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BUG: KMSAN: uninit-value in ppp_async_encode drivers/net/ppp/ppp_async.c:550 [inline]
BUG: KMSAN: uninit-value in ppp_async_push+0xd0b/0x21a0 drivers/net/ppp/ppp_async.c:680
CPU: 1 PID: 17789 Comm: syz-executor.4 Not tainted 5.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x21c/0x280 lib/dump_stack.c:118
 kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:118
 __msan_warning+0x5f/0xa0 mm/kmsan/kmsan_instr.c:197
 ppp_async_encode drivers/net/ppp/ppp_async.c:550 [inline]
 ppp_async_push+0xd0b/0x21a0 drivers/net/ppp/ppp_async.c:680
 ppp_async_send+0x144/0x1e0 drivers/net/ppp/ppp_async.c:639
 __ppp_channel_push+0x1a7/0x3b0 drivers/net/ppp/ppp_generic.c:1999
 ppp_channel_push drivers/net/ppp/ppp_generic.c:2026 [inline]
 ppp_write+0x785/0x810 drivers/net/ppp/ppp_generic.c:516
 vfs_write+0x6cc/0x1b00 fs/read_write.c:603
 ksys_write+0x275/0x500 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write+0x92/0xb0 fs/read_write.c:667
 __ia32_sys_write+0x4a/0x70 fs/read_write.c:667
 do_syscall_32_irqs_on arch/x86/entry/common.c:80 [inline]
 __do_fast_syscall_32+0x102/0x160 arch/x86/entry/common.c:139
 do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:162
 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:205
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7fc6549
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000f559f0cc EFLAGS: 00000296 ORIG_RAX: 0000000000000004
RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:121 [inline]
 kmsan_internal_poison_shadow+0x5c/0xf0 mm/kmsan/kmsan.c:104
 kmsan_slab_alloc+0x8d/0xe0 mm/kmsan/kmsan_hooks.c:76
 slab_alloc_node mm/slub.c:2906 [inline]
 __kmalloc_node_track_caller+0xa48/0x1610 mm/slub.c:4512
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0x318/0xb00 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1094 [inline]
 ppp_write+0x11f/0x810 drivers/net/ppp/ppp_generic.c:500
 vfs_write+0x6cc/0x1b00 fs/read_write.c:603
 ksys_write+0x275/0x500 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write+0x92/0xb0 fs/read_write.c:667
 __ia32_sys_write+0x4a/0x70 fs/read_write.c:667
 do_syscall_32_irqs_on arch/x86/entry/common.c:80 [inline]
 __do_fast_syscall_32+0x102/0x160 arch/x86/entry/common.c:139
 do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:162
 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:205
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
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