Hello, syzbot found the following crash on: HEAD commit: 8bbbc5cf kmsan: don't compile memmove git tree: https://github.com/google/kmsan.git master console output: https://syzkaller.appspot.com/x/log.txt?x=1661da7ee00000 kernel config: https://syzkaller.appspot.com/x/.config?x=cd0e9a6b0e555cc3 dashboard link: https://syzkaller.appspot.com/bug?extid=9bcb0c9409066696d3aa compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=111141a1e00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13ad5245e00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+9bcb0c9409066696d3aa@xxxxxxxxxxxxxxxxxxxxxxxxx ===================================================== BUG: KMSAN: uninit-value in number+0x9f8/0x2000 lib/vsprintf.c:459 CPU: 1 PID: 11897 Comm: syz-executor136 Not tainted 5.6.0-rc2-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+0x1c9/0x220 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:118 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215 number+0x9f8/0x2000 lib/vsprintf.c:459 vsnprintf+0x1d85/0x31b0 lib/vsprintf.c:2640 vscnprintf+0xc2/0x180 lib/vsprintf.c:2677 vprintk_store+0xef/0x11d0 kernel/printk/printk.c:1917 vprintk_emit+0x2c0/0x860 kernel/printk/printk.c:1984 vprintk_default+0x90/0xa0 kernel/printk/printk.c:2029 vprintk_func+0x636/0x820 kernel/printk/printk_safe.c:386 printk+0x18b/0x1d3 kernel/printk/printk.c:2062 canfd_rcv+0x370/0x3a0 net/can/af_can.c:697 __netif_receive_skb_one_core net/core/dev.c:5198 [inline] __netif_receive_skb net/core/dev.c:5312 [inline] netif_receive_skb_internal net/core/dev.c:5402 [inline] netif_receive_skb+0xe77/0xf20 net/core/dev.c:5461 tun_rx_batched include/linux/skbuff.h:4321 [inline] tun_get_user+0x6aef/0x6f60 drivers/net/tun.c:1997 tun_chr_write_iter+0x1f2/0x360 drivers/net/tun.c:2026 call_write_iter include/linux/fs.h:1901 [inline] new_sync_write fs/read_write.c:483 [inline] __vfs_write+0xa5a/0xca0 fs/read_write.c:496 vfs_write+0x44a/0x8f0 fs/read_write.c:558 ksys_write+0x267/0x450 fs/read_write.c:611 __do_sys_write fs/read_write.c:623 [inline] __se_sys_write+0x92/0xb0 fs/read_write.c:620 __x64_sys_write+0x4a/0x70 fs/read_write.c:620 do_syscall_64+0xb8/0x160 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x440239 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffd3d6d1f28 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000003172 RCX: 0000000000440239 RDX: 0000000000000004 RSI: 0000000020000200 RDI: 0000000000000003 RBP: 656c6c616b7a7973 R08: 0000000000401ac0 R09: 0000000000401ac0 R10: 0000000000401ac0 R11: 0000000000000246 R12: 0000000000401ac0 R13: 0000000000401b50 R14: 0000000000000000 R15: 0000000000000000 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline] kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:127 kmsan_slab_alloc+0x8a/0xe0 mm/kmsan/kmsan_hooks.c:82 slab_alloc_node mm/slub.c:2793 [inline] __kmalloc_node_track_caller+0xb40/0x1200 mm/slub.c:4401 __kmalloc_reserve net/core/skbuff.c:142 [inline] __alloc_skb+0x2fd/0xac0 net/core/skbuff.c:210 alloc_skb include/linux/skbuff.h:1051 [inline] alloc_skb_with_frags+0x18c/0xa70 net/core/skbuff.c:5766 sock_alloc_send_pskb+0xada/0xc60 net/core/sock.c:2242 tun_alloc_skb drivers/net/tun.c:1529 [inline] tun_get_user+0x10ae/0x6f60 drivers/net/tun.c:1843 tun_chr_write_iter+0x1f2/0x360 drivers/net/tun.c:2026 call_write_iter include/linux/fs.h:1901 [inline] new_sync_write fs/read_write.c:483 [inline] __vfs_write+0xa5a/0xca0 fs/read_write.c:496 vfs_write+0x44a/0x8f0 fs/read_write.c:558 ksys_write+0x267/0x450 fs/read_write.c:611 __do_sys_write fs/read_write.c:623 [inline] __se_sys_write+0x92/0xb0 fs/read_write.c:620 __x64_sys_write+0x4a/0x70 fs/read_write.c:620 do_syscall_64+0xb8/0x160 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x44/0xa9 ===================================================== --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. syzbot can test patches for this bug, for details see: https://goo.gl/tpsmEJ#testing-patches
