syzbot


KMSAN: uninit-value in strcmp

Status: fixed on 2018/05/17 10:02
Subsystems: tipc
[Documentation on labels]
Reported-by: syzbot+df0257c92ffd4fcc58cd@syzkaller.appspotmail.com
Fix commit: 94f6a80c0c11 tipc: eliminate KMSAN uninit-value in strcmp complaint
First crash: 2270d, last: 2268d
Discussions (4)
Title Replies (including bot) Last reply
[PATCH 4.16 000/279] 4.16.17-stable review 280 (280) 2018/07/09 03:28
[PATCH 4.14 000/189] 4.14.51-stable review 181 (181) 2018/06/20 18:48
[PATCH net] tipc: eliminate KMSAN uninit-value in strcmp complaint 2 (2) 2018/05/10 12:25
KMSAN: uninit-value in strcmp 3 (4) 2018/05/08 13:12

Sample crash report:
==================================================================
BUG: KMSAN: uninit-value in strcmp+0xf7/0x160 lib/string.c:329
CPU: 1 PID: 4527 Comm: syz-executor655 Not tainted 4.16.0+ #87
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:53
 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683
 strcmp+0xf7/0x160 lib/string.c:329
 tipc_nl_node_get_link+0x220/0x6f0 net/tipc/node.c:1881
 genl_family_rcv_msg net/netlink/genetlink.c:599 [inline]
 genl_rcv_msg+0x1686/0x1810 net/netlink/genetlink.c:624
 netlink_rcv_skb+0x378/0x600 net/netlink/af_netlink.c:2447
 genl_rcv+0x63/0x80 net/netlink/genetlink.c:635
 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline]
 netlink_unicast+0x166b/0x1740 net/netlink/af_netlink.c:1337
 netlink_sendmsg+0x1048/0x1310 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg net/socket.c:640 [inline]
 ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046
 __sys_sendmsg net/socket.c:2080 [inline]
 SYSC_sendmsg+0x2a3/0x3d0 net/socket.c:2091
 SyS_sendmsg+0x54/0x80 net/socket.c:2087
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x445589
RSP: 002b:00007fb7ee66cdb8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000006dac24 RCX: 0000000000445589
RDX: 0000000000000000 RSI: 0000000020023000 RDI: 0000000000000003
RBP: 00000000006dac20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fffa2bf3f3f R14: 00007fb7ee66d9c0 R15: 0000000000000001

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
 kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188
 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314
 kmsan_slab_alloc+0x11/0x20 mm/kmsan/kmsan.c:321
 slab_post_alloc_hook mm/slab.h:445 [inline]
 slab_alloc_node mm/slub.c:2737 [inline]
 __kmalloc_node_track_caller+0xaed/0x11c0 mm/slub.c:4369
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x2cf/0x9f0 net/core/skbuff.c:206
 alloc_skb include/linux/skbuff.h:984 [inline]
 netlink_alloc_large_skb net/netlink/af_netlink.c:1183 [inline]
 netlink_sendmsg+0x9a6/0x1310 net/netlink/af_netlink.c:1875
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg net/socket.c:640 [inline]
 ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046
 __sys_sendmsg net/socket.c:2080 [inline]
 SYSC_sendmsg+0x2a3/0x3d0 net/socket.c:2091
 SyS_sendmsg+0x54/0x80 net/socket.c:2087
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/05/03 16:55 https://github.com/google/kmsan.git master d2d741e5d189 9ce14f4b .config console log report syz C ci-upstream-kmsan-gce
2018/05/05 13:34 https://github.com/google/kmsan.git master d2d741e5d189 6a0382b5 .config console log report ci-upstream-kmsan-gce
2018/05/03 16:35 https://github.com/google/kmsan.git master d2d741e5d189 9ce14f4b .config console log report ci-upstream-kmsan-gce
* Struck through repros no longer work on HEAD.