=============================
WARNING: suspicious RCU usage
audit: type=1804 audit(1677342585.594:40): pid=11163 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="ToMToU" comm="syz-executor.5" name="/root/syzkaller-testdir1798787238/syzkaller.cqD7tI/44/file0/bus" dev="loop5" ino=43 res=1
4.14.307-syzkaller #0 Not tainted
-----------------------------
net/sched/act_sample.c:95 suspicious rcu_dereference_protected() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
1 lock held by syz-executor.0/11310:
 #0:  (rtnl_mutex){+.+.}, at: [<ffffffff85c8dcdd>] rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0:  (rtnl_mutex){+.+.}, at: [<ffffffff85c8dcdd>] rtnetlink_rcv_msg+0x31d/0xb10 net/core/rtnetlink.c:4317

stack backtrace:
CPU: 0 PID: 11310 Comm: syz-executor.0 Not tainted 4.14.307-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/16/2023
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x281 lib/dump_stack.c:58
 tcf_sample_init+0x71c/0x8c0 net/sched/act_sample.c:95
 tcf_action_init_1+0x51a/0x9e0 net/sched/act_api.c:691
 tcf_action_init+0x26d/0x400 net/sched/act_api.c:760
 tcf_action_add net/sched/act_api.c:1088 [inline]
 tc_ctl_action+0x2e3/0x510 net/sched/act_api.c:1140
 rtnetlink_rcv_msg+0x3be/0xb10 net/core/rtnetlink.c:4322
 netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2461
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x651/0xbc0 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb5/0x100 net/socket.c:656
 ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062
 __sys_sendmsg+0xa3/0x120 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x5e/0xd3
RIP: 0033:0x7fcc85be90f9
RSP: 002b:00007fcc8415b168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fcc85d08f80 RCX: 00007fcc85be90f9
RDX: 0000000000000000 RSI: 0000000020002980 RDI: 0000000000000004
RBP: 00007fcc85c44ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe2e8e3bbf R14: 00007fcc8415b300 R15: 0000000000022000
XFS (loop4): Mounting V4 Filesystem
XFS (loop1): Mounting V4 Filesystem
XFS (loop4): Ending clean mount
XFS (loop1): Ending clean mount
XFS (loop4): Unmounting Filesystem
XFS (loop1): Unmounting Filesystem
hfsplus: unable to find HFS+ superblock
hfsplus: unable to find HFS+ superblock
hfsplus: bad catalog entry type
hfsplus: unable to find HFS+ superblock
unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1
hfsplus: bad catalog entry type
hfsplus: bad catalog entry type
hfsplus: bad catalog entry type
BTRFS: device fsid 395ef67a-297e-477c-816d-cd80a5b93e5d devid 1 transid 8 /dev/loop0
BTRFS error (device loop0): unsupported checksum algorithm 2
BTRFS error (device loop0): superblock checksum mismatch
BTRFS error (device loop0): open_ctree failed
print_req_error: I/O error, dev loop0, sector 0
kauditd_printk_skb: 2 callbacks suppressed
audit: type=1804 audit(1677342594.795:43): pid=11674 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.4" name="/root/syzkaller-testdir3420092928/syzkaller.lIXOox/55/file0/bus" dev="loop4" ino=7 res=1
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
netlink: 64 bytes leftover after parsing attributes in process `syz-executor.4'.
netlink: 4 bytes leftover after parsing attributes in process `syz-executor.2'.
9pnet: Could not find request transport: xen
netlink: 12 bytes leftover after parsing attributes in process `syz-executor.2'.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
netlink: 64 bytes leftover after parsing attributes in process `syz-executor.4'.
9pnet: Could not find request transport: xen
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
9pnet: Could not find request transport: xen
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
netlink: 64 bytes leftover after parsing attributes in process `syz-executor.4'.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
9pnet: Could not find request transport: xen
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
netlink: 64 bytes leftover after parsing attributes in process `syz-executor.4'.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
9pnet: Could not find request transport: xen
9pnet: Could not find request transport: xen
overlayfs: fs on 'file0' does not support file handles, falling back to index=off.
overlayfs: fs on './file0' does not support file handles, falling back to index=off.
9pnet: Could not find request transport: xen
audit: type=1800 audit(1677342597.975:44): pid=11855 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.5" name="file0" dev="sda1" ino=14128 res=0
audit: type=1804 audit(1677342597.985:45): pid=11855 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir1798787238/syzkaller.cqD7tI/65/file0" dev="sda1" ino=14128 res=1
audit: type=1804 audit(1677342597.995:46): pid=11855 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="ToMToU" comm="syz-executor.5" name="/root/syzkaller-testdir1798787238/syzkaller.cqD7tI/65/file0" dev="sda1" ino=14128 res=1
audit: type=1800 audit(1677342598.905:47): pid=11890 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.5" name="file0" dev="sda1" ino=14120 res=0