syzbot


WARNING in kcov_remote_start (2)

Status: upstream: reported on 2026/02/26 04:25
Reported-by: syzbot+31fb1b78fb8148d34bef@syzkaller.appspotmail.com
First crash: 1d23h, last: 1d23h
Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 WARNING in kcov_remote_start -1 4 414d 513d 0/3 auto-obsoleted due to no activity on 2025/04/19 19:40
upstream WARNING in kcov_remote_start (4) usb -1 107983 597d 628d 26/29 fixed on 2024/07/10 08:24
upstream WARNING in kcov_remote_start (2) usb -1 C 1153 2369d 2369d 0/29 closed as invalid on 2019/09/04 14:27
upstream WARNING in kcov_remote_start (5) wireless -1 4243 493d 593d 28/29 fixed on 2024/10/22 14:56
upstream WARNING in kcov_remote_start (3) usb -1 265513 632d 701d 25/29 fixed on 2024/06/05 13:52
upstream WARNING in kcov_remote_start usb -1 C 655 2369d 2369d 0/29 closed as invalid on 2019/09/03 16:37
upstream WARNING in kcov_remote_start (6) wireless -1 10102 33m 480d 0/29 upstream: reported on 2024/11/04 21:25
linux-6.1 WARNING in kcov_remote_start -1 7 3d11h 244d 0/3 upstream: reported on 2025/06/28 15:34

Sample crash report:
netlink: 'syz.4.6851': attribute type 10 has an invalid length.
team0: Device wlan1 is of different type
------------[ cut here ]------------
WARNING: CPU: 1 PID: 27926 at kernel/kcov.c:844 __refcount_sub_and_test include/linux/refcount.h:283 [inline]
WARNING: CPU: 1 PID: 27926 at kernel/kcov.c:844 __refcount_dec_and_test include/linux/refcount.h:315 [inline]
WARNING: CPU: 1 PID: 27926 at kernel/kcov.c:844 refcount_dec_and_test include/linux/refcount.h:333 [inline]
WARNING: CPU: 1 PID: 27926 at kernel/kcov.c:844 kcov_put kernel/kcov.c:415 [inline]
WARNING: CPU: 1 PID: 27926 at kernel/kcov.c:844 kcov_remote_start+0x368/0x4a0 kernel/kcov.c:888
Modules linked in:
CPU: 1 PID: 27926 Comm: syz.4.6851 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:kcov_remote_start+0x368/0x4a0 kernel/kcov.c:844
Code: e8 bd ac 39 00 4c 89 ff e8 75 6b 44 00 e9 d7 fc ff ff 0f 8d d1 fc ff ff 4c 89 ff be 03 00 00 00 e8 1d 9b 6a 02 e9 bf fc ff ff <0f> 0b 41 f7 c6 00 02 00 00 74 05 e8 e8 20 06 00 48 c7 04 24 00 00
RSP: 0018:ffffc9000307e038 EFLAGS: 00010002
RAX: 0000000080000200 RBX: ffff88805d6fbb80 RCX: 0000000000000002
RDX: ffffc900144e5000 RSI: 000000000005d2e2 RDI: 000000000005d2e3
RBP: ffffc9000307e290 R08: ffff88805d6fbb80 R09: 0000000000000004
R10: 0000000000000003 R11: 0000000000000002 R12: ffff88805f7d43c0
R13: 1ffff1100befa892 R14: 0000000000000246 R15: 0000000000000000
FS:  00007fa899d746c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31711ff8 CR3: 000000005db9b000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff1 DR7: 0000000000000600
Call Trace:
 <TASK>
 kcov_remote_start_common include/linux/kcov.h:50 [inline]
 ieee80211_rx_list+0x620/0x2790 net/mac80211/rx.c:4977
 ieee80211_rx_napi+0x178/0x390 net/mac80211/rx.c:5018
 ieee80211_rx include/net/mac80211.h:4573 [inline]
 ieee80211_handle_queued_frames+0x105/0x1b0 net/mac80211/main.c:237
 ieee80211_stop_device+0x16/0x80 net/mac80211/util.c:2150
 ieee80211_do_stop+0x165b/0x1d40 net/mac80211/iface.c:639
 ieee80211_stop+0x127/0x190 net/mac80211/iface.c:667
 __dev_close_many+0x1d3/0x2b0 net/core/dev.c:1634
 dev_close_many+0x21f/0x400 net/core/dev.c:1659
 dev_close+0x154/0x210 net/core/dev.c:1685
 team_port_add drivers/net/team/team.c:1324 [inline]
 team_add_slave+0x178e/0x2780 drivers/net/team/team.c:1997
 do_set_master net/core/rtnetlink.c:2577 [inline]
 do_setlink+0xe90/0x3d60 net/core/rtnetlink.c:2788
 __rtnl_newlink net/core/rtnetlink.c:3452 [inline]
 rtnl_newlink+0x1658/0x1a50 net/core/rtnetlink.c:3574
 rtnetlink_rcv_msg+0x844/0xf30 net/core/rtnetlink.c:5684
 netlink_rcv_skb+0x1f5/0x440 net/netlink/af_netlink.c:2507
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x774/0x920 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:706 [inline]
 __sock_sendmsg net/socket.c:718 [inline]
 ____sys_sendmsg+0x5b7/0x8f0 net/socket.c:2445
 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2499
 __sys_sendmsg net/socket.c:2528 [inline]
 __do_sys_sendmsg net/socket.c:2537 [inline]
 __se_sys_sendmsg+0x1af/0x290 net/socket.c:2535
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fa89bb3b629
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa899d74028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fa89bdb5090 RCX: 00007fa89bb3b629
RDX: 0000000000000000 RSI: 0000200000000600 RDI: 000000000000000c
RBP: 00007fa89bbd1b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa89bdb5128 R14: 00007fa89bdb5090 R15: 00007ffe296eae18
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/26 04:25 linux-5.15.y 3330a8d33e08 e0f78d93 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf WARNING in kcov_remote_start
* Struck through repros no longer work on HEAD.