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BUG: KMSAN: uninit-value in ppp_async_encode drivers/net/ppp/ppp_async.c:551 [inline]
BUG: KMSAN: uninit-value in ppp_async_push+0xd0b/0x21a0 drivers/net/ppp/ppp_async.c:681
CPU: 1 PID: 16721 Comm: syz-executor.0 Not tainted 5.12.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x24c/0x2e0 lib/dump_stack.c:120
 kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:121
 __msan_warning+0x5c/0xa0 mm/kmsan/kmsan_instr.c:197
 ppp_async_encode drivers/net/ppp/ppp_async.c:551 [inline]
 ppp_async_push+0xd0b/0x21a0 drivers/net/ppp/ppp_async.c:681
 ppp_async_send+0x144/0x1e0 drivers/net/ppp/ppp_async.c:640
 __ppp_channel_push+0x1a7/0x3b0 drivers/net/ppp/ppp_generic.c:2109
 ppp_channel_push drivers/net/ppp/ppp_generic.c:2136 [inline]
 ppp_write+0x785/0x810 drivers/net/ppp/ppp_generic.c:517
 do_loop_readv_writev fs/read_write.c:764 [inline]
 do_iter_write+0xb7c/0x1090 fs/read_write.c:868
 vfs_writev fs/read_write.c:939 [inline]
 do_pwritev+0x551/0xb80 fs/read_write.c:1036
 __do_sys_pwritev fs/read_write.c:1083 [inline]
 __se_sys_pwritev+0xc6/0xe0 fs/read_write.c:1078
 __x64_sys_pwritev+0x62/0x80 fs/read_write.c:1078
 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665d9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa9f5864188 EFLAGS: 00000246 ORIG_RAX: 0000000000000128
RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665d9
RDX: 0000000000000005 RSI: 0000000020000880 RDI: 0000000000000006
RBP: 00000000004bfcb9 R08: 0000000000000004 R09: 0000000000000000
R10: 00000000000000f1 R11: 0000000000000246 R12: 000000000056bf80
R13: 0000000000a9fb1f R14: 00007fa9f5864300 R15: 0000000000022000

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:120 [inline]
 kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:103
 kmsan_slab_alloc+0x8e/0xe0 mm/kmsan/kmsan_hooks.c:76
 slab_alloc_node mm/slub.c:2922 [inline]
 __kmalloc_node_track_caller+0xa4f/0x1470 mm/slub.c:4609
 kmalloc_reserve net/core/skbuff.c:353 [inline]
 __alloc_skb+0x4dd/0xe90 net/core/skbuff.c:424
 alloc_skb include/linux/skbuff.h:1103 [inline]
 ppp_write+0x11f/0x810 drivers/net/ppp/ppp_generic.c:501
 do_loop_readv_writev fs/read_write.c:764 [inline]
 do_iter_write+0xb7c/0x1090 fs/read_write.c:868
 vfs_writev fs/read_write.c:939 [inline]
 do_pwritev+0x551/0xb80 fs/read_write.c:1036
 __do_sys_pwritev fs/read_write.c:1083 [inline]
 __se_sys_pwritev+0xc6/0xe0 fs/read_write.c:1078
 __x64_sys_pwritev+0x62/0x80 fs/read_write.c:1078
 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48
 entry_SYSCALL_64_after_hwframe+0x44/0xae
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