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BUG: KMSAN: uninit-value in number+0x6d0/0x2150 lib/vsprintf.c:463
CPU: 1 PID: 9943 Comm: syz-executor.3 Not tainted 5.10.0-rc1-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+0x1df/0x240 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:118
 __msan_warning+0x5f/0xa0 mm/kmsan/kmsan_instr.c:197
 number+0x6d0/0x2150 lib/vsprintf.c:463
 vsnprintf+0x1ba7/0x3170 lib/vsprintf.c:2684
 vscnprintf+0xc2/0x180 lib/vsprintf.c:2721
 vprintk_store+0xec/0x1240 kernel/printk/printk.c:1954
 vprintk_emit+0x249/0x750 kernel/printk/printk.c:2018
 vprintk_default+0x86/0xa0 kernel/printk/printk.c:2052
 vprintk_func+0x21e/0x220 kernel/printk/printk_safe.c:393
 printk+0x180/0x1cd kernel/printk/printk.c:2083
 canfd_rcv+0x370/0x3a0 net/can/af_can.c:699
 __netif_receive_skb_one_core net/core/dev.c:5315 [inline]
 __netif_receive_skb net/core/dev.c:5429 [inline]
 netif_receive_skb_internal net/core/dev.c:5534 [inline]
 netif_receive_skb+0xe4e/0xef0 net/core/dev.c:5593
 tun_rx_batched include/linux/skbuff.h:4351 [inline]
 tun_get_user+0x7071/0x7400 drivers/net/tun.c:1939
 tun_chr_write_iter+0x1f7/0x370 drivers/net/tun.c:1968
 call_write_iter include/linux/fs.h:1887 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x1378/0x1550 fs/read_write.c:605
 ksys_write+0x281/0x460 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write+0x92/0xb0 fs/read_write.c:667
 __x64_sys_write+0x4a/0x70 fs/read_write.c:667
 do_syscall_64+0xa2/0x120 arch/x86/entry/common.c:48
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c4a9
Code: 2d b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f089e88ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f089e88f6d4 RCX: 000000000045c4a9
RDX: 0000000000000004 RSI: 0000000020000200 RDI: 0000000000000003
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000d0b R14: 00000000004cef9f R15: 000000000076bf2c

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+0x98e/0x1740 mm/slub.c:4512
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0x2d8/0xa90 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1094 [inline]
 alloc_skb_with_frags+0x186/0xa60 net/core/skbuff.c:5832
 sock_alloc_send_pskb+0xad2/0xc60 net/core/sock.c:2329
 tun_alloc_skb drivers/net/tun.c:1461 [inline]
 tun_get_user+0x12d0/0x7400 drivers/net/tun.c:1778
 tun_chr_write_iter+0x1f7/0x370 drivers/net/tun.c:1968
 call_write_iter include/linux/fs.h:1887 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x1378/0x1550 fs/read_write.c:605
 ksys_write+0x281/0x460 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write+0x92/0xb0 fs/read_write.c:667
 __x64_sys_write+0x4a/0x70 fs/read_write.c:667
 do_syscall_64+0xa2/0x120 arch/x86/entry/common.c:48
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
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