c:675
 ppp_async_encode drivers/net/ppp/ppp_async.c:548 [inline]
 ppp_async_push+0xc05/0x2660 drivers/net/ppp/ppp_async.c:675
 ppp_async_send+0x130/0x1b0 drivers/net/ppp/ppp_async.c:634
 ppp_push+0x220/0x22b0 drivers/net/ppp/ppp_generic.c:1883
 ppp_send_frame drivers/net/ppp/ppp_generic.c:1846 [inline]
 __ppp_xmit_process+0x123a/0x2780 drivers/net/ppp/ppp_generic.c:1646
 ppp_xmit_process+0x100/0x2b0 drivers/net/ppp/ppp_generic.c:1667
 ppp_write+0x63a/0x7d0 drivers/net/ppp/ppp_generic.c:521
 do_loop_readv_writev fs/read_write.c:764 [inline]
 vfs_writev+0xb0e/0x1450 fs/read_write.c:973
 do_pwritev fs/read_write.c:1072 [inline]
 __do_compat_sys_pwritev fs/read_write.c:1196 [inline]
 __se_compat_sys_pwritev fs/read_write.c:1190 [inline]
 __ia32_compat_sys_pwritev+0x315/0x530 fs/read_write.c:1190
 ia32_sys_call+0x3098/0x40a0 arch/x86/include/generated/asm/syscalls_32.h:335
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0xb4/0x120 arch/x86/entry/common.c:386
 do_fast_syscall_32+0x38/0x80 arch/x86/entry/common.c:411
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:449
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:3877 [inline]
 slab_alloc_node mm/slub.c:3918 [inline]
 kmem_cache_alloc_node+0x622/0xc90 mm/slub.c:3961
 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:577
 __alloc_skb+0x35b/0x7a0 net/core/skbuff.c:668
 alloc_skb include/linux/skbuff.h:1319 [inline]
 ppp_write+0xe5/0x7d0 drivers/net/ppp/ppp_generic.c:509
 do_loop_readv_writev fs/read_write.c:764 [inline]
 vfs_writev+0xb0e/0x1450 fs/read_write.c:973
 do_pwritev fs/read_write.c:1072 [inline]
 __do_compat_sys_pwritev fs/read_write.c:1196 [inline]
 __se_compat_sys_pwritev fs/read_write.c:1190 [inline]
 __ia32_compat_sys_pwritev+0x315/0x530 fs/read_write.c:1190
 ia32_sys_call+0x3098/0x40a0 arch/x86/include/generated/asm/syscalls_32.h:335
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0xb4/0x120 arch/x86/entry/common.c:386
 do_fast_syscall_32+0x38/0x80 arch/x86/entry/common.c:411
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:449
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

CPU: 1 PID: 5381 Comm: syz-executor.2 Not tainted 6.9.0-syzkaller-02339-g101b7a97143a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
=====================================================